Fixed Offline Mode

# Conflicts:
#	.idea/misc.xml
#	app/src/main/java/de/sebse/fuplanner/MainActivity.java
#	app/src/main/java/de/sebse/fuplanner/fragments/ScheduleFragment.java

.gitignore

@@ -1,8 +1,8 @@
 *.iml
 .gradle
 /local.properties
-/.idea/workspace.xml
-/.idea/libraries
+/.idea/*
+/.idea - PC/*
 .DS_Store
 /build
 /captures

.idea/codeStyles/Project.xml

@@ -1,29 +0,0 @@
-<component name="ProjectCodeStyleConfiguration">
-  <code_scheme name="Project" version="173">
-    <Objective-C-extensions>
-      <file>
-        <option name="com.jetbrains.cidr.lang.util.OCDeclarationKind" value="Import" />
-        <option name="com.jetbrains.cidr.lang.util.OCDeclarationKind" value="Macro" />
-        <option name="com.jetbrains.cidr.lang.util.OCDeclarationKind" value="Typedef" />
-        <option name="com.jetbrains.cidr.lang.util.OCDeclarationKind" value="Enum" />
-        <option name="com.jetbrains.cidr.lang.util.OCDeclarationKind" value="Constant" />
-        <option name="com.jetbrains.cidr.lang.util.OCDeclarationKind" value="Global" />
-        <option name="com.jetbrains.cidr.lang.util.OCDeclarationKind" value="Struct" />
-        <option name="com.jetbrains.cidr.lang.util.OCDeclarationKind" value="FunctionPredecl" />
-        <option name="com.jetbrains.cidr.lang.util.OCDeclarationKind" value="Function" />
-      </file>
-      <class>
-        <option name="com.jetbrains.cidr.lang.util.OCDeclarationKind" value="Property" />
-        <option name="com.jetbrains.cidr.lang.util.OCDeclarationKind" value="Synthesize" />
-        <option name="com.jetbrains.cidr.lang.util.OCDeclarationKind" value="InitMethod" />
-        <option name="com.jetbrains.cidr.lang.util.OCDeclarationKind" value="StaticMethod" />
-        <option name="com.jetbrains.cidr.lang.util.OCDeclarationKind" value="InstanceMethod" />
-        <option name="com.jetbrains.cidr.lang.util.OCDeclarationKind" value="DeallocMethod" />
-      </class>
-      <extensions>
-        <pair source="cpp" header="h" fileNamingConvention="NONE" />
-        <pair source="c" header="h" fileNamingConvention="NONE" />
-      </extensions>
-    </Objective-C-extensions>
-  </code_scheme>
-</component>

.idea/gradle.xml

@@ -1,18 +0,0 @@
-<?xml version="1.0" encoding="UTF-8"?>
-<project version="4">
-  <component name="GradleSettings">
-    <option name="linkedExternalProjectsSettings">
-      <GradleProjectSettings>
-        <option name="distributionType" value="DEFAULT_WRAPPED" />
-        <option name="externalProjectPath" value="$PROJECT_DIR$" />
-        <option name="modules">
-          <set>
-            <option value="$PROJECT_DIR$" />
-            <option value="$PROJECT_DIR$/app" />
-          </set>
-        </option>
-        <option name="resolveModulePerSourceSet" value="false" />
-      </GradleProjectSettings>
-    </option>
-  </component>
-</project>

.idea/misc.xml

@@ -1,29 +0,0 @@
-<?xml version="1.0" encoding="UTF-8"?>
-<project version="4">
-  <component name="NullableNotNullManager">
-    <option name="myDefaultNullable" value="android.support.annotation.Nullable" />
-    <option name="myDefaultNotNull" value="android.support.annotation.NonNull" />
-    <option name="myNullables">
-      <value>
-        <list size="5">
-          <item index="0" class="java.lang.String" itemvalue="org.jetbrains.annotations.Nullable" />
-          <item index="1" class="java.lang.String" itemvalue="javax.annotation.Nullable" />
-          <item index="2" class="java.lang.String" itemvalue="javax.annotation.CheckForNull" />
-          <item index="3" class="java.lang.String" itemvalue="edu.umd.cs.findbugs.annotations.Nullable" />
-          <item index="4" class="java.lang.String" itemvalue="android.support.annotation.Nullable" />
-        </list>
-      </value>
-    </option>
-    <option name="myNotNulls">
-      <value>
-        <list size="4">
-          <item index="0" class="java.lang.String" itemvalue="org.jetbrains.annotations.NotNull" />
-          <item index="1" class="java.lang.String" itemvalue="javax.annotation.Nonnull" />
-          <item index="2" class="java.lang.String" itemvalue="edu.umd.cs.findbugs.annotations.NonNull" />
-          <item index="3" class="java.lang.String" itemvalue="android.support.annotation.NonNull" />
-        </list>
-      </value>
-    </option>
-  </component>
-  <component name="ProjectRootManager" version="2" languageLevel="JDK_1_8" default="true" project-jdk-name="1.8" project-jdk-type="JavaSDK" />
-</project>

.idea/modules.xml

@@ -1,9 +0,0 @@
-<?xml version="1.0" encoding="UTF-8"?>
-<project version="4">
-  <component name="ProjectModuleManager">
-    <modules>
-      <module fileurl="file://$PROJECT_DIR$/.idea/FUPlanner.iml" filepath="$PROJECT_DIR$/.idea/FUPlanner.iml" />
-      <module fileurl="file://$PROJECT_DIR$/app/app.iml" filepath="$PROJECT_DIR$/app/app.iml" />
-    </modules>
-  </component>
-</project>

.idea/runConfigurations.xml

@@ -1,12 +0,0 @@
-<?xml version="1.0" encoding="UTF-8"?>
-<project version="4">
-  <component name="RunConfigurationProducerService">
-    <option name="ignoredProducers">
-      <set>
-        <option value="org.jetbrains.plugins.gradle.execution.test.runner.AllInPackageGradleConfigurationProducer" />
-        <option value="org.jetbrains.plugins.gradle.execution.test.runner.TestClassGradleConfigurationProducer" />
-        <option value="org.jetbrains.plugins.gradle.execution.test.runner.TestMethodGradleConfigurationProducer" />
-      </set>
-    </option>
-  </component>
-</project>

.idea/vcs.xml

@@ -1,7 +0,0 @@
-<?xml version="1.0" encoding="UTF-8"?>
-<project version="4">
-  <component name="VcsDirectoryMappings">
-    <mapping directory="" vcs="Git" />
-    <mapping directory="$PROJECT_DIR$" vcs="Git" />
-  </component>
-</project>

app/build.gradle

@@ -2,14 +2,14 @@ apply plugin: 'com.android.application'
 
 android {
     compileSdkVersion 28
-    buildToolsVersion '27.0.3'
+    buildToolsVersion '28.0.3'
     defaultConfig {
         applicationId "de.sebse.fuplanner"
         minSdkVersion 15
         targetSdkVersion 28
-        versionCode 1
-        versionName "1.0"
-        testInstrumentationRunner "android.support.test.runner.AndroidJUnitRunner"
+        versionCode 10
+        versionName "1.2.2"
+        testInstrumentationRunner "androidx.test.runner.AndroidJUnitRunner"
     }
     buildTypes {
         release {
@@ -27,28 +27,28 @@ android {
 
 
 dependencies {
-    implementation 'com.android.support:recyclerview-v7:28.0.0-rc01'
+    implementation 'androidx.recyclerview:recyclerview:1.0.0'
     implementation fileTree(include: ['*.jar'], dir: 'libs')
-    androidTestImplementation('com.android.support.test.espresso:espresso-core:2.2.2', {
+    androidTestImplementation('androidx.test.espresso:espresso-core:3.1.0-beta02', {
         exclude group: 'com.android.support', module: 'support-annotations'
     })
-    implementation 'com.android.support:appcompat-v7:28.0.0-rc01'
-    implementation 'com.android.support:preference-v7:28.0.0-rc01'
-    implementation 'com.android.support:design:28.0.0-rc01'
-    implementation 'com.android.support.constraint:constraint-layout:1.1.2'
-    implementation 'com.android.volley:volley:1.0.0'
+    implementation 'androidx.preference:preference:1.0.0'
+    implementation 'com.google.android.material:material:1.0.0'
+    implementation 'androidx.constraintlayout:constraintlayout:2.0.0-alpha2'
+    implementation 'com.android.volley:volley:1.1.0'
     //noinspection GradleDependency
     implementation 'com.google.android.gms:play-services-auth:15.0.0'
-    implementation 'com.android.support:support-v4:28.0.0-rc01'
+    implementation 'androidx.legacy:legacy-support-v4:1.0.0'
     testImplementation 'junit:junit:4.12'
     implementation fileTree(include: ['*.jar'], dir: 'libs')
-    implementation 'com.android.support:appcompat-v7:28.0.0-rc01'
+    implementation 'androidx.appcompat:appcompat:1.0.2'
     implementation 'org.jbundle.util.osgi.wrapped:org.jbundle.util.osgi.wrapped.org.apache.http.client:4.1.2'
-    implementation 'com.android.support:support-v4:28.0.0-rc01'
+    implementation 'androidx.legacy:legacy-support-v4:1.0.0'
     implementation 'org.jetbrains:annotations-java5:15.0'
     //implementation 'com.github.quivr:android-week-view:2.0.2'//com.github.alamkanak:android-week-view:1.2.6
     implementation 'com.ms-square:expandableTextView:0.1.4'
     // https://github.com/bignerdranch/expandable-recycler-view
     implementation 'com.bignerdranch.android:expandablerecyclerview:3.0.0-RC1'
+    implementation 'com.github.Cutta:TagView:1.3'
     implementation files('libs/jericho-html-3.4.jar')
 }

app/src/androidTest/java/de/sebse/fuplanner/ExampleInstrumentedTest.java

@@ -1,12 +1,13 @@
 package de.sebse.fuplanner;
 
 import android.content.Context;
-import android.support.test.InstrumentationRegistry;
-import android.support.test.runner.AndroidJUnit4;
 
 import org.junit.Test;
 import org.junit.runner.RunWith;
 
+import androidx.test.InstrumentationRegistry;
+import androidx.test.runner.AndroidJUnit4;
+
 import static org.junit.Assert.*;
 
 /**

app/src/main/AndroidManifest.xml

@@ -4,6 +4,9 @@
 
     <uses-permission android:name="android.permission.INTERNET" />
 
+    <uses-permission android:name="android.permission.WRITE_EXTERNAL_STORAGE" />
+
+
     <application
         android:allowBackup="true"
         android:icon="@mipmap/ic_launcher"
@@ -21,6 +24,15 @@
                 <category android:name="android.intent.category.LAUNCHER" />
             </intent-filter>
         </activity>
+        <provider
+            android:name="androidx.core.content.FileProvider"
+            android:authorities="${applicationId}.my.provider"
+            android:exported="false"
+            android:grantUriPermissions="true">
+            <meta-data
+                android:name="android.support.FILE_PROVIDER_PATHS"
+                android:resource="@xml/provider_paths"/>
+        </provider>
     </application>
 
 </manifest>

app/src/main/java/de/sebse/fuplanner/MainActivity.java

@@ -2,24 +2,28 @@ package de.sebse.fuplanner;
 
 import android.content.Intent;
 import android.os.Bundle;
-import android.support.annotation.NonNull;
-import android.support.annotation.StringRes;
-import android.support.design.widget.NavigationView;
-import android.support.v4.app.Fragment;
-import android.support.v4.app.FragmentManager;
-import android.support.v4.app.FragmentTransaction;
-import android.support.v4.view.GravityCompat;
-import android.support.v4.widget.DrawerLayout;
-import android.support.v7.app.ActionBarDrawerToggle;
-import android.support.v7.app.AppCompatActivity;
-import android.support.v7.widget.Toolbar;
 import android.view.Menu;
 import android.view.MenuItem;
 import android.view.View;
 import android.widget.TextView;
+import android.widget.Toast;
 
+import com.android.volley.NetworkResponse;
+import com.google.android.material.navigation.NavigationView;
+
+import java.util.HashMap;
 import java.util.Iterator;
 
+import androidx.annotation.NonNull;
+import androidx.annotation.StringRes;
+import androidx.appcompat.app.ActionBarDrawerToggle;
+import androidx.appcompat.app.AppCompatActivity;
+import androidx.appcompat.widget.Toolbar;
+import androidx.core.view.GravityCompat;
+import androidx.drawerlayout.widget.DrawerLayout;
+import androidx.fragment.app.Fragment;
+import androidx.fragment.app.FragmentManager;
+import androidx.fragment.app.FragmentTransaction;
 import de.sebse.fuplanner.fragments.CanteensFragment;
 import de.sebse.fuplanner.fragments.LoginFragment;
 import de.sebse.fuplanner.fragments.ModulesFragment;
@@ -30,17 +34,23 @@ import de.sebse.fuplanner.fragments.canteen.DaySwitcherFragment;
 import de.sebse.fuplanner.fragments.moddetails.ModDetailFragment;
 import de.sebse.fuplanner.services.Canteen.CanteenBrowser;
 import de.sebse.fuplanner.services.Canteen.types.Canteen;
+import de.sebse.fuplanner.services.GoogleAuth.Credentials;
 import de.sebse.fuplanner.services.GoogleAuth.GoogleAuth;
 import de.sebse.fuplanner.services.KVV.KVV;
+import de.sebse.fuplanner.services.KVV.KVVListener;
 import de.sebse.fuplanner.services.KVV.types.LoginToken;
 import de.sebse.fuplanner.services.KVV.types.Modules;
-import de.sebse.fuplanner.tools.MainAcitivityListener;
+import de.sebse.fuplanner.tools.MainActivityListener;
+import de.sebse.fuplanner.tools.NewAsyncQueue;
+import de.sebse.fuplanner.tools.RequestPermissionsResultListener;
 import de.sebse.fuplanner.tools.logging.Logger;
+import de.sebse.fuplanner.tools.network.NetworkCallback;
+import de.sebse.fuplanner.tools.network.NetworkError;
+import de.sebse.fuplanner.tools.network.NetworkErrorCallback;
 
 public class MainActivity extends AppCompatActivity
-        implements MainAcitivityListener,
+        implements MainActivityListener, KVVListener,
         NavigationView.OnNavigationItemSelectedListener,
-        LoginFragment.OnLoginFragmentInteractionListener,
         ModulesFragment.OnModulesFragmentInteractionListener,
         CanteensFragment.OnCanteensFragmentInteractionListener {
 
@@ -66,16 +76,18 @@ public class MainActivity extends AppCompatActivity
     private int fragmentPage = FRAGMENT_NONE;
     private String fragmentData = "";
     private CanteenBrowser mCanteenBrowser;
-    private boolean mOfflineMode = false;
+    private HashMap<String, RequestPermissionsResultListener> permissionListeners = new HashMap<>();
+    private boolean mOfflineBanner;
+    private NewAsyncQueue mQueue = new NewAsyncQueue();
 
     @Override
     protected void onCreate(Bundle savedInstanceState) {
         super.onCreate(savedInstanceState);
-        int newFragmentPage = FRAGMENT_NONE;
-        String newFragmentData = "";
+        int desiredPage = getDefaultFragmentAfterLogin();
+        String desiredData = "";
         if (savedInstanceState != null) {
-            newFragmentPage = savedInstanceState.getInt(ARG_FRAGMENT_PAGE, fragmentPage);
-            newFragmentData = savedInstanceState.getString(ARG_FRAGMENT_STATUS, fragmentData);
+            desiredPage = savedInstanceState.getInt(ARG_FRAGMENT_PAGE, desiredPage);
+            desiredData = savedInstanceState.getString(ARG_FRAGMENT_STATUS, desiredData);
         }
 
         setContentView(R.layout.activity_main);
@@ -92,25 +104,12 @@ public class MainActivity extends AppCompatActivity
         mNavigationView.setNavigationItemSelectedListener(this);
         mFragmentManager = getSupportFragmentManager();
 
-        LoginToken loginToken = getKVV().easyLogin();
-        if (newFragmentPage != FRAGMENT_LOGIN && newFragmentPage != FRAGMENT_STARTUP && newFragmentPage != FRAGMENT_NONE) {
-            if (loginToken != null)
-                toLoginState(loginToken, newFragmentPage, newFragmentData);
-            else
-                checkAndDoLogin();
-        } else {
-            if (loginToken != null)
-                toLoginState(loginToken, getDefaultFragmentAfterLogin(), "");
-            else
-                checkAndDoLogin();
+        if (!getKVV().account().restoreOnlineLogin()) {
+            desiredPage = FRAGMENT_LOGIN;
+            desiredData = "";
         }
-
-        /*this.getCanteenBrowser().getCanteens(success -> {
-            Canteen canteen = success.get(0);
-            this.getCanteenBrowser().getCanteen(canteen, success1 -> {
-                this.getCanteenBrowser().getDay(canteen.get(0), log::d, log::e, true);
-            }, log::e, true);
-        }, log::e, true);*/
+        updateNavigation();
+        changeFragment(desiredPage, desiredData);
     }
 
     @Override
@@ -162,7 +161,6 @@ public class MainActivity extends AppCompatActivity
     public boolean onNavigationItemSelected(@NonNull MenuItem item) {
         // Handle navigation view item clicks here.
         int id = item.getItemId();
-
         switch (id) {
             case R.id.nav_modules:
                 changeFragment(FRAGMENT_MODULES);
@@ -170,7 +168,7 @@ public class MainActivity extends AppCompatActivity
             case R.id.nav_schedule:
                 changeFragment(FRAGMENT_SCHEDULE);
                 break;
-            case R.id.nav_dining:
+            case R.id.nav_canteens:
                 changeFragment(FRAGMENT_CANTEENS);
                 break;
             case R.id.nav_settings:
@@ -184,16 +182,16 @@ public class MainActivity extends AppCompatActivity
                 startActivity(sendIntent);
                 break;
             case R.id.nav_logout:
-                this.getKVV().logout();
+                getKVV().account().logout(true);
+                getKVV().modules().list().delete();
                 this.getGoogleAuth().getLoginState(credentials -> {
                     if (credentials != null) {
                         this.getGoogleAuth().deleteLoginState(credentials.getUsername(), credentials.getPassword());
                     }
-                    this.toLogoutState();
                 });
                 break;
-        }
 
+        }
         DrawerLayout drawer = findViewById(R.id.drawer_layout);
         drawer.closeDrawer(GravityCompat.START);
 
@@ -214,11 +212,25 @@ public class MainActivity extends AppCompatActivity
 
     @Override
     protected void onSaveInstanceState(Bundle savedInstanceState) {
-        savedInstanceState.putInt(ARG_FRAGMENT_PAGE, fragmentPage);
-        savedInstanceState.putString(ARG_FRAGMENT_STATUS, fragmentData);
+        if (fragmentPage != FRAGMENT_STARTUP && fragmentPage != FRAGMENT_NONE && fragmentPage != FRAGMENT_LOGIN) {
+            Fragment fragment = mFragmentManager.findFragmentByTag(String.valueOf(fragmentPage));
+            savedInstanceState.putInt(ARG_FRAGMENT_PAGE, fragmentPage);
+            if (fragment instanceof ModDetailFragment) {
+                savedInstanceState.putString(ARG_FRAGMENT_STATUS, ((ModDetailFragment) fragment).getData());
+            } else {
+                savedInstanceState.putString(ARG_FRAGMENT_STATUS, fragmentData);
+            }
+        }
         super.onSaveInstanceState(savedInstanceState);
     }
 
+    @Override
+    public void onRequestPermissionsResult(int requestCode, @NonNull String[] permissions, @NonNull int[] grantResults) {
+        for (RequestPermissionsResultListener listener: permissionListeners.values()) {
+            listener.callback(requestCode, permissions, grantResults);
+        }
+    }
+
     /* --------------------------------------------*/
     /* --------------------------------------------*/
     /* --------------------------------------------*/
@@ -230,9 +242,17 @@ public class MainActivity extends AppCompatActivity
         return this.mGoogleAuth;
     }
 
+    /*@Deprecated
+    public de.sebse.fuplanner.services.KVV.KVV getKVV() {
+        if (this.mKVV == null) {
+            this.mKVV = new de.sebse.fuplanner.services.KVV.KVV(this);
+        }
+        return this.mKVV;
+    }*/
+
     public KVV getKVV() {
         if (this.mKVV == null) {
-            this.mKVV = new KVV(this);
+            this.mKVV = new KVV(this, this);
         }
         return this.mKVV;
     }
@@ -249,40 +269,21 @@ public class MainActivity extends AppCompatActivity
     }
 
     private void toLogoutState() {
+        setOfflineBanner(false);
+        setRefreshFailedBanner(false);
+        updateNavigation();
         changeFragment(FRAGMENT_LOGIN);
-        setOfflineBanner(true);
     }
 
-    private void toLoginState(LoginToken loginToken, int newFragment, String newData) {
-        if (loginToken == null) {
-            toLogoutState();
-        } else {
-            toLoginState(loginToken.getFullname(), loginToken.getEmail(), newFragment, newData, true);
-        }
-    }
-
-    private void toLoginState(String fullname, String email, int newFragment, String newData, boolean onlineMode) {
-        changeFragment(newFragment, newData);
+    private void toLoginState(String fullName, String email, int newFragment, boolean onlineMode) {
+        setOfflineBanner(!onlineMode);
+        updateNavigation();
 
         View header = mNavigationView.getHeaderView(0);
-        ((TextView) header.findViewById(R.id.login_name)).setText(fullname);
+        ((TextView) header.findViewById(R.id.login_name)).setText(fullName);
         ((TextView) header.findViewById(R.id.login_mail)).setText(email);
-        setOfflineBanner(onlineMode);
-    }
 
-    private void checkAndDoLogin() {
-        changeFragment(FRAGMENT_STARTUP);
-        getGoogleAuth().getLoginState(credentials -> {
-            if (credentials == null || credentials.getUsername() == null || credentials.getPassword() == null) {
-                toLogoutState();
-                return;
-            }
-            this.getKVV().login(credentials.getUsername(), credentials.getPassword(), success -> toLoginState(success, getDefaultFragmentAfterLogin(), ""),
-            error -> {
-                log.e(error);
-                toLogoutState();
-            });
-        });
+        changeFragment(newFragment);
     }
 
     private void changeFragment(int newFragment) {
@@ -290,27 +291,34 @@ public class MainActivity extends AppCompatActivity
     }
 
     private void changeFragment(int newFragment, String newData) {
-        onTitleTextChange(R.string.courses);
+        if (mFragmentManager.isStateSaved())
+            return;
+        if (newFragment == FRAGMENT_CANTEENS_DETAILS && newData.equals(""))
+            newFragment = FRAGMENT_CANTEENS;
+        if (newFragment == FRAGMENT_MODULES_DETAILS && newData.equals(""))
+            newFragment = FRAGMENT_MODULES;
+
+        onTitleTextChange(R.string.app_name);
         Fragment fragment;
         switch (newFragment) {
-            case FRAGMENT_MODULES:
-                fragment = ModulesFragment.newInstance();
-                break;
             case FRAGMENT_MODULES_DETAILS:
                 fragment = ModDetailFragment.newInstance(newData);
                 break;
+            case FRAGMENT_MODULES:
+                fragment = ModulesFragment.newInstance();
+                break;
             case FRAGMENT_LOGIN:
                 fragment = LoginFragment.newInstance();
                 break;
             case FRAGMENT_SCHEDULE:
                 fragment = ScheduleFragment.newInstance();
                 break;
-            case FRAGMENT_CANTEENS:
-                fragment = CanteensFragment.newInstance();
-                break;
             case FRAGMENT_CANTEENS_DETAILS:
                 fragment = DaySwitcherFragment.newInstance(Integer.parseInt(newData));
                 break;
+            case FRAGMENT_CANTEENS:
+                fragment = CanteensFragment.newInstance();
+                break;
             case FRAGMENT_PREFERENCES:
                 fragment = PrefsFragment.newInstance();
                 break;
@@ -324,39 +332,100 @@ public class MainActivity extends AppCompatActivity
         fragmentTransaction.commit();
 
         if (newFragment == FRAGMENT_STARTUP) {
-            findViewById(R.id.app_bar_layout).setVisibility(View.GONE);
+            findViewById(R.id.app_bar_include).setVisibility(View.GONE);
         } else {
-            findViewById(R.id.app_bar_layout).setVisibility(View.VISIBLE);
+            findViewById(R.id.app_bar_include).setVisibility(View.VISIBLE);
         }
-        // switch to logout
-        if ((fragmentPage != FRAGMENT_STARTUP && fragmentPage != FRAGMENT_LOGIN) && (newFragment == FRAGMENT_STARTUP || newFragment == FRAGMENT_LOGIN)) {
-            View header = mNavigationView.getHeaderView(0);
-            //header.findViewById(R.id.imageView).setVisibility(View.GONE);
-            header.findViewById(R.id.login_name).setVisibility(View.GONE);
-            header.findViewById(R.id.login_mail).setVisibility(View.GONE);
-            header.findViewById(R.id.btn_login_page).setVisibility(View.VISIBLE);
-            header.findViewById(R.id.btn_login_page).setOnClickListener(v -> {
+
+        this.fragmentPage = newFragment;
+        this.fragmentData = newData;
+
+        invalidateOptionsMenu();
+    }
+
+    private void setOfflineBanner(boolean visible) {
+        View offline_header = findViewById(R.id.offline_msg);
+        offline_header.setVisibility(visible ? View.VISIBLE : View.GONE);
+        mOfflineBanner = visible;
+    }
+
+    private void setRefreshFailedBanner(boolean refreshFailed) {
+        View viewNoConnection = findViewById(R.id.no_connection_msg);
+        if (!mOfflineBanner && refreshFailed)
+            viewNoConnection.setVisibility(View.VISIBLE);
+        else
+            viewNoConnection.setVisibility(View.GONE);
+    }
+
+    private void setNavigationSelection() {
+        MenuItem item;
+        switch (fragmentPage) {
+            case FRAGMENT_MODULES_DETAILS:
+                getKVV().modules().list().find(fragmentData, success -> {
+                    int size = mNavigationView.getMenu().size();
+                    //noinspection ConstantConditions
+                    String title = success == null ? null : success.title;
+                    for (int k = 0; k < size; k++) {
+                        mNavigationView.getMenu().getItem(k).setChecked(mNavigationView.getMenu().getItem(k).getTitle().equals(title));
+                    }
+                }, log::e);
+                break;
+            case FRAGMENT_MODULES:
+                item = mNavigationView.getMenu().findItem(R.id.nav_modules);
+                if (item != null)
+                    item.setChecked(true);
+                break;
+            case FRAGMENT_SCHEDULE:
+                item = mNavigationView.getMenu().findItem(R.id.nav_schedule);
+                if (item != null)
+                    item.setChecked(true);
+                break;
+            case FRAGMENT_CANTEENS_DETAILS:
+                getCanteenBrowser().getCanteens(success -> {
+                    int size = mNavigationView.getMenu().size();
+                    Canteen canteen = success.getCanteen(Integer.parseInt(fragmentData));
+                    //noinspection ConstantConditions
+                    String title = canteen == null ? null : canteen.getName();
+                    for (int k = 0; k < size; k++) {
+                        mNavigationView.getMenu().getItem(k).setChecked(mNavigationView.getMenu().getItem(k).getTitle().equals(title));
+                    }
+                }, log::e);
+                break;
+            case FRAGMENT_CANTEENS:
+                mNavigationView.getMenu().findItem(R.id.nav_canteens).setChecked(true);
+                break;
+            case FRAGMENT_PREFERENCES:
+                mNavigationView.getMenu().findItem(R.id.nav_settings).setChecked(true);
+                break;
+            default:  // FRAGMENT_STARTUP / FRAGMENT_LOGIN
+                break;
+        }
+    }
+
+    private void setNavigationHeader(boolean isLoggedIn) {
+        View header = mNavigationView.getHeaderView(0);
+        int login = isLoggedIn ? View.VISIBLE : View.GONE;
+        int btn = !isLoggedIn ? View.VISIBLE : View.GONE;
+
+        header.findViewById(R.id.login_name).setVisibility(login);
+        header.findViewById(R.id.login_mail).setVisibility(login);
+        View viewBtn = header.findViewById(R.id.btn_login_page);
+        viewBtn.setVisibility(btn);
+        if (!viewBtn.hasOnClickListeners())
+            viewBtn.setOnClickListener(v -> {
                 DrawerLayout drawer = findViewById(R.id.drawer_layout);
                 if (drawer.isDrawerOpen(GravityCompat.START)) {
                     drawer.closeDrawer(GravityCompat.START);
                 }
                 changeFragment(FRAGMENT_LOGIN);
             });
-            mNavigationView.getMenu().clear();
-            mNavigationView.inflateMenu(R.menu.activity_main_drawer);
-            afterAnyMenuInflate();
-        } // switch to login
-        else if ((fragmentPage == FRAGMENT_STARTUP || fragmentPage == FRAGMENT_LOGIN || fragmentPage == FRAGMENT_NONE) && (newFragment != FRAGMENT_STARTUP && newFragment != FRAGMENT_LOGIN && newFragment != FRAGMENT_CANTEENS && newFragment != FRAGMENT_CANTEENS_DETAILS)) {
-            View header = mNavigationView.getHeaderView(0);
-            //header.findViewById(R.id.imageView).setVisibility(View.VISIBLE);
-            header.findViewById(R.id.login_name).setVisibility(View.VISIBLE);
-            header.findViewById(R.id.login_mail).setVisibility(View.VISIBLE);
-            header.findViewById(R.id.btn_login_page).setVisibility(View.GONE);
-            mNavigationView.getMenu().clear();
-            mNavigationView.inflateMenu(R.menu.activity_main_drawer_login);
-            mNavigationView.setCheckedItem(R.id.nav_modules);
-            afterAnyMenuInflate();
-            getKVV().getModuleList(success -> {
+    }
+
+    private void afterAnyMenuInflate(boolean isLoggedIn, Runnable done) {
+        int MAX_COUNT = isLoggedIn ? 2 : 1;
+        final int[] count = {0};
+        if (isLoggedIn) {
+            getKVV().modules().list().recv(success -> {
                 int i = 0;
                 for (Iterator<Modules.Module> it = success.latestSemesterIterator(); it.hasNext(); ) {
                     Modules.Module module = it.next();
@@ -367,55 +436,12 @@ public class MainActivity extends AppCompatActivity
                     });
                     i++;
                 }
-            }, log::e);
+                if (++count[0] == MAX_COUNT) done.run();
+            }, msg -> {
+                if (++count[0] == MAX_COUNT) done.run();
+                log.e(msg);
+            });
         }
-        if (newFragment == FRAGMENT_MODULES_DETAILS) {
-            getKVV().getModule(newData, success -> {
-                int size = mNavigationView.getMenu().size();
-                //noinspection ConstantConditions
-                String title = success == null ? null : success.title;
-                for (int k = 0; k < size; k++) {
-                    mNavigationView.getMenu().getItem(k).setChecked(mNavigationView.getMenu().getItem(k).getTitle().equals(title));
-                }
-            }, log::e);
-        }
-        if (newFragment == FRAGMENT_CANTEENS_DETAILS) {
-            getCanteenBrowser().getCanteens(success -> {
-                int size = mNavigationView.getMenu().size();
-                Canteen canteen = success.getCanteen(Integer.parseInt(newData));
-                //noinspection ConstantConditions
-                String title = canteen == null ? null : canteen.getName();
-                for (int k = 0; k < size; k++) {
-                    mNavigationView.getMenu().getItem(k).setChecked(mNavigationView.getMenu().getItem(k).getTitle().equals(title));
-                }
-            }, log::e);
-        }
-
-        this.fragmentPage = newFragment;
-        this.fragmentData = newData;
-        invalidateOptionsMenu();
-    }
-
-    private void setOfflineBanner(boolean onlineMode) {
-        View offline_header = findViewById(R.id.offline_msg);
-        if (onlineMode)
-            offline_header.setVisibility(View.GONE);
-        else
-            offline_header.setVisibility(View.VISIBLE);
-        mOfflineMode = !onlineMode;
-    }
-
-    private void setRefreshFailedBanner(boolean refreshFailed) {
-        View viewNoConnection = findViewById(R.id.no_connection_msg);
-        if (!mOfflineMode && refreshFailed)
-            viewNoConnection.setVisibility(View.VISIBLE);
-        else
-            viewNoConnection.setVisibility(View.GONE);
-
-    }
-
-
-    private void afterAnyMenuInflate() {
         getCanteenBrowser().getCanteens(success -> {
             int i = 0;
             for (Canteen canteen: success) {
@@ -426,7 +452,27 @@ public class MainActivity extends AppCompatActivity
                 });
                 i++;
             }
-        }, log::e);
+            if (++count[0] == MAX_COUNT) done.run();
+        }, msg -> {
+            if (++count[0] == MAX_COUNT) done.run();
+            log.e(msg);
+        });
+    }
+
+    private void updateNavigation() {
+        mQueue.add(() -> {
+            boolean isLoggedIn = getKVV().account().isLoggedIn();
+            setNavigationHeader(isLoggedIn);
+            mNavigationView.getMenu().clear();
+            if (isLoggedIn)
+                mNavigationView.inflateMenu(R.menu.activity_main_drawer_login);
+            else
+                mNavigationView.inflateMenu(R.menu.activity_main_drawer);
+            afterAnyMenuInflate(isLoggedIn, () -> {
+                setNavigationSelection();
+                mQueue.next();
+            });
+        });
     }
 
 
@@ -435,32 +481,90 @@ public class MainActivity extends AppCompatActivity
 
 
 
-    public void onLoginFragmentInteraction(LoginToken loginToken, boolean onlineMode) {
-        toLoginState(loginToken.getFullname(), loginToken.getEmail(), getDefaultFragmentAfterLogin(), "", onlineMode);
-    }
 
+
+    @Override
     public void onModulesFragmentInteraction(final String itemID) {
         changeFragment(FRAGMENT_MODULES_DETAILS, itemID);
     }
 
+    @Override
     public void onCanteensFragmentInteraction(final int itemID) {
         changeFragment(FRAGMENT_CANTEENS_DETAILS, String.valueOf(itemID));
     }
 
+    @Override
     public void onTitleTextChange(String newTitle) {
         setTitle(newTitle);
     }
 
+    @Override
     public void onTitleTextChange(@StringRes int titleId) {
         setTitle(titleId);
     }
 
-    public void loginTokenInvalid(boolean doPrecheck) {
-        getKVV().invalidate();
-        checkAndDoLogin();
-    }
-
-    public void refreshFailed(boolean isFailed) {
+    @Override
+    public void onRefreshCompleted(boolean isFailed) {
         setRefreshFailedBanner(isFailed);
     }
+
+    @Override
+    public void addRequestPermissionsResultListener(RequestPermissionsResultListener listener, String id) {
+        permissionListeners.put(id, listener);
+    }
+
+    @Override
+    public void removeRequestPermissionsResultListener(String id) {
+        permissionListeners.remove(id);
+    }
+
+    @Override
+    public void showToast(@StringRes int msgStringRes) {
+        showToast(getString(msgStringRes));
+    }
+
+    @Override
+    public void showToast(String message) {
+        Toast.makeText(this, message, Toast.LENGTH_SHORT).show();
+    }
+
+
+
+
+
+
+
+
+
+
+    @Override
+    public void getCredentials(NetworkCallback<Credentials> callback, NetworkErrorCallback error) {
+        getGoogleAuth().getLoginState(credentials -> {
+            if (credentials == null || credentials.getUsername() == null || credentials.getPassword() == null) {
+                error.onError(new NetworkError(200100, 403, "No Google Login available!"));
+            } else {
+                callback.onResponse(credentials);
+            }
+        });
+    }
+
+    @Override
+    public void onLogin(LoginToken token, boolean enteringOnlineMode) {
+        toLoginState(token.getFullName(), token.getEmail(), getDefaultFragmentAfterLogin(), enteringOnlineMode);
+    }
+
+    @Override
+    public void onLogout() {
+        toLogoutState();
+    }
+
+    @Override
+    public void onModuleListChange() {
+        updateNavigation();
+    }
+
+    @Override
+    public void onKVVNetworkResponse(NetworkResponse error) {
+        setRefreshFailedBanner(error != null);
+    }
 }

app/src/main/java/de/sebse/fuplanner/fragments/CanteensAdapter.java

@@ -1,16 +1,15 @@
 package de.sebse.fuplanner.fragments;
 
-import android.support.annotation.NonNull;
-import android.support.v7.widget.RecyclerView;
 import android.view.LayoutInflater;
 import android.view.View;
 import android.view.ViewGroup;
 
+import androidx.annotation.NonNull;
+import androidx.recyclerview.widget.RecyclerView;
 import de.sebse.fuplanner.R;
 import de.sebse.fuplanner.fragments.CanteensFragment.OnCanteensFragmentInteractionListener;
 import de.sebse.fuplanner.services.Canteen.types.Canteen;
 import de.sebse.fuplanner.services.Canteen.types.Canteens;
-import de.sebse.fuplanner.services.KVV.types.Modules;
 import de.sebse.fuplanner.tools.ui.ItemViewHolder;
 
 /**

app/src/main/java/de/sebse/fuplanner/fragments/CanteensFragment.java

@@ -2,19 +2,19 @@ package de.sebse.fuplanner.fragments;
 
 import android.content.Context;
 import android.os.Bundle;
-import android.support.annotation.NonNull;
-import android.support.v4.app.Fragment;
-import android.support.v4.widget.SwipeRefreshLayout;
-import android.support.v7.widget.LinearLayoutManager;
-import android.support.v7.widget.RecyclerView;
 import android.view.LayoutInflater;
 import android.view.View;
 import android.view.ViewGroup;
 
+import androidx.annotation.NonNull;
+import androidx.fragment.app.Fragment;
+import androidx.recyclerview.widget.LinearLayoutManager;
+import androidx.recyclerview.widget.RecyclerView;
+import androidx.swiperefreshlayout.widget.SwipeRefreshLayout;
 import de.sebse.fuplanner.MainActivity;
 import de.sebse.fuplanner.R;
 import de.sebse.fuplanner.services.Canteen.CanteenBrowser;
-import de.sebse.fuplanner.tools.MainAcitivityListener;
+import de.sebse.fuplanner.tools.MainActivityListener;
 import de.sebse.fuplanner.tools.logging.Logger;
 
 /**
@@ -28,6 +28,7 @@ public class CanteensFragment extends Fragment {
     private final Logger log = new Logger(this);
     private CanteensAdapter adapter;
     private SwipeRefreshLayout swipeLayout;
+    private MainActivityListener mMainActivityListener;
 
     /**
      * Mandatory empty constructor for the fragment manager to instantiate the
@@ -69,6 +70,8 @@ public class CanteensFragment extends Fragment {
             CanteenBrowser browser = ((MainActivity) getActivity()).getCanteenBrowser();
             browser.getCanteens(success -> {
                 adapter.setCanteens(success);
+                //if (mMainActivityListener != null)
+                //    mMainActivityListener.refreshNavigation();
                 swipeLayout.setRefreshing(false);
             }, error -> {
                 log.e(error.toString());
@@ -87,16 +90,18 @@ public class CanteensFragment extends Fragment {
             throw new RuntimeException(context.toString()
                     + " must implement OnCanteensFragmentInteractionListener");
         }
-        if (context instanceof MainAcitivityListener)
-            ((MainAcitivityListener) context).onTitleTextChange(R.string.canteens);
-        else
-            throw new RuntimeException(context.toString() + "must implement MainActivityListener");
+        if (context instanceof MainActivityListener) {
+            mMainActivityListener = (MainActivityListener) context;
+            mMainActivityListener.onTitleTextChange(R.string.canteens);
+        } else
+            throw new RuntimeException(context.toString() + " must implement MainActivityListener");
     }
 
     @Override
     public void onDetach() {
         super.onDetach();
         mListener = null;
+        mMainActivityListener = null;
     }
 
     public interface OnCanteensFragmentInteractionListener {

app/src/main/java/de/sebse/fuplanner/fragments/LoginFragment.java

@@ -3,36 +3,27 @@ package de.sebse.fuplanner.fragments;
 import android.app.ProgressDialog;
 import android.content.Context;
 import android.os.Bundle;
-import android.support.annotation.NonNull;
-import android.support.v4.app.Fragment;
 import android.view.LayoutInflater;
 import android.view.View;
 import android.view.ViewGroup;
 import android.widget.Button;
 import android.widget.EditText;
 
-import java.io.IOException;
-
-import de.sebse.fuplanner.MainActivity;
+import androidx.annotation.NonNull;
+import androidx.annotation.Nullable;
+import androidx.fragment.app.Fragment;
 import de.sebse.fuplanner.R;
-import de.sebse.fuplanner.services.GoogleAuth.GoogleAuth;
-import de.sebse.fuplanner.services.KVV.KVV;
-import de.sebse.fuplanner.services.KVV.types.LoginToken;
-import de.sebse.fuplanner.services.KVV.types.Modules;
-import de.sebse.fuplanner.tools.MainAcitivityListener;
+import de.sebse.fuplanner.tools.MainActivityListener;
 import de.sebse.fuplanner.tools.logging.Logger;
 
 /**
  * A simple {@link Fragment} subclass.
- * Activities that contain this fragment must implement the
- * {@link LoginFragment.OnLoginFragmentInteractionListener} interface
- * to handle interaction events.
  * Use the {@link LoginFragment#newInstance} factory method to
  * create an instance of this fragment.
  */
 public class LoginFragment extends Fragment {
-    private OnLoginFragmentInteractionListener mListener;
     private final Logger log = new Logger(this);
+    @Nullable private MainActivityListener mActivityListener;
 
     public LoginFragment() {
         // Required empty public constructor
@@ -56,21 +47,11 @@ public class LoginFragment extends Fragment {
                              Bundle savedInstanceState) {
         // Inflate the layout for this fragment
         View v = inflater.inflate(R.layout.fragment_login, container, false);
-        try {
-            Context context = getContext();
-            if (context != null) {
-                Modules modules = Modules.load(context);
-                if (modules != null) {
-                    Button offline_btn = v.findViewById(R.id.btn_offline);
-                    offline_btn.setVisibility(View.VISIBLE);
-                    offline_btn.setText(v.getResources().getString(R.string.enter_offline_mode, modules.getToken().getUsername()));
-                    offline_btn.setOnClickListener(v1 -> mListener.onLoginFragmentInteraction(modules.getToken(), false));
-                }
-            }
-        } catch (IOException e) {
-            e.printStackTrace();
-        } catch (ClassNotFoundException e) {
-            e.printStackTrace();
+        if (mActivityListener != null && mActivityListener.getKVV().account().isOfflineStoredAvailable()) {
+            Button offline_btn = v.findViewById(R.id.btn_offline);
+            offline_btn.setVisibility(View.VISIBLE);
+            offline_btn.setText(v.getResources().getString(R.string.enter_offline_mode, mActivityListener.getKVV().modules().list().getUsername()));
+            offline_btn.setOnClickListener(v1 -> mActivityListener.getKVV().account().doOfflineLogin());
         }
 
         View btn_login = v.findViewById(R.id.btn_login);
@@ -83,27 +64,29 @@ public class LoginFragment extends Fragment {
 
             EditText input_usr = ((View) view.getParent()).findViewById(R.id.input_username);
             EditText input_pwd = ((View) view.getParent()).findViewById(R.id.input_password);
-            if (input_usr != null) {
-                if (input_pwd != null) {
-                    if (LoginFragment.this.getActivity() == null) {
-                        log.e("Login fragment has no activity!");
-                        return;
+
+            String username = input_usr.getText().toString();
+            String password = input_pwd.getText().toString();
+
+            mActivityListener.getKVV().account().doOnlineLogin(username, password, success -> {
+                progressDialog.dismiss();
+                mActivityListener.getGoogleAuth().setLoginState(username, password);
+                input_usr.setError(null);
+                input_pwd.setError(null);
+            }, error -> {
+                progressDialog.dismiss();
+                // Invalid password
+                if (mActivityListener != null) {
+                    if (error.getCode() == 100131) {
+                        mActivityListener.showToast(R.string.invalid_credentials);
+                        input_usr.setError(input_usr.getResources().getString(R.string.invalid_credentials));
+                        input_pwd.setError(input_pwd.getResources().getString(R.string.invalid_credentials));
+                    } else {
+                        mActivityListener.showToast(v.getResources().getString(R.string.error_occurred_code, error.getCode()));
                     }
-                    String username = input_usr.getText().toString();
-                    String password = input_pwd.getText().toString();
-                    KVV kvv = ((MainActivity) getActivity()).getKVV();
-                    GoogleAuth gauth = ((MainActivity) getActivity()).getGoogleAuth();
-                    kvv.login(username, password, success -> {
-                        progressDialog.dismiss();
-                        gauth.setLoginState(username, password);
-                        if (mListener != null)
-                            mListener.onLoginFragmentInteraction(success, true);
-                    }, error -> {
-                        progressDialog.dismiss();
-                        log.e("Error on KVV login!", error);
-                    });
                 }
-            }
+                log.e("Error on KVV login!", error);
+            });
         });
 
         return v;
@@ -114,35 +97,16 @@ public class LoginFragment extends Fragment {
     @Override
     public void onAttach(Context context) {
         super.onAttach(context);
-        if (context instanceof OnLoginFragmentInteractionListener) {
-            mListener = (OnLoginFragmentInteractionListener) context;
-        } else {
-            throw new RuntimeException(context.toString()
-                    + " must implement OnLoginFragmentInteractionListener");
-        }
-        if (context instanceof MainAcitivityListener)
-            ((MainAcitivityListener) context).onTitleTextChange(R.string.courses);
-        else
-            throw new RuntimeException(context.toString() + "must implement MainActivityListener");
+        if (context instanceof MainActivityListener) {
+            mActivityListener = (MainActivityListener) context;
+            mActivityListener.onTitleTextChange(R.string.log_in);
+        } else
+            throw new RuntimeException(context.toString() + " must implement MainActivityListener");
     }
 
     @Override
     public void onDetach() {
         super.onDetach();
-        mListener = null;
-    }
-
-    /**
-     * This interface must be implemented by activities that contain this
-     * fragment to allow an interaction in this fragment to be communicated
-     * to the activity and potentially other fragments contained in that
-     * activity.
-     * <p>
-     * See the Android Training lesson <a href=
-     * "http://developer.android.com/training/basics/fragments/communicating.html"
-     * >Communicating with Other Fragments</a> for more information.
-     */
-    public interface OnLoginFragmentInteractionListener {
-        void onLoginFragmentInteraction(LoginToken loginToken, boolean onlineMode);
+        mActivityListener = null;
     }
 }

app/src/main/java/de/sebse/fuplanner/fragments/ModulesAdapter.java

@@ -1,66 +1,115 @@
 package de.sebse.fuplanner.fragments;
 
-import android.support.annotation.NonNull;
-import android.support.v7.widget.RecyclerView;
+import android.util.Pair;
 import android.view.LayoutInflater;
 import android.view.View;
 import android.view.ViewGroup;
 
+import java.util.ArrayList;
+
+import androidx.annotation.NonNull;
+import androidx.recyclerview.widget.RecyclerView;
 import de.sebse.fuplanner.R;
 import de.sebse.fuplanner.fragments.ModulesFragment.OnModulesFragmentInteractionListener;
+import de.sebse.fuplanner.services.KVV.types.Lecturer;
 import de.sebse.fuplanner.services.KVV.types.Modules;
+import de.sebse.fuplanner.services.KVV.types.Semester;
+import de.sebse.fuplanner.tools.ui.CustomViewHolder;
 import de.sebse.fuplanner.tools.ui.ItemViewHolder;
+import de.sebse.fuplanner.tools.ui.StringViewHolder;
 
 /**
  * {@link RecyclerView.Adapter} that can display a {@link Modules.Module} and makes a call to the
  * specified {@link OnModulesFragmentInteractionListener}.
  */
-class ModulesAdapter extends RecyclerView.Adapter<ItemViewHolder> {
+class ModulesAdapter extends RecyclerView.Adapter<CustomViewHolder> {
+
+    private static final int TYPE_HEADER = 0;
+    private static final int TYPE_ITEM = 2;
 
     private Modules mValues;
     private final OnModulesFragmentInteractionListener mListener;
+    private final ArrayList<Pair<Integer, Object>> mPositionalData;
 
     ModulesAdapter(OnModulesFragmentInteractionListener listener) {
         mValues = null;
         mListener = listener;
+        mPositionalData = new ArrayList<>();
     }
 
     public void setModules(Modules modules) {
         mValues = modules;
+        mPositionalData.clear();
+        Semester lastSemester = null;
+        for (Modules.Module module : mValues) {
+            Semester semester = module.semester;
+            if (semester == null)
+                continue;
+            if (!semester.equals(lastSemester)) {
+                mPositionalData.add(new Pair<>(TYPE_HEADER, semester));
+                lastSemester = semester;
+            }
+            mPositionalData.add(new Pair<>(TYPE_ITEM, module));
+        }
         this.notifyDataSetChanged();
     }
 
+    @Override
+    public int getItemViewType(int position) {
+        return mPositionalData.get(position).first;
+    }
+
     @NonNull
     @Override
-    public ItemViewHolder onCreateViewHolder(@NonNull ViewGroup parent, int viewType) {
-        View view = LayoutInflater.from(parent.getContext())
-                .inflate(R.layout.list_all_items, parent, false);
-        return new ItemViewHolder(view);
+    public CustomViewHolder onCreateViewHolder(@NonNull ViewGroup parent, int viewType) {
+        if (viewType == TYPE_HEADER) {
+            View view = LayoutInflater.from(parent.getContext())
+                    .inflate(R.layout.list_all_caption, parent, false);
+            return new StringViewHolder(view);
+        } else {
+            View view = LayoutInflater.from(parent.getContext())
+                    .inflate(R.layout.list_all_items, parent, false);
+            return new ItemViewHolder(view);
+        }
     }
 
     @Override
-    public void onBindViewHolder(@NonNull ItemViewHolder holder, int position) {
-        if (mValues == null)
-            return;
-        Modules.Module module = mValues.getByIndex(holder.getAdapterPosition());
-        holder.mTitle.setText(module.title);
-        holder.mSubLeft.setText(module.semester);
-        holder.mSubRight.setText(module.type);
-
-        holder.mView.setOnClickListener(v -> {
-            if (null != mListener) {
-                // Notify the active callbacks interface (the activity, if the
-                // fragment is attached to one) that an item has been selected.
-                mListener.onModulesFragmentInteraction(module.getID());
+    public void onBindViewHolder(@NonNull CustomViewHolder holder, int position) {
+        Pair<Integer, Object> pair = mPositionalData.get(holder.getAdapterPosition());
+        if (pair.first == TYPE_HEADER) {
+            StringViewHolder sHolder = (StringViewHolder) holder;
+            String localizedSemester;
+            Semester semester = (Semester) pair.second;
+            if (semester.getType() == Semester.SEM_WS)
+                localizedSemester = holder.mView.getResources().getString(R.string.winter_semester, semester.getYear(), semester.getYear()+1);
+            else
+                localizedSemester = holder.mView.getResources().getString(R.string.summer_semester, semester.getYear());
+            sHolder.mString.setText(localizedSemester);
+        } else if (pair.first == TYPE_ITEM) {
+            ItemViewHolder iHolder = (ItemViewHolder) holder;
+            Modules.Module module = ((Modules.Module) pair.second);
+            iHolder.mTitle.setText(module.title);
+            StringBuilder lecturers = new StringBuilder();
+            for (Lecturer lecturer: module.lecturer) {
+                if (!lecturer.isResponsible())
+                    continue;
+                if (lecturers.length() > 0)
+                    lecturers.append(", ");
+                lecturers.append(lecturer.getNameShort());
             }
-        });
+            iHolder.mSubLeft.setText(lecturers);
+            iHolder.mSubRight.setText(module.type);
+
+            iHolder.mView.setOnClickListener(v -> {
+                if (mListener != null) {
+                    mListener.onModulesFragmentInteraction(module.getID());
+                }
+            });
+        }
     }
 
     @Override
     public int getItemCount() {
-        if (mValues != null) {
-            return mValues.size();
-        }
-        return 0;
+        return mPositionalData.size();
     }
 }

app/src/main/java/de/sebse/fuplanner/fragments/ModulesFragment.java

@@ -2,19 +2,18 @@ package de.sebse.fuplanner.fragments;
 
 import android.content.Context;
 import android.os.Bundle;
-import android.support.annotation.NonNull;
-import android.support.v4.app.Fragment;
-import android.support.v4.widget.SwipeRefreshLayout;
-import android.support.v7.widget.LinearLayoutManager;
-import android.support.v7.widget.RecyclerView;
 import android.view.LayoutInflater;
 import android.view.View;
 import android.view.ViewGroup;
 
-import de.sebse.fuplanner.MainActivity;
+import androidx.annotation.NonNull;
+import androidx.annotation.Nullable;
+import androidx.fragment.app.Fragment;
+import androidx.recyclerview.widget.LinearLayoutManager;
+import androidx.recyclerview.widget.RecyclerView;
+import androidx.swiperefreshlayout.widget.SwipeRefreshLayout;
 import de.sebse.fuplanner.R;
-import de.sebse.fuplanner.services.KVV.KVV;
-import de.sebse.fuplanner.tools.MainAcitivityListener;
+import de.sebse.fuplanner.tools.MainActivityListener;
 import de.sebse.fuplanner.tools.logging.Logger;
 
 /**
@@ -28,6 +27,7 @@ public class ModulesFragment extends Fragment {
     private final Logger log = new Logger(this);
     private ModulesAdapter adapter;
     private SwipeRefreshLayout swipeLayout;
+    @Nullable private MainActivityListener mMainActivityListener;
 
     /**
      * Mandatory empty constructor for the fragment manager to instantiate the
@@ -65,10 +65,11 @@ public class ModulesFragment extends Fragment {
     }
 
     private void refresh(boolean forceRefresh) {
-        if (getActivity() != null) {
-            KVV kvv = ((MainActivity) getActivity()).getKVV();
-            kvv.getModuleList(success -> {
+        if (mMainActivityListener != null) {
+            mMainActivityListener.getKVV().modules().list().recv(success -> {
                 adapter.setModules(success);
+                //if (mMainActivityListener != null)
+                //    mMainActivityListener.refreshNavigation();
                 swipeLayout.setRefreshing(false);
             }, error -> {
                 log.e(error.toString());
@@ -87,16 +88,19 @@ public class ModulesFragment extends Fragment {
             throw new RuntimeException(context.toString()
                     + " must implement OnModulesFragmentInteractionListener");
         }
-        if (context instanceof MainAcitivityListener)
-            ((MainAcitivityListener) context).onTitleTextChange(R.string.courses);
+        if (context instanceof MainActivityListener) {
+            mMainActivityListener = (MainActivityListener) context;
+            mMainActivityListener.onTitleTextChange(R.string.courses);
+        }
         else
-            throw new RuntimeException(context.toString() + "must implement MainActivityListener");
+            throw new RuntimeException(context.toString() + " must implement MainActivityListener");
     }
 
     @Override
     public void onDetach() {
         super.onDetach();
         mListener = null;
+        mMainActivityListener = null;
     }
 
     public interface OnModulesFragmentInteractionListener {

app/src/main/java/de/sebse/fuplanner/fragments/PrefsFragment.java

@@ -2,9 +2,9 @@ package de.sebse.fuplanner.fragments;
 
 import android.content.SharedPreferences;
 import android.os.Bundle;
-import android.support.v7.preference.ListPreference;
-import android.support.v7.preference.Preference;
-import android.support.v7.preference.PreferenceFragmentCompat;
+import androidx.preference.ListPreference;
+import androidx.preference.Preference;
+import androidx.preference.PreferenceFragmentCompat;
 
 import de.sebse.fuplanner.R;
 import de.sebse.fuplanner.tools.logging.Logger;

app/src/main/java/de/sebse/fuplanner/fragments/ScheduleFragment.java

@@ -4,8 +4,6 @@ import android.app.AlertDialog;
 import android.content.Context;
 import android.graphics.RectF;
 import android.os.Bundle;
-import android.support.annotation.NonNull;
-import android.support.v4.app.Fragment;
 import android.view.LayoutInflater;
 import android.view.View;
 import android.view.ViewGroup;
@@ -15,12 +13,13 @@ import java.util.Calendar;
 import java.util.Iterator;
 import java.util.List;
 
+import androidx.annotation.NonNull;
+import androidx.fragment.app.Fragment;
 import de.sebse.fuplanner.R;
-import de.sebse.fuplanner.services.KVV.KVV;
 import de.sebse.fuplanner.services.KVV.types.Event;
 import de.sebse.fuplanner.services.KVV.types.Modules;
-import de.sebse.fuplanner.tools.DateUtils;
-import de.sebse.fuplanner.tools.MainAcitivityListener;
+import de.sebse.fuplanner.tools.UtilsDate;
+import de.sebse.fuplanner.tools.MainActivityListener;
 import de.sebse.fuplanner.tools.logging.Logger;
 import de.sebse.fuplanner.tools.ui.weekview.MonthLoader;
 import de.sebse.fuplanner.tools.ui.weekview.WeekView;
@@ -29,14 +28,14 @@ import de.sebse.fuplanner.tools.ui.weekview.WeekViewEvent;
 /**
  * A simple {@link Fragment} subclass.
  * Activities that contain this fragment must implement the
- * {@link MainAcitivityListener} interface
+ * {@link MainActivityListener} interface
  * to handle interaction events.
  * Use the {@link ScheduleFragment#newInstance} factory method to
  * create an instance of this fragment.
  *
  */
 public class ScheduleFragment extends Fragment implements MonthLoader.MonthChangeListener, WeekView.ScrollListener, WeekView.DoubleTapListener, WeekView.EventClickListener {
-    private MainAcitivityListener mListener;
+    private MainActivityListener mListener;
     private WeekView mWeekView;
     private final Logger log = new Logger(this);
     private Modules mModules = null;
@@ -59,24 +58,22 @@ public class ScheduleFragment extends Fragment implements MonthLoader.MonthChang
     }
 
     public void invalidate(boolean forceRefresh) {
-        if (mListener != null) {
-            KVV kvv = mListener.getKVV();
-            kvv.getModuleList((Modules success) -> {
-                mModules = success;
-                final int[] i = {0};
-                for (Modules.Module module: mModules) {
-                    kvv.getModuleEvents(module, success1 -> {
-                        i[0]++;
-                        if (i[0] >= mModules.size()) {
-                            if (mWeekView != null) {
-                                mWeekView.invalidate();
-                                mWeekView.notifyDatasetChanged();
-                            }
+        if (mListener == null) return;
+        mListener.getKVV().modules().list().recv(modules -> {
+            mModules = modules;
+            final int[] i = {0};
+            for (Modules.Module module: mModules) {
+                mListener.getKVV().modules().events().recv(module, success1 -> {
+                    i[0]++;
+                    if (i[0] >= mModules.size()) {
+                        if (mWeekView != null) {
+                            mWeekView.invalidate();
+                            mWeekView.notifyDatasetChanged();
                         }
-                    }, log::e, forceRefresh);
-                }
-            }, log::e, forceRefresh);
-        }
+                    }
+                }, log::e, forceRefresh);
+            }
+        }, log::e, forceRefresh);
     }
 
     @Override
@@ -99,8 +96,8 @@ public class ScheduleFragment extends Fragment implements MonthLoader.MonthChang
     @Override
     public void onAttach(Context context) {
         super.onAttach(context);
-        if (context instanceof MainAcitivityListener) {
-            mListener = (MainAcitivityListener) context;
+        if (context instanceof MainActivityListener) {
+            mListener = (MainActivityListener) context;
         } else {
             throw new RuntimeException(context.toString()
                     + " must implement OnFragmentInteractionListener");
@@ -144,7 +141,7 @@ public class ScheduleFragment extends Fragment implements MonthLoader.MonthChang
     public void onFirstVisibleDayChanged(Calendar newFirstVisibleDay, Calendar oldFirstVisibleDay) {
         Calendar newLastVisibleDay = (Calendar) newFirstVisibleDay.clone();
         newLastVisibleDay.add(Calendar.HOUR, 24*mWeekView.getNumberOfVisibleDays());
-        mListener.onTitleTextChange(getResources().getString(R.string.date_scale, DateUtils.getModifiedDate(newFirstVisibleDay.getTimeInMillis()), DateUtils.getModifiedDate(newLastVisibleDay.getTimeInMillis())));
+        mListener.onTitleTextChange(getResources().getString(R.string.date_scale, UtilsDate.getModifiedDate(newFirstVisibleDay.getTimeInMillis()), UtilsDate.getModifiedDate(newLastVisibleDay.getTimeInMillis())));
     }
 
 
@@ -157,9 +154,11 @@ public class ScheduleFragment extends Fragment implements MonthLoader.MonthChang
         Calendar firstVisibleDay = mWeekView.getFirstVisibleDay();
         Calendar c = Calendar.getInstance();
         c.set(firstVisibleDay.get(Calendar.YEAR), firstVisibleDay.get(Calendar.MONTH), firstVisibleDay.get(Calendar.DAY_OF_MONTH), 0,0 );
-        c.add(Calendar.DATE, 2); // die Grenze beim tippen, wann ver nach vorne und wann nach hinten springt
+        // Limit when to go a week backwards and when to the next week
+        c.add(Calendar.DATE, 2);
 
-        if (c.getTimeInMillis() > time.getTimeInMillis()){//nach links blättern
+        // skip to next week
+        if (c.getTimeInMillis() > time.getTimeInMillis()){
             firstVisibleDay.add(Calendar.DATE, -1);
             while (firstVisibleDay.get(Calendar.DAY_OF_WEEK) != Calendar.MONDAY) {
                 firstVisibleDay.add(Calendar.DATE, -1);
@@ -172,6 +171,7 @@ public class ScheduleFragment extends Fragment implements MonthLoader.MonthChang
             }
         }
         mWeekView.goToDate(firstVisibleDay);
+        onFirstVisibleDayChanged(firstVisibleDay, mWeekView.getLastVisibleDay());
     }
 
     @Override
@@ -180,24 +180,21 @@ public class ScheduleFragment extends Fragment implements MonthLoader.MonthChang
         String moduleId = idParts[0];
         AlertDialog.Builder alertDialogBuilder = new AlertDialog.Builder(getContext());
 
-        if (mListener != null) {
-            KVV kvv = mListener.getKVV();
-            kvv.getModuleList((Modules success) -> {
-                Modules.Module module = success.get(moduleId);
-                String moduleName = module.title;
-                alertDialogBuilder
-                        .setTitle(event.getName())
-                        .setMessage(
-                                getResources().getString(R.string.module_name, moduleName) + "\n" +
-                                        getResources().getString(R.string.location_name, event.getLocation()) + "\n" +
-                                        getResources().getString(R.string.date_scale, DateUtils.getModifiedTime(getContext(), event.getStartTime().getTimeInMillis()), DateUtils.getModifiedTime(getContext(), event.getEndTime().getTimeInMillis()+1))
-                        )
-                        .setCancelable(true)
-                        .setNeutralButton(R.string.close, (dialog, id) -> dialog.cancel());
+        if (mListener == null) return;
+        mListener.getKVV().modules().list().find(moduleId, module -> {
+            String moduleName = module.title;
+            alertDialogBuilder
+                    .setTitle(event.getName())
+                    .setMessage(
+                            getResources().getString(R.string.module_name, moduleName) + "\n" +
+                                    getResources().getString(R.string.location_name, event.getLocation()) + "\n" +
+                                    getResources().getString(R.string.date_scale, UtilsDate.getModifiedTime(getContext(), event.getStartTime().getTimeInMillis()), UtilsDate.getModifiedTime(getContext(), event.getEndTime().getTimeInMillis()+1))
+                    )
+                    .setCancelable(true)
+                    .setNeutralButton(R.string.close, (dialog, id) -> dialog.cancel());
 
-                AlertDialog alertDialog = alertDialogBuilder.create();
-                alertDialog.show();
-            }, log::e);
-        }
+            AlertDialog alertDialog = alertDialogBuilder.create();
+            alertDialog.show();
+        }, log::e);
     }
 }

app/src/main/java/de/sebse/fuplanner/fragments/StartupFragment.java

@@ -1,12 +1,12 @@
 package de.sebse.fuplanner.fragments;
 
 import android.os.Bundle;
-import android.support.annotation.NonNull;
-import android.support.v4.app.Fragment;
 import android.view.LayoutInflater;
 import android.view.View;
 import android.view.ViewGroup;
 
+import androidx.annotation.NonNull;
+import androidx.fragment.app.Fragment;
 import de.sebse.fuplanner.R;
 
 /**

app/src/main/java/de/sebse/fuplanner/fragments/canteen/DaySwitcherAdapter.java

@@ -1,11 +1,11 @@
 package de.sebse.fuplanner.fragments.canteen;
 
-import android.support.v4.app.Fragment;
-import android.support.v4.app.FragmentManager;
-import android.support.v4.app.FragmentStatePagerAdapter;
+import androidx.fragment.app.Fragment;
+import androidx.fragment.app.FragmentManager;
+import androidx.fragment.app.FragmentStatePagerAdapter;
 
 import de.sebse.fuplanner.services.Canteen.types.Canteen;
-import de.sebse.fuplanner.tools.DateUtils;
+import de.sebse.fuplanner.tools.UtilsDate;
 
 class DaySwitcherAdapter extends FragmentStatePagerAdapter {
     private Canteen mCanteen = null;
@@ -39,7 +39,7 @@ class DaySwitcherAdapter extends FragmentStatePagerAdapter {
     // Returns the page title for the top indicator
     @Override
     public CharSequence getPageTitle(int position) {
-        return DateUtils.getModifiedDate(mCanteen.get(position).getCalendar().getTimeInMillis());
+        return UtilsDate.getModifiedDate(mCanteen.get(position).getCalendar().getTimeInMillis());
     }
 
 }

app/src/main/java/de/sebse/fuplanner/fragments/canteen/DaySwitcherFragment.java

@@ -2,18 +2,18 @@ package de.sebse.fuplanner.fragments.canteen;
 
 import android.content.Context;
 import android.os.Bundle;
-import android.support.annotation.NonNull;
-import android.support.v4.app.Fragment;
-import android.support.v4.view.ViewPager;
 import android.view.LayoutInflater;
 import android.view.View;
 import android.view.ViewGroup;
 
+import androidx.annotation.NonNull;
+import androidx.fragment.app.Fragment;
+import androidx.viewpager.widget.ViewPager;
 import de.sebse.fuplanner.MainActivity;
 import de.sebse.fuplanner.R;
 import de.sebse.fuplanner.services.Canteen.CanteenBrowser;
 import de.sebse.fuplanner.services.Canteen.types.Canteen;
-import de.sebse.fuplanner.tools.MainAcitivityListener;
+import de.sebse.fuplanner.tools.MainActivityListener;
 import de.sebse.fuplanner.tools.logging.Logger;
 import de.sebse.fuplanner.tools.network.NetworkCallback;
 import de.sebse.fuplanner.tools.network.NetworkErrorCallback;
@@ -21,7 +21,7 @@ import de.sebse.fuplanner.tools.network.NetworkErrorCallback;
 /**
  * A simple {@link Fragment} subclass.
  * Activities that contain this fragment must implement the
- * {@link MainAcitivityListener} interface
+ * {@link MainActivityListener} interface
  * to handle interaction events.
  * Use the {@link DaySwitcherFragment#newInstance} factory method to
  * create an instance of this fragment.
@@ -32,9 +32,8 @@ public class DaySwitcherFragment extends Fragment implements DaySwitcherListener
     // Parameters
     private int mCanteenId;
 
-    private MainAcitivityListener mListener;
+    private MainActivityListener mListener;
     private final Logger log = new Logger(this);
-    private ViewPager mViewPager;
     private DaySwitcherAdapter adapterViewPager;
 
     public DaySwitcherFragment() {
@@ -78,11 +77,11 @@ public class DaySwitcherFragment extends Fragment implements DaySwitcherListener
         // Inflate the layout for this fragment
         View v = inflater.inflate(R.layout.fragment_mod_detail, container, false);
 
-        mViewPager = v.findViewById(R.id.vpPager);
+        ViewPager mViewPager = v.findViewById(R.id.vpPager);
         adapterViewPager = new DaySwitcherAdapter(getChildFragmentManager());
         mViewPager.setAdapter(adapterViewPager);
 
-        refresh(false);
+        refresh();
 
         return v;
     }
@@ -90,8 +89,8 @@ public class DaySwitcherFragment extends Fragment implements DaySwitcherListener
     @Override
     public void onAttach(Context context) {
         super.onAttach(context);
-        if (context instanceof MainAcitivityListener) {
-            mListener = (MainAcitivityListener) context;
+        if (context instanceof MainActivityListener) {
+            mListener = (MainActivityListener) context;
         } else {
             throw new RuntimeException(context.toString()
                     + " must implement MainActivityListener");
@@ -104,8 +103,8 @@ public class DaySwitcherFragment extends Fragment implements DaySwitcherListener
         mListener = null;
     }
 
-    private void refresh(boolean forceRefresh) {
-        refresh(forceRefresh, null, null);
+    private void refresh() {
+        refresh(false, null, null);
     }
 
     private void refresh(boolean forceRefresh, NetworkCallback<Canteen> callback, NetworkErrorCallback errorCallback) {
@@ -113,6 +112,7 @@ public class DaySwitcherFragment extends Fragment implements DaySwitcherListener
             CanteenBrowser browser = ((MainActivity) getActivity()).getCanteenBrowser();
             browser.getCanteens(canteens -> {
                 Canteen canteen = canteens.getCanteen(mCanteenId);
+                canteen.cleanUpDays();
                 adapterViewPager.setModule(canteen);
                 browser.getCanteen(canteen, success -> {
                     adapterViewPager.setModule();

app/src/main/java/de/sebse/fuplanner/fragments/canteen/MealAdapter.java

@@ -4,16 +4,28 @@ import android.content.Context;
 import android.view.LayoutInflater;
 import android.view.View;
 import android.view.ViewGroup;
-import android.widget.BaseExpandableListAdapter;
 
+import java.util.ArrayList;
+import java.util.HashMap;
+import java.util.List;
+
+import androidx.annotation.NonNull;
+import androidx.annotation.StringRes;
+import androidx.recyclerview.widget.RecyclerView;
 import de.sebse.fuplanner.R;
 import de.sebse.fuplanner.services.Canteen.types.Day;
 import de.sebse.fuplanner.services.Canteen.types.Meal;
 import de.sebse.fuplanner.tools.Preferences;
-import de.sebse.fuplanner.tools.ui.ItemViewHolder;
+import de.sebse.fuplanner.tools.ui.MealViewHolder;
 import de.sebse.fuplanner.tools.ui.StringViewHolder;
 
-class MealAdapter extends BaseExpandableListAdapter {
+class MealAdapter extends RecyclerView.Adapter<RecyclerView.ViewHolder> {
+    private String[] CATEGORY_KEYS = new String[]{"Essen", "Aktionen", "Beilagen", "Desserts", "Salate", "Suppen", "Vorspeisen"};
+    @StringRes
+    private int[] CATEGORY_VALS = new int[]{R.string.meals, R.string.special_meals, R.string.side_dishes, R.string.desserts, R.string.salads, R.string.soups, R.string.starters};
+    @StringRes
+    private int CATEGORY_OTHER = R.string.others;
+    private ArrayList<Object> matches = new ArrayList<>();
 
     private Day mDay = null;
     private final Context mContext;
@@ -22,105 +34,104 @@ class MealAdapter extends BaseExpandableListAdapter {
         mContext = context;
     }
 
+    @NonNull
     @Override
-    public String getChild(int groupPosition, int childPosititon) {
-        StringBuilder sb = new StringBuilder();
-        sb.append("\n\n");
-        for (String s : this.getGroup(groupPosition).getNotes())
-        {
-            sb.append(s);
-            sb.append("\n\n");
+    public RecyclerView.ViewHolder onCreateViewHolder(@NonNull ViewGroup viewGroup, int viewType) {
+        if (viewType == 0) {
+            View view = LayoutInflater.from(viewGroup.getContext())
+                    .inflate(R.layout.list_canteen_items, viewGroup, false);
+            return new MealViewHolder(view);
+        } else {
+            View view = LayoutInflater.from(viewGroup.getContext())
+                    .inflate(R.layout.list_all_caption, viewGroup, false);
+            return new StringViewHolder(view);
         }
-        return sb.toString();
     }
 
     @Override
-    public long getChildId(int groupPosition, int childPosition) {
-        return childPosition;
-    }
-
-    @Override
-    public View getChildView(int groupPosition, final int childPosition,
-                             boolean isLastChild, View convertView, ViewGroup parent) {
-
-        final String childText = getChild(groupPosition, childPosition);
-
-        if (convertView == null) {
-            convertView = LayoutInflater.from(parent.getContext())
-                    .inflate(R.layout.list_all_string, parent, false);
+    public void onBindViewHolder(@NonNull RecyclerView.ViewHolder holder, int position) {
+        if (holder.getItemViewType() == 0) {
+            MealViewHolder viewHolder = ((MealViewHolder) holder);
+            viewHolder.reset();
+            Meal meal = getMeal(position);
+            viewHolder.mTitle.setText(meal.getName());
+            String value;
+            switch (Preferences.getString(mContext, R.array.pref_price_group)) {
+                case "student":
+                    if (meal.getPriceStdnt() < 0)
+                        value = mContext.getResources().getString(R.string.no_price_available);
+                    else
+                        value = mContext.getString(R.string.price, meal.getPriceStdnt());
+                    break;
+                case "employee":
+                    if (meal.getPriceEmply() < 0)
+                        value = mContext.getResources().getString(R.string.no_price_available);
+                    else
+                        value = mContext.getString(R.string.price, meal.getPriceEmply());
+                    break;
+                case "other":
+                    if (meal.getPriceOther() < 0)
+                        value = mContext.getResources().getString(R.string.no_price_available);
+                    else
+                        value = mContext.getString(R.string.price, meal.getPriceOther());
+                    break;
+                default:
+                    String value1;
+                    if (meal.getPriceStdnt() < 0)
+                        value1 = " -/- ";
+                    else
+                        value1 = mContext.getString(R.string.price, meal.getPriceStdnt());
+                    String value2;
+                    if (meal.getPriceEmply() < 0)
+                        value2 = " -/- ";
+                    else
+                        value2 = mContext.getString(R.string.price, meal.getPriceEmply());
+                    String value3;
+                    if (meal.getPriceOther() < 0)
+                        value3 = " -/- ";
+                    else
+                        value3 = mContext.getString(R.string.price, meal.getPriceOther());
+                        value = mContext.getString(R.string.prices, value1, value2, value3);
+            }
+            viewHolder.mSubTitle.setText(value);
+            StringBuilder string = new StringBuilder();
+            List<String> notes = meal.getNotes();
+            for (int i1 = 0, notesSize = notes.size(); i1 < notesSize; i1++) {
+                if (i1 != 0)
+                    string.append("\n");
+                String s = notes.get(i1);
+                string.append(" - ").append(s);
+            }
+            viewHolder.mNotes.setText(string.toString());
+            viewHolder.mIconVegan.setVisibility(meal.getVegan() == Meal.VEGAN_VEGAN ? View.VISIBLE : View.GONE);
+            viewHolder.mIconVegetarian.setVisibility(meal.getVegan() == Meal.VEGAN_VEGETARIAN ? View.VISIBLE : View.GONE);
+            viewHolder.mIconBio.setVisibility((meal.getCertificates() & Meal.CERT_BIO) != 0 ? View.VISIBLE : View.GONE);
+            viewHolder.mIconMsc.setVisibility((meal.getCertificates() & Meal.CERT_MSC) != 0 ? View.VISIBLE : View.GONE);
+        } else {
+            StringViewHolder viewHolder = ((StringViewHolder) holder);
+            viewHolder.mString.setText(getHeading(position));
         }
-
-        StringViewHolder itemHolder = new StringViewHolder(convertView);
-        itemHolder.mString.setText(childText);
-
-        return convertView;
     }
 
     @Override
-    public int getChildrenCount(int groupPosition) {
-        return 1;
+    public int getItemCount() {
+        return matches.size();
     }
 
     @Override
-    public Meal getGroup(int groupPosition) {
+    public int getItemViewType(int position) {
+        return matches.get(position) instanceof String ? 1 : 0;
+    }
+
+    private Meal getMeal(int position) {
         if (this.mDay != null)
-            return this.mDay.get(groupPosition);
+            return this.mDay.get((Integer) matches.get(position));
         else
             return null;
     }
 
-    @Override
-    public int getGroupCount() {
-        if (this.mDay != null)
-            return this.mDay.size();
-        else
-            return 0;
-    }
-
-    @Override
-    public long getGroupId(int groupPosition) {
-        return groupPosition;
-    }
-
-    @Override
-    public View getGroupView(int groupPosition, boolean isExpanded,
-                             View convertView, ViewGroup parent) {
-        Meal meal = getGroup(groupPosition);
-        if (convertView == null) {
-            convertView = LayoutInflater.from(parent.getContext())
-                    .inflate(R.layout.list_all_items, parent, false);
-        }
-
-        ItemViewHolder itemHolder = new ItemViewHolder(convertView);
-        itemHolder.mTitle.setText(meal.getName());
-        itemHolder.mSubLeft.setText(meal.getCategory());
-        String value;
-        switch (Preferences.getString(mContext, R.array.pref_price_group)) {
-            case "student":
-                value = mContext.getString(R.string.price, meal.getPriceStdnt());
-                break;
-            case "employee":
-                value = mContext.getString(R.string.price, meal.getPriceEmply());
-                break;
-            case "other":
-                value = mContext.getString(R.string.price, meal.getPriceOther());
-                break;
-            default:
-                value = mContext.getString(R.string.prices, meal.getPriceStdnt(), meal.getPriceEmply(), meal.getPriceOther());
-        }
-        itemHolder.mSubRight.setText(value);
-
-        return convertView;
-    }
-
-    @Override
-    public boolean hasStableIds() {
-        return false;
-    }
-
-    @Override
-    public boolean isChildSelectable(int groupPosition, int childPosition) {
-        return false;
+    private String getHeading(int position) {
+        return (String) matches.get(position);
     }
 
     public void setDay(Day day) {
@@ -129,6 +140,37 @@ class MealAdapter extends BaseExpandableListAdapter {
     }
 
     public void setDay() {
+        HashMap<String, ArrayList<Integer>> map = new HashMap<>();
+        for (int i = 0; i < this.mDay.size(); i++) {
+            String category = this.mDay.get(i).getCategory();
+            boolean found = false;
+            for (String category_key : CATEGORY_KEYS) {
+                if (category_key.equals(category)) {
+                    found = true;
+                    break;
+                }
+            }
+            if (!found) category = "---";
+            ArrayList<Integer> list = map.get(category);
+            if (list == null) {
+                list = new ArrayList<>();
+                map.put(category, list);
+            }
+            list.add(i);
+        }
+        matches.clear();
+        for (int i = 0; i < CATEGORY_KEYS.length; i++) {
+            ArrayList<Integer> list = map.get(CATEGORY_KEYS[i]);
+            if (list != null) {
+                matches.add(mContext.getString(CATEGORY_VALS[i]));
+                matches.addAll(list);
+            }
+        }
+        ArrayList<Integer> list = map.get("---");
+        if (list != null) {
+            matches.add(mContext.getString(CATEGORY_OTHER));
+            matches.addAll(list);
+        }
         this.notifyDataSetChanged();
     }
 }

app/src/main/java/de/sebse/fuplanner/fragments/canteen/MealFragment.java

@@ -3,14 +3,14 @@ package de.sebse.fuplanner.fragments.canteen;
 
 import android.content.Context;
 import android.os.Bundle;
-import android.support.annotation.NonNull;
-import android.support.v4.app.Fragment;
-import android.support.v4.widget.SwipeRefreshLayout;
 import android.view.LayoutInflater;
 import android.view.View;
 import android.view.ViewGroup;
-import android.widget.ExpandableListView;
 
+import androidx.annotation.NonNull;
+import androidx.fragment.app.Fragment;
+import androidx.recyclerview.widget.RecyclerView;
+import androidx.swiperefreshlayout.widget.SwipeRefreshLayout;
 import de.sebse.fuplanner.MainActivity;
 import de.sebse.fuplanner.R;
 import de.sebse.fuplanner.services.Canteen.CanteenBrowser;
@@ -43,9 +43,9 @@ public class MealFragment extends Fragment {
      * Use this factory method to create a new instance of
      * this fragment using the provided parameters.
      *
-     * @param canteenId Item position in module list.
-     * @param dayPosition Item position in module list.
-     * @return A new instance of fragment ModDetailAnnounceFragment.
+     * @param canteenId ID od current canteen.
+     * @param dayPosition day to show.
+     * @return A new instance of fragment MealFragment.
      */
     public static MealFragment newInstance(int canteenId, int dayPosition) {
         MealFragment fragment = new MealFragment();
@@ -69,9 +69,9 @@ public class MealFragment extends Fragment {
     public View onCreateView(@NonNull LayoutInflater inflater, ViewGroup container,
                              Bundle savedInstanceState) {
         // Inflate the layout for this fragment
-        View view = inflater.inflate(R.layout.fragment_expandable_list_view, container, false);
+        View view = inflater.inflate(R.layout.fragment_recycler_view, container, false);
         // Set the adapter
-        ExpandableListView expandableListView = view.findViewById(R.id.list);
+        RecyclerView expandableListView = view.findViewById(R.id.list);
         adapter = new MealAdapter(getContext());
         expandableListView.setAdapter(adapter);
 

app/src/main/java/de/sebse/fuplanner/fragments/moddetails/ModDetailAdapter.java

@@ -1,9 +1,9 @@
 package de.sebse.fuplanner.fragments.moddetails;
 
 import android.content.Context;
-import android.support.v4.app.Fragment;
-import android.support.v4.app.FragmentManager;
-import android.support.v4.app.FragmentStatePagerAdapter;
+import androidx.fragment.app.Fragment;
+import androidx.fragment.app.FragmentManager;
+import androidx.fragment.app.FragmentStatePagerAdapter;
 
 import de.sebse.fuplanner.R;
 
@@ -38,6 +38,8 @@ class ModDetailAdapter extends FragmentStatePagerAdapter {
                 return ModDetailEventFragment.newInstance(mItemPos);
             case ModulePart.GRADEBOOK:
                 return ModDetailGradebookFragment.newInstance(mItemPos);
+            case ModulePart.RESOURCES:
+                return ModDetailResourceFragment.newInstance(mItemPos);
             default:
                 return null;
         }
@@ -57,6 +59,8 @@ class ModDetailAdapter extends FragmentStatePagerAdapter {
                 return this.mContext.getResources().getString(R.string.events);
             case ModulePart.GRADEBOOK:
                 return this.mContext.getResources().getString(R.string.gradebook);
+            case ModulePart.RESOURCES:
+                return this.mContext.getResources().getString(R.string.resources);
             default:
                 return "";
         }

app/src/main/java/de/sebse/fuplanner/fragments/moddetails/ModDetailAnnounceAdapter.java

@@ -1,107 +1,38 @@
 package de.sebse.fuplanner.fragments.moddetails;
 
+import android.content.res.Resources;
 import android.view.LayoutInflater;
 import android.view.View;
 import android.view.ViewGroup;
-import android.widget.BaseExpandableListAdapter;
 
-import java.util.ArrayList;
+import com.cunoraz.tagview.Tag;
 
+import java.io.UnsupportedEncodingException;
+import java.net.URLDecoder;
+import java.util.List;
+
+import androidx.annotation.NonNull;
+import androidx.annotation.Nullable;
+import androidx.core.content.ContextCompat;
+import androidx.recyclerview.widget.RecyclerView;
 import de.sebse.fuplanner.R;
+import de.sebse.fuplanner.services.KVV.ui.Download;
 import de.sebse.fuplanner.services.KVV.types.Announcement;
 import de.sebse.fuplanner.services.KVV.types.Modules;
-import de.sebse.fuplanner.tools.DateUtils;
-import de.sebse.fuplanner.tools.ui.ItemViewHolder;
-import de.sebse.fuplanner.tools.ui.StringViewHolder;
+import de.sebse.fuplanner.tools.Regex;
+import de.sebse.fuplanner.tools.UtilsDate;
+import de.sebse.fuplanner.tools.logging.Logger;
+import de.sebse.fuplanner.tools.ui.AnnouncementViewHolder;
+import de.sebse.fuplanner.tools.ui.CustomViewHolder;
 
-class ModDetailAnnounceAdapter extends BaseExpandableListAdapter {
+class ModDetailAnnounceAdapter extends RecyclerView.Adapter<CustomViewHolder> {
 
-    private Modules.Module mModule = null;
+    @Nullable private Modules.Module mModule = null;
+    private Logger log = new Logger(this);
+    @NonNull private Download.OnDownloadRequestInterface requestInterface;
 
-    @Override
-    public String getChild(int groupPosition, int childPosititon) {
-        StringBuilder s = new StringBuilder(this.getGroup(groupPosition).getBody());
-        ArrayList<String> urls = this.getGroup(groupPosition).getUrls();
-        for (int j =0; j<urls.size(); j++){
-            s.append("\n");
-            s.append(urls.get(j));
-        }
-        return s.toString();
-    }
-
-    @Override
-    public long getChildId(int groupPosition, int childPosition) {
-        return childPosition;
-    }
-
-    @Override
-    public View getChildView(int groupPosition, final int childPosition,
-                             boolean isLastChild, View convertView, ViewGroup parent) {
-
-        final String childText = getChild(groupPosition, childPosition);
-
-        if (convertView == null) {
-            convertView = LayoutInflater.from(parent.getContext())
-                    .inflate(R.layout.list_all_string, parent, false);
-        }
-
-        StringViewHolder itemHolder = new StringViewHolder(convertView);
-        itemHolder.mString.setText(childText);
-
-        return convertView;
-    }
-
-    @Override
-    public int getChildrenCount(int groupPosition) {
-        return 1;
-    }
-
-    @Override
-    public Announcement getGroup(int groupPosition) {
-        if (this.mModule != null && this.mModule.announcements != null)
-            return this.mModule.announcements.get(groupPosition);
-        else
-            return null;
-    }
-
-    @Override
-    public int getGroupCount() {
-        if (this.mModule != null && this.mModule.announcements != null)
-            return this.mModule.announcements.size();
-        else
-            return 0;
-    }
-
-    @Override
-    public long getGroupId(int groupPosition) {
-        return groupPosition;
-    }
-
-    @Override
-    public View getGroupView(int groupPosition, boolean isExpanded,
-                             View convertView, ViewGroup parent) {
-        Announcement announce = getGroup(groupPosition);
-        if (convertView == null) {
-            convertView = LayoutInflater.from(parent.getContext())
-                    .inflate(R.layout.list_all_items, parent, false);
-        }
-
-        ItemViewHolder itemHolder = new ItemViewHolder(convertView);
-        itemHolder.mTitle.setText(announce.getTitle());
-        itemHolder.mSubLeft.setText(announce.getCreatedBy());
-        itemHolder.mSubRight.setText(DateUtils.getModifiedDateTime(parent.getContext(), announce.getCreatedOn()));
-
-        return convertView;
-    }
-
-    @Override
-    public boolean hasStableIds() {
-        return false;
-    }
-
-    @Override
-    public boolean isChildSelectable(int groupPosition, int childPosition) {
-        return false;
+    ModDetailAnnounceAdapter(@NonNull Download.OnDownloadRequestInterface requestInterface) {
+        this.requestInterface = requestInterface;
     }
 
     public void setModule(Modules.Module module) {
@@ -112,4 +43,87 @@ class ModDetailAnnounceAdapter extends BaseExpandableListAdapter {
     public void setModule() {
         this.notifyDataSetChanged();
     }
+
+    @NonNull
+    public CustomViewHolder onCreateViewHolder(@NonNull ViewGroup viewGroup, int viewType) {
+        if (viewType == 0) {
+            View view = LayoutInflater.from(viewGroup.getContext())
+                    .inflate(R.layout.list_announcement_items, viewGroup, false);
+            return new AnnouncementViewHolder(view);
+        } else {
+            View view = LayoutInflater.from(viewGroup.getContext())
+                    .inflate(R.layout.list_all_no_items, viewGroup, false);
+            return new CustomViewHolder(view);
+        }
+    }
+
+    @Override
+    public void onBindViewHolder(@NonNull CustomViewHolder customHolder, int position) {
+        if (customHolder instanceof AnnouncementViewHolder) {
+            AnnouncementViewHolder holder = (AnnouncementViewHolder) customHolder;
+            holder.reset();
+            Announcement item = getAnnouncement(position);
+            holder.mTitle.setText(item.getTitle());
+            holder.mSubTitle.setText(UtilsDate.getModifiedDateTime(holder.mView.getContext(), item.getCreatedOn()));
+            holder.mTagGroup.removeAll();
+
+            List<String> notes = item.getUrls();
+            if (!notes.isEmpty()) {
+                holder.mTagGroup.setVisibility(View.VISIBLE);
+                for (int i = 0, notesSize = notes.size(); i < notesSize; i++) {
+                    String name = urlToName(notes.get(i), i, holder.mView.getResources());
+                    Tag tag = new Tag(name);
+                    tag.id = i;
+                    tag.layoutColor = ContextCompat.getColor(holder.mView.getContext(), R.color.colorFUBlue);
+                    holder.mTagGroup.addTag(tag);
+                }
+                holder.mTagGroup.setOnTagClickListener((tag, i) -> {
+                    String s = notes.get(i);
+                    if (s != null) {
+                        String name = urlToName(s, i, holder.mView.getResources());
+                        requestInterface.request(name, s);
+                    }
+                });
+            } else {
+                holder.mTagGroup.setVisibility(View.GONE);
+            }
+            holder.mNotes.setText(item.getBody());
+        }
+    }
+
+    private String urlToName(String url, int index, Resources res) {
+
+        try {
+            return URLDecoder.decode(Regex.regex("/([^/]*)$", url), "UTF-8");
+        } catch (NoSuchFieldException e) {
+            e.printStackTrace();
+            return res.getString(R.string.attachment_nr, index);
+        } catch (UnsupportedEncodingException e) {
+            e.printStackTrace();
+            return res.getString(R.string.attachment_nr, index);
+        }
+    }
+
+    @Override
+    public int getItemCount() {
+        if (mModule != null && mModule.announcements != null)
+            return Math.max(mModule.announcements.size(), 1);
+        else
+            return 0;
+    }
+
+    @Override
+    public int getItemViewType(int position) {
+        if (mModule != null && mModule.announcements != null && mModule.announcements.size() == 0)
+            return 1;
+        else
+            return 0;
+    }
+
+    private Announcement getAnnouncement(int index) {
+        if (mModule != null && mModule.announcements != null)
+            return mModule.announcements.get(index);
+        else
+            return null;
+    }
 }

app/src/main/java/de/sebse/fuplanner/fragments/moddetails/ModDetailAnnounceFragment.java

@@ -1,19 +1,22 @@
 package de.sebse.fuplanner.fragments.moddetails;
 
 
+import android.content.Context;
 import android.os.Bundle;
-import android.support.annotation.NonNull;
-import android.support.v4.app.Fragment;
-import android.support.v4.widget.SwipeRefreshLayout;
 import android.view.LayoutInflater;
 import android.view.View;
 import android.view.ViewGroup;
-import android.widget.ExpandableListView;
 
+import androidx.annotation.NonNull;
+import androidx.annotation.Nullable;
+import androidx.fragment.app.Fragment;
+import androidx.recyclerview.widget.RecyclerView;
+import androidx.swiperefreshlayout.widget.SwipeRefreshLayout;
 import de.sebse.fuplanner.MainActivity;
 import de.sebse.fuplanner.R;
-import de.sebse.fuplanner.services.KVV.KVV;
+import de.sebse.fuplanner.services.KVV.ui.Download;
 import de.sebse.fuplanner.services.KVV.types.Modules;
+import de.sebse.fuplanner.tools.MainActivityListener;
 import de.sebse.fuplanner.tools.logging.Logger;
 
 /**
@@ -21,13 +24,15 @@ import de.sebse.fuplanner.tools.logging.Logger;
  * Use the {@link ModDetailAnnounceFragment#newInstance} factory method to
  * create an instance of this fragment.
  */
-public class ModDetailAnnounceFragment extends Fragment {
+public class ModDetailAnnounceFragment extends Fragment implements Download.OnDownloadRequestInterface {
     private static final String ARG_POSITION = "itemPosition";
 
     private String mItemPos;
     private final Logger log = new Logger(this);
     private ModDetailAnnounceAdapter adapter;
     private SwipeRefreshLayout swipeLayout;
+    private Download download;
+    @Nullable private MainActivityListener mListener;
 
 
     public ModDetailAnnounceFragment() {
@@ -61,10 +66,10 @@ public class ModDetailAnnounceFragment extends Fragment {
     public View onCreateView(@NonNull LayoutInflater inflater, ViewGroup container,
                              Bundle savedInstanceState) {
         // Inflate the layout for this fragment
-        View view = inflater.inflate(R.layout.fragment_expandable_list_view, container, false);
+        View view = inflater.inflate(R.layout.fragment_recycler_view, container, false);
         // Set the adapter
-        ExpandableListView expandableListView = view.findViewById(R.id.list);
-        adapter = new ModDetailAnnounceAdapter();
+        RecyclerView expandableListView = view.findViewById(R.id.list);
+        adapter = new ModDetailAnnounceAdapter(this);
         expandableListView.setAdapter(adapter);
 
         // Getting SwipeContainerLayout
@@ -77,22 +82,50 @@ public class ModDetailAnnounceFragment extends Fragment {
     }
 
     private void refresh(boolean forceRefresh) {
-        if (getActivity() != null) {
-            KVV kvv = ((MainActivity) getActivity()).getKVV();
-            kvv.getModule(mItemPos, (Modules.Module module) -> {
-                adapter.setModule(module);
-                kvv.getModuleAnnouncements(module, success1 -> {
-                    adapter.setModule();
-                    swipeLayout.setRefreshing(false);
-                }, error -> {
-                    swipeLayout.setRefreshing(false);
-                    log.e(error);
-                }, forceRefresh);
-            }, error -> {
-                swipeLayout.setRefreshing(false);
-                log.e(error);
-            }, forceRefresh);
+        if (mListener == null)
+            return;
+        mListener.getKVV().modules().announcements().recv(mItemPos, success -> {
+            adapter.setModule(success);
+            swipeLayout.setRefreshing(false);
+        }, error -> {
+            swipeLayout.setRefreshing(false);
+            log.e(error);
+        }, forceRefresh);
+    }
+
+    @Override
+    public void request(String title, String url) {
+        if (mListener == null)
+            return;
+        mListener.getKVV().modules().list().find(mItemPos, (Modules.Module module) -> {
+            String folderName = "FU-"+module.title.replaceAll("[:*<>|/\"\\\\]", "-");
+            folderName += "/Assignment";
+            getDownload().openDownloadDialog(title, url, folderName);
+        }, log::e);
+    }
+
+    @Override
+    public void onAttach(Context context) {
+        super.onAttach(context);
+        if (context instanceof MainActivityListener) {
+            this.mListener = ((MainActivityListener) context);
+            this.mListener.addRequestPermissionsResultListener(getDownload().getRequestPermissionsResultListener(), "ModDetailAnnounceFragment");
+        } else
+            throw new RuntimeException(context.toString() + " must implement MainActivityListener");
+    }
+
+    @Override
+    public void onDetach() {
+        super.onDetach();
+        if (this.mListener != null) {
+            this.mListener.removeRequestPermissionsResultListener("ModDetailAnnounceFragment");
+            this.mListener = null;
         }
     }
 
+    Download getDownload() {
+        if (download == null)
+            download = new Download(this::getContext, () -> (MainActivity) getActivity());
+        return download;
+    }
 }

app/src/main/java/de/sebse/fuplanner/fragments/moddetails/ModDetailAssignmentAdapter.java

@@ -1,110 +1,38 @@
 package de.sebse.fuplanner.fragments.moddetails;
 
+import android.content.res.Resources;
 import android.view.LayoutInflater;
 import android.view.View;
 import android.view.ViewGroup;
-import android.widget.BaseExpandableListAdapter;
 
+import com.cunoraz.tagview.Tag;
+
+import java.io.UnsupportedEncodingException;
+import java.net.URLDecoder;
+import java.util.List;
+
+import androidx.annotation.NonNull;
+import androidx.annotation.Nullable;
+import androidx.core.content.ContextCompat;
+import androidx.recyclerview.widget.RecyclerView;
 import de.sebse.fuplanner.R;
+import de.sebse.fuplanner.services.KVV.ui.Download;
 import de.sebse.fuplanner.services.KVV.types.Assignment;
 import de.sebse.fuplanner.services.KVV.types.Modules;
-import de.sebse.fuplanner.tools.DateUtils;
-import de.sebse.fuplanner.tools.ui.ItemViewHolder;
-import de.sebse.fuplanner.tools.ui.StringViewHolder;
+import de.sebse.fuplanner.tools.Regex;
+import de.sebse.fuplanner.tools.UtilsDate;
+import de.sebse.fuplanner.tools.logging.Logger;
+import de.sebse.fuplanner.tools.ui.AnnouncementViewHolder;
+import de.sebse.fuplanner.tools.ui.CustomViewHolder;
 
-class ModDetailAssignmentAdapter extends BaseExpandableListAdapter {
+class ModDetailAssignmentAdapter extends RecyclerView.Adapter<CustomViewHolder> {
 
-    private Modules.Module mModule = null;
+    @Nullable private Modules.Module mModule = null;
+    private Logger log = new Logger(this);
+    @NonNull private Download.OnDownloadRequestInterface requestInterface;
 
-    @Override
-    public String getChild(int groupPosition, int childPosititon) {
-        StringBuilder sb = new StringBuilder();
-        sb.append(this.getGroup(groupPosition).getInstructions());
-        sb.append("\n\n");
-        for (String s : this.getGroup(groupPosition).getUrls())
-        {
-            sb.append(s);
-            sb.append("\n\n");
-        }
-        return sb.toString();
-    }
-
-    @Override
-    public long getChildId(int groupPosition, int childPosition) {
-        return childPosition;
-    }
-
-    @Override
-    public View getChildView(int groupPosition, final int childPosition,
-                             boolean isLastChild, View convertView, ViewGroup parent) {
-
-        final String childText = getChild(groupPosition, childPosition);
-
-        if (convertView == null) {
-            convertView = LayoutInflater.from(parent.getContext())
-                    .inflate(R.layout.list_all_string, parent, false);
-        }
-
-        StringViewHolder itemHolder = new StringViewHolder(convertView);
-        itemHolder.mString.setText(childText);
-
-        return convertView;
-    }
-
-    @Override
-    public int getChildrenCount(int groupPosition) {
-        return 1;
-    }
-
-    @Override
-    public Assignment getGroup(int groupPosition) {
-        if (this.mModule != null && this.mModule.assignments != null)
-            return this.mModule.assignments.get(groupPosition);
-        else
-            return null;
-    }
-
-    @Override
-    public int getGroupCount() {
-        if (this.mModule != null && this.mModule.assignments != null)
-            return this.mModule.assignments.size();
-        else
-            return 0;
-    }
-
-    @Override
-    public long getGroupId(int groupPosition) {
-        return groupPosition;
-    }
-
-    @Override
-    public View getGroupView(int groupPosition, boolean isExpanded,
-                             View convertView, ViewGroup parent) {
-        Assignment assignment = getGroup(groupPosition);
-        if (convertView == null) {
-            convertView = LayoutInflater.from(parent.getContext())
-                    .inflate(R.layout.list_all_items, parent, false);
-        }
-
-        ItemViewHolder itemHolder = new ItemViewHolder(convertView);
-        itemHolder.mTitle.setText(assignment.getTitle());
-        if(assignment.isOpen())
-            itemHolder.mSubLeft.setText(itemHolder.mView.getResources().getText(R.string.open));
-        else
-            itemHolder.mSubLeft.setText(itemHolder.mView.getResources().getText(R.string.closed));
-        itemHolder.mSubRight.setText(DateUtils.getModifiedDateTime(parent.getContext(), assignment.getDueDate()));
-
-        return convertView;
-    }
-
-    @Override
-    public boolean hasStableIds() {
-        return false;
-    }
-
-    @Override
-    public boolean isChildSelectable(int groupPosition, int childPosition) {
-        return false;
+    ModDetailAssignmentAdapter(@NonNull Download.OnDownloadRequestInterface requestInterface) {
+        this.requestInterface = requestInterface;
     }
 
     public void setModule(Modules.Module module) {
@@ -115,4 +43,87 @@ class ModDetailAssignmentAdapter extends BaseExpandableListAdapter {
     public void setModule() {
         this.notifyDataSetChanged();
     }
+
+    @NonNull
+    public CustomViewHolder onCreateViewHolder(@NonNull ViewGroup viewGroup, int viewType) {
+        if (viewType == 0) {
+            View view = LayoutInflater.from(viewGroup.getContext())
+                    .inflate(R.layout.list_announcement_items, viewGroup, false);
+            return new AnnouncementViewHolder(view);
+        } else {
+            View view = LayoutInflater.from(viewGroup.getContext())
+                    .inflate(R.layout.list_all_no_items, viewGroup, false);
+            return new CustomViewHolder(view);
+        }
+    }
+
+    @Override
+    public void onBindViewHolder(@NonNull CustomViewHolder customHolder, int position) {
+        if (customHolder instanceof AnnouncementViewHolder) {
+            AnnouncementViewHolder holder = (AnnouncementViewHolder) customHolder;
+            holder.reset();
+            Assignment item = getAssignment(position);
+            holder.mTitle.setText(item.getTitle());
+            holder.mSubTitle.setText(UtilsDate.getModifiedDateTime(holder.mView.getContext(), item.getDueDate()));
+            holder.mTagGroup.removeAll();
+
+            List<String> notes = item.getUrls();
+            if (!notes.isEmpty()) {
+                holder.mTagGroup.setVisibility(View.VISIBLE);
+                for (int i = 0, notesSize = notes.size(); i < notesSize; i++) {
+                    String name = urlToName(notes.get(i), i, holder.mView.getResources());
+                    Tag tag = new Tag(name);
+                    tag.id = i;
+                    tag.layoutColor = ContextCompat.getColor(holder.mView.getContext(), R.color.colorFUBlue);
+                    holder.mTagGroup.addTag(tag);
+                }
+                holder.mTagGroup.setOnTagClickListener((tag, i) -> {
+                    String s = notes.get(i);
+                    if (s != null) {
+                        String name = urlToName(s, i, holder.mView.getResources());
+                        requestInterface.request(name, s);
+                    }
+                });
+            } else {
+                holder.mTagGroup.setVisibility(View.GONE);
+            }
+            holder.mNotes.setText(item.getInstructions());
+        }
+    }
+
+    private String urlToName(String url, int index, Resources res) {
+
+        try {
+            return URLDecoder.decode(Regex.regex("/([^/]*)$", url), "UTF-8");
+        } catch (NoSuchFieldException e) {
+            e.printStackTrace();
+            return res.getString(R.string.attachment_nr, index);
+        } catch (UnsupportedEncodingException e) {
+            e.printStackTrace();
+            return res.getString(R.string.attachment_nr, index);
+        }
+    }
+
+    @Override
+    public int getItemCount() {
+        if (mModule != null && mModule.assignments != null)
+            return Math.max(mModule.assignments.size(), 1);
+        else
+            return 0;
+    }
+
+    @Override
+    public int getItemViewType(int position) {
+        if (mModule != null && mModule.assignments != null && mModule.assignments.size() == 0)
+            return 1;
+        else
+            return 0;
+    }
+
+    private Assignment getAssignment(int index) {
+        if (mModule != null && mModule.assignments != null)
+            return mModule.assignments.get(index);
+        else
+            return null;
+    }
 }

app/src/main/java/de/sebse/fuplanner/fragments/moddetails/ModDetailAssignmentFragment.java

@@ -1,19 +1,22 @@
 package de.sebse.fuplanner.fragments.moddetails;
 
 
+import android.content.Context;
 import android.os.Bundle;
-import android.support.annotation.NonNull;
-import android.support.v4.app.Fragment;
-import android.support.v4.widget.SwipeRefreshLayout;
 import android.view.LayoutInflater;
 import android.view.View;
 import android.view.ViewGroup;
-import android.widget.ExpandableListView;
 
+import androidx.annotation.NonNull;
+import androidx.annotation.Nullable;
+import androidx.fragment.app.Fragment;
+import androidx.recyclerview.widget.RecyclerView;
+import androidx.swiperefreshlayout.widget.SwipeRefreshLayout;
 import de.sebse.fuplanner.MainActivity;
 import de.sebse.fuplanner.R;
-import de.sebse.fuplanner.services.KVV.KVV;
+import de.sebse.fuplanner.services.KVV.ui.Download;
 import de.sebse.fuplanner.services.KVV.types.Modules;
+import de.sebse.fuplanner.tools.MainActivityListener;
 import de.sebse.fuplanner.tools.logging.Logger;
 
 /**
@@ -21,13 +24,15 @@ import de.sebse.fuplanner.tools.logging.Logger;
  * Use the {@link ModDetailAssignmentFragment#newInstance} factory method to
  * create an instance of this fragment.
  */
-public class ModDetailAssignmentFragment extends Fragment {
+public class ModDetailAssignmentFragment extends Fragment implements Download.OnDownloadRequestInterface {
     private static final String ARG_POSITION = "itemPosition";
 
     private String mItemPos;
     private final Logger log = new Logger(this);
     private ModDetailAssignmentAdapter adapter;
     private SwipeRefreshLayout swipeLayout;
+    private Download download;
+    @Nullable private MainActivityListener mListener;
 
 
     public ModDetailAssignmentFragment() {
@@ -61,10 +66,10 @@ public class ModDetailAssignmentFragment extends Fragment {
     public View onCreateView(@NonNull LayoutInflater inflater, ViewGroup container,
                              Bundle savedInstanceState) {
         // Inflate the layout for this fragment
-        View view = inflater.inflate(R.layout.fragment_expandable_list_view, container, false);
+        View view = inflater.inflate(R.layout.fragment_recycler_view, container, false);
         // Set the adapter
-        ExpandableListView expandableListView = view.findViewById(R.id.list);
-        adapter = new ModDetailAssignmentAdapter();
+        RecyclerView expandableListView = view.findViewById(R.id.list);
+        adapter = new ModDetailAssignmentAdapter(this);
         expandableListView.setAdapter(adapter);
 
         // Getting SwipeContainerLayout
@@ -77,22 +82,51 @@ public class ModDetailAssignmentFragment extends Fragment {
     }
 
     private void refresh(boolean forceRefresh) {
-        if (getActivity() != null) {
-            KVV kvv = ((MainActivity) getActivity()).getKVV();
-            kvv.getModule(mItemPos, (Modules.Module module) -> {
-                adapter.setModule(module);
-                kvv.getModuleAssignments(module, success1 -> {
-                    adapter.setModule();
-                    swipeLayout.setRefreshing(false);
-                }, error -> {
-                    swipeLayout.setRefreshing(false);
-                    log.e(error);
-                }, forceRefresh);
-            }, error -> {
-                swipeLayout.setRefreshing(false);
-                log.e(error);
-            }, forceRefresh);
+        if (mListener == null)
+            return;
+        mListener.getKVV().modules().assignments().recv(mItemPos, success -> {
+            adapter.setModule(success);
+            swipeLayout.setRefreshing(false);
+        }, error -> {
+            swipeLayout.setRefreshing(false);
+            log.e(error);
+        }, forceRefresh);
+    }
+
+    @Override
+    public void request(String title, String url) {
+        log.d(title, url, mListener);
+        if (mListener == null)
+            return;
+        mListener.getKVV().modules().list().find(mItemPos, (Modules.Module module) -> {
+            String folderName = "FU-"+module.title.replaceAll("[:*<>|/\"\\\\]", "-");
+            folderName += "/Assignment";
+            getDownload().openDownloadDialog(title, url, folderName);
+        }, log::e);
+    }
+
+    @Override
+    public void onAttach(Context context) {
+        super.onAttach(context);
+        if (context instanceof MainActivityListener) {
+            this.mListener = ((MainActivityListener) context);
+            this.mListener.addRequestPermissionsResultListener(getDownload().getRequestPermissionsResultListener(), "ModDetailAssignmentFragment");
+        } else
+            throw new RuntimeException(context.toString() + " must implement MainActivityListener");
+    }
+
+    @Override
+    public void onDetach() {
+        super.onDetach();
+        if (this.mListener != null) {
+            this.mListener.removeRequestPermissionsResultListener("ModDetailAssignmentFragment");
+            this.mListener = null;
         }
     }
 
+    Download getDownload() {
+        if (download == null)
+            download = new Download(this::getContext, () -> (MainActivity) getActivity());
+        return download;
+    }
 }

app/src/main/java/de/sebse/fuplanner/fragments/moddetails/ModDetailEventAdapter.java

@@ -1,31 +1,43 @@
 package de.sebse.fuplanner.fragments.moddetails;
 
-import android.support.annotation.NonNull;
-import android.support.v7.widget.RecyclerView;
-import android.util.Pair;
+import android.content.res.Resources;
 import android.view.LayoutInflater;
 import android.view.View;
 import android.view.ViewGroup;
-import android.widget.TextView;
 
 import java.util.ArrayList;
+import java.util.LinkedHashMap;
+import java.util.Map;
 
+import androidx.annotation.NonNull;
+import androidx.recyclerview.widget.RecyclerView;
 import de.sebse.fuplanner.R;
 import de.sebse.fuplanner.services.KVV.types.Event;
+import de.sebse.fuplanner.services.KVV.types.EventList;
+import de.sebse.fuplanner.services.KVV.types.GroupedEvents;
 import de.sebse.fuplanner.services.KVV.types.Modules;
-import de.sebse.fuplanner.tools.DateUtils;
+import de.sebse.fuplanner.tools.Triplet;
+import de.sebse.fuplanner.tools.logging.Logger;
 import de.sebse.fuplanner.tools.ui.CustomViewHolder;
-import de.sebse.fuplanner.tools.ui.ItemViewHolder;
+import de.sebse.fuplanner.tools.ui.ListViewHolder;
 
-class ModDetailEventAdapter extends RecyclerView.Adapter<RecyclerView.ViewHolder> {
-    private static final int TYPE_HEADER = 0;
-    private static final int TYPE_ITEM = 1;
+class ModDetailEventAdapter extends RecyclerView.Adapter<CustomViewHolder> {
+    private static final String VALUE_LECTURE = "Class section - Lecture";
+    private static final String VALUE_TUTORIAL = "Class section - Small Group";
+    private static final String VALUE_EXAM = "Exam";
+    private static final String VALUE_DEADLINE = "Deadline";
+    private static final String VALUE_OTHER = "Other";
+    private static final String[] VALUES_GROUPED = {VALUE_LECTURE, VALUE_TUTORIAL};
+    private static final String[] VALUES_UNGROUPED = {VALUE_EXAM, VALUE_DEADLINE};
 
-    private static final int SECTION_UPCOMING = 0;
-    private static final int SECTION_PAST = 1;
+    private static final int TYPE_NONE = 0;
+    private static final int TYPE_GROUPED = 1;
+    private static final int TYPE_UNGROUPED = 2;
 
     private Modules.Module mValue;
-    private final ArrayList<Pair<Integer, Integer>> mPositionalData;
+    private final ArrayList<Triplet<Integer, String, Object>> mPositionalData;
+
+    private final Logger log = new Logger(this);
 
     ModDetailEventAdapter() {
         mValue = null;
@@ -39,36 +51,55 @@ class ModDetailEventAdapter extends RecyclerView.Adapter<RecyclerView.ViewHolder
     }
 
     public void setModule() {
-        mPositionalData.clear();
-        addPositionalListData(getUpcomingEventsCount(), SECTION_UPCOMING);
-        mPositionalData.add(new Pair<>(TYPE_HEADER, SECTION_PAST));
-        addPositionalListData(getPastEventsCount(), SECTION_PAST);
-
-        this.notifyDataSetChanged();
-    }
-
-    private void addPositionalListData(int count, int category) {
-        for (int i = 0; i < count; i++) {
-            mPositionalData.add(new Pair<>(TYPE_ITEM, category+1024*i));
+        LinkedHashMap<String, GroupedEvents> listsGrouped = new LinkedHashMap<>();
+        LinkedHashMap<String, EventList> listsUngrouped = new LinkedHashMap<>();
+        for (String value : VALUES_GROUPED) listsGrouped.put(value, new GroupedEvents());
+        for (String value : VALUES_UNGROUPED) listsUngrouped.put(value, new EventList());
+        listsUngrouped.put(VALUE_OTHER, new EventList());
+        for (int i = 0; i < getEventsCount(); i++) {
+            assert mValue.events != null;
+            Event event = mValue.events.get(i);
+            String type = event.getType();
+            GroupedEvents groupedEvents = listsGrouped.get(type);
+            if (groupedEvents != null) {
+                groupedEvents.add(event);
+            } else {
+                EventList ungroupedEvents = listsUngrouped.get(type);
+                if (ungroupedEvents == null) {
+                    ungroupedEvents = listsUngrouped.get(VALUE_OTHER);
+                }
+                assert ungroupedEvents != null;
+                ungroupedEvents.add(event);
+            }
         }
+
+        mPositionalData.clear();
+        for (Map.Entry<String, GroupedEvents> value: listsGrouped.entrySet()) {
+            if (value.getValue().getGroups().size() > 0)
+                mPositionalData.add(new Triplet<>(TYPE_GROUPED, value.getKey(), value.getValue()));
+        }
+        for (Map.Entry<String, EventList> value: listsUngrouped.entrySet()) {
+            if (value.getValue().size() > 0)
+                mPositionalData.add(new Triplet<>(TYPE_UNGROUPED, value.getKey(), value.getValue()));
+        }
+        if (mPositionalData.size() == 0)
+            mPositionalData.add(new Triplet<>(TYPE_NONE, null, null));
+        this.notifyDataSetChanged();
     }
 
     @NonNull
     @Override
-    public RecyclerView.ViewHolder onCreateViewHolder(@NonNull ViewGroup parent, int viewType) {
+    public CustomViewHolder onCreateViewHolder(@NonNull ViewGroup parent, int viewType) {
         View view;
         switch (viewType) {
-            case TYPE_HEADER:
+            case TYPE_NONE:
                 view = LayoutInflater.from(parent.getContext())
-                        .inflate(R.layout.list_all_caption, parent, false);
-                return new HeaderViewHolder(view);
-            case TYPE_ITEM:
-                view = LayoutInflater.from(parent.getContext())
-                        .inflate(R.layout.list_all_items, parent, false);
-                return new ItemViewHolder(view);
+                        .inflate(R.layout.list_all_no_items, parent, false);
+                return new CustomViewHolder(view);
             default:
-                //noinspection ConstantConditions
-                return null;
+                view = LayoutInflater.from(parent.getContext())
+                        .inflate(R.layout.list_all_cardview_list, parent, false);
+                return new ListViewHolder(view);
         }
     }
 
@@ -81,51 +112,46 @@ class ModDetailEventAdapter extends RecyclerView.Adapter<RecyclerView.ViewHolder
     }
 
     @Override
-    public void onBindViewHolder(@NonNull final RecyclerView.ViewHolder holder, int position) {
+    public void onBindViewHolder(@NonNull final CustomViewHolder holder, int position) {
         if (mValue == null || position > mPositionalData.size())
             return;
-        Pair<Integer, Integer> data = mPositionalData.get(position);
-        switch (data.first) {
-            case TYPE_HEADER:
-                HeaderViewHolder h = (HeaderViewHolder) holder;
-                switch (data.second) {
-                    case SECTION_PAST:
-                        h.mCaption.setText(R.string.past_events);
-                        break;
-                    case SECTION_UPCOMING:
-                        h.mCaption.setText(R.string.upcoming_events);
-                        break;
-                }
-                break;
-            case TYPE_ITEM:
-                int section = data.second % 1024;
-                int index = data.second / 1024;
-                ItemViewHolder i = (ItemViewHolder) holder;
-                Event event = null;
-                switch (section) {
-                    case SECTION_UPCOMING:
-                        event = mValue.events.getUpcoming(index);
-                        break;
-                    case SECTION_PAST:
-                        event = mValue.events.getPast(index);
-                        break;
-                }
-                //noinspection ConstantConditions
-                i.mTitle.setText(event.getTitle());
-                i.mSubLeft.setText(event.getType());
-                String start, end;
-                if (DateUtils.dateEquals(event.getStartDate(), System.currentTimeMillis()))
-                    start = DateUtils.getModifiedTime(i.mView.getContext(), event.getStartDate());
-                else
-                    start = DateUtils.getModifiedDateTime(i.mView.getContext(), event.getStartDate());
-                if (DateUtils.dateEquals(event.getStartDate(), event.getEndDate()))
-                    end = DateUtils.getModifiedTime(i.mView.getContext(), event.getEndDate());
-                else
-                    end = DateUtils.getModifiedDateTime(i.mView.getContext(), event.getEndDate());
-                i.mSubRight.setText(i.mView.getResources().getString(R.string.date_scale,
-                        start, end
-                ));
-                break;
+        Triplet<Integer, String, Object> data = mPositionalData.get(position);
+        if (data.first != TYPE_NONE) {
+            ListViewHolder h;
+            ModDetailEventAdapterInner adapter;
+            h = (ListViewHolder) holder;
+            Resources resources = h.mView.getResources();
+            adapter = new ModDetailEventAdapterInner();
+            String title;
+            switch (data.second) {
+                case VALUE_LECTURE:
+                    title = resources.getString(R.string.lecture);
+                    break;
+                case VALUE_TUTORIAL:
+                    title = resources.getString(R.string.tutorial);
+                    break;
+                case VALUE_EXAM:
+                    title = resources.getString(R.string.exam);
+                    break;
+                case VALUE_DEADLINE:
+                    title = resources.getString(R.string.deadline);
+                    break;
+                case VALUE_OTHER:
+                    title = resources.getString(R.string.others);
+                    break;
+                default:
+                    title = data.second;
+            }
+            h.mString.setText(title);
+            switch (data.first) {
+                case TYPE_GROUPED:
+                    adapter.setData((GroupedEvents) data.third, h.mView.getContext());
+                    break;
+                case TYPE_UNGROUPED:
+                    adapter.setData((EventList) data.third, h.mView.getContext());
+                    break;
+            }
+            h.mList.setAdapter(adapter);
         }
     }
 
@@ -134,38 +160,9 @@ class ModDetailEventAdapter extends RecyclerView.Adapter<RecyclerView.ViewHolder
         return mPositionalData.size();
     }
 
-    private int getUpcomingEventsCount() {
+    private int getEventsCount() {
         if (mValue.events != null)
-            return mValue.events.sizeUpcoming();
+            return mValue.events.size();
         return 0;
     }
-
-    private int getPastEventsCount() {
-        if (mValue.events != null)
-            return mValue.events.sizePast();
-        return 0;
-    }
-
-
-
-
-
-
-
-
-    class HeaderViewHolder extends CustomViewHolder {
-        final TextView mCaption;
-
-        HeaderViewHolder(View view) {
-            super(view);
-            mCaption = view.findViewById(R.id.caption);
-        }
-
-        @Override
-        public String toString() {
-            return super.toString() + " '" + mCaption.getText() + "'";
-        }
-    }
-
-
 }

app/src/main/java/de/sebse/fuplanner/fragments/moddetails/ModDetailEventAdapterInner.java

@@ -0,0 +1,104 @@
+package de.sebse.fuplanner.fragments.moddetails;
+
+import android.content.Context;
+import android.view.LayoutInflater;
+import android.view.View;
+import android.view.ViewGroup;
+
+import java.util.ArrayList;
+
+import androidx.annotation.NonNull;
+import androidx.recyclerview.widget.RecyclerView;
+import de.sebse.fuplanner.R;
+import de.sebse.fuplanner.services.KVV.types.Event;
+import de.sebse.fuplanner.services.KVV.types.EventList;
+import de.sebse.fuplanner.services.KVV.types.GroupedEvents;
+import de.sebse.fuplanner.tools.UtilsDate;
+import de.sebse.fuplanner.tools.ui.ItemViewHolder;
+
+class ModDetailEventAdapterInner extends RecyclerView.Adapter<ItemViewHolder> {
+    private final ArrayList<Entry> mPositionalData;
+
+    ModDetailEventAdapterInner() {
+        mPositionalData = new ArrayList<>();
+    }
+
+    public void setData(GroupedEvents events, final Context context) {
+        mPositionalData.clear();
+        for (GroupedEvents.Group group : events.getGroups()) {
+            long firstDateTime = group.getFirstDate()+group.getStartTime();
+            long lastDateTime = group.getLastDate()+group.getStartTime()+group.getDuration();
+            String start, end, weekday, startTime, endTime;
+            StringBuilder excepts = null;
+            start = UtilsDate.getModifiedDate(firstDateTime);
+            end = UtilsDate.getModifiedDate(lastDateTime);
+            weekday = UtilsDate.getModifiedDate(context, firstDateTime, "E");
+            startTime = UtilsDate.getModifiedTime(context, firstDateTime);
+            endTime = UtilsDate.getModifiedTime(context, lastDateTime);
+            for (long skippedDate : group.getSkippedDates()) {
+                if (excepts == null) {
+                    excepts = new StringBuilder(UtilsDate.getModifiedDate(skippedDate));
+                } else {
+                    excepts.append(", ").append(UtilsDate.getModifiedDate(skippedDate));
+                }
+            }
+            mPositionalData.add(new Entry(
+                    context.getString(R.string.event_scale, weekday, startTime, endTime),
+                    context.getString(R.string.date_scale, start, end),
+                    excepts != null ? context.getString(R.string.except_list, excepts.toString()) : ""));
+        }
+        this.notifyDataSetChanged();
+    }
+
+    public void setData(EventList events, final Context context) {
+        mPositionalData.clear();
+        for (Event event : events) {
+            String date;
+            String start, end;
+            if (UtilsDate.dateEquals(event.getStartDate(), System.currentTimeMillis()))
+                start = UtilsDate.getModifiedTime(context, event.getStartDate());
+            else
+                start = UtilsDate.getModifiedDateTime(context, event.getStartDate());
+            if (UtilsDate.dateEquals(event.getStartDate(), event.getEndDate()))
+                end = UtilsDate.getModifiedTime(context, event.getEndDate());
+            else
+                end = UtilsDate.getModifiedDateTime(context, event.getEndDate());
+            date = context.getString(R.string.date_scale, start, end);
+            mPositionalData.add(new Entry(event.getTitle(), date, ""));
+        }
+        this.notifyDataSetChanged();
+    }
+
+    @NonNull
+    @Override
+    public ItemViewHolder onCreateViewHolder(@NonNull ViewGroup parent, int viewType) {
+        View view;
+        view = LayoutInflater.from(parent.getContext())
+                .inflate(R.layout.list_all_items, parent, false);
+        return new ItemViewHolder(view);
+    }
+
+    @Override
+    public void onBindViewHolder(@NonNull final ItemViewHolder holder, int position) {
+        holder.mTitle.setText(mPositionalData.get(position).title);
+        holder.mSubLeft.setText(mPositionalData.get(position).subtitleLeft);
+        holder.mSubRight.setText(mPositionalData.get(position).subtitleRight);
+    }
+
+    @Override
+    public int getItemCount() {
+        return mPositionalData.size();
+    }
+
+    private class Entry {
+        private String title;
+        private String subtitleLeft;
+        private String subtitleRight;
+
+        private Entry(String title, String subtitleLeft, String subtitleRight) {
+            this.title = title;
+            this.subtitleLeft = subtitleLeft;
+            this.subtitleRight = subtitleRight;
+        }
+    }
+}

app/src/main/java/de/sebse/fuplanner/fragments/moddetails/ModDetailEventFragment.java

@@ -3,19 +3,18 @@ package de.sebse.fuplanner.fragments.moddetails;
 
 import android.content.Context;
 import android.os.Bundle;
-import android.support.annotation.NonNull;
-import android.support.v4.app.Fragment;
-import android.support.v4.widget.SwipeRefreshLayout;
-import android.support.v7.widget.LinearLayoutManager;
-import android.support.v7.widget.RecyclerView;
 import android.view.LayoutInflater;
 import android.view.View;
 import android.view.ViewGroup;
 
-import de.sebse.fuplanner.MainActivity;
+import androidx.annotation.NonNull;
+import androidx.annotation.Nullable;
+import androidx.fragment.app.Fragment;
+import androidx.recyclerview.widget.LinearLayoutManager;
+import androidx.recyclerview.widget.RecyclerView;
+import androidx.swiperefreshlayout.widget.SwipeRefreshLayout;
 import de.sebse.fuplanner.R;
-import de.sebse.fuplanner.services.KVV.KVV;
-import de.sebse.fuplanner.services.KVV.types.Modules;
+import de.sebse.fuplanner.tools.MainActivityListener;
 import de.sebse.fuplanner.tools.logging.Logger;
 
 /**
@@ -30,6 +29,7 @@ public class ModDetailEventFragment extends Fragment {
     private final Logger log = new Logger(this);
     private ModDetailEventAdapter adapter;
     private SwipeRefreshLayout swipeLayout;
+    @Nullable private MainActivityListener mListener;
 
 
     public ModDetailEventFragment() {
@@ -81,22 +81,31 @@ public class ModDetailEventFragment extends Fragment {
     }
 
     private void refresh(boolean forceRefresh) {
-        if (getActivity() != null) {
-            KVV kvv = ((MainActivity) getActivity()).getKVV();
-            kvv.getModule(mItemPos, (Modules.Module module) -> {
-                adapter.setModule(module);
-                kvv.getModuleEvents(module, success1 -> {
-                    adapter.setModule();
-                    swipeLayout.setRefreshing(false);
-                }, error -> {
-                    swipeLayout.setRefreshing(false);
-                    log.e(error);
-                }, forceRefresh);
-            }, error -> {
-                swipeLayout.setRefreshing(false);
-                log.e(error);
-            }, forceRefresh);
-        }
+        if (mListener == null)
+            return;
+        mListener.getKVV().modules().events().recv(mItemPos, success -> {
+            adapter.setModule(success);
+            swipeLayout.setRefreshing(false);
+        }, error -> {
+            swipeLayout.setRefreshing(false);
+            log.e(error);
+        }, forceRefresh);
     }
 
+    @Override
+    public void onAttach(Context context) {
+        super.onAttach(context);
+        if (context instanceof MainActivityListener) {
+            this.mListener = ((MainActivityListener) context);
+        } else
+            throw new RuntimeException(context.toString() + " must implement MainActivityListener");
+    }
+
+    @Override
+    public void onDetach() {
+        super.onDetach();
+        if (this.mListener != null) {
+            this.mListener = null;
+        }
+    }
 }

app/src/main/java/de/sebse/fuplanner/fragments/moddetails/ModDetailFragment.java

@@ -2,22 +2,22 @@ package de.sebse.fuplanner.fragments.moddetails;
 
 import android.content.Context;
 import android.os.Bundle;
-import android.support.annotation.NonNull;
-import android.support.v4.app.Fragment;
-import android.support.v4.view.ViewPager;
 import android.view.LayoutInflater;
 import android.view.View;
 import android.view.ViewGroup;
 
+import androidx.annotation.NonNull;
+import androidx.fragment.app.Fragment;
+import androidx.viewpager.widget.ViewPager;
 import de.sebse.fuplanner.R;
 import de.sebse.fuplanner.services.KVV.types.Modules;
-import de.sebse.fuplanner.tools.MainAcitivityListener;
+import de.sebse.fuplanner.tools.MainActivityListener;
 import de.sebse.fuplanner.tools.logging.Logger;
 
 /**
  * A simple {@link Fragment} subclass.
  * Activities that contain this fragment must implement the
- * {@link MainAcitivityListener} interface
+ * {@link MainActivityListener} interface
  * to handle interaction events.
  * Use the {@link ModDetailFragment#newInstance} factory method to
  * create an instance of this fragment.
@@ -28,9 +28,10 @@ public class ModDetailFragment extends Fragment implements ModDetailListener {
     // Parameters
     private String mItemPos;
 
-    private MainAcitivityListener mListener;
+    private MainActivityListener mListener;
     private final Logger log = new Logger(this);
     private ViewPager mViewPager;
+    private String mPageRestoreRequest = null;
 
     public ModDetailFragment() {
         // Required empty public constructor
@@ -46,7 +47,11 @@ public class ModDetailFragment extends Fragment implements ModDetailListener {
     public static Fragment newInstance(String itemPosition) {
         ModDetailFragment fragment = new ModDetailFragment();
         Bundle args = new Bundle();
-        args.putString(ARG_POSITION, itemPosition);
+        if (!itemPosition.contains("."))
+            args.putString(ARG_POSITION, itemPosition+"."+0);
+        else
+            args.putString(ARG_POSITION, itemPosition);
+
         fragment.setArguments(args);
         return fragment;
     }
@@ -55,11 +60,19 @@ public class ModDetailFragment extends Fragment implements ModDetailListener {
     public void onCreate(Bundle savedInstanceState) {
         super.onCreate(savedInstanceState);
         if (getArguments() != null) {
-            mItemPos = getArguments().getString(ARG_POSITION);
+            String itemPosition = getArguments().getString(ARG_POSITION);
+            if (!itemPosition.contains(".")) {
+                mItemPos = itemPosition;
+                mPageRestoreRequest = null;
+            } else {
+                String[] split = itemPosition.split("\\.", 2);
+                mItemPos = split[0];
+                mPageRestoreRequest = split[1];
+            }
         }
         if (mListener != null) {
             mListener.onTitleTextChange(R.string.courses);
-            mListener.getKVV().getModuleList(success -> {
+            mListener.getKVV().modules().list().recv(success -> {
                 Modules.Module module = success.get(mItemPos);
                 if (mListener != null && module != null)
                     mListener.onTitleTextChange(module.title);
@@ -76,14 +89,16 @@ public class ModDetailFragment extends Fragment implements ModDetailListener {
         mViewPager = v.findViewById(R.id.vpPager);
         ModDetailAdapter adapterViewPager = new ModDetailAdapter(getChildFragmentManager(), mItemPos, getContext());
         mViewPager.setAdapter(adapterViewPager);
+        if (mPageRestoreRequest != null)
+            mViewPager.setCurrentItem(Integer.parseInt(mPageRestoreRequest));
         return v;
     }
 
     @Override
     public void onAttach(Context context) {
         super.onAttach(context);
-        if (context instanceof MainAcitivityListener) {
-            mListener = (MainAcitivityListener) context;
+        if (context instanceof MainActivityListener) {
+            mListener = (MainActivityListener) context;
         } else {
             throw new RuntimeException(context.toString()
                     + " must implement MainActivityListener");
@@ -100,4 +115,8 @@ public class ModDetailFragment extends Fragment implements ModDetailListener {
     public void gotoFragmentPart(int part, int index) {
         mViewPager.setCurrentItem(ModulePart.getPageByPart(part), true);
     }
+
+    public String getData() {
+        return mItemPos+"."+mViewPager.getCurrentItem();
+    }
 }

app/src/main/java/de/sebse/fuplanner/fragments/moddetails/ModDetailGradebookAdapter.java

@@ -1,8 +1,6 @@
 package de.sebse.fuplanner.fragments.moddetails;
 
 import android.annotation.SuppressLint;
-import android.support.annotation.NonNull;
-import android.support.v7.widget.RecyclerView;
 import android.util.Pair;
 import android.view.LayoutInflater;
 import android.view.View;
@@ -11,10 +9,12 @@ import android.widget.TextView;
 
 import java.util.ArrayList;
 
+import androidx.annotation.NonNull;
+import androidx.recyclerview.widget.RecyclerView;
 import de.sebse.fuplanner.R;
-import de.sebse.fuplanner.services.KVV.types.Gradebook;
+import de.sebse.fuplanner.services.KVV.types.Grade;
 import de.sebse.fuplanner.services.KVV.types.Modules;
-import de.sebse.fuplanner.tools.ui.CustomViewHolder;
+import de.sebse.fuplanner.tools.ui.StringViewHolder;
 
 class ModDetailGradebookAdapter extends RecyclerView.Adapter<RecyclerView.ViewHolder> {
     private static final int TYPE_TOTAL = 0;
@@ -58,11 +58,11 @@ class ModDetailGradebookAdapter extends RecyclerView.Adapter<RecyclerView.ViewHo
             case TYPE_TOTAL:
                 view = LayoutInflater.from(parent.getContext())
                         .inflate(R.layout.list_all_caption, parent, false);
-                return new HeaderViewHolder(view);
+                return new StringViewHolder(view);
             case TYPE_GRADE:
                 view = LayoutInflater.from(parent.getContext())
-                        .inflate(R.layout.list_modetails_gradebook, parent, false);
-                return new GradebookViewHolder(view);
+                        .inflate(R.layout.list_moddetails_gradebook, parent, false);
+                return new GradeViewHolder(view);
             default:
                 //noinspection ConstantConditions
                 return null;
@@ -85,13 +85,13 @@ class ModDetailGradebookAdapter extends RecyclerView.Adapter<RecyclerView.ViewHo
         Pair<Integer, Integer> data = mPositionalData.get(position);
         switch (data.first) {
             case TYPE_TOTAL:
-                HeaderViewHolder h = (HeaderViewHolder) holder;
-                h.mCaption.setText(h.mView.getResources().getString(R.string.current_percentage, mValue.getGradebookPercent()*100));
+                StringViewHolder h = (StringViewHolder) holder;
+                h.mString.setText(h.mView.getResources().getString(R.string.current_percentage, mValue.getGradebookPercent()*100));
             break;
             case TYPE_GRADE:
                 int index = data.second / 1024;
-                GradebookViewHolder i = (GradebookViewHolder) holder;
-                Gradebook gradebook = mValue.gradebook.get(index);
+                GradeViewHolder i = (GradeViewHolder) holder;
+                Grade gradebook = mValue.gradebook.get(index);
 
                 i.mTitle.setText(gradebook.getItemName());
                 i.mGrade.setText(String.valueOf(gradebook.getPoints()));
@@ -118,27 +118,13 @@ class ModDetailGradebookAdapter extends RecyclerView.Adapter<RecyclerView.ViewHo
 
 
 
-    class HeaderViewHolder extends CustomViewHolder {
-        final TextView mCaption;
 
-        HeaderViewHolder(View view) {
-            super(view);
-            mCaption = view.findViewById(R.id.caption);
-        }
-
-        @Override
-        public String toString() {
-            return super.toString() + " '" + mCaption.getText() + "'";
-        }
-    }
-
-
-    private class GradebookViewHolder extends RecyclerView.ViewHolder {
+    private class GradeViewHolder extends RecyclerView.ViewHolder {
         private final TextView mGrade;
         private final TextView mGradeMax;
         private final TextView mTitle;
 
-        GradebookViewHolder(View view) {
+        GradeViewHolder(View view) {
             super(view);
             mTitle = view.findViewById(R.id.title);
             mGrade = view.findViewById(R.id.grade);

app/src/main/java/de/sebse/fuplanner/fragments/moddetails/ModDetailGradebookFragment.java

@@ -3,19 +3,18 @@ package de.sebse.fuplanner.fragments.moddetails;
 
 import android.content.Context;
 import android.os.Bundle;
-import android.support.annotation.NonNull;
-import android.support.v4.app.Fragment;
-import android.support.v4.widget.SwipeRefreshLayout;
-import android.support.v7.widget.LinearLayoutManager;
-import android.support.v7.widget.RecyclerView;
 import android.view.LayoutInflater;
 import android.view.View;
 import android.view.ViewGroup;
 
-import de.sebse.fuplanner.MainActivity;
+import androidx.annotation.NonNull;
+import androidx.annotation.Nullable;
+import androidx.fragment.app.Fragment;
+import androidx.recyclerview.widget.LinearLayoutManager;
+import androidx.recyclerview.widget.RecyclerView;
+import androidx.swiperefreshlayout.widget.SwipeRefreshLayout;
 import de.sebse.fuplanner.R;
-import de.sebse.fuplanner.services.KVV.KVV;
-import de.sebse.fuplanner.services.KVV.types.Modules;
+import de.sebse.fuplanner.tools.MainActivityListener;
 import de.sebse.fuplanner.tools.logging.Logger;
 
 /**
@@ -30,6 +29,7 @@ public class ModDetailGradebookFragment extends Fragment {
     private final Logger log = new Logger(this);
     private ModDetailGradebookAdapter adapter;
     private SwipeRefreshLayout swipeLayout;
+    @Nullable private MainActivityListener mListener;
 
 
     public ModDetailGradebookFragment() {
@@ -81,22 +81,31 @@ public class ModDetailGradebookFragment extends Fragment {
     }
 
     private void refresh(boolean forceRefresh) {
-        if (getActivity() != null) {
-            KVV kvv = ((MainActivity) getActivity()).getKVV();
-            kvv.getModule(mItemPos, (Modules.Module module) -> {
-                adapter.setModule(module);
-                kvv.getModuleGradebook(module, success1 -> {
-                    adapter.setModule();
-                    swipeLayout.setRefreshing(false);
-                }, error -> {
-                    swipeLayout.setRefreshing(false);
-                    log.e(error);
-                }, forceRefresh);
-            }, error -> {
-                swipeLayout.setRefreshing(false);
-                log.e(error);
-            }, forceRefresh);
-        }
+        if (mListener == null)
+            return;
+        mListener.getKVV().modules().gradebook().recv(mItemPos, success -> {
+            adapter.setModule(success);
+            swipeLayout.setRefreshing(false);
+        }, error -> {
+            swipeLayout.setRefreshing(false);
+            log.e(error);
+        }, forceRefresh);
     }
 
+    @Override
+    public void onAttach(Context context) {
+        super.onAttach(context);
+        if (context instanceof MainActivityListener) {
+            this.mListener = ((MainActivityListener) context);
+        } else
+            throw new RuntimeException(context.toString() + " must implement MainActivityListener");
+    }
+
+    @Override
+    public void onDetach() {
+        super.onDetach();
+        if (this.mListener != null) {
+            this.mListener = null;
+        }
+    }
 }

app/src/main/java/de/sebse/fuplanner/fragments/moddetails/ModDetailOverviewAdapter.java

@@ -1,27 +1,31 @@
 package de.sebse.fuplanner.fragments.moddetails;
 
-import android.support.annotation.NonNull;
-import android.support.annotation.Nullable;
-import android.support.v7.widget.RecyclerView;
+import android.content.Intent;
+import android.net.Uri;
 import android.util.Pair;
 import android.view.LayoutInflater;
 import android.view.View;
 import android.view.ViewGroup;
-import android.widget.TextView;
 
 import com.ms.square.android.expandabletextview.ExpandableTextView;
 
 import java.util.ArrayList;
 
+import androidx.annotation.NonNull;
+import androidx.annotation.Nullable;
+import androidx.recyclerview.widget.RecyclerView;
 import de.sebse.fuplanner.R;
 import de.sebse.fuplanner.services.KVV.types.Announcement;
 import de.sebse.fuplanner.services.KVV.types.Assignment;
 import de.sebse.fuplanner.services.KVV.types.Event;
+import de.sebse.fuplanner.services.KVV.types.Lecturer;
 import de.sebse.fuplanner.services.KVV.types.Modules;
-import de.sebse.fuplanner.tools.DateUtils;
+import de.sebse.fuplanner.tools.UtilsDate;
 import de.sebse.fuplanner.tools.logging.Logger;
 import de.sebse.fuplanner.tools.ui.CustomViewHolder;
 import de.sebse.fuplanner.tools.ui.ItemViewHolder;
+import de.sebse.fuplanner.tools.ui.MailViewHolder;
+import de.sebse.fuplanner.tools.ui.StringViewHolder;
 
 class ModDetailOverviewAdapter extends RecyclerView.Adapter<RecyclerView.ViewHolder> {
     private static final int MAX_ITEMS_PER_PREVIEW = 2;
@@ -30,6 +34,7 @@ class ModDetailOverviewAdapter extends RecyclerView.Adapter<RecyclerView.ViewHol
     private static final int TYPE_DESCRIPTION = 1;
     private static final int TYPE_ITEM = 2;
     private static final int TYPE_SHOW_MORE = 3;
+    private static final int TYPE_MAIL = 4;
 
     @Nullable private final ModDetailListener mListener;
 
@@ -52,6 +57,10 @@ class ModDetailOverviewAdapter extends RecyclerView.Adapter<RecyclerView.ViewHol
         mPositionalData.clear();
         mPositionalData.add(new Pair<>(TYPE_HEADER, ModulePart.DESCRIPTION));
         mPositionalData.add(new Pair<>(TYPE_DESCRIPTION, null));
+        mPositionalData.add(new Pair<>(TYPE_HEADER, ModulePart.LECTURERS));
+        for (int i = 0; i < mValue.lecturer.size(); i++) {
+            mPositionalData.add(new Pair<>(TYPE_MAIL, ModulePart.LECTURERS+1024*i));
+        }
         mPositionalData.add(new Pair<>(TYPE_HEADER, ModulePart.ANNOUNCEMENT));
         addPositionalListData(getAnnounceCount(), ModulePart.ANNOUNCEMENT);
         mPositionalData.add(new Pair<>(TYPE_HEADER, ModulePart.ASSIGNMENT));
@@ -77,7 +86,7 @@ class ModDetailOverviewAdapter extends RecyclerView.Adapter<RecyclerView.ViewHol
             case TYPE_HEADER:
                 view = LayoutInflater.from(parent.getContext())
                         .inflate(R.layout.list_all_caption, parent, false);
-                return new HeaderViewHolder(view);
+                return new StringViewHolder(view);
             case TYPE_DESCRIPTION:
                 view = LayoutInflater.from(parent.getContext())
                         .inflate(R.layout.list_moddetails_description, parent, false);
@@ -90,6 +99,10 @@ class ModDetailOverviewAdapter extends RecyclerView.Adapter<RecyclerView.ViewHol
                 view = LayoutInflater.from(parent.getContext())
                         .inflate(R.layout.list_all_show_more, parent, false);
                 return new CustomViewHolder(view);
+            case TYPE_MAIL:
+                view = LayoutInflater.from(parent.getContext())
+                        .inflate(R.layout.list_all_mails, parent, false);
+                return new MailViewHolder(view);
             default:
                 //noinspection ConstantConditions
                 return null;
@@ -111,19 +124,22 @@ class ModDetailOverviewAdapter extends RecyclerView.Adapter<RecyclerView.ViewHol
         Pair<Integer, Object> data = mPositionalData.get(position);
         switch (data.first) {
             case TYPE_HEADER:
-                HeaderViewHolder h = (HeaderViewHolder) holder;
+                StringViewHolder h = (StringViewHolder) holder;
                 switch ((Integer) data.second) {
                     case ModulePart.DESCRIPTION:
-                        h.mCaption.setText(R.string.description);
+                        h.mString.setText(R.string.description);
+                        break;
+                    case ModulePart.LECTURERS:
+                        h.mString.setText(h.mView.getResources().getString(R.string.lecturers));
                         break;
                     case ModulePart.ANNOUNCEMENT:
-                        h.mCaption.setText(h.mView.getResources().getString(R.string.announcements_count, getAnnounceCount()));
+                        h.mString.setText(h.mView.getResources().getString(R.string.announcements_count, getAnnounceCount()));
                         break;
                     case ModulePart.ASSIGNMENT:
-                        h.mCaption.setText(h.mView.getResources().getString(R.string.assignments_count, getAssignmentCount()));
+                        h.mString.setText(h.mView.getResources().getString(R.string.assignments_count, getAssignmentCount()));
                         break;
                     case ModulePart.EVENT:
-                        h.mCaption.setText(h.mView.getResources().getString(R.string.upcoming_events_count, getEventsCount()));
+                        h.mString.setText(h.mView.getResources().getString(R.string.upcoming_events_count, getEventsCount()));
                         break;
                 }
                 break;
@@ -141,7 +157,7 @@ class ModDetailOverviewAdapter extends RecyclerView.Adapter<RecyclerView.ViewHol
                         Announcement announce = mValue.announcements.get(index);
                         i.mTitle.setText(announce.getTitle());
                         i.mSubLeft.setText(announce.getCreatedBy());
-                        i.mSubRight.setText(DateUtils.getModifiedDateTime(i.mView.getContext(), announce.getCreatedOn()));
+                        i.mSubRight.setText(UtilsDate.getModifiedDateTime(i.mView.getContext(), announce.getCreatedOn()));
                         i.mView.setOnClickListener(view -> {
                             if (mListener != null) mListener.gotoFragmentPart(section, index);
                         });
@@ -154,7 +170,7 @@ class ModDetailOverviewAdapter extends RecyclerView.Adapter<RecyclerView.ViewHol
                             i.mSubLeft.setText(i.mView.getResources().getText(R.string.open));
                         else
                             i.mSubLeft.setText(i.mView.getResources().getText(R.string.closed));
-                        i.mSubRight.setText(DateUtils.getModifiedDateTime(i.mView.getContext(), assignment.getDueDate()));
+                        i.mSubRight.setText(UtilsDate.getModifiedDateTime(i.mView.getContext(), assignment.getDueDate()));
                         i.mView.setOnClickListener(view -> {
                             if (mListener != null) mListener.gotoFragmentPart(section, index);
                         });
@@ -165,14 +181,14 @@ class ModDetailOverviewAdapter extends RecyclerView.Adapter<RecyclerView.ViewHol
                         i.mTitle.setText(event.getTitle());
                         i.mSubLeft.setText(event.getType());
                         String start, end;
-                        if (DateUtils.dateEquals(event.getStartDate(), System.currentTimeMillis()))
-                            start = DateUtils.getModifiedTime(i.mView.getContext(), event.getStartDate());
+                        if (UtilsDate.dateEquals(event.getStartDate(), System.currentTimeMillis()))
+                            start = UtilsDate.getModifiedTime(i.mView.getContext(), event.getStartDate());
                         else
-                            start = DateUtils.getModifiedDateTime(i.mView.getContext(), event.getStartDate());
-                        if (DateUtils.dateEquals(event.getStartDate(), event.getEndDate()))
-                            end = DateUtils.getModifiedTime(i.mView.getContext(), event.getEndDate());
+                            start = UtilsDate.getModifiedDateTime(i.mView.getContext(), event.getStartDate());
+                        if (UtilsDate.dateEquals(event.getStartDate(), event.getEndDate()))
+                            end = UtilsDate.getModifiedTime(i.mView.getContext(), event.getEndDate());
                         else
-                            end = DateUtils.getModifiedDateTime(i.mView.getContext(), event.getEndDate());
+                            end = UtilsDate.getModifiedDateTime(i.mView.getContext(), event.getEndDate());
                         i.mSubRight.setText(i.mView.getResources().getString(R.string.date_scale,
                                 start, end
                                 ));
@@ -182,6 +198,26 @@ class ModDetailOverviewAdapter extends RecyclerView.Adapter<RecyclerView.ViewHol
                         break;
                 }
                 break;
+            case TYPE_MAIL:
+                section = ((Integer) data.second) % 1024;
+                index = ((Integer) data.second) / 1024;
+                MailViewHolder m = (MailViewHolder) holder;
+                switch (section) {
+                    case ModulePart.LECTURERS:
+                        Lecturer lecturer = mValue.lecturer.get(index);
+                        m.mTitle.setText(lecturer.getName());
+                        m.mSubLeft.setText(lecturer.getMail());
+                        m.mIcon.setOnClickListener(view -> {
+                            String defaultText = m.mView.getResources().getString(R.string.mail_default_text,
+                                    lecturer.getName());
+                            Intent emailIntent = new Intent(Intent.ACTION_SENDTO);
+                            emailIntent.setData(Uri.parse("mailto:"+lecturer.getMail()));
+                            emailIntent.putExtra(Intent.EXTRA_SUBJECT, mValue.title);
+                            emailIntent.putExtra(Intent.EXTRA_TEXT, defaultText);
+                            m.mView.getContext().startActivity(Intent.createChooser(emailIntent, mValue.title));
+                        });
+                        break;
+                }
             case TYPE_SHOW_MORE:
                 CustomViewHolder c = (CustomViewHolder) holder;
                 c.mView.setOnClickListener(view -> {
@@ -221,19 +257,7 @@ class ModDetailOverviewAdapter extends RecyclerView.Adapter<RecyclerView.ViewHol
 
 
 
-    class HeaderViewHolder extends CustomViewHolder {
-        final TextView mCaption;
 
-        HeaderViewHolder(View view) {
-            super(view);
-            mCaption = view.findViewById(R.id.caption);
-        }
-
-        @Override
-        public String toString() {
-            return super.toString() + " '" + mCaption.getText() + "'";
-        }
-    }
 
     class DescriptionViewHolder extends CustomViewHolder {
         final ExpandableTextView mText;
@@ -243,6 +267,7 @@ class ModDetailOverviewAdapter extends RecyclerView.Adapter<RecyclerView.ViewHol
             mText = view.findViewById(R.id.expand_text_view);//.findViewById(R.id.description);
         }
 
+        @NonNull
         @Override
         public String toString() {
             return super.toString() + " '" + mText.getText() + "'";

app/src/main/java/de/sebse/fuplanner/fragments/moddetails/ModDetailOverviewFragment.java

@@ -3,20 +3,18 @@ package de.sebse.fuplanner.fragments.moddetails;
 
 import android.content.Context;
 import android.os.Bundle;
-import android.support.annotation.NonNull;
-import android.support.annotation.Nullable;
-import android.support.v4.app.Fragment;
-import android.support.v4.widget.SwipeRefreshLayout;
-import android.support.v7.widget.LinearLayoutManager;
-import android.support.v7.widget.RecyclerView;
 import android.view.LayoutInflater;
 import android.view.View;
 import android.view.ViewGroup;
 
-import de.sebse.fuplanner.MainActivity;
+import androidx.annotation.NonNull;
+import androidx.annotation.Nullable;
+import androidx.fragment.app.Fragment;
+import androidx.recyclerview.widget.LinearLayoutManager;
+import androidx.recyclerview.widget.RecyclerView;
+import androidx.swiperefreshlayout.widget.SwipeRefreshLayout;
 import de.sebse.fuplanner.R;
-import de.sebse.fuplanner.services.KVV.KVV;
-import de.sebse.fuplanner.services.KVV.types.Modules;
+import de.sebse.fuplanner.tools.MainActivityListener;
 import de.sebse.fuplanner.tools.logging.Logger;
 
 /**
@@ -31,7 +29,8 @@ public class ModDetailOverviewFragment extends Fragment {
     private final Logger log = new Logger(this);
     private ModDetailOverviewAdapter adapter;
     private SwipeRefreshLayout swipeLayout;
-    @Nullable private ModDetailListener mListener;
+    @Nullable private ModDetailListener mDetailListener;
+    @Nullable private MainActivityListener mListener;
 
 
     public ModDetailOverviewFragment() {
@@ -70,7 +69,7 @@ public class ModDetailOverviewFragment extends Fragment {
         Context context = view.getContext();
         RecyclerView recyclerView = view.findViewById(R.id.list);
         recyclerView.setLayoutManager(new LinearLayoutManager(context));
-        adapter = new ModDetailOverviewAdapter(mListener);
+        adapter = new ModDetailOverviewAdapter(mDetailListener);
         recyclerView.setAdapter(adapter);
 
         // Getting SwipeContainerLayout
@@ -82,19 +81,15 @@ public class ModDetailOverviewFragment extends Fragment {
         return view;
     }
 
+
+
+
     private void refresh(boolean forceRefresh) {
-        if (getActivity() != null) {
-            KVV kvv = ((MainActivity) getActivity()).getKVV();
-            kvv.getModule(mItemPos, (Modules.Module module) -> {
-                adapter.setModule(module);
-                kvv.getModuleDetails(module, pair -> {
-                    adapter.setModule();
-                    if (pair.second)
-                        swipeLayout.setRefreshing(false);
-                }, error -> {
+        if (mListener != null) {
+            mListener.getKVV().modules().details().recv(mItemPos, pair -> {
+                adapter.setModule(pair.first);
+                if (pair.second)
                     swipeLayout.setRefreshing(false);
-                    log.e(error);
-                }, forceRefresh);
             }, error -> {
                 swipeLayout.setRefreshing(false);
                 log.e(error);
@@ -104,15 +99,27 @@ public class ModDetailOverviewFragment extends Fragment {
 
     @Override
     public void onAttach(Context context) {
+        super.onAttach(context);
+        if (context instanceof MainActivityListener) {
+            this.mListener = ((MainActivityListener) context);
+        } else
+            throw new RuntimeException(context.toString() + " must implement MainActivityListener");
+
+
         super.onAttach(context);
         Fragment parentFragment = getParentFragment();
         if (parentFragment != null) {
             if (parentFragment instanceof ModDetailListener) {
-                mListener = (ModDetailListener) parentFragment;
+                mDetailListener = (ModDetailListener) parentFragment;
             } else {
-                throw new RuntimeException(context.toString()
-                        + " must implement ModDetailListener");
+                throw new RuntimeException(context.toString() + " must implement ModDetailListener");
             }
         } else log.w("No parent fragment!");
     }
+
+    @Override
+    public void onDetach() {
+        super.onDetach();
+        this.mListener = null;
+    }
 }

app/src/main/java/de/sebse/fuplanner/fragments/moddetails/ModDetailResourceAdapter.java

@@ -0,0 +1,34 @@
+package de.sebse.fuplanner.fragments.moddetails;
+
+import java.util.ArrayList;
+import java.util.List;
+
+import de.sebse.fuplanner.services.KVV.types.Modules;
+import de.sebse.fuplanner.services.KVV.types.Resource;
+import de.sebse.fuplanner.tools.ui.treeview.TreeNode;
+import de.sebse.fuplanner.tools.ui.treeview.TreeViewAdapter;
+import de.sebse.fuplanner.tools.ui.treeview.TreeViewBinder;
+
+class ModDetailResourceAdapter extends TreeViewAdapter {
+    private Modules.Module mValue;
+    public ModDetailResourceAdapter(List<? extends TreeViewBinder> viewBinders) {
+        super(viewBinders);
+        mValue = null;
+    }
+
+    public void setModule(Modules.Module module) {
+        mValue = module;
+        this.setModule();
+    }
+
+    public void setModule() {
+        if (mValue == null || mValue.resources == null) {
+            return;
+        }
+        List<TreeNode> nodes = new ArrayList<>();
+        for (Resource res: mValue.resources) {
+            nodes.add(res.getTreeNode());
+        }
+        refresh(nodes);
+    }
+}

app/src/main/java/de/sebse/fuplanner/fragments/moddetails/ModDetailResourceFragment.java

@@ -0,0 +1,163 @@
+package de.sebse.fuplanner.fragments.moddetails;
+
+
+import android.content.Context;
+import android.os.Bundle;
+import android.view.LayoutInflater;
+import android.view.View;
+import android.view.ViewGroup;
+import android.widget.ImageView;
+
+import java.util.Arrays;
+
+import androidx.annotation.NonNull;
+import androidx.annotation.Nullable;
+import androidx.fragment.app.Fragment;
+import androidx.recyclerview.widget.LinearLayoutManager;
+import androidx.recyclerview.widget.RecyclerView;
+import androidx.swiperefreshlayout.widget.SwipeRefreshLayout;
+import de.sebse.fuplanner.MainActivity;
+import de.sebse.fuplanner.R;
+import de.sebse.fuplanner.services.KVV.ui.Download;
+import de.sebse.fuplanner.services.KVV.types.Modules;
+import de.sebse.fuplanner.services.KVV.types.Resource;
+import de.sebse.fuplanner.tools.MainActivityListener;
+import de.sebse.fuplanner.tools.logging.Logger;
+import de.sebse.fuplanner.tools.ui.treeview.DirectoryNodeBinder;
+import de.sebse.fuplanner.tools.ui.treeview.FileNodeBinder;
+import de.sebse.fuplanner.tools.ui.treeview.TreeNode;
+import de.sebse.fuplanner.tools.ui.treeview.TreeViewAdapter;
+
+/**
+ * A simple {@link Fragment} subclass.
+ * Use the {@link ModDetailResourceFragment#newInstance} factory method to
+ * create an instance of this fragment.
+ */
+public class ModDetailResourceFragment extends Fragment {
+    private static final String ARG_POSITION = "itemPosition";
+
+    private String mItemPos;
+    private final Logger log = new Logger(this);
+    private ModDetailResourceAdapter adapter;
+    private SwipeRefreshLayout swipeLayout;
+    private Download download;
+    @Nullable private MainActivityListener mListener;
+
+
+    public ModDetailResourceFragment() {
+        // Required empty public constructor
+    }
+
+    /**
+     * Use this factory method to create a new instance of
+     * this fragment using the provided parameters.
+     *
+     * @param itemPosition Item position in module list.
+     * @return A new instance of fragment ModDetailAnnounceFragment.
+     */
+    public static ModDetailResourceFragment newInstance(String itemPosition) {
+        ModDetailResourceFragment fragment = new ModDetailResourceFragment();
+        Bundle args = new Bundle();
+        args.putString(ARG_POSITION, itemPosition);
+        fragment.setArguments(args);
+        return fragment;
+    }
+
+    @Override
+    public void onCreate(Bundle savedInstanceState) {
+        super.onCreate(savedInstanceState);
+        if (getArguments() != null) {
+            mItemPos = getArguments().getString(ARG_POSITION);
+        }
+}
+
+    @Override
+    public View onCreateView(@NonNull LayoutInflater inflater, ViewGroup container,
+                             Bundle savedInstanceState) {
+        // Inflate the layout for this fragment
+        View view = inflater.inflate(R.layout.fragment_recycler_view, container, false);
+        // Set the adapter
+        Context context = view.getContext();
+        RecyclerView recyclerView = view.findViewById(R.id.list);
+        recyclerView.setLayoutManager(new LinearLayoutManager(context));
+
+        adapter = new ModDetailResourceAdapter(Arrays.asList(new FileNodeBinder(), new DirectoryNodeBinder()));
+        adapter.setOnTreeNodeListener(new TreeViewAdapter.OnTreeNodeListener() {
+            @Override
+            public boolean onClick(TreeNode node, RecyclerView.ViewHolder holder) {
+                if (!node.isLeaf()) {
+                    // Update and toggle the node.
+                    onToggle(!node.isExpand(), holder);
+                } else if (node.getContent() instanceof Resource.File && ModDetailResourceFragment.this.mListener != null) { // if leaf is file
+                    ModDetailResourceFragment.this.mListener.getKVV().modules().resources().recv(mItemPos, (Modules.Module module) -> {
+                        String folderName = "FU-"+module.title.replaceAll("[:*<>|/\"\\\\]", "-");
+                        Resource.File file = (Resource.File) node.getContent();
+                        getDownload().openDownloadDialog(file, folderName);
+                    }, log::e);
+                }
+                return false;
+            }
+
+            @Override
+            public void onToggle(boolean isExpand, RecyclerView.ViewHolder holder) {
+                DirectoryNodeBinder.ViewHolder dirViewHolder = (DirectoryNodeBinder.ViewHolder) holder;
+                final ImageView ivArrow = dirViewHolder.getIvArrow();
+                int rotateDegree = isExpand ? 90 : -90;
+                ivArrow.animate().rotationBy(rotateDegree).start();
+            }
+        });
+
+        recyclerView.setAdapter(adapter);
+
+        // Getting SwipeContainerLayout
+        swipeLayout = view.findViewById(R.id.swipe_container);
+        // Adding Listener
+        swipeLayout.setOnRefreshListener(() -> refresh(true));
+        refresh(false);
+
+        return view;
+    }
+
+    @Override
+    public void onAttach(Context context) {
+        super.onAttach(context);
+        if (context instanceof MainActivityListener) {
+            this.mListener = ((MainActivityListener) context);
+            this.mListener.addRequestPermissionsResultListener(getDownload().getRequestPermissionsResultListener(), "ModDetailResourceFragment");
+        } else
+            throw new RuntimeException(context.toString() + " must implement MainActivityListener");
+    }
+
+    @Override
+    public void onDetach() {
+        super.onDetach();
+        if (this.mListener != null) {
+            this.mListener.removeRequestPermissionsResultListener("ModDetailResourceFragment");
+            this.mListener = null;
+        }
+    }
+
+    private void refresh(boolean forceRefresh) {
+        if (mListener == null)
+            return;
+        mListener.getKVV().modules().assignments().recv(mItemPos, success -> {
+            adapter.setModule(success);
+            swipeLayout.setRefreshing(false);
+        }, error -> {
+            swipeLayout.setRefreshing(false);
+            log.e(error);
+        }, forceRefresh);
+    }
+
+    Download getDownload() {
+        if (download == null)
+            download = new Download(this::getContext, () -> (MainActivity) getActivity());
+        return download;
+    }
+
+
+
+
+
+
+}

app/src/main/java/de/sebse/fuplanner/fragments/moddetails/ModulePart.java

@@ -7,7 +7,9 @@ class ModulePart {
     static final int ASSIGNMENT = 3;
     static final int EVENT = 4;
     static final int GRADEBOOK = 5;
-    private static final int[] pages = new int[]{OVERVIEW, ANNOUNCEMENT, ASSIGNMENT, EVENT, GRADEBOOK};
+    static final int RESOURCES = 6;
+    static final int LECTURERS = 7;
+    private static final int[] pages = new int[]{OVERVIEW, ANNOUNCEMENT, ASSIGNMENT, GRADEBOOK, RESOURCES, EVENT};
 
     static int getPageCount() {
         return pages.length;

app/src/main/java/de/sebse/fuplanner/services/Canteen/CanteenBrowser.java

@@ -13,7 +13,7 @@ import de.sebse.fuplanner.services.Canteen.types.Canteen;
 import de.sebse.fuplanner.services.Canteen.types.Canteens;
 import de.sebse.fuplanner.services.Canteen.types.Day;
 import de.sebse.fuplanner.tools.AsyncQueue;
-import de.sebse.fuplanner.tools.MainAcitivityListener;
+import de.sebse.fuplanner.tools.MainActivityListener;
 import de.sebse.fuplanner.tools.network.HTTPService;
 import de.sebse.fuplanner.tools.network.NetworkCallback;
 import de.sebse.fuplanner.tools.network.NetworkError;
@@ -23,15 +23,15 @@ public class CanteenBrowser extends HTTPService {
     private Canteens canteens;
     private final AsyncQueue queue = new AsyncQueue();
     private final Context context;
-    private MainAcitivityListener mListener;
+    private MainActivityListener mListener;
 
     public CanteenBrowser(Context context) {
         super(context);
         this.context = context;
-        if (context instanceof MainAcitivityListener)
+        if (context instanceof MainActivityListener)
             mListener = (MainActivity) context;
         else
-            throw new RuntimeException(context.toString() + "must implement MainActivityListener");
+            throw new RuntimeException(context.toString() + " must implement MainActivityListener");
         try {
             this.canteens = Canteens.load(context);
         } catch (IOException e) {
@@ -65,7 +65,7 @@ public class CanteenBrowser extends HTTPService {
     }
 
     private void upgradeCanteens(final NetworkCallback<Canteens> callback, final NetworkErrorCallback errorCallback) {
-        get("https://openmensa.org/api/v2/canteens", null, response -> {
+        get("https://openmensa.org/api/v2/canteens?near[lat]=52.449743&near[lng]=13.282245&near[dist]=7", null, response -> {
             String body = response.getParsed();
             if (body == null) {
                 errorCallback.onError(new NetworkError(201101, 403, "No canteen list retrieved!"));
@@ -192,9 +192,9 @@ public class CanteenBrowser extends HTTPService {
                     double priceEmply = 0;
                     double priceOther = 0;
                     if (prices != null) {
-                        priceStdnt = prices.getDouble("students");
-                        priceEmply = prices.getDouble("employees");
-                        priceOther = prices.getDouble("others");
+                        priceOther = prices.optDouble("others", -1);
+                        priceEmply = prices.optDouble("employees", priceOther);
+                        priceStdnt = prices.optDouble("students", priceEmply);
                     }
                     JSONArray noteArray = meal.getJSONArray("notes");
                     String[] notes = new String[noteArray.length()];
@@ -206,6 +206,7 @@ public class CanteenBrowser extends HTTPService {
                 }
             } catch (JSONException e) {
                 e.printStackTrace();
+                log.d(body);
                 errorCallback.onError(new NetworkError(201302, 403, "Cannot parse meal list!"));
                 return;
             }
@@ -224,17 +225,14 @@ public class CanteenBrowser extends HTTPService {
     private<T> NetworkCallback<T> saveOnCallback(NetworkCallback<T> callback, boolean forceRefresh){
         return (success -> {
             if (forceRefresh)
-                mListener.refreshFailed(false);
+                mListener.onRefreshCompleted(false);
             callback.onResponse(success);
         });
     }
 
     private NetworkErrorCallback errorOnCallback(NetworkErrorCallback errorCallback){
         return (error -> {
-            if (error.getHttpStatus() == 401 || error.getHttpStatus() == 403)
-                mListener.loginTokenInvalid(false);
-            else
-                mListener.refreshFailed(true);
+            mListener.onRefreshCompleted(true);
             errorCallback.onError(error);
         });
     }

app/src/main/java/de/sebse/fuplanner/services/Canteen/types/Canteen.java

@@ -1,6 +1,6 @@
 package de.sebse.fuplanner.services.Canteen.types;
 
-import android.support.annotation.NonNull;
+import androidx.annotation.NonNull;
 
 import java.io.Serializable;
 import java.util.Calendar;
@@ -50,6 +50,17 @@ public class Canteen implements Serializable, Iterable<Day> {
         }
     }
 
+    public void cleanUpDays() {
+        SortedListDay newList = new SortedListDay();
+        Calendar cal = Calendar.getInstance();
+        for (Day day : list) {
+            if (Canteen.calendarToKey(day.getCalendar()).compareTo(Canteen.calendarToKey(cal)) >= 0) {
+                newList.add(day);
+            }
+        }
+        list = newList;
+    }
+
     public int size() {
         return this.list.size();
     }

app/src/main/java/de/sebse/fuplanner/services/Canteen/types/Canteens.java

@@ -1,7 +1,7 @@
 package de.sebse.fuplanner.services.Canteen.types;
 
 import android.content.Context;
-import android.support.annotation.NonNull;
+import androidx.annotation.NonNull;
 
 import java.io.FileInputStream;
 import java.io.FileOutputStream;
@@ -12,7 +12,7 @@ import java.io.Serializable;
 import java.util.Iterator;
 
 public class Canteens implements Serializable, Iterable<Canteen> {
-    public static final int[] availableCanteens = {27, 28, 42};
+    public static final int[] availableCanteens = {27, 42, 813, 810, 811, 812, 821};
     private static final String FILE_NAME = "CanteensSaving";
     private SortedListCanteen list = new SortedListCanteen();
 
@@ -68,7 +68,7 @@ public class Canteens implements Serializable, Iterable<Canteen> {
 
             @Override
             public void remove() {
-                throw new UnsupportedOperationException("You are not alloed to remove an entry!");
+                throw new UnsupportedOperationException("You are not allowed to remove an entry!");
             }
         };
     }

app/src/main/java/de/sebse/fuplanner/services/Canteen/types/Day.java

@@ -1,6 +1,6 @@
 package de.sebse.fuplanner.services.Canteen.types;
 
-import android.support.annotation.NonNull;
+import androidx.annotation.NonNull;
 
 import java.io.Serializable;
 import java.util.Calendar;

app/src/main/java/de/sebse/fuplanner/services/Canteen/types/Meal.java

@@ -6,14 +6,14 @@ import java.util.Collections;
 import java.util.List;
 
 public class Meal implements Serializable {
-    public static final int LIGHT_NONE = 0;
-    public static final int LIGHT_GREEN = 1;
-    public static final int LIGHT_YELLOW = 2;
-    public static final int LIGHT_RED = 3;
-    public static final int VEGAN_NONE = 0;
-    public static final int VEGAN_VEGETERIAN = 1;
+    private static final int LIGHT_NONE = 0;
+    private static final int LIGHT_GREEN = 1;
+    private static final int LIGHT_YELLOW = 2;
+    private static final int LIGHT_RED = 3;
+    private static final int VEGAN_NONE = 0;
+    public static final int VEGAN_VEGETARIAN = 1;
     public static final int VEGAN_VEGAN = 2;
-    public static final int CERT_NONE = 0b0000;
+    private static final int CERT_NONE = 0b0000;
     public static final int CERT_BIO =  0b0001;
     public static final int CERT_MSC =  0b0010;
 
@@ -42,7 +42,7 @@ public class Meal implements Serializable {
         for (String note : notes) {
             switch (note.toLowerCase()) {
                 case "vegetarisch":
-                    vegan = VEGAN_VEGETERIAN;
+                    vegan = VEGAN_VEGETARIAN;
                     break;
                 case "vegan":
                     vegan = VEGAN_VEGAN;

app/src/main/java/de/sebse/fuplanner/services/GoogleAuth/GoogleAuth.java

@@ -2,8 +2,6 @@ package de.sebse.fuplanner.services.GoogleAuth;
 
 import android.content.Intent;
 import android.content.IntentSender;
-import android.support.annotation.Nullable;
-import android.support.v4.app.FragmentActivity;
 import android.util.Log;
 import android.widget.Toast;
 
@@ -17,6 +15,9 @@ import com.google.android.gms.common.api.ApiException;
 import com.google.android.gms.common.api.CommonStatusCodes;
 import com.google.android.gms.common.api.ResolvableApiException;
 
+import androidx.annotation.Nullable;
+import androidx.fragment.app.FragmentActivity;
+
 import static android.app.Activity.RESULT_OK;
 
 /**
@@ -28,6 +29,7 @@ public class GoogleAuth {
 
     private static final String TAG = "GoogleAuth";
     private final FragmentActivity activity;
+    private static final String FU_PLANNER_PROVIDER = "FUPlanner";
     private CredentialsClient mCredentialsClient;
     private boolean mIsResolving;
     @Nullable
@@ -60,6 +62,7 @@ public class GoogleAuth {
             connect();
         CredentialRequest request = new CredentialRequest.Builder()
                 .setPasswordLoginSupported(true)
+                .setAccountTypes(FU_PLANNER_PROVIDER)
                 .build();
 
 

app/src/main/java/de/sebse/fuplanner/services/KVV/KVV.java

@@ -1,195 +1,47 @@
 package de.sebse.fuplanner.services.KVV;
 
 import android.content.Context;
-import android.support.annotation.NonNull;
-import android.util.Pair;
 
-import java.io.IOException;
-import java.util.ArrayList;
+import org.jetbrains.annotations.NotNull;
+
 import java.util.HashMap;
 
-import de.sebse.fuplanner.services.KVV.types.LoginToken;
-import de.sebse.fuplanner.services.KVV.types.Modules;
-import de.sebse.fuplanner.tools.MainAcitivityListener;
-import de.sebse.fuplanner.tools.network.NetworkCallback;
-import de.sebse.fuplanner.tools.network.NetworkErrorCallback;
-
-/**
- * Created by sebastian on 29.10.17.
- */
-
 public class KVV {
-    private final Context context;
-    private LoginToken lastToken;
-    private boolean isLoginPending = true;
-    private final ArrayList<LastTokenCallback> updatingList;
     private final HashMap<String, Object> addons = new HashMap<>();
-    private final MainAcitivityListener mListener;
+    private final KVVListener mListener;
+    private final Context mContext;
 
-    public KVV(Context context) {
-        mListener = (MainAcitivityListener) context;
-        this.context = context;
-        this.updatingList = new ArrayList<>();
+    public KVV(KVVListener listener, Context context) {
+        this.mListener = listener;
+        this.mContext = context;
     }
 
-    public LoginToken easyLogin() {
-        KVVLogin login = new KVVLogin(this.context);
-        lastToken = login.easyLogin();
-        this.endUpdate();
-        return lastToken;
+    @NotNull
+    public Login account() {
+        return (Login) addAndGet("account", () -> new Login(mListener, mContext));
     }
 
-    public void login(@NonNull String username, @NonNull String password, final NetworkCallback<LoginToken> callback, NetworkErrorCallback error) {
-        KVVLogin login = new KVVLogin(this.context);
-        login.login(username, password, success -> {
-            lastToken = success;
-            this.endUpdate();
-            try {
-                login.saveOffline();
-            } catch (IOException e) {
-                e.printStackTrace();
-            }
-            callback.onResponse(success);
-        }, error1 -> {
-            this.endUpdate();
-            error.onError(error1);
-        });
+    @NotNull
+    public Modules modules() {
+        return (Modules) addAndGet("module", () -> new Modules(account(), mListener, mContext));
     }
 
-    public void logout() {
-        KVVModuleList modules = (KVVModuleList) addons.get("modules");
-        if (modules != null) {
-            modules.deleteModulesOffline(this.context);
+
+
+
+
+
+    @NotNull
+    private Object addAndGet(@NotNull String addon, @NotNull ModuleCreatorInterface creatorInterface) {
+        Object o = addons.get(addon);
+        if (o == null) {
+            o = creatorInterface.create();
+            addons.put(addon, o);
         }
-        invalidate();
+        return o;
     }
 
-    public void invalidate() {
-        if (lastToken != null) {
-            new KVVLogin(context).deleteOffline();
-            lastToken = null;
-        }
-        addons.clear();
-        this.isLoginPending = true;
-    }
-
-    public void getModule(String id, final NetworkCallback<Modules.Module> callback, final NetworkErrorCallback error) {
-        getModule(id, callback, error, false);
-    }
-
-    public void getModule(String id, final NetworkCallback<Modules.Module> callback, final NetworkErrorCallback error, boolean forceRefresh) {
-        getModulePart(modules -> modules.getModule(id, saveOnCallback(modules, callback, forceRefresh), errorOnCallback(error), forceRefresh));
-    }
-
-    public void getModuleList(final NetworkCallback<Modules> callback, final NetworkErrorCallback error) {
-        getModuleList(callback, error, false);
-    }
-
-    public void getModuleList(final NetworkCallback<Modules> callback, final NetworkErrorCallback error, boolean forceRefresh) {
-        getModulePart(modules -> modules.getModuleList(saveOnCallback(modules, callback, forceRefresh), errorOnCallback(error), forceRefresh));
-    }
-
-    public void getModuleDetails(Modules.Module module, final NetworkCallback<Pair<Modules.Module, Boolean>> callback, final NetworkErrorCallback error) {
-        getModuleDetails(module, callback, error, false);
-    }
-
-    public void getModuleDetails(Modules.Module module, final NetworkCallback<Pair<Modules.Module, Boolean>> callback, final NetworkErrorCallback error, boolean forceRefresh) {
-        getModulePart(modules -> modules.getModuleDetails(module, saveOnCallback(modules, callback, forceRefresh), errorOnCallback(error), forceRefresh));
-    }
-
-    public void getModuleAnnouncements(Modules.Module module, final NetworkCallback<Modules.Module> callback, final NetworkErrorCallback error) {
-        getModuleAnnouncements(module, callback, error, false);
-    }
-
-    public void getModuleAnnouncements(Modules.Module module, final NetworkCallback<Modules.Module> callback, final NetworkErrorCallback error, boolean forceRefresh) {
-        getModulePart(modules -> modules.getAnnouncements(module, saveOnCallback(modules, callback, forceRefresh), errorOnCallback(error), forceRefresh));
-    }
-
-    public void getModuleAssignments(Modules.Module module, final NetworkCallback<Modules.Module> callback, final NetworkErrorCallback error) {
-        getModuleAssignments(module, callback, error, false);
-    }
-
-    public void getModuleAssignments(Modules.Module module, final NetworkCallback<Modules.Module> callback, final NetworkErrorCallback error, boolean forceRefresh) {
-        getModulePart(modules -> modules.getAssignments(module, saveOnCallback(modules, callback, forceRefresh), errorOnCallback(error), forceRefresh));
-    }
-
-    public void getModuleEvents(Modules.Module module, final NetworkCallback<Modules.Module> callback, final NetworkErrorCallback error) {
-        getModuleEvents(module, callback, error, false);
-    }
-
-    public void getModuleEvents(Modules.Module module, final NetworkCallback<Modules.Module> callback, final NetworkErrorCallback error, boolean forceRefresh) {
-        getModulePart(modules -> modules.getEvents(module, saveOnCallback(modules, callback, forceRefresh), errorOnCallback(error), forceRefresh));
-    }
-
-    public void getModuleGradebook(Modules.Module module, final NetworkCallback<Modules.Module> callback, final NetworkErrorCallback error) {
-        getModuleGradebook(module, callback, error, false);
-    }
-
-    public void getModuleGradebook(Modules.Module module, final NetworkCallback<Modules.Module> callback, final NetworkErrorCallback error, boolean forceRefresh) {
-        getModulePart(modules -> modules.getGradebook(module, saveOnCallback(modules, callback, forceRefresh), errorOnCallback(error), forceRefresh));
-    }
-
-    public void getModuleResources(Modules.Module module, final NetworkCallback<Modules.Module> callback, final NetworkErrorCallback error) {
-        getModuleResources(module, callback, error, false);
-    }
-
-    public void getModuleResources(Modules.Module module, final NetworkCallback<Modules.Module> callback, final NetworkErrorCallback error, boolean forceRefresh) {
-        getModulePart(modules -> modules.getResources(module, saveOnCallback(modules, callback, forceRefresh), errorOnCallback(error), forceRefresh));
-    }
-
-
-
-    private void getModulePart(ModListFunction func) {
-        this.getLastToken(token -> {
-            KVVModuleList modules = (KVVModuleList) addons.get("modules");
-            if (modules == null) {
-                modules = new KVVModuleList(this.context, token);
-                addons.put("modules", modules);
-            }
-            func.apply(modules);
-        });
-    }
-
-    private<T> NetworkCallback<T> saveOnCallback(KVVModuleList modules, NetworkCallback<T> callback, boolean forceRefresh){
-        return (success -> {
-            try {
-                modules.saveModulesOffline(this.context);
-            } catch (IOException e) {
-                e.printStackTrace();
-            }
-            if (forceRefresh)
-                mListener.refreshFailed(false);
-            callback.onResponse(success);
-        });
-    }
-
-    private NetworkErrorCallback errorOnCallback(NetworkErrorCallback errorCallback){
-        return (error -> {
-            if (error.getHttpStatus() == 401 || error.getHttpStatus() == 403)
-                mListener.loginTokenInvalid(false);
-            else
-                mListener.refreshFailed(true);
-            errorCallback.onError(error);
-        });
-    }
-
-    @FunctionalInterface
-    interface ModListFunction {
-        void apply(KVVModuleList mod);
-    }
-
-    private void getLastToken(LastTokenCallback lastTokenCallback) {
-        if (this.isLoginPending) {
-            this.updatingList.add(lastTokenCallback);
-        } else {
-            lastTokenCallback.onReceived(this.lastToken);
-        }
-    }
-
-    private void endUpdate() {
-        this.isLoginPending = false;
-        for (LastTokenCallback s: this.updatingList) {
-            s.onReceived(this.lastToken);
-        }
+    private interface ModuleCreatorInterface {
+        @NotNull Object create();
     }
 }

app/src/main/java/de/sebse/fuplanner/services/KVV/KVVListener.java

@@ -0,0 +1,20 @@
+package de.sebse.fuplanner.services.KVV;
+
+import com.android.volley.NetworkResponse;
+
+import de.sebse.fuplanner.services.GoogleAuth.Credentials;
+import de.sebse.fuplanner.services.KVV.types.LoginToken;
+import de.sebse.fuplanner.tools.network.NetworkCallback;
+import de.sebse.fuplanner.tools.network.NetworkErrorCallback;
+
+public interface KVVListener {
+    void getCredentials(NetworkCallback<Credentials> callback, NetworkErrorCallback error);
+
+    void onLogin(LoginToken token, boolean enteringOnlineMode);
+
+    void onLogout();
+
+    void onModuleListChange();
+
+    void onKVVNetworkResponse(NetworkResponse error);
+}

app/src/main/java/de/sebse/fuplanner/services/KVV/KVVModuleList.java

@@ -1,517 +0,0 @@
-package de.sebse.fuplanner.services.KVV;
-
-import android.content.Context;
-import android.util.Pair;
-
-import net.htmlparser.jericho.Source;
-
-import org.json.JSONArray;
-import org.json.JSONException;
-import org.json.JSONObject;
-
-import java.io.IOException;
-import java.util.ArrayList;
-import java.util.HashSet;
-import java.util.concurrent.atomic.AtomicInteger;
-import java.util.concurrent.atomic.AtomicReference;
-import java.util.regex.MatchResult;
-
-import de.sebse.fuplanner.services.KVV.types.Announcement;
-import de.sebse.fuplanner.services.KVV.types.Assignment;
-import de.sebse.fuplanner.services.KVV.types.Event;
-import de.sebse.fuplanner.services.KVV.types.Gradebook;
-import de.sebse.fuplanner.services.KVV.types.Lecturer;
-import de.sebse.fuplanner.services.KVV.types.LoginToken;
-import de.sebse.fuplanner.services.KVV.types.Modules;
-import de.sebse.fuplanner.services.KVV.types.AssignmentList;
-import de.sebse.fuplanner.services.KVV.types.Resource;
-import de.sebse.fuplanner.tools.AsyncQueue;
-import de.sebse.fuplanner.services.KVV.types.EventList;
-import de.sebse.fuplanner.tools.Regex;
-import de.sebse.fuplanner.tools.network.HTTPService;
-import de.sebse.fuplanner.tools.network.NetworkCallback;
-import de.sebse.fuplanner.tools.network.NetworkError;
-import de.sebse.fuplanner.tools.network.NetworkErrorCallback;
-
-/**
- * Created by sebastian on 29.10.17.
- */
-
-class KVVModuleList extends HTTPService {
-    private final LoginToken token;
-    private Modules moduleList;
-    private final AsyncQueue queueModuleDetails = new AsyncQueue();
-
-    KVVModuleList(Context context, LoginToken token) {
-        super(context);
-        this.token = token;
-        try {
-            Modules modules = Modules.load(context);
-            if (token == null || token.isSameUser(modules.getToken()))
-                this.moduleList = modules;
-        } catch (IOException e) {
-            e.printStackTrace();
-        } catch (ClassNotFoundException e) {
-            e.printStackTrace();
-        }
-    }
-
-
-
-
-    public void getModuleList(final NetworkCallback<Modules> callback, final NetworkErrorCallback errorCallback, boolean forceRefresh) {
-        queueModuleDetails.add("list", () -> {
-            if (this.moduleList != null && !forceRefresh) {
-                callback.onResponse(this.moduleList);
-                queueModuleDetails.next("list");
-                return;
-            }
-            this.getModuleListUpgrade(success -> {
-                if (this.moduleList == null)
-                    this.moduleList = success;
-                else
-                    this.moduleList.updateList(success);
-                callback.onResponse(this.moduleList);
-                queueModuleDetails.next("list");
-            }, queueModuleDetails.check("list", errorCallback));
-        });
-    }
-
-    private void getModuleListUpgrade(final NetworkCallback<Modules> callback, final NetworkErrorCallback errorCallback) {
-        if (token == null) {
-            errorCallback.onError(new NetworkError(101105, 500, "Currently running in offline mode!"));
-            return;
-        }
-        get("https://kvv.imp.fu-berlin.de/direct/site.json", token.getCookies(), response -> {
-            String body = response.getParsed();
-            if (body == null) {
-                errorCallback.onError(new NetworkError(101101, 403, "No module list retrieved!"));
-                return;
-            }
-            Modules modules = new Modules(token);
-            try {
-                JSONObject json = new JSONObject(body);
-                JSONArray sites = json.getJSONArray("site_collection");
-
-                for (int i = 0; i < sites.length(); i++) {
-                    JSONObject site = sites.getJSONObject(i);
-                    String semester = site.getJSONObject("props").getString("term_eid");
-                    HashSet<String> lvNumbers = new HashSet<>();
-                    for (MatchResult matchResult : Regex.allMatches("[0-9]+", site.getJSONObject("props").getString("kvv_lvnumbers"))) {
-                        lvNumbers.add(matchResult.group());
-                    }
-                    String title = site.getString("entityTitle");
-                    HashSet<Lecturer> lecturers = new HashSet<>();
-                    for (String lecturer : site.getJSONObject("props").getString("kvv_lecturers").split("#")) {
-                        if (lecturer.length() > 2)
-                            lecturers.add(new Lecturer(lecturer));
-                    }
-                    String type = site.getJSONObject("props").getString("kvv_coursetype");
-                    String description = site.getString("description");
-                    description = new Source(description).getRenderer().toString();
-                    String id = site.getString("id");
-                    modules.addModule(semester, lvNumbers, title, lecturers, type, description, id);
-                }
-            } catch (JSONException e) {
-                e.printStackTrace();
-                errorCallback.onError(new NetworkError(101102, 403, "Cannot parse module list!"));
-                return;
-            } catch (NoSuchFieldException e) {
-                e.printStackTrace();
-                errorCallback.onError(new NetworkError(101103, 403, "Cannot parse module list!"));
-                return;
-            }
-            // Empty module *may be* because token is invalid -> check
-            if (modules.size() == 0)
-                testLogin(token, token -> callback.onResponse(modules), errorCallback);
-            else
-                callback.onResponse(modules);
-        }, error -> errorCallback.onError(new NetworkError(101104, error.networkResponse.statusCode, "Cannot get module list!")));
-    }
-
-    public void deleteModulesOffline(Context context) {
-        if (this.moduleList != null)
-            this.moduleList.delete(context);
-    }
-
-    public void saveModulesOffline(Context context) throws IOException {
-        if (this.moduleList != null)
-            this.moduleList.save(context);
-    }
-
-    public void getModule(String id, final NetworkCallback<Modules.Module> callback, final NetworkErrorCallback errorCallback, boolean forceRefresh) {
-        this.getModuleList(success -> callback.onResponse(success.get(id)), errorCallback, forceRefresh);
-    }
-
-
-
-
-
-
-    public void getModuleDetails(Modules.Module module, final NetworkCallback<Pair<Modules.Module, Boolean>> callback, final NetworkErrorCallback errorCallback, boolean forceRefresh) {
-        AtomicInteger returns = new AtomicInteger(0);
-        AtomicReference<NetworkError> lastError = new AtomicReference<>(null);
-        final AtomicInteger items = new AtomicInteger(0);
-        NetworkCallback<Modules.Module> successCb = success -> {
-            returns.getAndIncrement();
-            callback.onResponse(Pair.create(module, false));
-            if (returns.get() == items.get()) {
-                callback.onResponse(Pair.create(module, true));
-                if (lastError.get() != null)
-                    errorCallback.onError(lastError.get());
-            }
-        };
-        NetworkErrorCallback errorCb = error -> {
-            lastError.set(error);
-            returns.getAndIncrement();
-            if (returns.get() == items.get()) {
-                callback.onResponse(Pair.create(module, true));
-                if (lastError.get() != null)
-                    errorCallback.onError(lastError.get());
-            }
-        };
-        Runnable[] methods = {
-                () -> this.getAssignments(module, successCb, errorCb, forceRefresh),
-                () -> this.getEvents(module, successCb, errorCb, forceRefresh),
-                () -> this.getAnnouncements(module, successCb, errorCb, forceRefresh),
-                () -> this.getGradebook(module, successCb, errorCb, forceRefresh),
-                () -> this.getResources(module, successCb, errorCb, forceRefresh)
-        };
-        items.set(methods.length);
-        for (Runnable method: methods) {
-            method.run();
-        }
-    }
-
-
-
-
-
-
-    public void getAnnouncements(Modules.Module module, final NetworkCallback<Modules.Module> callback, final NetworkErrorCallback errorCallback, boolean forceRefresh) {
-        queueModuleDetails.add(module.getID(), () -> {
-            if (module.announcements != null && !forceRefresh) {
-                callback.onResponse(module);
-                queueModuleDetails.next(module.getID());
-                return;
-            }
-            getAnnouncementsUpgrade(module.getID(), success -> {
-                module.announcements = success;
-                callback.onResponse(module);
-                queueModuleDetails.next(module.getID());
-            }, queueModuleDetails.check(module.getID(), errorCallback));
-        });
-    }
-
-    private void getAnnouncementsUpgrade(String ID, final NetworkCallback<ArrayList<Announcement>> callback, final NetworkErrorCallback errorCallback) {
-        if (token == null) {
-            errorCallback.onError(new NetworkError(101204, 500, "Currently running in offline mode!"));
-            return;
-        }
-        get(String.format("https://kvv.imp.fu-berlin.de/direct/announcement/site/%s.json?n=999999&d=999999999", ID), token.getCookies(), response -> {
-            String body = response.getParsed();
-            if (body == null) {
-                errorCallback.onError(new NetworkError(101201, 403, "No announcements retrieved!"));
-                return;
-            }
-            ArrayList<Announcement> announcements = new ArrayList<>();
-            try {
-                JSONObject json = new JSONObject(body);
-                JSONArray sites = json.getJSONArray("announcement_collection");
-
-                for (int i = 0; i < sites.length(); i++) {
-                    JSONObject site = sites.getJSONObject(i);
-                    String id = site.getString("announcementId");
-                    String title = site.getString("title");
-                    String text = site.getString("body");
-                    text = new Source(text).getRenderer().toString();
-                    String createdBy = site.getString("createdByDisplayName");
-                    long createdOn = site.getLong("createdOn");
-
-
-
-                    //PDFs links rausziehen
-                    JSONArray attachments = site.getJSONArray("attachments");
-                    ArrayList<String> urls = new ArrayList<>();
-                    for (int j =0; j<attachments.length(); j++){
-                        urls.add(attachments.getJSONObject(j).optString("url",null));
-                    }
-
-                    announcements.add(new Announcement(id, title, text, createdBy, createdOn, urls));
-                }
-
-            } catch (JSONException e) {
-                e.printStackTrace();
-                errorCallback.onError(new NetworkError(101202, 403, "Cannot parse announcements!"));
-                return;
-            }
-            // Empty announcements *may be* because token is invalid -> check
-            if (announcements.size() == 0)
-                testLogin(token, token -> callback.onResponse(announcements), errorCallback);
-            else
-                callback.onResponse(announcements);
-        }, error -> errorCallback.onError(new NetworkError(101203, error.networkResponse.statusCode, "Cannot get announcements!")));
-    }
-
-
-
-
-
-    public void getAssignments(Modules.Module module, final NetworkCallback<Modules.Module> callback, final NetworkErrorCallback errorCallback, boolean forceRefresh) {
-        queueModuleDetails.add(module.getID(), () -> {
-            if (module.assignments != null && !forceRefresh) {
-                callback.onResponse(module);
-                queueModuleDetails.next(module.getID());
-                return;
-            }
-            getAssignmentsUpgrade(module.getID(), success -> {
-                module.assignments = success;
-                callback.onResponse(module);
-                queueModuleDetails.next(module.getID());
-            }, queueModuleDetails.check(module.getID(), errorCallback));
-        });
-    }
-
-    private void getAssignmentsUpgrade(String ID, final NetworkCallback<AssignmentList> callback, final NetworkErrorCallback errorCallback) {
-        if (token == null) {
-            errorCallback.onError(new NetworkError(101304, 500, "Currently running in offline mode!"));
-            return;
-        }
-        get(String.format("https://kvv.imp.fu-berlin.de/direct/assignment/site/%s.json", ID), token.getCookies(), response ->{
-            String body = response.getParsed();
-            if (body == null) {
-                errorCallback.onError(new NetworkError(101301, 403, "No assignments retrieved!"));
-                return;
-            }
-            AssignmentList assignments = new AssignmentList();
-            try {
-                JSONObject json = new JSONObject(body);
-                JSONArray sites = json.getJSONArray("assignment_collection");
-
-                for (int i = 0; i < sites.length(); i++) {
-                    JSONObject site = sites.getJSONObject(i);
-                    String id = site.getString("id");
-                    String title = site.getString("title");
-                    String instructions = site.getString("instructions");
-                    instructions = new Source(instructions).getRenderer().toString();
-                    long dueTime = site.getJSONObject("dueTime").getLong("time");
-                    String gradebookItemName = site.optString("gradebookItemName", null);
-                    String gradeScale = site.getString("gradeScale");
-                    JSONArray attachments = site.getJSONArray("attachments");
-                    ArrayList<String> urls = new ArrayList<>();
-                    for (int j = 0; j<attachments.length(); j++){
-                        urls.add(attachments.getJSONObject(j).getString("url"));
-                    }
-                    assignments.add(0, new Assignment(id, title, dueTime, gradebookItemName, gradeScale, urls, instructions));
-                }
-            } catch (JSONException e) {
-                e.printStackTrace();
-                errorCallback.onError(new NetworkError(101302, 403, "Cannot parse announcements!"));
-                return;
-            }
-            // Empty assignments *may be* because token is invalid -> check
-            if (assignments.size() == 0)
-                testLogin(token, token -> callback.onResponse(assignments), errorCallback);
-            else
-                callback.onResponse(assignments);
-            }, error -> errorCallback.onError(new NetworkError(101303, error.networkResponse.statusCode, "Cannot get assignments!")));
-
-
-    }
-
-
-
-
-
-
-    public void getEvents(Modules.Module module, final NetworkCallback<Modules.Module> callback, final NetworkErrorCallback errorCallback, boolean forceRefresh) {
-        queueModuleDetails.add(module.getID(), () -> {
-            if (module.events != null && !forceRefresh) {
-                callback.onResponse(module);
-                queueModuleDetails.next(module.getID());
-                return;
-            }
-            getEventsUpgrade(module.getID(), success -> {
-                module.events = success;
-                callback.onResponse(module);
-                queueModuleDetails.next(module.getID());
-            }, queueModuleDetails.check(module.getID(), errorCallback));
-        });
-    }
-
-    private void getEventsUpgrade(String ID, final NetworkCallback<EventList> callback, final NetworkErrorCallback errorCallback) {
-        if (token == null) {
-            errorCallback.onError(new NetworkError(101404, 500, "Currently running in offline mode!"));
-            return;
-        }
-        get(String.format("https://kvv.imp.fu-berlin.de/direct/calendar/site/%s.json?detailed=true", ID), token.getCookies(), response -> {
-            String body = response.getParsed();
-            if (body == null) {
-                errorCallback.onError(new NetworkError(101401, 403, "No calendar retrieved!"));
-                return;
-            }
-            EventList events = new EventList();
-            try {
-                JSONObject json = new JSONObject(body);
-                JSONArray sites = json.getJSONArray("calendar_collection");
-
-                for (int i = 0; i < sites.length(); i++) {
-                    JSONObject site = sites.getJSONObject(i);
-                    String id = site.getString("eventId");
-                    String type = site.getString("type");
-                    String title = site.getString("title");
-                    String siteId = site.getString("siteId");
-                    long duration = site.getLong("duration");
-                    long firstTime = site.getJSONObject("firstTime").getLong("time");
-                    String location = site.getString("location");
-                    events.add(new Event(id, type, title, duration, firstTime, siteId, location));
-                }
-            } catch (JSONException e) {
-                e.printStackTrace();
-                errorCallback.onError(new NetworkError(101402, 403, "Cannot parse calendar entries!"));
-                return;
-            }
-            events.sort();
-            // Empty events *may be* because token is invalid -> check
-            if (events.size() == 0)
-                testLogin(token, token -> callback.onResponse(events), errorCallback);
-            else
-                callback.onResponse(events);
-        }, error -> errorCallback.onError(new NetworkError(101403, error.networkResponse.statusCode, "Cannot get calendar entries!")));
-    }
-
-
-
-
-
-    public void getGradebook(Modules.Module module, final NetworkCallback<Modules.Module> callback, final NetworkErrorCallback errorCallback, boolean forceRefresh) {
-        queueModuleDetails.add(module.getID(), () -> {
-            if (module.gradebook != null && !forceRefresh) {
-                callback.onResponse(module);
-                queueModuleDetails.next(module.getID());
-                return;
-            }
-            getGradebookUpgrade(module.getID(), success -> {
-                module.gradebook = success;
-                callback.onResponse(module);
-                queueModuleDetails.next(module.getID());
-            }, queueModuleDetails.check(module.getID(), errorCallback));
-        });
-    }
-
-    private void getGradebookUpgrade(String ID, final NetworkCallback<ArrayList<Gradebook>> callback, final NetworkErrorCallback errorCallback) {
-        if (token == null) {
-            errorCallback.onError(new NetworkError(101504, 500, "Currently running in offline mode!"));
-            return;
-        }
-        get(String.format("https://kvv.imp.fu-berlin.de/direct/gradebook/site/%s.json", ID ), token.getCookies(), response ->{
-            String body = response.getParsed();
-            if (body == null) {
-                errorCallback.onError(new NetworkError(101501, 403, "No assignments retrieved!"));
-                return;
-            }
-            ArrayList<Gradebook> gradebook = new ArrayList<>();
-            try {
-                JSONObject json = new JSONObject(body);
-                JSONArray sites = json.getJSONArray("assignments");
-
-                for (int i = 0; i < sites.length(); i++) {
-                    JSONObject site = sites.getJSONObject(i);
-                    double grade = site.optDouble("grade", 0);
-                    String itemName = site.optString("itemName", null);
-                    double maxPoints = site.optDouble("points", -1);
-
-                    gradebook.add(0, new Gradebook(itemName, grade, maxPoints));
-                }
-
-            }catch (JSONException e) {
-                e.printStackTrace();
-                errorCallback.onError(new NetworkError(101502, 403, "Cannot parse gradebook for announcements!"));
-                return;
-            }
-            callback.onResponse(gradebook);
-        }, error -> errorCallback.onError(new NetworkError(101503, error.networkResponse.statusCode, "Cannot get gradebook for assignments!")));
-
-    }
-
-    public void getResources(Modules.Module module, final NetworkCallback<Modules.Module> callback, final NetworkErrorCallback errorCallback, boolean forceRefresh) {
-        queueModuleDetails.add(module.getID(), () -> {
-            if (module.resources != null && !forceRefresh) {
-                callback.onResponse(module);
-                queueModuleDetails.next(module.getID());
-                return;
-            }
-            getResourcesUpgrade(module.getID(), success -> {
-                module.resources = success;
-                callback.onResponse(module);
-                queueModuleDetails.next(module.getID());
-            }, queueModuleDetails.check(module.getID(), errorCallback));
-        });
-    }
-
-    private void getResourcesUpgrade(String ID, final NetworkCallback<ArrayList<Resource>> callback, final NetworkErrorCallback errorCallback) {
-        if (token == null) {
-            errorCallback.onError(new NetworkError(101604, 500, "Currently running in offline mode!"));
-            return;
-        }
-        get(String.format("https://kvv.imp.fu-berlin.de/direct/content/site/%s.json", ID ), token.getCookies(), response ->{
-            String body = response.getParsed();
-            if (body == null) {
-                errorCallback.onError(new NetworkError(101601, 403, "No resources retrieved!"));
-                return;
-            }
-            ArrayList<Resource> resources = new ArrayList<>();
-            try {
-                JSONObject json = new JSONObject(body);
-                JSONArray sites = json.getJSONArray("content_collection");
-
-                for (int i = 0; i < sites.length(); i++) {
-                    JSONObject site = sites.getJSONObject(i);
-                    String author = site.getString("author");
-                    String title = site.getString("title");
-                    long modifiedDate = site.getLong("modifiedDate");
-                    String url = site.getString("url");
-                    resources.add(new Resource(author, title, modifiedDate, url));
-                }
-
-            } catch (JSONException e) {
-                e.printStackTrace();
-                errorCallback.onError(new NetworkError(101602, 403, "Cannot parse resources!"));
-                return;
-            }
-            // Empty resources *may be* because token is invalid -> check
-            if (resources.size() == 0)
-                testLogin(token, token -> callback.onResponse(resources), errorCallback);
-            else
-                callback.onResponse(resources);
-
-
-            callback.onResponse(resources);
-        }, error -> errorCallback.onError(new NetworkError(101603, error.networkResponse.statusCode, "Cannot get resources!")));
-
-    }
-
-
-
-
-
-
-
-    // TODO Better, more elegant solution than duplicate code KVVLogin
-    private void testLogin(LoginToken loginToken, NetworkCallback<LoginToken> callback, NetworkErrorCallback errorCallback) {
-        get(String.format("https://kvv.imp.fu-berlin.de/direct/profile/%s.json", loginToken.getUsername()), loginToken.getCookies(), response -> {
-            String body = response.getParsed();
-            try {
-                JSONObject json = new JSONObject(body);
-                String displayName = json.getString("displayName");
-                String email = json.getString("email");
-                loginToken.setAdditionals(displayName, email);
-                callback.onResponse(loginToken);
-            } catch (JSONException e) {
-                errorCallback.onError(new NetworkError(100201, 403, "Cannot parse profile!"));
-            }
-        }, error -> errorCallback.onError(new NetworkError(100200, error.networkResponse.statusCode, "Testing login failed!")));
-    }
-
-
-}

app/src/main/java/de/sebse/fuplanner/services/KVV/LastTokenCallback.java

@@ -1,11 +0,0 @@
-package de.sebse.fuplanner.services.KVV;
-
-import de.sebse.fuplanner.services.KVV.types.LoginToken;
-
-/**
- * Created by sebastian on 31.01.18.
- */
-
-interface LastTokenCallback {
-    void onReceived(LoginToken token);
-}

app/src/main/java/de/sebse/fuplanner/services/KVV/Login.java

@@ -2,72 +2,191 @@ package de.sebse.fuplanner.services.KVV;
 
 import android.content.Context;
 
+
+import org.jetbrains.annotations.NotNull;
 import org.json.JSONException;
 import org.json.JSONObject;
 
+import java.io.FileNotFoundException;
 import java.io.IOException;
 import java.util.HashMap;
 import java.util.regex.Matcher;
 import java.util.regex.Pattern;
 
+import androidx.annotation.Nullable;
 import de.sebse.fuplanner.services.KVV.types.LoginToken;
 import de.sebse.fuplanner.tools.network.HTTPService;
 import de.sebse.fuplanner.tools.network.NetworkCallback;
 import de.sebse.fuplanner.tools.network.NetworkError;
 import de.sebse.fuplanner.tools.network.NetworkErrorCallback;
 
-/**
- * Created by sebastian on 24.10.17.
- */
+public class Login extends HTTPService {
+    private KVVListener mListener;
+    @Nullable private LoginToken mToken;
+    private boolean mLoginPending = false;
+    private boolean mOnlineMode = false;
 
-class KVVLogin extends HTTPService {
-    private final Context mContext;
-    private LoginToken loginToken;
+    Login(KVVListener listener, Context context) {
+        super(context);
+        this.mListener = listener;
+    }
 
-    KVVLogin(Context context) {
-        super(context, false);
-        this.mContext = context;
+    public void doOnlineLogin(@NotNull String username, @NotNull String password, NetworkCallback<LoginToken> callback, NetworkErrorCallback errorCallback) {
+        if (mLoginPending) {
+            errorCallback.onError(new NetworkError(100160, -1, "Login already pending!"));
+        }
+        mLoginPending = true;
+        doLogin(username, password, token -> {
+            testLoginToken(token, token2 -> {
+                setToken(token2, true);
+                mLoginPending = false;
+                callback.onResponse(token2);
+            }, error -> {
+                mLoginPending = false;
+                errorCallback.onError(error);
+            });
+        }, error -> {
+            mLoginPending = false;
+            errorCallback.onError(error);
+        });
+    }
+
+    public boolean restoreOnlineLogin() {
+        return restoreLogin(true);
+    }
+
+    public boolean doOfflineLogin() {
+        return restoreLogin(false);
+    }
+
+    private boolean restoreLogin(boolean enteringOnlineMode) {
+        if (mLoginPending || mToken != null)
+            return false;
+        mLoginPending = true;
+        boolean result = false;
         try {
-            this.loginToken = LoginToken.load(context);
+            result = setToken(LoginToken.load(getContext()), enteringOnlineMode);
+        } catch (FileNotFoundException ignored) {
         } catch (IOException e) {
             e.printStackTrace();
         } catch (ClassNotFoundException e) {
             e.printStackTrace();
         }
+        mLoginPending = false;
+        return result;
     }
 
-    public LoginToken easyLogin() {
-        return this.loginToken;
+    public boolean isOfflineStoredAvailable() {
+        try {
+            LoginToken load = LoginToken.load(getContext());
+            return load != null;
+        } catch (FileNotFoundException ignored) {
+        } catch (IOException e) {
+            e.printStackTrace();
+        } catch (ClassNotFoundException e) {
+            e.printStackTrace();
+        }
+        return false;
     }
 
-    public void login(String username, String password, NetworkCallback<LoginToken> callback, NetworkErrorCallback errorCallback) {
-        if (this.loginToken != null) {
-            if (this.loginToken.getUsername().equals(username)) {
-                testLogin(this.loginToken, success -> callback.onResponse(this.loginToken), error -> {
-                    this.loginToken = null;
-                    login(username, password, callback, errorCallback);
-                });
-            } else {
-                this.loginToken = null;
-                login(username, password, callback, errorCallback);
+    public boolean logout(boolean delete) {
+        if (mLoginPending)
+            return false;
+        if (mToken == null)
+            return true;
+        if (delete)
+            mToken.delete(getContext());
+        mToken = null;
+        return handleCallbacks();
+    }
+
+    public boolean isLoginPending() {
+        return mLoginPending;
+    }
+
+    public boolean isLoggedIn() {
+        return mToken != null;
+    }
+
+    public boolean isInOfflineMode() {
+        return isLoggedIn() && !mOnlineMode;
+    }
+
+    public boolean isInOnlineMode() {
+        return isLoggedIn() && mOnlineMode;
+    }
+
+    void testLoginToken(@NotNull NetworkCallback<LoginToken> callback, @NotNull NetworkErrorCallback errorCallback) {
+        if (mToken == null) {
+            errorCallback.onError(new NetworkError(100173, -1, "Not logged in!"));
+            return;
+        }
+        testLoginToken(mToken, callback, errorCallback);
+    }
+
+    private void testLoginToken(@NotNull LoginToken token, @NotNull NetworkCallback<LoginToken> callback, @NotNull NetworkErrorCallback errorCallback) {
+        get(String.format("https://kvv.imp.fu-berlin.de/direct/profile/%s.json", token.getUsername()), token.getCookies(), response -> {
+            String body = response.getParsed();
+            if (body == null) {
+                errorCallback.onError(new NetworkError(100172, 403, "Testing login failed!"));
+                return;
             }
+            try {
+                JSONObject json = new JSONObject(body);
+                String displayName = json.getString("displayName");
+                String email = json.getString("email");
+                token.setAdditionals(displayName, email);
+                callback.onResponse(token);
+            } catch (JSONException e) {
+                errorCallback.onError(new NetworkError(100171, 403, "Cannot parse profile!"));
+            }
+        }, error -> errorCallback.onError(new NetworkError(100170, error.networkResponse.statusCode, "Testing login failed!")));
+    }
+
+    @Nullable public LoginToken getLoginToken() {
+        return mToken;
+    }
+
+    void refreshLogin(NetworkCallback<LoginToken> success, NetworkErrorCallback error) {
+        mListener.getCredentials(credentials -> {
+            doOnlineLogin(credentials.getUsername(), credentials.getPassword(), success, error);
+        }, e -> {
+            logout(false);
+            error.onError(e);
+        });
+    }
+
+
+
+    private boolean handleCallbacks() {
+        if (mToken != null) {
+            mListener.onLogin(mToken, mOnlineMode);
+            return true;
         } else {
-            doLogin(username, password, token -> {
-                this.loginToken = token;
-                testLogin(this.loginToken, success -> callback.onResponse(this.loginToken), errorCallback);
-            }, errorCallback);
+            mListener.onLogout();
+            return false;
         }
     }
 
-    public void deleteOffline() {
-        if (this.loginToken != null)
-            this.loginToken.delete(mContext);
+    private boolean setToken(@Nullable LoginToken token, boolean enteringOnlineMode) {
+        if (token == null)
+            return false;
+        boolean isOnlyRefresh = mToken != null;
+        mToken = token;
+        if (enteringOnlineMode) {
+            try {
+                mToken.save(getContext());
+            } catch (IOException e) {
+                e.printStackTrace();
+            }
+        }
+        mOnlineMode = enteringOnlineMode;
+        return isOnlyRefresh || handleCallbacks();
     }
 
-    public void saveOffline() throws IOException {
-        if (this.loginToken != null)
-            this.loginToken.save(mContext);
-    }
+
+
+
 
 
 
@@ -92,21 +211,6 @@ class KVVLogin extends HTTPService {
         }, error);
     }
 
-    private void testLogin(LoginToken loginToken, NetworkCallback<LoginToken> callback, NetworkErrorCallback errorCallback) {
-        get(String.format("https://kvv.imp.fu-berlin.de/direct/profile/%s.json", loginToken.getUsername()), loginToken.getCookies(), response -> {
-            String body = response.getParsed();
-            try {
-                JSONObject json = new JSONObject(body);
-                String displayName = json.getString("displayName");
-                String email = json.getString("email");
-                loginToken.setAdditionals(displayName, email);
-                callback.onResponse(loginToken);
-            } catch (JSONException e) {
-                errorCallback.onError(new NetworkError(100201, 403, "Cannot parse profile!"));
-            }
-        }, error -> errorCallback.onError(new NetworkError(100200, error.networkResponse.statusCode, "Testing login failed!")));
-    }
-
     /*
     GET https://kvv.imp.fu-berlin.de/portal/login
     -> JSESSIONID 5c10406f-588c-4c16-96e9-c80d115417de.tomcat1
@@ -233,10 +337,16 @@ class KVVLogin extends HTTPService {
         cookies.put("ROUTEID", ROUTEID);
         cookies.put("_idp_session", _idp_session);
         get("https://identity.fu-berlin.de/idp-fub/profile/SAML2/Redirect/SSO", cookies, response -> {
+            String body = response.getParsed();
+            if (body == null) {
+                errorCallback.onError(new NetworkError(100143, -1, "Error on getting SAML response!"));
+                return;
+            }
+
             HashMap<String, String> object = new HashMap<>();
 
             Pattern pattern = Pattern.compile("ss&#x3a;mem&#x3a;([0-9a-f]+)");
-            Matcher matcher = pattern.matcher(response.getParsed());
+            Matcher matcher = pattern.matcher(body);
             if (!matcher.find()) {
                 errorCallback.onError(new NetworkError(100142, -1, "Error on getting SAML response!"));
                 return;
@@ -244,7 +354,7 @@ class KVVLogin extends HTTPService {
             object.put("RelayState", "ss:mem:"+matcher.group(1));
 
             pattern = Pattern.compile("name=\"SAMLResponse\" value=\"([0-9a-zA-Z+]+=*)");
-            matcher = pattern.matcher(response.getParsed());
+            matcher = pattern.matcher(body);
             if (!matcher.find()) {
                 errorCallback.onError(new NetworkError(100141, -1, "Error on getting SAML response!"));
                 return;
@@ -332,5 +442,3 @@ class KVVLogin extends HTTPService {
         return result;
     }
 }
-
-

app/src/main/java/de/sebse/fuplanner/services/KVV/Modules.java

@@ -0,0 +1,81 @@
+package de.sebse.fuplanner.services.KVV;
+
+import android.content.Context;
+
+import org.jetbrains.annotations.NotNull;
+
+import java.util.HashMap;
+
+public class Modules {
+    private final HashMap<String, Part> mAddons = new HashMap<>();
+    private ModulesList mList = null;
+    private final Login mLogin;
+    private KVVListener mListener;
+    private final Context context;
+
+    Modules(Login login, KVVListener listener, Context context) {
+        this.mLogin = login;
+        this.mListener = listener;
+        this.context = context;
+    }
+
+    @NotNull
+    public ModulesDetails details() {
+        return (ModulesDetails) addAndGet("details", () -> {
+            PartModules[] parts = {announcements(), assignments(), events(), gradebook(), resources()};
+            return new ModulesDetails(mLogin, list(), context, parts);
+        });
+    }
+
+    @NotNull
+    public ModulesAnnouncements announcements() {
+        return (ModulesAnnouncements) addAndGet("announcements", () -> new ModulesAnnouncements(mLogin, list(), context));
+    }
+
+    @NotNull
+    public ModulesAssignments assignments() {
+        return (ModulesAssignments) addAndGet("assignments", () -> new ModulesAssignments(mLogin, list(), context));
+    }
+
+    @NotNull
+    public ModulesEvents events() {
+        return (ModulesEvents) addAndGet("events", () -> new ModulesEvents(mLogin, list(), context));
+    }
+
+    @NotNull
+    public ModulesGradebook gradebook() {
+        return (ModulesGradebook) addAndGet("gradebook", () -> new ModulesGradebook(mLogin, list(), context));
+    }
+
+    @NotNull
+    public ModulesResources resources() {
+        return (ModulesResources) addAndGet("resources", () -> new ModulesResources(mLogin, list(), context));
+    }
+
+    @NotNull
+    public ModulesList list() {
+        if (mList == null) {
+            mList = new ModulesList(mLogin, mListener, context);
+            mList.addErrorListener("Modules", error -> mListener.onKVVNetworkResponse(error.networkResponse));
+            mList.addSuccessListener("Modules", success -> mListener.onKVVNetworkResponse(null));
+        }
+        return mList;
+    }
+
+
+    @NotNull
+    private Part addAndGet(@NotNull String addon, @NotNull ModuleCreatorInterface creatorInterface) {
+        Part o = mAddons.get(addon);
+        if (o == null) {
+            o = creatorInterface.create();
+            o.addErrorListener("Modules", error -> mListener.onKVVNetworkResponse(error.networkResponse));
+            o.addSuccessListener("Modules", success -> mListener.onKVVNetworkResponse(null));
+            mAddons.put(addon, o);
+        }
+        return o;
+    }
+
+    private interface ModuleCreatorInterface {
+        @NotNull Part create();
+    }
+}

app/src/main/java/de/sebse/fuplanner/services/KVV/ModulesAnnouncements.java

@@ -0,0 +1,91 @@
+package de.sebse.fuplanner.services.KVV;
+
+import android.content.Context;
+
+import org.json.JSONArray;
+import org.json.JSONException;
+import org.json.JSONObject;
+
+import java.util.ArrayList;
+
+import de.sebse.fuplanner.services.KVV.types.Announcement;
+import de.sebse.fuplanner.services.KVV.types.Modules;
+import de.sebse.fuplanner.tools.network.NetworkCallback;
+import de.sebse.fuplanner.tools.network.NetworkError;
+import de.sebse.fuplanner.tools.network.NetworkErrorCallback;
+
+public class ModulesAnnouncements extends PartModules<ArrayList<Announcement>> {
+
+    ModulesAnnouncements(Login login, ModulesList list, Context context) {
+        super(login, list, context);
+    }
+
+    @Override
+    protected ArrayList<Announcement> getPart(Modules.Module module) {
+        return module.announcements;
+    }
+
+    @Override
+    protected boolean setPart(Modules.Module module, ArrayList<Announcement> part) {
+        boolean changed = module.announcements == null || module.announcements.hashCode() != part.hashCode();
+        module.announcements = part;
+        return changed;
+    }
+
+    @Override
+    protected void upgrade(final String ID, final NetworkCallback<ArrayList<Announcement>> callback, final NetworkErrorCallback errorCallback) {
+        if (!mLogin.isInOnlineMode() || mLogin.getLoginToken() == null) {
+            errorCallback.onError(new NetworkError(101204, 500, "Currently running in offline mode!"));
+            return;
+        }
+        super.get(String.format("https://kvv.imp.fu-berlin.de/direct/announcement/site/%s.json?n=999999&d=999999999", ID), mLogin.getLoginToken().getCookies(), response -> {
+            String body = response.getParsed();
+            if (body == null) {
+                errorCallback.onError(new NetworkError(101201, 403, "No announcements retrieved!"));
+                return;
+            }
+            ArrayList<Announcement> announcements = new ArrayList<>();
+            JSONArray sites;
+            try {
+                JSONObject json = new JSONObject(body);
+                sites = json.getJSONArray("announcement_collection");
+            } catch (JSONException e) {
+                e.printStackTrace();
+                errorCallback.onError(new NetworkError(101202, 403, "Cannot parse announcements!"));
+                return;
+            }
+
+            for (int i = 0; i < sites.length(); i++) {
+                try {
+                    JSONObject site = sites.getJSONObject(i);
+                    String id = site.getString("announcementId");
+                    String title = site.getString("title");
+                    String text = site.getString("body");
+                    text = String.valueOf(fromHtml(text));
+                    String createdBy = site.getString("createdByDisplayName");
+                    long createdOn = site.getLong("createdOn");
+
+                    // Extract attachment links
+                    JSONArray attachments = site.getJSONArray("attachments");
+                    ArrayList<String> urls = new ArrayList<>();
+                    for (int j = 0; j < attachments.length(); j++) {
+                        urls.add(attachments.getJSONObject(j).optString("url", null));
+                    }
+
+                    announcements.add(new Announcement(id, title, text, createdBy, createdOn, urls));
+                } catch (JSONException e) {
+                    log.e(new NetworkError(101205, 403, "Cannot parse announcements!"));
+                    log.e("ID:", i, "JSON:", sites);
+                    e.printStackTrace();
+                    return;
+                }
+            }
+
+            // Empty announcements *may be* because token is invalid -> check
+            if (announcements.size() == 0)
+                mLogin.testLoginToken(token -> callback.onResponse(announcements), errorCallback);
+            else
+                callback.onResponse(announcements);
+        }, error -> errorCallback.onError(new NetworkError(101203, error.networkResponse.statusCode, "Cannot get announcements!")));
+    }
+}

app/src/main/java/de/sebse/fuplanner/services/KVV/ModulesAssignments.java

@@ -0,0 +1,90 @@
+package de.sebse.fuplanner.services.KVV;
+
+import android.content.Context;
+
+import org.json.JSONArray;
+import org.json.JSONException;
+import org.json.JSONObject;
+
+import java.util.ArrayList;
+
+import de.sebse.fuplanner.services.KVV.types.Assignment;
+import de.sebse.fuplanner.services.KVV.types.AssignmentList;
+import de.sebse.fuplanner.services.KVV.types.Modules;
+import de.sebse.fuplanner.tools.network.NetworkCallback;
+import de.sebse.fuplanner.tools.network.NetworkError;
+import de.sebse.fuplanner.tools.network.NetworkErrorCallback;
+
+public class ModulesAssignments extends PartModules<AssignmentList> {
+
+    ModulesAssignments(Login login, ModulesList list, Context context) {
+        super(login, list, context);
+    }
+
+    @Override
+    protected AssignmentList getPart(Modules.Module module) {
+        return module.assignments;
+    }
+
+    @Override
+    protected boolean setPart(Modules.Module module, AssignmentList part) {
+        boolean changed = module.assignments == null || module.assignments.hashCode() != part.hashCode();
+        module.assignments = part;
+        return changed;
+    }
+
+    @Override
+    protected void upgrade(final String ID, final NetworkCallback<AssignmentList> callback, final NetworkErrorCallback errorCallback) {
+        if (!mLogin.isInOnlineMode() || mLogin.getLoginToken() == null) {
+            errorCallback.onError(new NetworkError(101304, 500, "Currently running in offline mode!"));
+            return;
+        }
+        get(String.format("https://kvv.imp.fu-berlin.de/direct/assignment/site/%s.json", ID), mLogin.getLoginToken().getCookies(), response -> {
+            String body = response.getParsed();
+            if (body == null) {
+                errorCallback.onError(new NetworkError(101301, 403, "No assignments retrieved!"));
+                return;
+            }
+            AssignmentList assignments = new AssignmentList();
+            JSONArray sites;
+            try {
+                JSONObject json = new JSONObject(body);
+                sites = json.getJSONArray("assignment_collection");
+            } catch (JSONException e) {
+                e.printStackTrace();
+                errorCallback.onError(new NetworkError(101302, 403, "Cannot parse assignments!"));
+                return;
+            }
+
+            for (int i = 0; i < sites.length(); i++) {
+                try {
+                    JSONObject site = sites.getJSONObject(i);
+                    String id = site.getString("id");
+                    String title = site.getString("title");
+                    String instructions = site.getString("instructions");
+                    instructions = String.valueOf(fromHtml(instructions));
+                    long dueTime = site.getJSONObject("dueTime").getLong("time");
+                    String gradebookItemName = site.optString("gradebookItemName", null);
+                    String gradeScale = site.getString("gradeScale");
+                    JSONArray attachments = site.getJSONArray("attachments");
+                    ArrayList<String> urls = new ArrayList<>();
+                    for (int j = 0; j < attachments.length(); j++) {
+                        urls.add(attachments.getJSONObject(j).getString("url"));
+                    }
+                    assignments.add(0, new Assignment(id, title, dueTime, gradebookItemName, gradeScale, urls, instructions));
+                } catch (JSONException e) {
+                    log.e(new NetworkError(101305, 403, "Cannot parse assignments!"));
+                    e.printStackTrace();
+                    log.e("ID:", i, "JSON:", sites);
+                    return;
+                }
+            }
+
+            // Empty assignments *may be* because token is invalid -> check
+            if (assignments.size() == 0)
+                mLogin.testLoginToken(token -> callback.onResponse(assignments), errorCallback);
+            else
+                callback.onResponse(assignments);
+        }, error -> errorCallback.onError(new NetworkError(101303, error.networkResponse.statusCode, "Cannot get assignments!")));
+    }
+}

app/src/main/java/de/sebse/fuplanner/services/KVV/ModulesDetails.java

@@ -0,0 +1,47 @@
+package de.sebse.fuplanner.services.KVV;
+
+import android.content.Context;
+import android.util.Pair;
+
+import java.util.concurrent.atomic.AtomicReference;
+
+import de.sebse.fuplanner.services.KVV.types.Modules;
+import de.sebse.fuplanner.tools.network.NetworkCallback;
+import de.sebse.fuplanner.tools.network.NetworkError;
+import de.sebse.fuplanner.tools.network.NetworkErrorCallback;
+
+final public class ModulesDetails extends Part<Pair<Modules.Module, Boolean>> {
+    private final PartModules[] parts;
+
+    ModulesDetails(Login login, ModulesList list, Context context, PartModules[] parts) {
+        super(login, list, context);
+        this.parts = parts;
+    }
+
+    @Override
+    protected void recv(final Modules.Module module, final NetworkCallback<Pair<Modules.Module, Boolean>> callback, final NetworkErrorCallback errorCallback, final boolean forceRefresh, final int retries) {
+        final int[] returned = {0};
+        AtomicReference<NetworkError> lastError = new AtomicReference<>(null);
+        NetworkCallback<Modules.Module> successCb = success -> {
+            returned[0] += 1;
+            callback.onResponse(Pair.create(module, false));
+            if (returned[0] == parts.length) {
+                callback.onResponse(Pair.create(module, true));
+                if (lastError.get() != null)
+                    errorCallback.onError(lastError.get());
+            }
+        };
+        NetworkErrorCallback errorCb = error -> {
+            lastError.set(error);
+            returned[0] += 1;
+            if (returned[0] == parts.length) {
+                callback.onResponse(Pair.create(module, true));
+                if (lastError.get() != null)
+                    errorCallback.onError(lastError.get());
+            }
+        };
+        for (PartModules<?> part: parts) {
+            part.recv(module, successCb, errorCb, forceRefresh, RETRY_COUNT);
+        }
+    }
+}

app/src/main/java/de/sebse/fuplanner/services/KVV/ModulesEvents.java

@@ -0,0 +1,83 @@
+package de.sebse.fuplanner.services.KVV;
+
+import android.content.Context;
+
+import org.json.JSONArray;
+import org.json.JSONException;
+import org.json.JSONObject;
+
+import de.sebse.fuplanner.services.KVV.types.Event;
+import de.sebse.fuplanner.services.KVV.types.EventList;
+import de.sebse.fuplanner.services.KVV.types.Modules;
+import de.sebse.fuplanner.tools.network.NetworkCallback;
+import de.sebse.fuplanner.tools.network.NetworkError;
+import de.sebse.fuplanner.tools.network.NetworkErrorCallback;
+
+public class ModulesEvents extends PartModules<EventList> {
+
+    ModulesEvents(Login login, ModulesList list, Context context) {
+        super(login, list, context);
+    }
+
+    @Override
+    protected EventList getPart(Modules.Module module) {
+        return module.events;
+    }
+
+    @Override
+    protected boolean setPart(Modules.Module module, EventList part) {
+        boolean changed = module.events == null || module.events.hashCode() != part.hashCode();
+        module.events = part;
+        return changed;
+    }
+
+    @Override
+    protected void upgrade(final String ID, final NetworkCallback<EventList> callback, final NetworkErrorCallback errorCallback) {
+        if (!mLogin.isInOnlineMode() || mLogin.getLoginToken() == null) {
+            errorCallback.onError(new NetworkError(101404, 500, "Currently running in offline mode!"));
+            return;
+        }
+        get(String.format("https://kvv.imp.fu-berlin.de/direct/calendar/site/%s.json?detailed=true", ID), mLogin.getLoginToken().getCookies(), response -> {
+            String body = response.getParsed();
+            if (body == null) {
+                errorCallback.onError(new NetworkError(101401, 403, "No events retrieved!"));
+                return;
+            }
+            EventList events = new EventList();
+            JSONArray sites;
+            try {
+                JSONObject json = new JSONObject(body);
+                sites = json.getJSONArray("calendar_collection");
+            } catch (JSONException e) {
+                e.printStackTrace();
+                errorCallback.onError(new NetworkError(101402, 403, "Cannot parse events!"));
+                return;
+            }
+
+            for (int i = 0; i < sites.length(); i++) {
+                try {
+                    JSONObject site = sites.getJSONObject(i);
+                    String id = site.getString("eventId");
+                    String type = site.getString("type");
+                    String title = site.getString("title");
+                    String siteId = site.getString("siteId");
+                    long duration = site.getLong("duration");
+                    long firstTime = site.getJSONObject("firstTime").getLong("time");
+                    String location = site.getString("location");
+                    events.add(new Event(id, type, title, duration, firstTime, siteId, location));
+                } catch (JSONException e) {
+                    log.e(new NetworkError(101405, 403, "Cannot parse events!"));
+                    e.printStackTrace();
+                    log.e("ID:", i, "JSON:", sites);
+                    return;
+                }
+            }
+
+            // Empty events *may be* because token is invalid -> check
+            if (events.size() == 0)
+                mLogin.testLoginToken(token -> callback.onResponse(events), errorCallback);
+            else
+                callback.onResponse(events);
+        }, error -> errorCallback.onError(new NetworkError(101403, error.networkResponse.statusCode, "Cannot get events!")));
+    }
+}

app/src/main/java/de/sebse/fuplanner/services/KVV/ModulesGradebook.java

@@ -0,0 +1,76 @@
+package de.sebse.fuplanner.services.KVV;
+
+import android.content.Context;
+
+import org.json.JSONArray;
+import org.json.JSONException;
+import org.json.JSONObject;
+
+import java.util.ArrayList;
+
+import de.sebse.fuplanner.services.KVV.types.Grade;
+import de.sebse.fuplanner.services.KVV.types.Modules;
+import de.sebse.fuplanner.tools.network.NetworkCallback;
+import de.sebse.fuplanner.tools.network.NetworkError;
+import de.sebse.fuplanner.tools.network.NetworkErrorCallback;
+
+public class ModulesGradebook extends PartModules<ArrayList<Grade>> {
+
+    ModulesGradebook(Login login, ModulesList list, Context context) {
+        super(login, list, context);
+    }
+
+    @Override
+    protected ArrayList<Grade> getPart(Modules.Module module) {
+        return module.gradebook;
+    }
+
+    @Override
+    protected boolean setPart(Modules.Module module, ArrayList<Grade> part) {
+        boolean changed = module.gradebook == null || module.gradebook.hashCode() != part.hashCode();
+        module.gradebook = part;
+        return changed;
+    }
+
+    @Override
+    protected void upgrade(final String ID, final NetworkCallback<ArrayList<Grade>> callback, final NetworkErrorCallback errorCallback) {
+        if (!mLogin.isInOnlineMode() || mLogin.getLoginToken() == null) {
+            errorCallback.onError(new NetworkError(101504, 500, "Currently running in offline mode!"));
+            return;
+        }
+        super.get(String.format("https://kvv.imp.fu-berlin.de/direct/gradebook/site/%s.json", ID), mLogin.getLoginToken().getCookies(), response -> {
+            String body = response.getParsed();
+            if (body == null) {
+                errorCallback.onError(new NetworkError(101501, 403, "No gradebook retrieved!"));
+                return;
+            }
+            ArrayList<Grade> gradebook = new ArrayList<>();
+            JSONArray sites;
+            try {
+                JSONObject json = new JSONObject(body);
+                sites = json.getJSONArray("assignments");
+            } catch (JSONException e) {
+                e.printStackTrace();
+                errorCallback.onError(new NetworkError(101502, 403, "Cannot parse gradebook!"));
+                return;
+            }
+
+            for (int i = 0; i < sites.length(); i++) {
+                try {
+                    JSONObject site = sites.getJSONObject(i);
+                    double grade = site.optDouble("grade", 0);
+                    String itemName = site.optString("itemName", null);
+                    double maxPoints = site.optDouble("points", -1);
+
+                    gradebook.add(0, new Grade(itemName, grade, maxPoints));
+                } catch (JSONException e) {
+                    log.e(new NetworkError(101505, 403, "Cannot parse gradebook!"));
+                    log.e("ID:", i, "JSON:", sites);
+                    e.printStackTrace();
+                    return;
+                }
+            }
+            callback.onResponse(gradebook);
+        }, error -> errorCallback.onError(new NetworkError(101503, error.networkResponse.statusCode, "Cannot get gradebook!")));
+    }
+}

app/src/main/java/de/sebse/fuplanner/services/KVV/ModulesList.java

@@ -0,0 +1,201 @@
+package de.sebse.fuplanner.services.KVV;
+
+import android.content.Context;
+
+import org.jetbrains.annotations.Nullable;
+import org.json.JSONArray;
+import org.json.JSONException;
+import org.json.JSONObject;
+
+import java.io.FileNotFoundException;
+import java.io.IOException;
+import java.util.HashSet;
+import java.util.LinkedHashSet;
+import java.util.regex.MatchResult;
+
+import de.sebse.fuplanner.services.KVV.types.Lecturer;
+import de.sebse.fuplanner.services.KVV.types.Modules;
+import de.sebse.fuplanner.services.KVV.types.Semester;
+import de.sebse.fuplanner.tools.NewAsyncQueue;
+import de.sebse.fuplanner.tools.Regex;
+import de.sebse.fuplanner.tools.network.HTTPService;
+import de.sebse.fuplanner.tools.network.NetworkCallback;
+import de.sebse.fuplanner.tools.network.NetworkError;
+import de.sebse.fuplanner.tools.network.NetworkErrorCallback;
+
+import static de.sebse.fuplanner.services.KVV.PartModules.RETRY_COUNT;
+
+public class ModulesList extends HTTPService {
+    private final Login mLogin;
+    private final KVVListener mListener;
+    @Nullable private Modules mModules;
+    private NewAsyncQueue mQueue = new NewAsyncQueue();
+
+    ModulesList(Login login, KVVListener listener, Context context) {
+        super(context);
+        this.mLogin = login;
+        this.mListener = listener;
+        restore();
+    }
+
+    @Nullable
+    public String getUsername() {
+        if (mModules != null) {
+            return mModules.getUsername();
+        }
+        return null;
+    }
+
+    public void find(String moduleID, NetworkCallback<Modules.Module> moduleNetworkCallback, NetworkErrorCallback errorCallback) {
+        find(moduleID, moduleNetworkCallback, errorCallback, RETRY_COUNT);
+    }
+
+    private void find(String moduleID, NetworkCallback<Modules.Module> moduleNetworkCallback, NetworkErrorCallback errorCallback, int retries) {
+        if (mModules != null && mLogin.getLoginToken() != null && !mLogin.getLoginToken().isSameUser(mModules.getUsername()))
+            delete();
+        if (retries < 0) {
+            errorCallback.onError(new NetworkError(101107, -1, "Too many retries!"));
+            return;
+        }
+        if (this.mModules != null) {
+            Modules.Module module = this.mModules.get(moduleID);
+            if (module != null) {
+                moduleNetworkCallback.onResponse(module);
+                return;
+            }
+        }
+        recv(success -> find(moduleID, moduleNetworkCallback, errorCallback, retries - 1), errorCallback, true, RETRY_COUNT);
+    }
+
+    void store() {
+        if (this.mModules != null) {
+            try {
+                this.mModules.save(getContext());
+            } catch (IOException e) {
+                e.printStackTrace();
+            }
+        }
+    }
+
+    private void restore() {
+        try {
+            this.mModules = Modules.load(getContext());
+        } catch (FileNotFoundException ignored) {
+        } catch (IOException e) {
+            e.printStackTrace();
+        } catch (ClassNotFoundException e) {
+            e.printStackTrace();
+        }
+    }
+
+    public void delete() {
+        if (this.mModules != null) {
+            this.mModules.delete(getContext());
+            this.mModules = null;
+        }
+    }
+
+    public void recv(final NetworkCallback<Modules> callback, final NetworkErrorCallback errorCallback) {
+        recv(callback, errorCallback, false);
+    }
+
+    public void recv(final NetworkCallback<Modules> callback, final NetworkErrorCallback errorCallback, boolean forceRefresh) {
+        recv(callback, errorCallback, forceRefresh, RETRY_COUNT);
+    }
+
+    private void recv(final NetworkCallback<Modules> callback, final NetworkErrorCallback errorCallback, boolean forceRefresh, final int retries) {
+        if (mModules != null && mLogin.getLoginToken() != null && !mLogin.getLoginToken().isSameUser(mModules.getUsername()))
+            delete();
+        mQueue.add(() -> {
+            if (this.mModules != null && !forceRefresh) {
+                callback.onResponse(this.mModules);
+                mQueue.next();
+                return;
+            }
+            this.upgrade(success -> {
+                if (this.mModules == null)
+                    this.mModules = success;
+                else
+                    this.mModules.updateList(success);
+                mListener.onModuleListChange();
+                store();
+                callback.onResponse(this.mModules);
+                mQueue.next();
+            }, error -> {
+                if (retries > 0 && (error.getHttpStatus() == 401 || error.getHttpStatus() == 403)) {
+                    mLogin.refreshLogin(success -> {
+                        recv(callback, errorCallback, forceRefresh, retries-1);
+                        mQueue.next();
+                    }, error1 -> {
+                        errorCallback.onError(error1);
+                        mQueue.next();
+                    });
+                    return;
+                }
+                errorCallback.onError(error);
+                mQueue.next();
+            });
+        });
+    }
+
+    private void upgrade(final NetworkCallback<Modules> callback, final NetworkErrorCallback errorCallback) {
+        if (!mLogin.isInOnlineMode() || mLogin.getLoginToken() == null) {
+            errorCallback.onError(new NetworkError(101105, 500, "Currently running in offline mode!"));
+            return;
+        }
+        get("https://kvv.imp.fu-berlin.de/direct/site.json", mLogin.getLoginToken().getCookies(), response -> {
+            String body = response.getParsed();
+            if (body == null) {
+                errorCallback.onError(new NetworkError(101101, 403, "No module list retrieved!"));
+                return;
+            }
+            Modules modules = new Modules(mLogin.getLoginToken().getUsername());
+            JSONArray sites;
+            try {
+                JSONObject json = new JSONObject(body);
+                sites = json.getJSONArray("site_collection");
+            } catch (JSONException e) {
+                e.printStackTrace();
+                errorCallback.onError(new NetworkError(101102, 403, "Cannot parse module list!"));
+                return;
+            }
+            for (int i = 0; i < sites.length(); i++) {
+                try {
+                    JSONObject site = sites.getJSONObject(i);
+                    String semester_string = site.getJSONObject("props").optString("term_eid", null);
+                    Semester semester = new Semester(semester_string);
+                    HashSet<String> lvNumbers = new HashSet<>();
+                    String kvv_lvnumbers = site.getJSONObject("props").optString("kvv_lvnumbers", null);
+                    if (kvv_lvnumbers != null) for (MatchResult matchResult : Regex.allMatches("[0-9]+", kvv_lvnumbers)) {
+                        lvNumbers.add(matchResult.group());
+                    }
+                    String title = site.getString("entityTitle");
+                    LinkedHashSet<Lecturer> lecturers = new LinkedHashSet<>();
+                    String kvv_lecturers = site.getJSONObject("props").optString("kvv_lecturers", null);
+                    if (kvv_lecturers != null) for (String lecturer : kvv_lecturers.split("#")) {
+                        if (lecturer.length() > 2)
+                            lecturers.add(new Lecturer(lecturer));
+                    }
+                    String type = site.getJSONObject("props").optString("kvv_coursetype", null);
+                    String description = site.optString("description", "");
+                    description = String.valueOf(PartModules.fromHtml(description));
+                    String id = site.getString("id");
+                    modules.addModule(semester, lvNumbers, title, lecturers, type, description, id);
+                } catch (JSONException e) {
+                    log.e(new NetworkError(101103, 403, "Cannot parse module list!"));
+                    log.e("ID:", i, "JSON:", sites);
+                    e.printStackTrace();
+                } catch (NoSuchFieldException e) {
+                    log.e(new NetworkError(101106, 403, "Cannot parse module list!"));
+                    log.e("ID:", i, "JSON:", sites);
+                    e.printStackTrace();
+                }
+            }
+            // Empty module *may be* because token is invalid -> check
+            if (modules.size() == 0)
+                mLogin.testLoginToken(token -> callback.onResponse(modules), errorCallback);
+            else
+                callback.onResponse(modules);
+        }, error -> errorCallback.onError(new NetworkError(101104, error.networkResponse.statusCode, "Cannot get module list!")));
+    }
+}

app/src/main/java/de/sebse/fuplanner/services/KVV/ModulesResources.java

@@ -0,0 +1,220 @@
+package de.sebse.fuplanner.services.KVV;
+
+import android.content.Context;
+import android.os.Environment;
+
+import org.json.JSONArray;
+import org.json.JSONException;
+import org.json.JSONObject;
+
+import java.io.File;
+import java.io.FileOutputStream;
+import java.util.ArrayList;
+
+import de.sebse.fuplanner.services.KVV.types.Modules;
+import de.sebse.fuplanner.services.KVV.types.Resource;
+import de.sebse.fuplanner.tools.Regex;
+import de.sebse.fuplanner.tools.network.NetworkCallback;
+import de.sebse.fuplanner.tools.network.NetworkError;
+import de.sebse.fuplanner.tools.network.NetworkErrorCallback;
+
+public class ModulesResources extends PartModules<ArrayList<Resource>> {
+
+    ModulesResources(Login login, ModulesList list, Context context) {
+        super(login, list, context);
+    }
+
+    @Override
+    protected ArrayList<Resource> getPart(Modules.Module module) {
+        return module.resources;
+    }
+
+    @Override
+    protected boolean setPart(Modules.Module module, ArrayList<Resource> part) {
+        boolean changed = module.resources == null || module.resources.hashCode() != part.hashCode();
+        module.resources = part;
+        return changed;
+    }
+
+    @Override
+    protected void upgrade(final String ID, final NetworkCallback<ArrayList<Resource>> callback, final NetworkErrorCallback errorCallback) {
+        if (!mLogin.isInOnlineMode() || mLogin.getLoginToken() == null) {
+            errorCallback.onError(new NetworkError(101604, 500, "Currently running in offline mode!"));
+            return;
+        }
+        get(String.format("https://kvv.imp.fu-berlin.de/direct/content/site/%s.json", ID), mLogin.getLoginToken().getCookies(), response -> {
+            String body = response.getParsed();
+            if (body == null) {
+                errorCallback.onError(new NetworkError(101601, 403, "No resources retrieved!"));
+                return;
+            }
+            ArrayList<Resource> resources = new ArrayList<>();
+            JSONArray sites;
+            try {
+                JSONObject json = new JSONObject(body);
+                sites = json.getJSONArray("content_collection");
+            } catch (JSONException e) {
+                e.printStackTrace();
+                errorCallback.onError(new NetworkError(101602, 403, "Cannot parse resources!"));
+                return;
+            }
+
+            for (int i = 0; i < sites.length(); i++) {
+                try {
+                    JSONObject site = sites.getJSONObject(i);
+                    String author = site.getString("author");
+                    String title = site.getString("title");
+                    long modifiedDate = site.getLong("modifiedDate");
+                    String url = site.getString("url");
+                    boolean visible = site.getBoolean("visible");
+                    String type = site.getString("type");
+                    String container = site.getString("container");
+                    if (type.equals("collection")){
+                        resources.add(new Resource.Folder(author, title, modifiedDate, url, visible, container));
+                    }
+                    else {
+                        resources.add(new Resource.File(author, title, modifiedDate, url, visible, container, type));
+                    }
+                } catch (JSONException e) {
+                    log.e(new NetworkError(101605, 403, "Cannot parse resources!"));
+                    e.printStackTrace();
+                    log.e("ID:", i, "JSON:", sites);
+                    return;
+                }
+            }
+
+            ArrayList<Resource> root = new ArrayList<>();
+            // Generate folder structure
+            for (Resource res: resources) {
+                if (!res.getContainer().equals("/content/group/")) {
+                    if (res.getContainer().equals("/content/group/"+ID+"/")){
+                        // if file in root folder
+                        root.add(res);
+                    } else {
+                        // in sub folder
+                        for (Resource res2: resources) {
+                            if (res2.getUrl().endsWith(res.getContainer()) && res2 instanceof Resource.Folder) {
+                                // Append File/Folder to list
+                                ((Resource.Folder) res2).add(res);
+                            }
+                        }
+                    }
+                }
+            }
+
+            // Empty resources *may be* because token is invalid -> check
+            if (resources.size() == 0)
+                mLogin.testLoginToken(token -> callback.onResponse(root), errorCallback);
+            else
+                callback.onResponse(root);
+        }, error -> errorCallback.onError(new NetworkError(101603, error.networkResponse.statusCode, "Cannot get resources!")));
+    }
+
+
+
+
+
+
+
+
+
+
+
+    public void file(final String filename, final String url, final String modulename, final NetworkCallback<String> callback, final NetworkErrorCallback errorCallback, boolean forceRefresh) {
+        file(filename, url, modulename, callback, errorCallback, forceRefresh, RETRY_COUNT);
+    }
+
+    public void file(final String filename, final String url, final String modulename, final NetworkCallback<String> callback, final NetworkErrorCallback errorCallback, boolean forceRefresh, int retries) {
+        if (isExternalStorageReadable()){
+            File f = new File(Environment.getExternalStoragePublicDirectory(
+                    Environment.DIRECTORY_DOWNLOADS)+"/"+modulename+"/"+filename);
+            // check if file already downloaded -> do not download again
+            if (f.exists() && !forceRefresh) {
+                callback.onResponse(f.getPath());
+                return;
+            }
+        }
+        fileUpgrade(filename, url , modulename, callback, error -> {
+            if (retries >= 0 && (error.getHttpStatus() == 401 || error.getHttpStatus() == 403)) {
+                mLogin.refreshLogin(success -> {
+                    file(filename, url, modulename, callback, errorCallback, forceRefresh, retries-1);
+                }, errorCallback);
+                return;
+            }
+            errorCallback.onError(error);
+        });
+    }
+
+    private void fileUpgrade(String filename, String url, String modulename, final NetworkCallback<String> callback, final NetworkErrorCallback errorCallback) {
+        if (!mLogin.isInOnlineMode() || mLogin.getLoginToken() == null) {
+            errorCallback.onError(new NetworkError(101604, 500, "Currently running in offline mode!"));
+            return;
+        }
+        get(url, mLogin.getLoginToken().getCookies(), response -> {
+            if (Regex.has("\\.[Uu][Rr][Ll]$", url)){
+                // Return redirected URL
+                String path = response.getHeaders().get("Location");
+                if (path == null){
+                    path = "";
+                }
+                callback.onResponse(path);
+            } else if (response.getBytes() == null) {
+                errorCallback.onError(new NetworkError(101705, 403, "Cannot get file!"));
+            } else if (isExternalStorageWritable()) {
+                String path = saveFileInDownloads(filename, response.getBytes(), modulename);
+                callback.onResponse(path);
+            } else {
+                errorCallback.onError(new NetworkError(101704, 403, "External storage not writable!"));
+            }
+        }, error -> errorCallback.onError(new NetworkError(101702, error.networkResponse.statusCode, "Cannot get file!")));
+
+
+    }
+
+
+
+
+
+
+
+    /* Checks if external storage is available for read and write */
+    private boolean isExternalStorageWritable() {
+        String state = Environment.getExternalStorageState();
+        if (Environment.MEDIA_MOUNTED.equals(state)) {
+            return true;
+        }
+        log.w("File system: Writing not possible!");
+        return false;
+    }
+
+    /* Checks if external storage is available to at least read */
+    private boolean isExternalStorageReadable() {
+        String state = Environment.getExternalStorageState();
+        if (Environment.MEDIA_MOUNTED.equals(state) ||
+                Environment.MEDIA_MOUNTED_READ_ONLY.equals(state)) {
+            return true;
+        }
+        log.w("File system: Reading not possible!");
+        return false;
+    }
+    private String saveFileInDownloads(String filename, byte[] data, String moduleName) {
+        // Saves file in folder: DOWNLOADS/moduleName
+        File folder = new File(Environment.getExternalStoragePublicDirectory(
+                Environment.DIRECTORY_DOWNLOADS), moduleName);
+        if (!folder.mkdir()) {
+            log.w( "Directory not created");
+        }
+        String path = "";
+        try {
+            // TODO check if enough storage space is available
+            FileOutputStream out = new FileOutputStream(folder.getPath()+"/"+filename);
+            out.write(data);
+            out.close();
+            path = folder.getPath()+"/"+filename;
+        } catch (Exception e) {
+            log.w("File not saved!");
+            e.printStackTrace();
+        }
+        return path;
+    }
+}

app/src/main/java/de/sebse/fuplanner/services/KVV/Part.java

@@ -0,0 +1,34 @@
+package de.sebse.fuplanner.services.KVV;
+
+import android.content.Context;
+
+import de.sebse.fuplanner.services.KVV.types.Modules;
+import de.sebse.fuplanner.tools.network.HTTPService;
+import de.sebse.fuplanner.tools.network.NetworkCallback;
+import de.sebse.fuplanner.tools.network.NetworkErrorCallback;
+
+public abstract class Part<T> extends HTTPService {
+    static final int RETRY_COUNT = 1;
+    protected final Login mLogin;
+    protected final ModulesList mList;
+
+    Part(Login login, ModulesList list, Context context) {
+        super(context);
+        this.mLogin = login;
+        this.mList = list;
+    }
+
+    public void recv(final String moduleID, final NetworkCallback<T> callback, final NetworkErrorCallback errorCallback) {
+        recv(moduleID, callback, errorCallback, false);
+    }
+
+    public void recv(final String moduleID, final NetworkCallback<T> callback, final NetworkErrorCallback errorCallback, final boolean forceRefresh) {
+        mList.find(moduleID, success -> recv(success, callback, errorCallback, forceRefresh), errorCallback);
+    }
+
+    public void recv(final Modules.Module module, final NetworkCallback<T> callback, final NetworkErrorCallback errorCallback, final boolean forceRefresh) {
+        recv(module, callback, errorCallback, forceRefresh, RETRY_COUNT);
+    }
+
+    abstract protected void recv(final Modules.Module module, final NetworkCallback<T> callback, final NetworkErrorCallback errorCallback, final boolean forceRefresh, final int retries);
+}

app/src/main/java/de/sebse/fuplanner/services/KVV/PartModules.java

@@ -0,0 +1,65 @@
+package de.sebse.fuplanner.services.KVV;
+
+import android.content.Context;
+import android.os.Build;
+import android.text.Html;
+import android.text.Spanned;
+
+import de.sebse.fuplanner.services.KVV.types.Modules;
+import de.sebse.fuplanner.tools.NewAsyncQueue;
+import de.sebse.fuplanner.tools.network.NetworkCallback;
+import de.sebse.fuplanner.tools.network.NetworkErrorCallback;
+
+abstract class PartModules<T> extends Part<Modules.Module> {
+    private NewAsyncQueue mQueue = new NewAsyncQueue();
+
+    PartModules(Login login, ModulesList list, Context context) {
+        super(login, list, context);
+    }
+
+    @Override
+    protected void recv(final Modules.Module module, final NetworkCallback<Modules.Module> callback, final NetworkErrorCallback errorCallback, final boolean forceRefresh, final int retries) {
+        mQueue.add(() -> {
+            if (getPart(module) != null && !forceRefresh) {
+                callback.onResponse(module);
+                mQueue.next();
+                return;
+            }
+            upgrade(module.getID(), success -> {
+                if (setPart(module, success)) {
+                    this.mList.store();
+                }
+                callback.onResponse(module);
+                mQueue.next();
+            }, error -> {
+                if (retries >= 0 && (error.getHttpStatus() == 401 || error.getHttpStatus() == 403)) {
+                    mLogin.refreshLogin(success -> {
+                        recv(module, callback, errorCallback, forceRefresh, retries-1);
+                        mQueue.next();
+                    }, error1 -> {
+                        errorCallback.onError(error1);
+                        mQueue.next();
+                    });
+                    return;
+                }
+                errorCallback.onError(error);
+                mQueue.next();
+            });
+        });
+    }
+
+    @SuppressWarnings("deprecation")
+    static Spanned fromHtml(String html){
+        if (Build.VERSION.SDK_INT >= Build.VERSION_CODES.N) {
+            return Html.fromHtml(html, Html.FROM_HTML_MODE_LEGACY);
+        } else {
+            return Html.fromHtml(html);
+        }
+    }
+
+    protected abstract T getPart(Modules.Module module);
+
+    protected abstract boolean setPart(Modules.Module module, T part);
+
+    protected abstract void upgrade(final String ID, final NetworkCallback<T> callback, final NetworkErrorCallback errorCallback);
+}

app/src/main/java/de/sebse/fuplanner/services/KVV/types/Announcement.java

@@ -1,5 +1,7 @@
 package de.sebse.fuplanner.services.KVV.types;
 
+import com.google.android.gms.common.internal.Objects;
+
 import java.io.Serializable;
 import java.util.ArrayList;
 
@@ -25,7 +27,7 @@ public class Announcement implements Serializable {
         return urls;
     }
 
-    public String getId() {
+    private String getId() {
         return id;
     }
 
@@ -54,4 +56,9 @@ public class Announcement implements Serializable {
                 "\nCreated on: "+getCreatedOn()+
                 "\nURLs: "+getUrls().toString();
     }
+
+    @Override
+    public int hashCode() {
+        return Objects.hashCode(getId(), getBody(), getCreatedBy(), getCreatedOn(), getTitle(), getUrls());
+    }
 }

app/src/main/java/de/sebse/fuplanner/services/KVV/types/Assignment.java

@@ -1,5 +1,7 @@
 package de.sebse.fuplanner.services.KVV.types;
 
+import com.google.android.gms.common.internal.Objects;
+
 import java.io.Serializable;
 import java.util.ArrayList;
 
@@ -7,8 +9,6 @@ public class Assignment implements Serializable {
     private final String id;
     private final String title;
     private final long dueTime;
-    private final String gradebookItemName;
-    private final String gradeScale;
     private final ArrayList<String> urls;
     private final String instructions;
 
@@ -16,14 +16,11 @@ public class Assignment implements Serializable {
         this.id = id;
         this.title = title;
         this.dueTime = dueTime;
-        this.gradebookItemName = gradebookItemName;
-        this.gradeScale = gradeScale;
         this.urls = urls;
-        //this.grade = grade;
         this.instructions = instructions;
     }
 
-    public String getId() {
+    private String getId() {
         return id;
     }
 
@@ -52,6 +49,11 @@ public class Assignment implements Serializable {
         return "ID: "+getId()+
                 "\nTitle: "+getTitle()+
                 "\nDue date: "+getDueDate()+
-                "\nInstuctions: "+getInstructions().substring(0, Math.min(getInstructions().length(), 100));
+                "\nInstructions: "+getInstructions().substring(0, Math.min(getInstructions().length(), 100));
+    }
+
+    @Override
+    public int hashCode() {
+        return Objects.hashCode(getId(), getDueDate(), getInstructions(), getTitle(), getUrls());
     }
 }

app/src/main/java/de/sebse/fuplanner/services/KVV/types/Event.java

@@ -1,5 +1,7 @@
 package de.sebse.fuplanner.services.KVV.types;
 
+import com.google.android.gms.common.internal.Objects;
+
 import java.io.Serializable;
 import java.nio.charset.StandardCharsets;
 import java.security.MessageDigest;
@@ -111,4 +113,9 @@ public class Event implements Serializable {
                 "\nStart Date: "+getStartDate()+
                 "\nEnd date: "+getEndDate();
     }
+
+    @Override
+    public int hashCode() {
+        return Objects.hashCode(getId(), getType(), getStartDate(), getEndDate(), getTitle(), getLocation());
+    }
 }

app/src/main/java/de/sebse/fuplanner/services/KVV/types/EventList.java

@@ -8,4 +8,9 @@ public class EventList extends DateSortedList<Event> {
     public long getDateByItem(Event item) {
         return item.getEndDate();
     }
+
+    @Override
+    public boolean reversed() {
+        return false;
+    }
 }

app/src/main/java/de/sebse/fuplanner/services/KVV/types/Grade.java

@@ -1,13 +1,15 @@
 package de.sebse.fuplanner.services.KVV.types;
 
+import com.google.android.gms.common.internal.Objects;
+
 import java.io.Serializable;
 
-public class Gradebook implements Serializable {
+public class Grade implements Serializable {
     private final String itemName;
     private final double grade;
     private final double maxPoints;
 
-    public Gradebook(String itemName, double points, double maxPoints) {
+    public Grade(String itemName, double points, double maxPoints) {
         this.itemName = itemName;
         this.grade = points;
         this.maxPoints = maxPoints;
@@ -31,4 +33,9 @@ public class Gradebook implements Serializable {
                 "\nPoints: "+ getPoints()+
                 "\nMax points: "+getMaxPoints();
     }
+
+    @Override
+    public int hashCode() {
+        return Objects.hashCode(getItemName(), getPoints(), getMaxPoints());
+    }
 }

app/src/main/java/de/sebse/fuplanner/services/KVV/types/GroupedEvents.java

@@ -0,0 +1,128 @@
+package de.sebse.fuplanner.services.KVV.types;
+
+
+import android.annotation.SuppressLint;
+
+import java.util.ArrayList;
+import java.util.Calendar;
+import java.util.Collections;
+import java.util.List;
+
+import androidx.annotation.NonNull;
+import de.sebse.fuplanner.tools.logging.Logger;
+
+public class GroupedEvents {
+    private ArrayList<Group> arrayList = new ArrayList<>();
+    private Logger log = new Logger(this);
+
+    public void add(Event event) {
+        Calendar calendar = Calendar.getInstance();
+        calendar.setTimeInMillis(event.getStartDate());
+        long dayOfWeek = calendar.get(Calendar.DAY_OF_WEEK);
+        for (Group group : arrayList) {
+            if (group.add(event)) {
+                return;
+            }
+        }
+        arrayList.add(new Group(event));
+    }
+
+    public List<Group> getGroups() {
+        return Collections.unmodifiableList(arrayList);
+    }
+
+    public class Group {
+        private long firstDate;
+        private long lastDate;
+        private ArrayList<Long> skippedDates;
+
+        private int dayOfWeek;
+        private long startTime;
+        private long duration;
+
+        private Group(Event event) {
+            Calendar calendar = Calendar.getInstance();
+            calendar.setTimeInMillis(event.getStartDate());
+            dayOfWeek = calendar.get(Calendar.DAY_OF_WEEK);
+            startTime = calendar.get(Calendar.HOUR_OF_DAY)*3600000+calendar.get(Calendar.MINUTE)*60000+calendar.get(Calendar.SECOND)*1000+calendar.get(Calendar.MILLISECOND);
+            duration = event.getEndDate()-event.getStartDate();
+
+            skippedDates = new ArrayList<>();
+            calendar.set(Calendar.HOUR_OF_DAY, 0);
+            calendar.set(Calendar.MINUTE, 0);
+            calendar.set(Calendar.SECOND, 0);
+            calendar.set(Calendar.MILLISECOND, 0);
+            firstDate = calendar.getTimeInMillis();
+            lastDate = firstDate;
+        }
+
+        private boolean add(Event event) {
+            Calendar calendar = Calendar.getInstance();
+            calendar.setTimeInMillis(event.getStartDate());
+            int dayOfWeek = calendar.get(Calendar.DAY_OF_WEEK);
+            int startTime = calendar.get(Calendar.HOUR_OF_DAY)*3600000+calendar.get(Calendar.MINUTE)*60000+calendar.get(Calendar.SECOND)*1000+calendar.get(Calendar.MILLISECOND);
+            long length = event.getEndDate()-event.getStartDate();
+            if (this.dayOfWeek != dayOfWeek || this.startTime != startTime || this.duration != length)
+                return false;
+            calendar.set(Calendar.HOUR_OF_DAY, 0);
+            calendar.set(Calendar.MINUTE, 0);
+            calendar.set(Calendar.SECOND, 0);
+            calendar.set(Calendar.MILLISECOND, 0);
+            long date = calendar.getTimeInMillis();
+            if (date < firstDate) {
+                firstDate = addDays(firstDate, -7);
+                while (firstDate > date) {
+                    skippedDates.add(firstDate);
+                    firstDate = addDays(firstDate, -7);
+                }
+            } else if (date > lastDate) {
+                lastDate = addDays(lastDate, 7);
+                while (lastDate < date) {
+                    skippedDates.add(lastDate);
+                    lastDate = addDays(lastDate, 7);
+                }
+            } else {
+                skippedDates.remove(date);
+            }
+            return true;
+        }
+
+        private long addDays(long timeInMillis, int days) {
+            Calendar calendar = Calendar.getInstance();
+            calendar.setTimeInMillis(timeInMillis);
+            calendar.add(Calendar.DAY_OF_YEAR, days);
+            return calendar.getTimeInMillis();
+        }
+
+        public long getFirstDate() {
+            return firstDate;
+        }
+
+        public long getLastDate() {
+            return lastDate;
+        }
+
+        public List<Long> getSkippedDates() {
+            return Collections.unmodifiableList(skippedDates);
+        }
+
+        public int getDayOfWeek() {
+            return dayOfWeek;
+        }
+
+        public long getStartTime() {
+            return startTime;
+        }
+
+        public long getDuration() {
+            return duration;
+        }
+
+        @SuppressLint("DefaultLocale")
+        @NonNull
+        @Override
+        public String toString() {
+            return String.format("%d - %d - %d - %s", dayOfWeek, startTime, duration, skippedDates);
+        }
+    }
+}

app/src/main/java/de/sebse/fuplanner/services/KVV/types/Lecturer.java

@@ -5,23 +5,25 @@ import java.util.regex.Matcher;
 import java.util.regex.Pattern;
 
 public class Lecturer implements Serializable {
-    private final String firstname;
+    private final String firstName;
     private final String surname;
     private final String mail;
+    private final boolean isResponsible;
 
     public Lecturer(String parsableString) throws NoSuchFieldException {
-        Pattern pattern = Pattern.compile("([^|]*)\\|([^|]*)\\|([^|]*)\\|\\|", Pattern.DOTALL);
+        Pattern pattern = Pattern.compile("([^|]*)\\|([^|]*)\\|([^|]*)\\|\\|([^|]*)", Pattern.DOTALL);
         Matcher matcher = pattern.matcher(parsableString);
         if (!matcher.find()) {
             throw new NoSuchFieldException();
         }
-        this.firstname = matcher.group(1);
+        this.firstName = matcher.group(1);
         this.surname = matcher.group(2);
         this.mail = matcher.group(3);
+        this.isResponsible = matcher.group(4).equals("true");
     }
 
-    public String getFirstname() {
-        return firstname;
+    public String getFirstName() {
+        return firstName;
     }
 
     public String getSurname() {
@@ -32,9 +34,21 @@ public class Lecturer implements Serializable {
         return mail;
     }
 
+    public boolean isResponsible() {
+        return isResponsible;
+    }
+
+    public String getName() {
+        return getFirstName() + " " + getSurname();
+    }
+
+    public String getNameShort() {
+        return getFirstName().substring(0, 1) + ". " + getSurname();
+    }
+
     @Override
     public String toString() {
-        return "First name: "+getFirstname()+
+        return "First name: "+ getFirstName()+
                 "\nSurname: "+getSurname()+
                 "\nMail: "+getMail();
     }

app/src/main/java/de/sebse/fuplanner/services/KVV/types/LoginToken.java

@@ -1,9 +1,9 @@
 package de.sebse.fuplanner.services.KVV.types;
 
 import android.content.Context;
-import android.support.annotation.Nullable;
 
 import java.io.FileInputStream;
+import java.io.FileNotFoundException;
 import java.io.FileOutputStream;
 import java.io.IOException;
 import java.io.ObjectInputStream;
@@ -11,21 +11,21 @@ import java.io.ObjectOutputStream;
 import java.io.Serializable;
 import java.util.HashMap;
 
+import androidx.annotation.Nullable;
+
 /**
  * Created by sebastian on 29.10.17.
  */
 
 public class LoginToken implements Serializable {
-    private static final long EASY_LOGIN_TIME_MILLIS = 1000 * 60 * 60 * 300;
     private static final String FILE_NAME = "LoginTokenSaving";
 
     private final String username;
     private final String shibsessionKey;
     private final String shibsessionName;
     private final String JSESSIONID;
-    private String fullname;
-    private String email;
-    private long saveDate = 0;
+    @Nullable private String fullName;
+    @Nullable private String email;
 
     public LoginToken(String username, String shibsessionKey, String shibsessionName, String JSESSIONID) {
         this.username = username;
@@ -36,17 +36,23 @@ public class LoginToken implements Serializable {
 
     @Nullable
     public static LoginToken load(Context context) throws IOException, ClassNotFoundException {
-        FileInputStream fis = context.openFileInput(FILE_NAME);
+        FileInputStream fis;
+        try {
+            fis = context.openFileInput(FILE_NAME);
+        } catch (FileNotFoundException e) {
+            return null;
+        }
         ObjectInputStream is = new ObjectInputStream(fis);
-        LoginToken loginToken = (LoginToken) is.readObject();
+        Object readObject = is.readObject();
+        if (!(readObject instanceof LoginToken))
+            return null;
+        LoginToken loginToken = (LoginToken) readObject;
         is.close();
         fis.close();
-        loginToken = (loginToken.saveDate > (System.currentTimeMillis() - EASY_LOGIN_TIME_MILLIS)) ? loginToken : null;
         return loginToken;
     }
 
     public void save(Context context) throws IOException {
-        saveDate = System.currentTimeMillis();
         FileOutputStream fos = context.openFileOutput(FILE_NAME, Context.MODE_PRIVATE);
         ObjectOutputStream os = new ObjectOutputStream(fos);
         os.writeObject(this);
@@ -58,8 +64,8 @@ public class LoginToken implements Serializable {
         context.deleteFile(FILE_NAME);
     }
 
-    public void setAdditionals(String fullname, String email) {
-        this.fullname = fullname;
+    public void setAdditionals(String fullName, String email) {
+        this.fullName = fullName;
         this.email = email;
     }
 
@@ -79,8 +85,8 @@ public class LoginToken implements Serializable {
         return JSESSIONID;
     }
 
-    public String getFullname() {
-        return fullname;
+    public String getFullName() {
+        return fullName;
     }
 
     public String getEmail() {
@@ -95,8 +101,8 @@ public class LoginToken implements Serializable {
         return cookies;
     }
 
-    public boolean isSameUser(LoginToken token) {
-        return token != null && this.getUsername().equals(token.getUsername());
+    public boolean isSameUser(String username) {
+        return this.getUsername().equals(username);
     }
 
     @Override

app/src/main/java/de/sebse/fuplanner/services/KVV/types/Modules.java

@@ -1,8 +1,8 @@
 package de.sebse.fuplanner.services.KVV.types;
 
 import android.content.Context;
-import android.support.annotation.NonNull;
-import android.support.annotation.Nullable;
+
+import org.jetbrains.annotations.NotNull;
 
 import java.io.FileInputStream;
 import java.io.FileOutputStream;
@@ -13,6 +13,10 @@ import java.io.Serializable;
 import java.util.ArrayList;
 import java.util.HashSet;
 import java.util.Iterator;
+import java.util.LinkedHashSet;
+
+import androidx.annotation.NonNull;
+import androidx.annotation.Nullable;
 
 /**
  * Created by sebastian on 29.10.17.
@@ -20,20 +24,21 @@ import java.util.Iterator;
 
 public class Modules implements Iterable<Modules.Module>, Serializable {
     private SortedListModule list;
-    private final LoginToken token;
+    private final String mUsername;
     //private transient Logger log = new Logger(this);
     private static final String FILE_NAME = "ModuleListSaving";
 
-    public Modules(LoginToken loginToken) {
-        this.token = loginToken;
+    public Modules(String username) {
+        this.mUsername = username;
         this.list = new SortedListModule();
     }
 
-    public void addModule(String semester, HashSet<String> lvNumber, String title, HashSet<Lecturer> lecturer, String type, String description, String ID) {
+    public void addModule(@Nullable Semester semester, HashSet<String> lvNumber, String title, LinkedHashSet<Lecturer> lecturer, String type, String description, String ID) {
         Module m = new Module(semester, lvNumber, title, lecturer, type, description, ID);
         this.list.add(m);
     }
 
+    @NonNull
     @Override
     public String toString() {
         return this.list.toString();
@@ -64,7 +69,10 @@ public class Modules implements Iterable<Modules.Module>, Serializable {
     public static Modules load(Context context) throws IOException, ClassNotFoundException {
         FileInputStream fis = context.openFileInput(FILE_NAME);
         ObjectInputStream is = new ObjectInputStream(fis);
-        Modules modules = (Modules) is.readObject();
+        Object readObject = is.readObject();
+        if (!(readObject instanceof Modules))
+            return null;
+        Modules modules = (Modules) readObject;
         is.close();
         fis.close();
         return modules;
@@ -82,8 +90,8 @@ public class Modules implements Iterable<Modules.Module>, Serializable {
         context.deleteFile(FILE_NAME);
     }
 
-    public LoginToken getToken() {
-        return token;
+    public String getUsername() {
+        return mUsername;
     }
 
     public void updateList(Modules modules) {
@@ -102,29 +110,25 @@ public class Modules implements Iterable<Modules.Module>, Serializable {
     }
 
     public class Module implements Serializable {
-        public final String semester;
-        public final HashSet<String> lvNumber;
-        public final String title;
-        public final HashSet<Lecturer> lecturer;
-        public final String type;
-        public final String description;
-        private final String ID;
+        @Nullable public final Semester semester;
+        @NotNull final HashSet<String> lvNumber;
+        @NotNull public final String title;
+        @NotNull
+        public final ArrayList<Lecturer> lecturer;
+        @Nullable public final String type;
+        @Nullable public final String description;
+        @NotNull private final String ID;
         @Nullable public ArrayList<Announcement> announcements;
         @Nullable public AssignmentList assignments;
         @Nullable public EventList events;
-        @Nullable public ArrayList<Gradebook> gradebook;
+        @Nullable public ArrayList<Grade> gradebook;
         @Nullable public ArrayList<Resource> resources;
 
-        /*private Module() {
-            this(null, null, null, null, null);
-            throw new AssertionError("Do not use this constructor!");
-        }*/
-
         public float getGradebookPercent(){
             float maxPoint = 0;
             float userPoint = 0;
             if (gradebook != null) {
-                for (Gradebook g : gradebook){
+                for (Grade g : gradebook){
                     maxPoint += g.getMaxPoints();
                     userPoint += g.getPoints();
                 }
@@ -134,24 +138,25 @@ public class Modules implements Iterable<Modules.Module>, Serializable {
             return userPoint/maxPoint;
         }
 
-        private Module(String semester, HashSet<String> lvNumber, String title, HashSet<Lecturer> lecturer, String type, String description, String ID) {
-            semester = semester.replace("SS", "S");
-            semester = semester.replaceAll("[0-9]{2}([0-9]{2})", "$1");
+        private Module(@Nullable Semester semester, @NotNull HashSet<String> lvNumber, @NotNull String title, @NotNull LinkedHashSet<Lecturer> lecturer, @Nullable String type, @Nullable String description, @NotNull String ID) {
+
             title = title.replaceAll("(.*?) (S[0-9]{2}|W[0-9/]{5})", "$1");
 
             this.semester = semester;
             this.lvNumber = lvNumber;
             this.title = title;
-            this.lecturer = lecturer;
+            this.lecturer = new ArrayList<>(lecturer);
             this.type = type;
             this.description = description;
             this.ID = ID;
         }
 
+        @NonNull
         public String getID() {
             return ID;
         }
 
+        @NonNull
         @Override
         public String toString() {
             return "Semester: "+semester+

app/src/main/java/de/sebse/fuplanner/services/KVV/types/Resource.java

@@ -1,22 +1,33 @@
 package de.sebse.fuplanner.services.KVV.types;
 
+import com.google.android.gms.common.internal.Objects;
+
 import java.io.Serializable;
+import java.util.ArrayList;
+
+import androidx.annotation.LayoutRes;
+import de.sebse.fuplanner.R;
+import de.sebse.fuplanner.tools.ui.treeview.LayoutItemType;
+import de.sebse.fuplanner.tools.ui.treeview.TreeNode;
 
 
+public abstract class Resource implements Serializable {
 
-public class Resource implements Serializable {
-
-    private final String author;
-    private final long modifiedDate;
-    private final String title;
-    private final String url;
+    final String author;
+    final long modifiedDate;
+    final String title;
+    final String url;
+    private final boolean visible;
+    private final String container;
 
 
-    public Resource(String author, String title, long modifiedDate, String url) {
+    Resource(String author, String title, long modifiedDate, String url, boolean visible, String container) {
         this.author = author;
         this.title = title;
         this.modifiedDate = modifiedDate;
         this.url = url;
+        this.visible = visible;
+        this.container = container;
     }
 
     public String getAuthor() {
@@ -35,16 +46,96 @@ public class Resource implements Serializable {
         return url;
     }
 
-    @Override
-    public String toString() {
-        return "Resource{" +
-                "author='" + author + '\'' +
-                ", modifiedDate=" + modifiedDate +
-                ", title='" + title + '\'' +
-                ", url='" + url + '\'' +
-                '}';
+    public String getContainer() {
+        return container;
     }
 
+    public boolean isVisible() {
+        return visible;
+    }
 
+    public abstract TreeNode getTreeNode();
 
+    @Override
+    public int hashCode() {
+        return Objects.hashCode(getAuthor(), getContainer(), getModifiedDate(), getTitle(), getUrl());
+    }
+
+    public static class File extends Resource implements LayoutItemType {
+        private final String type;
+
+        public File(String author, String title, long modifiedDate, String url, boolean visible, String container, String type) {
+            super(author, title, modifiedDate, url, visible, container);
+            this.type = type;
+        }
+
+        @Override
+        public String toString() {
+            return "Resource{" +
+                    "author='" + author + '\'' +
+                    ", modifiedDate=" + modifiedDate +
+                    ", title='" + title + '\'' +
+                    ", url='" + url + '\'' +
+                    ", type='" + type + '\'' +
+                    '}';
+        }
+
+        @Override
+        public TreeNode getTreeNode() {
+            return new TreeNode<>(this);
+        }
+
+        @Override
+        public @LayoutRes int getLayoutId() {
+            return R.layout.item_file;
+        }
+    }
+
+    public static class Folder extends Resource implements LayoutItemType {
+
+        private final ArrayList<Resource> children;
+        public Folder(String author, String title, long modifiedDate, String url, boolean visible, String container) {
+            super(author, title, modifiedDate, url, visible, container);
+            children = new ArrayList<>();
+        }
+
+        public void add(Resource res){
+            children.add(res);
+        }
+
+        public Resource get(int id){
+            return children.get(id);
+        }
+
+        public int size(){
+            return children.size();
+        }
+
+        @Override
+        public String toString() {
+            return "Resource{" +
+                    "author='" + author + '\'' +
+                    ", modifiedDate=" + modifiedDate +
+                    ", title='" + title + '\'' +
+                    ", url='" + url + '\'' +
+                    ", children='" + children + '\'' +
+                    '}';
+        }
+
+        @Override
+        public TreeNode getTreeNode() {
+            TreeNode dir = new TreeNode<>(this);
+            for (Resource res: children) {
+                dir.addChild(res.getTreeNode());
+            }
+            return dir;
+        }
+
+        @Override
+        public @LayoutRes int getLayoutId() {
+            return R.layout.item_dir;
+        }
+    }
 }
+
+

app/src/main/java/de/sebse/fuplanner/services/KVV/types/Semester.java

@@ -0,0 +1,55 @@
+package de.sebse.fuplanner.services.KVV.types;
+
+import java.io.Serializable;
+
+import androidx.annotation.Nullable;
+import de.sebse.fuplanner.tools.Regex;
+
+public class Semester implements Serializable {
+    public static final int SEM_WS = 1;
+    public static final int SEM_SS = 2;
+    private int type;
+    private int year;
+
+    public Semester(int type, int year) {
+        this.type = type;
+        this.year = year;
+    }
+
+    public Semester(String semester_string) throws NoSuchFieldException {
+        /*Semester sem = null;
+            if (semester != null) {
+                sem = new Semester(semester)
+                semester = semester.replace("SS", "S");
+                semester = semester.replaceAll("[0-9]{2}([0-9]{2})", "$1");
+            }*/
+
+
+        /*String s1type = Regex.regex("^(S|WS) ", a);
+        int s1year = Integer.parseInt(Regex.regex("^(S|WS) ([0-9]{2})", a, 2));
+        String s2type = Regex.regex("^(S|WS) ", b);
+        int s2year = Integer.parseInt(Regex.regex("^(S|WS) ([0-9]{2})", b, 2));*/
+
+        String type = Regex.regex("^(SS|WS) ", semester_string);
+        String year = Regex.regex("^(SS|WS) ([0-9]{2})", semester_string, 2);
+        this.type = type.equals("SS") ? SEM_SS : SEM_WS;
+        this.year = Integer.parseInt(year);
+    }
+
+    public int getType() {
+        return type;
+    }
+
+    public int getYear() {
+        return year;
+    }
+
+    @Override
+    public boolean equals(@Nullable Object obj) {
+        if (obj instanceof Semester) {
+            Semester other = (Semester) obj;
+            return other.type == type && other.year == year;
+        }
+        return false;
+    }
+}

app/src/main/java/de/sebse/fuplanner/services/KVV/types/SortedListModule.java

@@ -1,9 +1,9 @@
 package de.sebse.fuplanner.services.KVV.types;
 
-import de.sebse.fuplanner.tools.Regex;
+import androidx.annotation.Nullable;
 import de.sebse.fuplanner.tools.SortedList;
 
-public class SortedListModule extends SortedList<Modules.Module, String, String> {
+public class SortedListModule extends SortedList<Modules.Module, String, Semester> {
     private static final int LARGER = 1;
     private static final int EQUAL = 0;
     private static final int SMALLER = -1;
@@ -27,7 +27,7 @@ public class SortedListModule extends SortedList<Modules.Module, String, String>
         super.add(e);
     }
 
-    public String getLatestSemester() {
+    public Semester getLatestSemester() {
         if (size() > 0)
             //noinspection ConstantConditions
             return this.get(0).semester;
@@ -35,7 +35,7 @@ public class SortedListModule extends SortedList<Modules.Module, String, String>
             return null;
     }
 
-    private static int compareSemester(String a, String b) throws NoSuchFieldException {
+    private static int compareSemester(@Nullable Semester a, @Nullable Semester b) throws NoSuchFieldException {
         if (a == null && b == null)
             return EQUAL;
         if (a == null)
@@ -43,17 +43,13 @@ public class SortedListModule extends SortedList<Modules.Module, String, String>
         if (b == null)
             return LARGER;
 
-        String s1type = Regex.regex("(S|WS)", a);
-        int s1year = Integer.parseInt(Regex.regex("(S|WS) ([0-9]{2})", a, 2));
-        String s2type = Regex.regex("(S|WS)", b);
-        int s2year = Integer.parseInt(Regex.regex("(S|WS) ([0-9]{2})", b, 2));
 
-        if (s1year == s2year) {
-            if (s1type.equals(s2type))
+        if (a.getYear() == b.getYear()) {
+            if (a.getType() == b.getType())
                 return EQUAL;
-            return s1type.equals("SS") ? SMALLER : LARGER;
+            return a.getType() == Semester.SEM_SS ? SMALLER : LARGER;
         }
-        return s1year < s2year ? SMALLER : LARGER;
+        return a.getYear() < b.getYear() ? SMALLER : LARGER;
     }
 
     @Override
@@ -62,7 +58,7 @@ public class SortedListModule extends SortedList<Modules.Module, String, String>
     }
 
     @Override
-    public boolean hasFilter(Modules.Module o1, String filter) {
-        return o1.semester.equals(filter);
+    public boolean hasFilter(Modules.Module o1, Semester filter) {
+        return o1.semester != null && o1.semester.equals(filter);
     }
 }

app/src/main/java/de/sebse/fuplanner/services/KVV/ui/Download.java

@@ -0,0 +1,264 @@
+package de.sebse.fuplanner.services.KVV.ui;
+
+import android.Manifest;
+import android.app.AlertDialog;
+import android.content.Context;
+import android.content.Intent;
+import android.content.pm.PackageManager;
+import android.content.res.Resources;
+import android.net.Uri;
+import android.os.Environment;
+
+import java.io.File;
+import java.util.ArrayList;
+import java.util.Arrays;
+
+import androidx.annotation.Nullable;
+import androidx.core.app.ActivityCompat;
+import androidx.core.content.FileProvider;
+import de.sebse.fuplanner.MainActivity;
+import de.sebse.fuplanner.R;
+import de.sebse.fuplanner.services.KVV.types.Resource;
+import de.sebse.fuplanner.tools.Regex;
+import de.sebse.fuplanner.tools.RequestPermissionsResultListener;
+import de.sebse.fuplanner.tools.UtilsDate;
+import de.sebse.fuplanner.tools.logging.Logger;
+
+import static androidx.core.content.ContextCompat.checkSelfPermission;
+
+public class Download {
+
+    private final ContextInterface contextInterface;
+    private final ActivityInterface activityInterface;
+    private RequestedDownload requestedDownload;
+    private Logger log = new Logger(this);
+
+
+    public Download(ContextInterface contextInterface, ActivityInterface activityInterface) {
+        this.contextInterface = contextInterface;
+        this.activityInterface = activityInterface;
+    }
+
+    public void openDownloadDialog(String title, String url, String folderName) {
+        openDownloadDialog(new Resource.File("", title, 0, url, true, "", ""), folderName);
+    }
+
+    public void openDownloadDialog(Resource.File file, String folderName) {
+        Context context = contextInterface.get();
+        if (context == null)
+            return;
+        AlertDialog.Builder alertDialogBuilder = new AlertDialog.Builder(context);
+        File f = new File(Environment.getExternalStoragePublicDirectory(
+                Environment.DIRECTORY_DOWNLOADS)+"/"+folderName+"/"+file.getTitle());
+        Resources resources = context.getResources();
+        String message = "";
+        if (file.getAuthor() != null && !file.getAuthor().isEmpty())
+            message += resources.getString(R.string.creator_name, file.getAuthor());
+        if (file.getModifiedDate() != 0) {
+            if (!message.isEmpty())
+                message += "\n";
+            message += resources.getString(R.string.last_modified_on, UtilsDate.getModifiedDateTime(context, file.getModifiedDate()));
+        }
+
+        alertDialogBuilder
+                .setTitle(file.getTitle())
+                .setMessage(message)
+                .setCancelable(true)
+                .setNeutralButton(R.string.close, (dialog, id) -> dialog.cancel());
+        // if already downloaded, show open button
+        if (f.exists()) {
+            alertDialogBuilder
+                    .setPositiveButton(R.string.download_again, (dialog, id) -> download(file, folderName, true))
+                    .setNegativeButton(R.string.openFile, (dialog, id) -> download(file, folderName, false));
+        } else {
+            alertDialogBuilder
+                    .setPositiveButton(R.string.download, (dialog, id) -> download(file, folderName, true));
+        }
+        AlertDialog alertDialog = alertDialogBuilder.create();
+        alertDialog.show();
+    }
+
+    private void download(Resource.File file, String folderName, boolean downloadNew){
+        MainActivity activity = activityInterface.get();
+        if (activity == null) {
+            showDownloadError();
+            return;
+        }
+        if (checkSelfPermission(activity, Manifest.permission.WRITE_EXTERNAL_STORAGE) == PackageManager.PERMISSION_GRANTED) {
+            // Access granted
+            downloadOrOpen(file, folderName, downloadNew);
+        } else {
+            this.requestedDownload = new RequestedDownload(file, folderName, downloadNew);
+            ActivityCompat.requestPermissions(activity,
+                    new String[]{Manifest.permission.WRITE_EXTERNAL_STORAGE},
+                    1);
+        }
+    }
+
+    private void downloadOrOpen(Resource.File file, String folderName, boolean downloadNew) {
+        if (!isExternalStorageWritable()) {
+            return;
+        }
+        MainActivity activity = activityInterface.get();
+        if (activity == null) {
+            showDownloadError();
+            return;
+        }
+        activity.getKVV().modules().resources().file(file.getTitle(), file.getUrl(), folderName, success -> {
+            Context context = contextInterface.get();
+            if (success.equals("")) {
+                showDownloadError();
+            } else {
+                if (Regex.has("^http", success)){
+                    Intent intent = new Intent(Intent.ACTION_VIEW, Uri.parse(success));
+                    context.startActivity(intent);
+                }
+                else {
+                    fileOpen(new File(success));
+                }
+
+            }
+        }, log::e, downloadNew);
+    }
+
+    private void showDownloadError() {
+        Context context = contextInterface.get();
+        if (context == null)
+            return;
+        AlertDialog.Builder alertDialogBuilder = new AlertDialog.Builder(context);
+        alertDialogBuilder
+                .setTitle(R.string.ErrorFileDownload)
+                .setMessage(
+                        R.string.ErrorFileDownloadText
+                )
+                .setCancelable(true)
+                .setNeutralButton(R.string.close, (dialog, id) -> dialog.cancel());
+        AlertDialog alertDialog = alertDialogBuilder.create();
+        alertDialog.show();
+    }
+
+    public RequestPermissionsResultListener getRequestPermissionsResultListener() {
+        return (requestCode, permissions, grantResults) -> {
+            if (requestedDownload == null) {
+                log.d("No request");
+                return;
+            }
+            if (activityInterface.get() == null) {
+                showDownloadError();
+                return;
+            }
+            ArrayList<Integer> intList = new ArrayList<>();
+            for (int i : grantResults)
+            {
+                intList.add(i);
+            }
+            log.d(requestCode, Arrays.asList(permissions), intList);
+            int pos = Arrays.asList(permissions).indexOf("android.permission.WRITE_EXTERNAL_STORAGE");
+            if (pos != -1) {
+                if (grantResults[pos] != -1) {
+                    downloadOrOpen(requestedDownload.file, requestedDownload.folderName, requestedDownload.downloadNew);
+                } else {
+                    log.d(requestedDownload, pos, grantResults[pos]);
+                    showDownloadError();
+                }
+                requestedDownload = null;
+            }
+        };
+    }
+
+    private class RequestedDownload {
+        Resource.File file;
+        String folderName;
+        boolean downloadNew;
+
+        RequestedDownload(Resource.File file, String folderName, boolean downloadNew) {
+            this.file = file;
+            this.folderName = folderName;
+            this.downloadNew = downloadNew;
+        }
+    }
+
+    /* Checks if external storage is available for read and write */
+    private boolean isExternalStorageWritable() {
+        String state = Environment.getExternalStorageState();
+        if (Environment.MEDIA_MOUNTED.equals(state)) {
+            return true;
+        }
+        log.e("File system: Writing not possible");
+        return false;
+    }
+
+    private void fileOpen(File url){
+        Uri uri = FileProvider.getUriForFile(contextInterface.get(), contextInterface.get().getApplicationContext().getPackageName() + ".my.provider", url);
+
+        Intent intent;
+        if (android.os.Build.VERSION.SDK_INT >= android.os.Build.VERSION_CODES.KITKAT) {
+            intent = new Intent(Intent.ACTION_VIEW);
+        } else {
+            intent = new Intent();
+        }
+        intent.addFlags(Intent.FLAG_GRANT_READ_URI_PERMISSION);
+        intent.addFlags(Intent.FLAG_GRANT_WRITE_URI_PERMISSION);
+        // Check what kind of file you are trying to open, by comparing the url with extensions.
+        // When the if condition is matched, plugin sets the correct intent (mime) type,
+        // so Android knew what application to use to open the file
+        if (url.toString().contains(".doc") || url.toString().contains(".docx")) {
+            // Word document
+            intent.setDataAndType(uri, "application/msword");
+        } else if(url.toString().contains(".pdf")) {
+            // PDF file
+            intent.setDataAndType(uri, "application/pdf");
+        } else if(url.toString().contains(".ppt") || url.toString().contains(".pptx")) {
+            // Powerpoint file
+            intent.setDataAndType(uri, "application/vnd.ms-powerpoint");
+        } else if(url.toString().contains(".xls") || url.toString().contains(".xlsx")) {
+            // Excel file
+            intent.setDataAndType(uri, "application/vnd.ms-excel");
+        } else if(url.toString().contains(".zip") || url.toString().contains(".rar")) {
+            // ZIP file
+            intent.setDataAndType(uri, "application/zip");
+        } else if(url.toString().contains(".rtf")) {
+            // RTF file
+            intent.setDataAndType(uri, "application/rtf");
+        } else if(url.toString().contains(".wav") || url.toString().contains(".mp3")) {
+            // WAV audio file
+            intent.setDataAndType(uri, "audio/x-wav");
+        } else if(url.toString().contains(".gif")) {
+            // GIF file
+            intent.setDataAndType(uri, "image/gif");
+        } else if(url.toString().contains(".jpg") || url.toString().contains(".jpeg") || url.toString().contains(".png")) {
+            // JPG file
+            intent.setDataAndType(uri, "image/jpeg");
+        } else if(url.toString().contains(".txt")) {
+            // Text file
+            intent.setDataAndType(uri, "text/plain");
+        } else if(url.toString().contains(".3gp") || url.toString().contains(".mpg") || url.toString().contains(".mpeg") || url.toString().contains(".mpe") || url.toString().contains(".mp4") || url.toString().contains(".avi")) {
+            // Video files
+            intent.setDataAndType(uri, "video/*");
+        } else {
+            //if you want you can also define the intent type for any other file
+
+            //additionally use else clause below, to manage other unknown extensions
+            //in this case, Android will show all applications installed on the device
+            //so you can choose which application to use
+            intent.setDataAndType(uri, "*/*");
+        }
+        intent.addFlags(Intent.FLAG_ACTIVITY_NEW_TASK);
+        contextInterface.get().startActivity(intent);
+
+    }
+
+    @FunctionalInterface
+    public interface ContextInterface {
+        @Nullable Context get();
+    }
+
+    @FunctionalInterface
+    public interface ActivityInterface {
+        @Nullable MainActivity get();
+    }
+
+    public interface OnDownloadRequestInterface {
+        void request(String title, String url);
+    }
+}

app/src/main/java/de/sebse/fuplanner/tools/AsyncQueue.java

@@ -8,7 +8,7 @@ import de.sebse.fuplanner.tools.network.NetworkErrorCallback;
 
 public class AsyncQueue {
     private final HashMap<String, LinkedList<AsyncQueueCallback>> mQueues = new HashMap<>();
-    private final HashMap<String, Boolean> mRunnings = new HashMap<>();
+    private final HashMap<String, Boolean> mIsRunning = new HashMap<>();
 
     public void add(String hash, AsyncQueueCallback callback) {
         if (isRunning(hash))
@@ -46,11 +46,11 @@ public class AsyncQueue {
     }
 
     private boolean isRunning(String hash) {
-        return mRunnings.containsKey(hash) && mRunnings.get(hash);
+        return mIsRunning.containsKey(hash) && mIsRunning.get(hash);
     }
 
     private void setRunning(String hash, boolean value) {
-        mRunnings.put(hash, value);
+        mIsRunning.put(hash, value);
     }
 
     private LinkedList<AsyncQueueCallback> getQueue(String hash) {

app/src/main/java/de/sebse/fuplanner/tools/ColorRGB.java

@@ -7,7 +7,7 @@ public class ColorRGB implements Color {
     private final int mGreen;
     private final int mBlue;
 
-    public ColorRGB(int red, int green, int blue) {
+    private ColorRGB(int red, int green, int blue) {
         this.mRed = red;
         this.mGreen = green;
         this.mBlue = blue;

app/src/main/java/de/sebse/fuplanner/tools/ColorRes.java

@@ -1,7 +1,7 @@
 package de.sebse.fuplanner.tools;
 
 import android.graphics.Paint;
-import android.support.annotation.ColorInt;
+import androidx.annotation.ColorInt;
 
 public class ColorRes implements Color {
     @ColorInt private final int mResId;

app/src/main/java/de/sebse/fuplanner/tools/DateSortedList.java

@@ -11,21 +11,20 @@ public abstract class DateSortedList<T> extends ArrayList<T> {
     public T getPast(int index) {
         if (split < 0)
             sort();
-        if (index >= split)
+        if (index >= this.sizePast())
             throw new ArrayIndexOutOfBoundsException(String.format("Index %d out of bounds! Only %d past events found!", index, split));
         if (reversed())
-            index = sizePast() - index - 1;
+            index += sizeUpcoming();
         return this.get(index);
     }
 
     public T getUpcoming(int index) {
         if (split < 0)
             sort();
-        index += split;
-        if (index >= this.size())
+        if (index >= this.sizeUpcoming())
             throw new ArrayIndexOutOfBoundsException(String.format("Index %d out of bounds! Only %d upcoming events found!", index-split, this.size()-split));
-        if (reversed())
-            index = sizeUpcoming() - index - 1;
+        if (!reversed())
+            index += this.sizePast();
         return this.get(index);
     }
 
@@ -34,7 +33,7 @@ public abstract class DateSortedList<T> extends ArrayList<T> {
         if (split < 0)
             sort();
         if (reversed())
-            index = size() - index - 1;
+            index = size() - 1 - index;
         return super.get(index);
     }
 

app/src/main/java/de/sebse/fuplanner/tools/EventListener.java

@@ -0,0 +1,26 @@
+package de.sebse.fuplanner.tools;
+
+import java.util.HashMap;
+
+public class EventListener<T> {
+    private HashMap<String, EventFunction<T>> list = new HashMap<>();
+
+    public void add(String id,EventFunction<T> listener) {
+        list.put(id, listener);
+    }
+
+    public void remove(String id) {
+        list.remove(id);
+    }
+
+    public void emit(T value) {
+        for (EventFunction<T> listener : list.values()) {
+            listener.apply(value);
+        }
+    }
+
+    @FunctionalInterface
+    public interface EventFunction<T> {
+        void apply(T value);
+    }
+}

app/src/main/java/de/sebse/fuplanner/tools/MainActivityListener.java

@@ -1,23 +1,30 @@
 package de.sebse.fuplanner.tools;
 
-import android.support.annotation.StringRes;
+import androidx.annotation.StringRes;
 
 import de.sebse.fuplanner.services.Canteen.CanteenBrowser;
 import de.sebse.fuplanner.services.GoogleAuth.GoogleAuth;
 import de.sebse.fuplanner.services.KVV.KVV;
 
-public interface MainAcitivityListener {
+public interface MainActivityListener {
     void onTitleTextChange(String newTitle);
 
     void onTitleTextChange(@StringRes int titleId);
 
+    void showToast(String message);
+
+    void showToast(@StringRes int msgStringRes);
+
     KVV getKVV();
 
     GoogleAuth getGoogleAuth();
 
-    void loginTokenInvalid(boolean doPrecheck);
-
-    void refreshFailed(boolean isFailed);
-
     CanteenBrowser getCanteenBrowser();
+
+    @Deprecated
+    void onRefreshCompleted(boolean isFailed);
+
+    void addRequestPermissionsResultListener(RequestPermissionsResultListener listener, String id);
+
+    void removeRequestPermissionsResultListener(String id);
 }

app/src/main/java/de/sebse/fuplanner/tools/NewAsyncQueue.java

@@ -0,0 +1,58 @@
+package de.sebse.fuplanner.tools;
+
+import java.util.LinkedList;
+
+import de.sebse.fuplanner.tools.network.NetworkCallback;
+import de.sebse.fuplanner.tools.network.NetworkErrorCallback;
+
+public class NewAsyncQueue {
+    private final LinkedList<AsyncQueueCallback> mQueue = new LinkedList<>();
+    private boolean mIsRunning = false;
+
+    public void add(AsyncQueueCallback callback) {
+        if (isRunning())
+            getQueue().addLast(callback);
+        else {
+            setRunning(true);
+            callback.run();
+        }
+    }
+
+    public void next() {
+        AsyncQueueCallback callback = getQueue().pollFirst();
+        if (callback == null)
+            setRunning(false);
+        else
+            callback.run();
+    }
+
+    public interface AsyncQueueCallback {
+        void run();
+    }
+
+    public NetworkErrorCallback check(NetworkErrorCallback value) {
+        return error -> {
+            value.onError(error);
+            next();
+        };
+    }
+
+    public <T> NetworkCallback<T> check(NetworkCallback<T> value) {
+        return success -> {
+            value.onResponse(success);
+            next();
+        };
+    }
+
+    private boolean isRunning() {
+        return mIsRunning;
+    }
+
+    private void setRunning(boolean value) {
+        mIsRunning = value;
+    }
+
+    private LinkedList<AsyncQueueCallback> getQueue() {
+        return mQueue;
+    }
+}

app/src/main/java/de/sebse/fuplanner/tools/Preferences.java

@@ -1,8 +1,8 @@
 package de.sebse.fuplanner.tools;
 
 import android.content.Context;
-import android.support.annotation.ArrayRes;
-import android.support.v7.preference.PreferenceManager;
+import androidx.annotation.ArrayRes;
+import androidx.preference.PreferenceManager;
 
 public class Preferences {
     public static String getString(Context context, @ArrayRes int key) {

app/src/main/java/de/sebse/fuplanner/tools/Regex.java

@@ -9,6 +9,14 @@ import java.util.regex.Matcher;
 import java.util.regex.Pattern;
 
 public class Regex {
+    public static boolean has(@Language("Regexp") String regex, String match) {
+        try {
+            regex(regex, match, 0);
+            return true;
+        } catch (NoSuchFieldException e) {
+            return false;
+        }
+    }
     public static String regex(@Language("Regexp") String regex, String match) throws NoSuchFieldException {
         return regex(regex, match, 1);
     }

app/src/main/java/de/sebse/fuplanner/tools/RequestPermissionsResultListener.java

@@ -0,0 +1,5 @@
+package de.sebse.fuplanner.tools;
+
+public interface RequestPermissionsResultListener {
+    void callback(int requestCode, String[] permissions, int[] grantResults);
+}

app/src/main/java/de/sebse/fuplanner/tools/SortedList.java

@@ -1,7 +1,7 @@
 package de.sebse.fuplanner.tools;
 
-import android.support.annotation.NonNull;
-import android.support.annotation.Nullable;
+import androidx.annotation.NonNull;
+import androidx.annotation.Nullable;
 
 import java.io.Serializable;
 import java.util.ArrayList;
@@ -25,6 +25,7 @@ public abstract class SortedList<T, I, F> implements Iterable<T>, Serializable {
 
     protected abstract boolean hasIdentifier(T o1, I id);
 
+    @SuppressWarnings("BooleanMethodIsAlwaysInverted")
     protected abstract boolean hasFilter(T o1, F filter);
 
     @Nullable

app/src/main/java/de/sebse/fuplanner/tools/Triplet.java

@@ -0,0 +1,14 @@
+package de.sebse.fuplanner.tools;
+
+public class Triplet<T, U, V> {
+
+    public final T first;
+    public final U second;
+    public final V third;
+
+    public Triplet(T first, U second, V third) {
+        this.first = first;
+        this.second = second;
+        this.third = third;
+    }
+}

app/src/main/java/de/sebse/fuplanner/tools/UtilsDate.java

@@ -4,16 +4,14 @@ import android.annotation.SuppressLint;
 import android.annotation.TargetApi;
 import android.content.Context;
 import android.os.Build;
-import android.support.annotation.Nullable;
+import androidx.annotation.Nullable;
 import android.text.format.DateFormat;
 
-import com.google.android.gms.common.logging.Logger;
-
 import java.text.SimpleDateFormat;
 import java.util.Date;
 import java.util.Locale;
 
-public class DateUtils {
+public class UtilsDate {
     @Deprecated
     public static String getModifiedDateTime(long modified) {
         return getModifiedDateTime(null, modified);
@@ -48,6 +46,8 @@ public class DateUtils {
 
         if (context != null && DateFormat.is24HourFormat(context))
             skeleton = skeleton.replaceAll("h", "H");
+        if (context != null && !DateFormat.is24HourFormat(context))
+            skeleton = skeleton.replaceAll("H", "h");
         if (Build.VERSION.SDK_INT >= Build.VERSION_CODES.JELLY_BEAN_MR2) {
             dateFormat = new SimpleDateFormat(getDateFormat(locale, skeleton));
         } else {

app/src/main/java/de/sebse/fuplanner/tools/UtilsUi.java

@@ -0,0 +1,17 @@
+package de.sebse.fuplanner.tools;
+
+import android.content.Context;
+import android.content.res.Resources;
+import android.util.DisplayMetrics;
+
+public class UtilsUi {
+    public static float convertPixelsToDp(float px, Context context) {
+        Resources resources = context.getResources();
+        DisplayMetrics metrics = resources.getDisplayMetrics();
+        return px / ((float) metrics.densityDpi / DisplayMetrics.DENSITY_DEFAULT);
+    }
+
+    public static float convertDpToPixels(Context context, float dp) {
+        return dp * context.getResources().getDisplayMetrics().density;
+    }
+}

app/src/main/java/de/sebse/fuplanner/tools/logging/Logger.java

@@ -10,10 +10,14 @@ public class Logger {
     }
 
     public Logger(Object object) {
+        this.tag = getClassName(object);
+    }
+
+    private static String getClassName(Object object) {
         if (object instanceof String)
-            this.tag = (String) object;
+            return (String) object;
         else
-            this.tag = object.getClass().getSimpleName();
+            return object.getClass().getSimpleName();
     }
 
     public void d(Object... msg) {

app/src/main/java/de/sebse/fuplanner/tools/network/BetterHurlStack.java

@@ -1,24 +1,18 @@
 package de.sebse.fuplanner.tools.network;
 
 import com.android.volley.AuthFailureError;
+import com.android.volley.Header;
 import com.android.volley.Request;
+import com.android.volley.toolbox.HttpResponse;
 import com.android.volley.toolbox.HurlStack;
 
-import org.apache.http.Header;
-import org.apache.http.HttpEntity;
-import org.apache.http.HttpResponse;
-import org.apache.http.ProtocolVersion;
-import org.apache.http.StatusLine;
-import org.apache.http.entity.BasicHttpEntity;
-import org.apache.http.message.BasicHeader;
-import org.apache.http.message.BasicHttpResponse;
-import org.apache.http.message.BasicStatusLine;
-
 import java.io.DataOutputStream;
+import java.io.FilterInputStream;
 import java.io.IOException;
 import java.io.InputStream;
 import java.net.HttpURLConnection;
 import java.net.URL;
+import java.util.ArrayList;
 import java.util.HashMap;
 import java.util.List;
 import java.util.Map;
@@ -28,12 +22,15 @@ import java.util.regex.Pattern;
 import javax.net.ssl.HttpsURLConnection;
 import javax.net.ssl.SSLSocketFactory;
 
+import androidx.annotation.VisibleForTesting;
+
 /**
  * Created by sebastian on 29.10.17.
  */
 
 public class BetterHurlStack extends HurlStack {
     private static final String HEADER_CONTENT_TYPE = "Content-Type";
+    private static final int HTTP_CONTINUE = 100;
 
     private final UrlRewriter mUrlRewriter;
     private final SSLSocketFactory mSslSocketFactory;
@@ -50,14 +47,14 @@ public class BetterHurlStack extends HurlStack {
     /**
      * @param urlRewriter Rewriter to use for request URLs
      */
-    BetterHurlStack(boolean followRedirects, UrlRewriter urlRewriter) {
+    private BetterHurlStack(boolean followRedirects, UrlRewriter urlRewriter) {
         this(followRedirects, urlRewriter, null);
     }
     /**
      * @param urlRewriter Rewriter to use for request URLs
      * @param sslSocketFactory SSL factory to use for HTTPS connections
      */
-    BetterHurlStack(boolean followRedirects, UrlRewriter urlRewriter, SSLSocketFactory sslSocketFactory) {
+    private BetterHurlStack(boolean followRedirects, UrlRewriter urlRewriter, SSLSocketFactory sslSocketFactory) {
         super(urlRewriter, sslSocketFactory);
         mUrlRewriter = urlRewriter;
         mSslSocketFactory = sslSocketFactory;
@@ -76,12 +73,12 @@ public class BetterHurlStack extends HurlStack {
     }
 
     @Override
-    public HttpResponse performRequest(Request<?> request, Map<String, String> additionalHeaders)
+    public HttpResponse executeRequest(Request<?> request, Map<String, String> additionalHeaders)
             throws IOException, AuthFailureError {
         String url = request.getUrl();
         HashMap<String, String> map = new HashMap<>();
-        map.putAll(request.getHeaders());
         map.putAll(additionalHeaders);
+        map.putAll(request.getHeaders());
         if (mUrlRewriter != null) {
             String rewritten = mUrlRewriter.rewriteUrl(url);
             if (rewritten == null) {
@@ -91,67 +88,85 @@ public class BetterHurlStack extends HurlStack {
         }
         URL parsedUrl = new URL(url);
         HttpURLConnection connection = openConnection(parsedUrl, request);
-        for (String headerName : map.keySet()) {
-            connection.addRequestProperty(headerName, map.get(headerName));
+        boolean keepConnectionOpen = false;
+        try {
+            for (String headerName : map.keySet()) {
+                connection.setRequestProperty(headerName, map.get(headerName));
+            }
+            setConnectionParametersForRequest(connection, request);
+            // Initialize HttpResponse with data from the HttpURLConnection.
+            int responseCode = connection.getResponseCode();
+            if (responseCode == -1) {
+                // -1 is returned by getResponseCode() if the response code could not be retrieved.
+                // Signal to the caller that something was wrong with the connection.
+                throw new IOException("Could not retrieve response code from HttpUrlConnection.");
+            }
+
+            if (!hasResponseBody(request.getMethod(), responseCode)) {
+                return new HttpResponse(responseCode, convertHeaders(connection.getHeaderFields()));
+            }
+
+            // Need to keep the connection open until the stream is consumed by the caller. Wrap the
+            // stream such that close() will disconnect the connection.
+            keepConnectionOpen = true;
+            return new HttpResponse(
+                    responseCode,
+                    convertHeaders(connection.getHeaderFields()),
+                    connection.getContentLength(),
+                    new UrlConnectionInputStream(connection));
+
+        } finally {
+            if (!keepConnectionOpen) {
+                connection.disconnect();
+            }
         }
-        setConnectionParametersForRequest(connection, request);
-        // Initialize HttpResponse with data from the HttpURLConnection.
-        ProtocolVersion protocolVersion = new ProtocolVersion("HTTP", 1, 1);
-        int responseCode = connection.getResponseCode();
-        if (responseCode == -1) {
-            // -1 is returned by getResponseCode() if the response code could not be retrieved.
-            // Signal to the caller that something was wrong with the connection.
-            throw new IOException("Could not retrieve response code from HttpUrlConnection.");
-        }
-        StatusLine responseStatus = new BasicStatusLine(protocolVersion,
-                connection.getResponseCode(), connection.getResponseMessage());
-        BasicHttpResponse response = new BasicHttpResponse(responseStatus);
-        response.setEntity(entityFromConnection(connection));
-        for (Map.Entry<String, List<String>> header : connection.getHeaderFields().entrySet()) {
-            if (header.getKey() != null) {
-                Header h;
-                if (header.getKey().equals("Set-Cookie")) {
+    }
+
+    @VisibleForTesting
+    private static List<Header> convertHeaders(Map<String, List<String>> responseHeaders) {
+        List<Header> headerList = new ArrayList<>(responseHeaders.size());
+        for (Map.Entry<String, List<String>> entry : responseHeaders.entrySet()) {
+            // HttpUrlConnection includes the status line as a header with a null key; omit it here
+            // since it's not really a header and the rest of Volley assumes non-null keys.
+            if (entry.getKey() != null) {
+                if (entry.getKey().equals("Set-Cookie")) {
                     Pattern pattern = Pattern.compile("^([^=]+=[^;]+;)");
                     StringBuilder cookieValue = new StringBuilder();
-                    for (String value: header.getValue()) {
+                    for (String value : entry.getValue()) {
                         Matcher matcher = pattern.matcher(value);
                         if (matcher.find()) {
                             cookieValue.append(matcher.group(1));
                         }
                     }
-                    h = new BasicHeader(header.getKey(), cookieValue.toString());
+                    headerList.add(new Header(entry.getKey(), cookieValue.toString()));
                 } else {
-                    h = new BasicHeader(header.getKey(), header.getValue().get(0));
+                    headerList.add(new Header(entry.getKey(), entry.getValue().get(0)));
                 }
-                response.addHeader(h);
             }
         }
-        return response;
+        return headerList;
     }
 
     /**
-     * Initializes an {@link HttpEntity} from the given {@link HttpURLConnection}.
-     * @param connection A http connection
-     * @return an HttpEntity populated with data from <code>connection</code>.
+     * Checks if a response message contains a body.
+     *
+     * @see <a href="https://tools.ietf.org/html/rfc7230#section-3.3">RFC 7230 section 3.3</a>
+     * @param requestMethod request method
+     * @param responseCode response status code
+     * @return whether the response has a body
      */
-    private static HttpEntity entityFromConnection(HttpURLConnection connection) {
-        BasicHttpEntity entity = new BasicHttpEntity();
-        InputStream inputStream;
-        try {
-            inputStream = connection.getInputStream();
-        } catch (IOException ioe) {
-            inputStream = connection.getErrorStream();
-        }
-        entity.setContent(inputStream);
-        entity.setContentLength(connection.getContentLength());
-        entity.setContentEncoding(connection.getContentEncoding());
-        entity.setContentType(connection.getContentType());
-        return entity;
+    private static boolean hasResponseBody(int requestMethod, int responseCode) {
+        return requestMethod != Request.Method.HEAD
+                && !(HTTP_CONTINUE <= responseCode && responseCode < HttpURLConnection.HTTP_OK)
+                && responseCode != HttpURLConnection.HTTP_NO_CONTENT
+                && responseCode != HttpURLConnection.HTTP_NOT_MODIFIED;
     }
 
+    // NOTE: Any request headers added here (via setRequestProperty or addRequestProperty) should be
+    // checked against the existing properties in the connection and not overridden if already set.
     @SuppressWarnings("deprecation")
-    /* package */ static void setConnectionParametersForRequest(HttpURLConnection connection,
-                                                                Request<?> request) throws IOException, AuthFailureError {
+    /* package */ private static void setConnectionParametersForRequest(
+            HttpURLConnection connection, Request<?> request) throws IOException, AuthFailureError {
         switch (request.getMethod()) {
             case Request.Method.DEPRECATED_GET_OR_POST:
                 // This is the deprecated way that needs to be handled for backwards compatibility.
@@ -159,16 +174,8 @@ public class BetterHurlStack extends HurlStack {
                 // GET.  Otherwise, it is assumed that the request is a POST.
                 byte[] postBody = request.getPostBody();
                 if (postBody != null) {
-                    // Prepare output. There is no need to set Content-Length explicitly,
-                    // since this is handled by HttpURLConnection using the size of the prepared
-                    // output stream.
-                    connection.setDoOutput(true);
                     connection.setRequestMethod("POST");
-                    connection.addRequestProperty(HEADER_CONTENT_TYPE,
-                            request.getPostBodyContentType());
-                    DataOutputStream out = new DataOutputStream(connection.getOutputStream());
-                    out.write(postBody);
-                    out.close();
+                    addBody(connection, request, postBody);
                 }
                 break;
             case Request.Method.GET:
@@ -209,14 +216,26 @@ public class BetterHurlStack extends HurlStack {
             throws IOException, AuthFailureError {
         byte[] body = request.getBody();
         if (body != null) {
-            connection.setDoOutput(true);
-            connection.addRequestProperty(HEADER_CONTENT_TYPE, request.getBodyContentType());
-            DataOutputStream out = new DataOutputStream(connection.getOutputStream());
-            out.write(body);
-            out.close();
+            addBody(connection, request, body);
         }
     }
 
+    private static void addBody(HttpURLConnection connection, Request<?> request, byte[] body)
+            throws IOException {
+        // Prepare output. There is no need to set Content-Length explicitly,
+        // since this is handled by HttpURLConnection using the size of the prepared
+        // output stream.
+        connection.setDoOutput(true);
+        // Set the content-type unless it was already set (by Request#getHeaders).
+        if (!connection.getRequestProperties().containsKey(HEADER_CONTENT_TYPE)) {
+            connection.setRequestProperty(
+                    HEADER_CONTENT_TYPE, request.getBodyContentType());
+        }
+        DataOutputStream out = new DataOutputStream(connection.getOutputStream());
+        out.write(body);
+        out.close();
+    }
+
     private HttpURLConnection openConnection(URL url, Request<?> request) throws IOException {
         HttpURLConnection connection = createConnection(url);
         int timeoutMs = request.getTimeoutMs();
@@ -230,4 +249,40 @@ public class BetterHurlStack extends HurlStack {
         }
         return connection;
     }
+
+
+    /**
+     * Wrapper for a {@link HttpURLConnection}'s InputStream which disconnects the connection on
+     * stream close.
+     */
+    static class UrlConnectionInputStream extends FilterInputStream {
+        private final HttpURLConnection mConnection;
+
+        UrlConnectionInputStream(HttpURLConnection connection) {
+            super(inputStreamFromConnection(connection));
+            mConnection = connection;
+        }
+
+        @Override
+        public void close() throws IOException {
+            super.close();
+            mConnection.disconnect();
+        }
+    }
+
+    /**
+     * Initializes an {@link InputStream} from the given {@link HttpURLConnection}.
+     *
+     * @param connection A http url connection
+     * @return an HttpEntity populated with data from <code>connection</code>.
+     */
+    private static InputStream inputStreamFromConnection(HttpURLConnection connection) {
+        InputStream inputStream;
+        try {
+            inputStream = connection.getInputStream();
+        } catch (IOException ioe) {
+            inputStream = connection.getErrorStream();
+        }
+        return inputStream;
+    }
 }

app/src/main/java/de/sebse/fuplanner/tools/network/HTTPService.java

@@ -1,7 +1,6 @@
 package de.sebse.fuplanner.tools.network;
 
 import android.content.Context;
-import android.support.annotation.Nullable;
 
 import com.android.volley.AuthFailureError;
 import com.android.volley.NetworkResponse;
@@ -17,6 +16,8 @@ import java.net.URLEncoder;
 import java.util.HashMap;
 import java.util.Map;
 
+import androidx.annotation.Nullable;
+import de.sebse.fuplanner.tools.EventListener;
 import de.sebse.fuplanner.tools.logging.Logger;
 
 /**
@@ -25,14 +26,30 @@ import de.sebse.fuplanner.tools.logging.Logger;
 
 public class HTTPService {
     private final RequestQueue requestQueue;
+    private final Context mContext;
     protected Logger log = new Logger(this);
+    private EventListener<VolleyError> errorResponseListener = new EventListener<>();
+    private EventListener<Result> successResponseListener = new EventListener<>();
 
     protected HTTPService(Context context) {
-        this(context, false);
+        this.mContext = context;
+        requestQueue = Volley.newRequestQueue(context, new BetterHurlStack(false));
     }
 
-    protected HTTPService(Context context, boolean followRedirects) {
-        requestQueue = Volley.newRequestQueue(context, new BetterHurlStack(followRedirects));
+    public void addErrorListener(String id, EventListener.EventFunction<VolleyError> listener) {
+        errorResponseListener.add(id, listener);
+    }
+
+    public void removeErrorListener(String id) {
+        errorResponseListener.remove(id);
+    }
+
+    public void addSuccessListener(String id, EventListener.EventFunction<Result> listener) {
+        successResponseListener.add(id, listener);
+    }
+
+    public void removeSuccessListener(String id) {
+        successResponseListener.remove(id);
     }
 
     protected void get(String url, @Nullable final HashMap<String, String> cookies, Response.Listener<Result> response, Response.ErrorListener error) {
@@ -40,24 +57,35 @@ public class HTTPService {
             @Override
             public void deliverError(VolleyError error) {
                 if (error == null) {
-                    super.deliverError(new VolleyError(new NetworkResponse(500, null, null, true, 0)));
+                    deliver(new VolleyError(new NetworkResponse(500, null, true, 0, null)));
                 } else if (error.networkResponse == null) {
                     int statusCode;
                     if (error instanceof TimeoutError)
                         statusCode = 408;
                     else
                         statusCode = 500;
-                    super.deliverError(new VolleyError(new NetworkResponse(statusCode, null, null, true, error.getNetworkTimeMs())));
+                    deliver(new VolleyError(new NetworkResponse(statusCode, null, true, error.getNetworkTimeMs(), null)));
                 } else {
                     final int status = error.networkResponse.statusCode;
                     if (status == 302) {
-                        super.deliverResponse(new Result(null, error.networkResponse.headers));
+                        deliverResponse(new Result(null, error.networkResponse.headers));
                     } else {
-                        super.deliverError(error);
+                        deliver(error);
                     }
                 }
             }
 
+            @Override
+            protected void deliverResponse(Result response) {
+                successResponseListener.emit(response);
+                super.deliverResponse(response);
+            }
+
+            private void deliver(VolleyError error) {
+                errorResponseListener.emit(error);
+                super.deliverError(error);
+            }
+
             public Map<String, String> getHeaders() throws AuthFailureError {
                 Map<String, String> params = super.getHeaders();
                 if (cookies != null) {
@@ -96,7 +124,6 @@ public class HTTPService {
                         sb.append('&');
                     }
                     try {
-                        //Log.e("Superissimo", e.getKey()+"|||"+e.getValue());
                         sb.append(URLEncoder.encode(e.getKey(), "UTF-8")).append('=').append(URLEncoder.encode(e.getValue(), "UTF-8"));
                     } catch (UnsupportedEncodingException ignored) {
                     }
@@ -112,24 +139,35 @@ public class HTTPService {
             @Override
             public void deliverError(VolleyError error) {
                 if (error == null) {
-                    super.deliverError(new VolleyError(new NetworkResponse(500, null, null, true, 0)));
+                    deliver(new VolleyError(new NetworkResponse(500, null, true, 0, null)));
                 } else if (error.networkResponse == null) {
                     int statusCode;
                     if (error instanceof TimeoutError)
                         statusCode = 408;
                     else
                         statusCode = 500;
-                    super.deliverError(new VolleyError(new NetworkResponse(statusCode, null, null, true, error.getNetworkTimeMs())));
+                    deliver(new VolleyError(new NetworkResponse(statusCode, null, true, error.getNetworkTimeMs(), null)));
                 } else {
                     final int status = error.networkResponse.statusCode;
                     if (status == 302) {
-                        super.deliverResponse(new Result(null, error.networkResponse.headers));
+                        deliverResponse(new Result(null, error.networkResponse.headers));
                     } else {
-                        super.deliverError(error);
+                        deliver(error);
                     }
                 }
             }
 
+            private void deliver(VolleyError error) {
+                errorResponseListener.emit(error);
+                super.deliverError(error);
+            }
+
+            @Override
+            protected void deliverResponse(Result response) {
+                successResponseListener.emit(response);
+                super.deliverResponse(response);
+            }
+
             public Map<String, String> getHeaders() throws AuthFailureError {
                 Map<String, String> params = super.getHeaders();
                 if (cookies != null) {
@@ -149,4 +187,8 @@ public class HTTPService {
         };
         requestQueue.add(request);
     }
+
+    protected Context getContext() {
+        return mContext;
+    }
 }

app/src/main/java/de/sebse/fuplanner/tools/network/HttpRequest.java

@@ -6,8 +6,6 @@ import com.android.volley.Request;
 import com.android.volley.Response;
 import com.android.volley.toolbox.HttpHeaderParser;
 
-import java.io.UnsupportedEncodingException;
-
 /**
  * Created by sebastian on 24.10.17.
  */
@@ -28,13 +26,7 @@ class HttpRequest extends Request<Result> {
 
     @Override
     protected Response<Result> parseNetworkResponse(NetworkResponse response) {
-        String parsed;
-        try {
-            parsed = new String(response.data, HttpHeaderParser.parseCharset(response.headers));
-        } catch (UnsupportedEncodingException e) {
-            parsed = new String(response.data);
-        }
-        Result result = new Result(parsed, response.headers);
+        Result result = new Result(response.data, response.headers);
 
         return Response.success(result, HttpHeaderParser.parseCacheHeaders(response));
     }

app/src/main/java/de/sebse/fuplanner/tools/network/NetworkCallback.java

@@ -1,6 +1,6 @@
 package de.sebse.fuplanner.tools.network;
 
-import android.support.annotation.NonNull;
+import androidx.annotation.NonNull;
 
 public interface NetworkCallback<T> {
     void onResponse(@NonNull T success);

app/src/main/java/de/sebse/fuplanner/tools/network/NetworkError.java

@@ -23,7 +23,7 @@ public class NetworkError {
         return httpStatus;
     }
 
-    public String getMessage() {
+    private String getMessage() {
         return message;
     }
 

app/src/main/java/de/sebse/fuplanner/tools/network/Result.java

@@ -1,21 +1,38 @@
 package de.sebse.fuplanner.tools.network;
 
+import com.android.volley.toolbox.HttpHeaderParser;
+
+import java.io.UnsupportedEncodingException;
 import java.util.Map;
 
+import androidx.annotation.Nullable;
+
 /**
  * Created by sebastian on 24.10.17.
  */
 public class Result {
-    private final String parsed;
+    @Nullable private final byte[] body;
     private final Map<String, String> headers;
 
-    public Result(String parsed, Map<String, String> headers) {
-        this.parsed = parsed;
+    Result(@Nullable byte[] body, Map<String, String> headers) {
+        this.body = body;
         this.headers = headers;
     }
 
+    @Nullable
     public String getParsed() {
-        return parsed;
+        if (this.body == null)
+            return null;
+        try {
+            return new String(this.body, HttpHeaderParser.parseCharset(headers));
+        } catch (UnsupportedEncodingException e) {
+            return new String(this.body);
+        }
+    }
+
+    @Nullable
+    public byte[] getBytes() {
+        return body;
     }
 
     public Map<String, String> getHeaders() {

app/src/main/java/de/sebse/fuplanner/tools/ui/AnnouncementViewHolder.java

@@ -0,0 +1,32 @@
+package de.sebse.fuplanner.tools.ui;
+
+import android.view.View;
+import android.widget.TextView;
+
+import com.cunoraz.tagview.TagView;
+
+import de.sebse.fuplanner.R;
+
+public class AnnouncementViewHolder extends ExpandableCardViewHolder {
+    public final TextView mTitle;
+    public final TextView mSubTitle;
+    public final TextView mNotes;
+    public final TagView mTagGroup;
+
+
+    public AnnouncementViewHolder(View view) {
+        super(view);
+        View outerView = getOuterView();
+        View innerView = getInnerView();
+        mTitle = outerView.findViewById(R.id.title);
+        mSubTitle = outerView.findViewById(R.id.sub_title);
+        mNotes = innerView.findViewById(R.id.notes);
+        mTagGroup = innerView.findViewById(R.id.tag_group);
+
+    }
+
+    @Override
+    public String toString() {
+        return super.toString() + " '" + mTitle.getText() + "' '" + mSubTitle.getText() + "'";
+    }
+}

app/src/main/java/de/sebse/fuplanner/tools/ui/CustomViewHolder.java

@@ -1,8 +1,9 @@
 package de.sebse.fuplanner.tools.ui;
 
-import android.support.v7.widget.RecyclerView;
 import android.view.View;
 
+import androidx.recyclerview.widget.RecyclerView;
+
 public class CustomViewHolder extends RecyclerView.ViewHolder {
     public final View mView;