Merge branch 'newkvv'

# Conflicts:
#	app/src/main/java/de/sebse/fuplanner/fragments/moddetails/ModDetailAnnounceFragment.java
#	app/src/main/java/de/sebse/fuplanner/fragments/moddetails/ModDetailAssignmentFragment.java
#	app/src/main/java/de/sebse/fuplanner/services/KVV/KVVModuleList.java

app/build.gradle

@@ -32,7 +32,6 @@ dependencies {
     androidTestImplementation('androidx.test.espresso:espresso-core:3.1.0-beta02', {
         exclude group: 'com.android.support', module: 'support-annotations'
     })
-    implementation 'androidx.appcompat:appcompat: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'
@@ -42,7 +41,7 @@ dependencies {
     implementation 'androidx.legacy:legacy-support-v4:1.0.0'
     testImplementation 'junit:junit:4.12'
     implementation fileTree(include: ['*.jar'], dir: 'libs')
-    implementation 'androidx.appcompat:appcompat:1.0.0'
+    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 'androidx.legacy:legacy-support-v4:1.0.0'
     implementation 'org.jetbrains:annotations-java5:15.0'

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

@@ -8,6 +8,7 @@ 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;
@@ -33,18 +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.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 MainActivityListener,
+        implements MainActivityListener, KVVListener,
         NavigationView.OnNavigationItemSelectedListener,
-        LoginFragment.OnLoginFragmentInteractionListener,
         ModulesFragment.OnModulesFragmentInteractionListener,
         CanteensFragment.OnCanteensFragmentInteractionListener {
 
@@ -68,21 +74,20 @@ public class MainActivity extends AppCompatActivity
     private NavigationView mNavigationView;
 
     private int fragmentPage = FRAGMENT_NONE;
-    private int currentPage = FRAGMENT_NONE;
     private String fragmentData = "";
-    private String currentData = "";
     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;
+        int desiredPage = getDefaultFragmentAfterLogin();
-        String newFragmentData = "";
+        String desiredData = "";
         if (savedInstanceState != null) {
-            newFragmentPage = savedInstanceState.getInt(ARG_FRAGMENT_PAGE, fragmentPage);
+            desiredPage = savedInstanceState.getInt(ARG_FRAGMENT_PAGE, desiredPage);
-            newFragmentData = savedInstanceState.getString(ARG_FRAGMENT_STATUS, fragmentData);
+            desiredData = savedInstanceState.getString(ARG_FRAGMENT_STATUS, desiredData);
         }
 
         setContentView(R.layout.activity_main);
@@ -99,15 +104,12 @@ public class MainActivity extends AppCompatActivity
         mNavigationView.setNavigationItemSelectedListener(this);
         mFragmentManager = getSupportFragmentManager();
 
-        LoginToken loginToken = getKVV().easyLogin();
+        if (!getKVV().account().restoreOnlineLogin()) {
-        if (loginToken == null) {
+            desiredPage = FRAGMENT_LOGIN;
-            checkAndDoLogin();
+            desiredData = "";
-        } else {
-            if (newFragmentPage != FRAGMENT_LOGIN && newFragmentPage != FRAGMENT_STARTUP && newFragmentPage != FRAGMENT_NONE)
-                toLoginState(loginToken, newFragmentPage, newFragmentData);
-            else
-                toLoginState(loginToken, getDefaultFragmentAfterLogin(), "");
         }
+        updateNavigation();
+        changeFragment(desiredPage, desiredData);
     }
 
     @Override
@@ -123,7 +125,7 @@ public class MainActivity extends AppCompatActivity
     @Override
     public boolean onCreateOptionsMenu(Menu menu) {
         // Inflate the menu; this adds items to the action bar if it is present.
-        if (currentPage == FRAGMENT_SCHEDULE) {
+        if (fragmentPage == FRAGMENT_SCHEDULE) {
             getMenuInflater().inflate(R.menu.options_schedule, menu);
             return true;
         }
@@ -180,12 +182,12 @@ 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;
 
@@ -210,14 +212,15 @@ public class MainActivity extends AppCompatActivity
 
     @Override
     protected void onSaveInstanceState(Bundle savedInstanceState) {
+        if (fragmentPage != FRAGMENT_STARTUP && fragmentPage != FRAGMENT_NONE && fragmentPage != FRAGMENT_LOGIN) {
             Fragment fragment = mFragmentManager.findFragmentByTag(String.valueOf(fragmentPage));
             savedInstanceState.putInt(ARG_FRAGMENT_PAGE, fragmentPage);
-        savedInstanceState.putString(ARG_FRAGMENT_STATUS, fragmentData);
             if (fragment instanceof ModDetailFragment) {
                 savedInstanceState.putString(ARG_FRAGMENT_STATUS, ((ModDetailFragment) fragment).getData());
             } else {
                 savedInstanceState.putString(ARG_FRAGMENT_STATUS, fragmentData);
             }
+        }
         super.onSaveInstanceState(savedInstanceState);
     }
 
@@ -239,9 +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;
     }
@@ -254,59 +265,25 @@ public class MainActivity extends AppCompatActivity
     }
 
     private int getDefaultFragmentAfterLogin() {
-        return getDefaultFragmentAfterLogin(new String[1]);
-    }
-
-    private int getDefaultFragmentAfterLogin(String[] id) {
-        if (fragmentPage == FRAGMENT_NONE){
-            id[0] = "";
         return FRAGMENT_MODULES;
     }
-        else {
-            id[0] = fragmentData;
-            return fragmentPage;
-        }
-    }
 
     private void toLogoutState() {
-        setOfflineBanner(true);
+        setOfflineBanner(false);
         setRefreshFailedBanner(false);
+        updateNavigation();
         changeFragment(FRAGMENT_LOGIN);
     }
 
-    private void toLoginState(LoginToken loginToken, int newFragment, String newData) {
+    private void toLoginState(String fullName, String email, int newFragment, boolean onlineMode) {
-        if (loginToken == null) {
+        setOfflineBanner(!onlineMode);
-            toLogoutState();
+        updateNavigation();
-        } else {
-            toLoginState(loginToken.getFullName(), loginToken.getEmail(), newFragment, newData, true);
-        }
-    }
-
-    private void toLoginState(String fullName, String email, int newFragment, String newData, boolean onlineMode) {
-        setOfflineBanner(onlineMode);
-        changeFragment(newFragment, newData);
 
         View header = mNavigationView.getHeaderView(0);
         ((TextView) header.findViewById(R.id.login_name)).setText(fullName);
         ((TextView) header.findViewById(R.id.login_mail)).setText(email);
-    }
 
-    private void checkAndDoLogin() {
+        changeFragment(newFragment);
-        changeFragment(FRAGMENT_STARTUP);
-        getGoogleAuth().getLoginState(credentials -> {
-            if (credentials == null || credentials.getUsername() == null || credentials.getPassword() == null) {
-                toLogoutState();
-                return;
-            }
-            String[] id = {""};
-
-            int fragment = getDefaultFragmentAfterLogin(id);
-            this.getKVV().login(credentials.getUsername(), credentials.getPassword(), success -> toLoginState(success, fragment , id[0]),
-            error -> {
-                log.e(error);
-                toLogoutState();
-            });
-        });
     }
 
     private void changeFragment(int newFragment) {
@@ -355,56 +332,36 @@ 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);
         }
 
-        boolean isChangeLoginState =
-                (
-                        (newFragment == FRAGMENT_STARTUP || newFragment == FRAGMENT_LOGIN) &&
-                        (currentPage != FRAGMENT_STARTUP && currentPage != FRAGMENT_LOGIN)
-                ) || (
-                        (currentPage == FRAGMENT_STARTUP || currentPage == FRAGMENT_LOGIN || currentPage == FRAGMENT_NONE) &&
-                        (newFragment != FRAGMENT_STARTUP && newFragment != FRAGMENT_LOGIN && (getKVV().isLoggedIn() || mOfflineMode))
-                );
-
-        if (newFragment != FRAGMENT_STARTUP && newFragment != FRAGMENT_NONE && newFragment != FRAGMENT_LOGIN) {
         this.fragmentPage = newFragment;
         this.fragmentData = newData;
-        }
+
-        this.currentPage = newFragment;
-        this.currentData = newData;
         invalidateOptionsMenu();
-        if (isChangeLoginState)
-            refreshNavigation();
-        else
-            setNavigationSelection(currentPage, currentData);
     }
 
-    private void setOfflineBanner(boolean onlineMode) {
+    private void setOfflineBanner(boolean visible) {
         View offline_header = findViewById(R.id.offline_msg);
-        if (onlineMode)
+        offline_header.setVisibility(visible ? View.VISIBLE : View.GONE);
-            offline_header.setVisibility(View.GONE);
+        mOfflineBanner = visible;
-        else
-            offline_header.setVisibility(View.VISIBLE);
-        mOfflineMode = !onlineMode;
     }
 
     private void setRefreshFailedBanner(boolean refreshFailed) {
         View viewNoConnection = findViewById(R.id.no_connection_msg);
-        if (!mOfflineMode && refreshFailed)
+        if (!mOfflineBanner && refreshFailed)
             viewNoConnection.setVisibility(View.VISIBLE);
         else
             viewNoConnection.setVisibility(View.GONE);
-
     }
 
-    private void setNavigationSelection(int fragment, String data) {
+    private void setNavigationSelection() {
         MenuItem item;
-        switch (fragment) {
+        switch (fragmentPage) {
             case FRAGMENT_MODULES_DETAILS:
-                getKVV().getModule(data, success -> {
+                getKVV().modules().list().find(fragmentData, success -> {
                     int size = mNavigationView.getMenu().size();
                     //noinspection ConstantConditions
                     String title = success == null ? null : success.title;
@@ -426,7 +383,7 @@ public class MainActivity extends AppCompatActivity
             case FRAGMENT_CANTEENS_DETAILS:
                 getCanteenBrowser().getCanteens(success -> {
                     int size = mNavigationView.getMenu().size();
-                    Canteen canteen = success.getCanteen(Integer.parseInt(data));
+                    Canteen canteen = success.getCanteen(Integer.parseInt(fragmentData));
                     //noinspection ConstantConditions
                     String title = canteen == null ? null : canteen.getName();
                     for (int k = 0; k < size; k++) {
@@ -464,9 +421,11 @@ public class MainActivity extends AppCompatActivity
             });
     }
 
-    private void afterAnyMenuInflate(boolean isLoggedIn) {
+    private void afterAnyMenuInflate(boolean isLoggedIn, Runnable done) {
+        int MAX_COUNT = isLoggedIn ? 2 : 1;
+        final int[] count = {0};
         if (isLoggedIn) {
-            getKVV().getModuleList(success -> {
+            getKVV().modules().list().recv(success -> {
                 int i = 0;
                 for (Iterator<Modules.Module> it = success.latestSemesterIterator(); it.hasNext(); ) {
                     Modules.Module module = it.next();
@@ -477,7 +436,11 @@ 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);
+            });
         }
         getCanteenBrowser().getCanteens(success -> {
             int i = 0;
@@ -489,7 +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();
+            });
+        });
     }
 
 
@@ -498,11 +481,7 @@ public class MainActivity extends AppCompatActivity
 
 
 
-    public void onLoginFragmentInteraction(LoginToken loginToken, boolean onlineMode) {
+
-        String[] id = {""};
-        int fragment = getDefaultFragmentAfterLogin(id);
-        toLoginState(loginToken.getFullName(), loginToken.getEmail(), fragment, id[0], onlineMode);
-    }
 
     @Override
     public void onModulesFragmentInteraction(final String itemID) {
@@ -524,21 +503,6 @@ public class MainActivity extends AppCompatActivity
         setTitle(titleId);
     }
 
-    @Override
-    public void loginTokenInvalid(boolean doLoginCheck) {
-        if (doLoginCheck) {
-            getKVV().testLogin(isSuccess -> {
-                if (!isSuccess) {
-                    getKVV().invalidate();
-                    checkAndDoLogin();
-                }
-            });
-        } else {
-            getKVV().invalidate();
-            checkAndDoLogin();
-        }
-    }
-
     @Override
     public void onRefreshCompleted(boolean isFailed) {
         setRefreshFailedBanner(isFailed);
@@ -564,16 +528,43 @@ public class MainActivity extends AppCompatActivity
         Toast.makeText(this, message, Toast.LENGTH_SHORT).show();
     }
 
+
+
+
+
+
+
+
+
+
     @Override
-    public void refreshNavigation() {
+    public void getCredentials(NetworkCallback<Credentials> callback, NetworkErrorCallback error) {
-        boolean isLoggedIn = getKVV().isLoggedIn() || mOfflineMode;
+        getGoogleAuth().getLoginState(credentials -> {
-        setNavigationHeader(isLoggedIn);
+            if (credentials == null || credentials.getUsername() == null || credentials.getPassword() == null) {
-        mNavigationView.getMenu().clear();
+                error.onError(new NetworkError(200100, 403, "No Google Login available!"));
-        if (isLoggedIn)
+            } else {
-            mNavigationView.inflateMenu(R.menu.activity_main_drawer_login);
+                callback.onResponse(credentials);
-        else
+            }
-            mNavigationView.inflateMenu(R.menu.activity_main_drawer);
+        });
-        afterAnyMenuInflate(isLoggedIn);
+    }
-        setNavigationSelection(currentPage, currentData);
+
+    @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

@@ -10,7 +10,6 @@ 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

@@ -70,8 +70,8 @@ public class CanteensFragment extends Fragment {
             CanteenBrowser browser = ((MainActivity) getActivity()).getCanteenBrowser();
             browser.getCanteens(success -> {
                 adapter.setCanteens(success);
-                if (mMainActivityListener != null)
+                //if (mMainActivityListener != null)
-                    mMainActivityListener.refreshNavigation();
+                //    mMainActivityListener.refreshNavigation();
                 swipeLayout.setRefreshing(false);
             }, error -> {
                 log.e(error.toString());

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

@@ -9,31 +9,21 @@ import android.view.ViewGroup;
 import android.widget.Button;
 import android.widget.EditText;
 
-import java.io.IOException;
-
 import androidx.annotation.NonNull;
+import androidx.annotation.Nullable;
 import androidx.fragment.app.Fragment;
-import de.sebse.fuplanner.MainActivity;
 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.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);
-    private MainActivityListener mActivityListener;
+    @Nullable private MainActivityListener mActivityListener;
 
     public LoginFragment() {
         // Required empty public constructor
@@ -57,21 +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 {
+        if (mActivityListener != null && mActivityListener.getKVV().account().isOfflineStoredAvailable()) {
-            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.setText(v.getResources().getString(R.string.enter_offline_mode, mActivityListener.getKVV().modules().list().getUsername()));
-                    offline_btn.setOnClickListener(v1 -> mListener.onLoginFragmentInteraction(modules.getToken(), false));
+            offline_btn.setOnClickListener(v1 -> mActivityListener.getKVV().account().doOfflineLogin());
-                }
-            }
-        } catch (IOException e) {
-            e.printStackTrace();
-        } catch (ClassNotFoundException e) {
-            e.printStackTrace();
         }
 
         View btn_login = v.findViewById(R.id.btn_login);
@@ -84,24 +64,15 @@ 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();
-                    KVV kvv = ((MainActivity) getActivity()).getKVV();
+
-                    GoogleAuth gauth = ((MainActivity) getActivity()).getGoogleAuth();
+            mActivityListener.getKVV().account().doOnlineLogin(username, password, success -> {
-                    kvv.login(username, password, success -> {
                 progressDialog.dismiss();
-                        gauth.setLoginState(username, password);
+                mActivityListener.getGoogleAuth().setLoginState(username, password);
-                        if (mListener != null) {
                 input_usr.setError(null);
                 input_pwd.setError(null);
-                            mListener.onLoginFragmentInteraction(success, true);
-                        }
             }, error -> {
                 progressDialog.dismiss();
                 // Invalid password
@@ -116,8 +87,6 @@ public class LoginFragment extends Fragment {
                 }
                 log.e("Error on KVV login!", error);
             });
-                }
-            }
         });
 
         return v;
@@ -128,12 +97,6 @@ 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 MainActivityListener) {
             mActivityListener = (MainActivityListener) context;
             mActivityListener.onTitleTextChange(R.string.log_in);
@@ -144,20 +107,6 @@ public class LoginFragment extends Fragment {
     @Override
     public void onDetach() {
         super.onDetach();
-        mListener = null;
+        mActivityListener = 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);
     }
 }

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

@@ -1,66 +1,115 @@
 package de.sebse.fuplanner.fragments;
 
+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) {
+    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) {
+    public void onBindViewHolder(@NonNull CustomViewHolder holder, int position) {
-        if (mValues == null)
+        Pair<Integer, Object> pair = mPositionalData.get(holder.getAdapterPosition());
-            return;
+        if (pair.first == TYPE_HEADER) {
-        Modules.Module module = mValues.getByIndex(holder.getAdapterPosition());
+            StringViewHolder sHolder = (StringViewHolder) holder;
-        holder.mTitle.setText(module.title);
+            String localizedSemester;
-        holder.mSubLeft.setText(module.semester);
+            Semester semester = (Semester) pair.second;
-        holder.mSubRight.setText(module.type);
+            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);
 
-        holder.mView.setOnClickListener(v -> {
+            iHolder.mView.setOnClickListener(v -> {
-            if (null != mListener) {
+                if (mListener != null) {
-                // Notify the active callbacks interface (the activity, if the
-                // fragment is attached to one) that an item has been selected.
                     mListener.onModulesFragmentInteraction(module.getID());
                 }
             });
         }
+    }
 
     @Override
     public int getItemCount() {
-        if (mValues != null) {
+        return mPositionalData.size();
-            return mValues.size();
-        }
-        return 0;
     }
 }

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

@@ -7,13 +7,12 @@ import android.view.View;
 import android.view.ViewGroup;
 
 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.KVV;
 import de.sebse.fuplanner.tools.MainActivityListener;
 import de.sebse.fuplanner.tools.logging.Logger;
 
@@ -28,7 +27,7 @@ public class ModulesFragment extends Fragment {
     private final Logger log = new Logger(this);
     private ModulesAdapter adapter;
     private SwipeRefreshLayout swipeLayout;
-    private MainActivityListener mMainActivityListener;
+    @Nullable private MainActivityListener mMainActivityListener;
 
     /**
      * Mandatory empty constructor for the fragment manager to instantiate the
@@ -66,12 +65,11 @@ public class ModulesFragment extends Fragment {
     }
 
     private void refresh(boolean forceRefresh) {
-        if (getActivity() != null) {
+        if (mMainActivityListener != null) {
-            KVV kvv = ((MainActivity) getActivity()).getKVV();
+            mMainActivityListener.getKVV().modules().list().recv(success -> {
-            kvv.getModuleList(success -> {
                 adapter.setModules(success);
-                if (mMainActivityListener != null)
+                //if (mMainActivityListener != null)
-                    mMainActivityListener.refreshNavigation();
+                //    mMainActivityListener.refreshNavigation();
                 swipeLayout.setRefreshing(false);
             }, error -> {
                 log.e(error.toString());

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

@@ -16,7 +16,6 @@ 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.UtilsDate;
@@ -59,13 +58,12 @@ public class ScheduleFragment extends Fragment implements MonthLoader.MonthChang
     }
 
     public void invalidate(boolean forceRefresh) {
-        if (mListener != null) {
+        if (mListener == null) return;
-            KVV kvv = mListener.getKVV();
+        mListener.getKVV().modules().list().recv(modules -> {
-            kvv.getModuleList((Modules success) -> {
+            mModules = modules;
-                mModules = success;
             final int[] i = {0};
             for (Modules.Module module: mModules) {
-                    kvv.getModuleEvents(module, success1 -> {
+                mListener.getKVV().modules().events().recv(module, success1 -> {
                     i[0]++;
                     if (i[0] >= mModules.size()) {
                         if (mWeekView != null) {
@@ -77,7 +75,6 @@ public class ScheduleFragment extends Fragment implements MonthLoader.MonthChang
             }
         }, log::e, forceRefresh);
     }
-    }
 
     @Override
     public View onCreateView(@NonNull LayoutInflater inflater, ViewGroup container, Bundle savedInstanceState) {
@@ -183,10 +180,8 @@ public class ScheduleFragment extends Fragment implements MonthLoader.MonthChang
         String moduleId = idParts[0];
         AlertDialog.Builder alertDialogBuilder = new AlertDialog.Builder(getContext());
 
-        if (mListener != null) {
+        if (mListener == null) return;
-            KVV kvv = mListener.getKVV();
+        mListener.getKVV().modules().list().find(moduleId, module -> {
-            kvv.getModuleList((Modules success) -> {
-                Modules.Module module = success.get(moduleId);
             String moduleName = module.title;
             alertDialogBuilder
                     .setTitle(event.getName())
@@ -202,5 +197,4 @@ public class ScheduleFragment extends Fragment implements MonthLoader.MonthChang
             alertDialog.show();
         }, log::e);
     }
-    }
 }

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

@@ -16,7 +16,7 @@ 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.Download;
+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.Regex;
@@ -76,12 +76,10 @@ class ModDetailAnnounceAdapter extends RecyclerView.Adapter<CustomViewHolder> {
                     tag.id = i;
                     tag.layoutColor = ContextCompat.getColor(holder.mView.getContext(), R.color.colorFUBlue);
                     holder.mTagGroup.addTag(tag);
-                    log.d(notes.get(i));
                 }
                 holder.mTagGroup.setOnTagClickListener((tag, i) -> {
                     String s = notes.get(i);
                     if (s != null) {
-                        log.d("Download", s);
                         String name = urlToName(s, i, holder.mView.getResources());
                         requestInterface.request(name, s);
                     }

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

@@ -6,16 +6,15 @@ import android.os.Bundle;
 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.Download;
+import de.sebse.fuplanner.services.KVV.ui.Download;
-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;
@@ -33,7 +32,7 @@ public class ModDetailAnnounceFragment extends Fragment implements Download.OnDo
     private ModDetailAnnounceAdapter adapter;
     private SwipeRefreshLayout swipeLayout;
     private Download download;
-    private MainActivityListener context;
+    @Nullable private MainActivityListener mListener;
 
 
     public ModDetailAnnounceFragment() {
@@ -83,41 +82,34 @@ public class ModDetailAnnounceFragment extends Fragment implements Download.OnDo
     }
 
     private void refresh(boolean forceRefresh) {
-        if (getActivity() != null) {
+        if (mListener == null)
-            KVV kvv = ((MainActivity) getActivity()).getKVV();
+            return;
-            kvv.getModule(mItemPos, (Modules.Module module) -> {
+        mListener.getKVV().modules().announcements().recv(mItemPos, success -> {
-                adapter.setModule(module);
+            adapter.setModule(success);
-                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);
-        }
     }
 
     @Override
     public void request(String title, String url) {
-        context.getKVV().getModule(mItemPos, (Modules.Module module) -> {
+        if (mListener == null)
-            if (module == 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, false);
+        }, log::e);
     }
 
     @Override
     public void onAttach(Context context) {
         super.onAttach(context);
         if (context instanceof MainActivityListener) {
-            this.context = ((MainActivityListener) context);
+            this.mListener = ((MainActivityListener) context);
-            this.context.addRequestPermissionsResultListener(getDownload().getRequestPermissionsResultListener(), "ModDetailAnnounceFragment");
+            this.mListener.addRequestPermissionsResultListener(getDownload().getRequestPermissionsResultListener(), "ModDetailAnnounceFragment");
         } else
             throw new RuntimeException(context.toString() + " must implement MainActivityListener");
     }
@@ -125,7 +117,10 @@ public class ModDetailAnnounceFragment extends Fragment implements Download.OnDo
     @Override
     public void onDetach() {
         super.onDetach();
-        this.context.removeRequestPermissionsResultListener("ModDetailAnnounceFragment");
+        if (this.mListener != null) {
+            this.mListener.removeRequestPermissionsResultListener("ModDetailAnnounceFragment");
+            this.mListener = null;
+        }
     }
 
     Download getDownload() {

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

@@ -16,7 +16,7 @@ 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.Download;
+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.Regex;
@@ -76,12 +76,10 @@ class ModDetailAssignmentAdapter extends RecyclerView.Adapter<CustomViewHolder>
                     tag.id = i;
                     tag.layoutColor = ContextCompat.getColor(holder.mView.getContext(), R.color.colorFUBlue);
                     holder.mTagGroup.addTag(tag);
-                    log.d(notes.get(i));
                 }
                 holder.mTagGroup.setOnTagClickListener((tag, i) -> {
                     String s = notes.get(i);
                     if (s != null) {
-                        log.d("Download", s);
                         String name = urlToName(s, i, holder.mView.getResources());
                         requestInterface.request(name, s);
                     }

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

@@ -6,16 +6,15 @@ import android.os.Bundle;
 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.Download;
+import de.sebse.fuplanner.services.KVV.ui.Download;
-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;
@@ -33,7 +32,7 @@ public class ModDetailAssignmentFragment extends Fragment implements Download.On
     private ModDetailAssignmentAdapter adapter;
     private SwipeRefreshLayout swipeLayout;
     private Download download;
-    private MainActivityListener context;
+    @Nullable private MainActivityListener mListener;
 
 
     public ModDetailAssignmentFragment() {
@@ -83,41 +82,35 @@ public class ModDetailAssignmentFragment extends Fragment implements Download.On
     }
 
     private void refresh(boolean forceRefresh) {
-        if (getActivity() != null) {
+        if (mListener == null)
-            KVV kvv = ((MainActivity) getActivity()).getKVV();
+            return;
-            kvv.getModule(mItemPos, (Modules.Module module) -> {
+        mListener.getKVV().modules().assignments().recv(mItemPos, success -> {
-                adapter.setModule(module);
+            adapter.setModule(success);
-                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);
-        }
     }
 
     @Override
     public void request(String title, String url) {
-        context.getKVV().getModule(mItemPos, (Modules.Module module) -> {
+        log.d(title, url, mListener);
-            if (module == null)
+        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, false);
+        }, log::e);
     }
 
     @Override
     public void onAttach(Context context) {
         super.onAttach(context);
         if (context instanceof MainActivityListener) {
-            this.context = ((MainActivityListener) context);
+            this.mListener = ((MainActivityListener) context);
-            this.context.addRequestPermissionsResultListener(getDownload().getRequestPermissionsResultListener(), "ModDetailAssignmentFragment");
+            this.mListener.addRequestPermissionsResultListener(getDownload().getRequestPermissionsResultListener(), "ModDetailAssignmentFragment");
         } else
             throw new RuntimeException(context.toString() + " must implement MainActivityListener");
     }
@@ -125,7 +118,10 @@ public class ModDetailAssignmentFragment extends Fragment implements Download.On
     @Override
     public void onDetach() {
         super.onDetach();
-        this.context.removeRequestPermissionsResultListener("ModDetailAssignmentFragment");
+        if (this.mListener != null) {
+            this.mListener.removeRequestPermissionsResultListener("ModDetailAssignmentFragment");
+            this.mListener = null;
+        }
     }
 
     Download getDownload() {

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

@@ -1,7 +1,6 @@
 package de.sebse.fuplanner.fragments.moddetails;
 
 import android.content.res.Resources;
-import android.util.Pair;
 import android.view.LayoutInflater;
 import android.view.View;
 import android.view.ViewGroup;
@@ -11,7 +10,6 @@ import java.util.LinkedHashMap;
 import java.util.Map;
 
 import androidx.annotation.NonNull;
-import androidx.recyclerview.widget.LinearLayoutManager;
 import androidx.recyclerview.widget.RecyclerView;
 import de.sebse.fuplanner.R;
 import de.sebse.fuplanner.services.KVV.types.Event;
@@ -19,12 +17,9 @@ 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.Triplet;
-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.ListViewHolder;
-import de.sebse.fuplanner.tools.ui.StringViewHolder;
 
 class ModDetailEventAdapter extends RecyclerView.Adapter<CustomViewHolder> {
     private static final String VALUE_LECTURE = "Class section - Lecture";

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

@@ -13,11 +13,8 @@ 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.Triplet;
 import de.sebse.fuplanner.tools.UtilsDate;
-import de.sebse.fuplanner.tools.ui.CustomViewHolder;
 import de.sebse.fuplanner.tools.ui.ItemViewHolder;
-import de.sebse.fuplanner.tools.ui.ListViewHolder;
 
 class ModDetailEventAdapterInner extends RecyclerView.Adapter<ItemViewHolder> {
     private final ArrayList<Entry> mPositionalData;

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

@@ -8,14 +8,13 @@ import android.view.View;
 import android.view.ViewGroup;
 
 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.KVV;
+import de.sebse.fuplanner.tools.MainActivityListener;
-import de.sebse.fuplanner.services.KVV.types.Modules;
 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) {
+        if (mListener == null)
-            KVV kvv = ((MainActivity) getActivity()).getKVV();
+            return;
-            kvv.getModule(mItemPos, (Modules.Module module) -> {
+        mListener.getKVV().modules().events().recv(mItemPos, success -> {
-                adapter.setModule(module);
+            adapter.setModule(success);
-                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);
-        }
     }
 
+    @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

@@ -72,7 +72,7 @@ public class ModDetailFragment extends Fragment implements ModDetailListener {
         }
         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);

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

@@ -12,7 +12,7 @@ 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.StringViewHolder;
 
@@ -62,7 +62,7 @@ class ModDetailGradebookAdapter extends RecyclerView.Adapter<RecyclerView.ViewHo
             case TYPE_GRADE:
                 view = LayoutInflater.from(parent.getContext())
                         .inflate(R.layout.list_moddetails_gradebook, parent, false);
-                return new GradebookViewHolder(view);
+                return new GradeViewHolder(view);
             default:
                 //noinspection ConstantConditions
                 return null;
@@ -90,8 +90,8 @@ class ModDetailGradebookAdapter extends RecyclerView.Adapter<RecyclerView.ViewHo
             break;
             case TYPE_GRADE:
                 int index = data.second / 1024;
-                GradebookViewHolder i = (GradebookViewHolder) holder;
+                GradeViewHolder i = (GradeViewHolder) holder;
-                Gradebook gradebook = mValue.gradebook.get(index);
+                Grade gradebook = mValue.gradebook.get(index);
 
                 i.mTitle.setText(gradebook.getItemName());
                 i.mGrade.setText(String.valueOf(gradebook.getPoints()));
@@ -119,12 +119,12 @@ class ModDetailGradebookAdapter extends RecyclerView.Adapter<RecyclerView.ViewHo
 
 
 
-    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

@@ -8,14 +8,13 @@ import android.view.View;
 import android.view.ViewGroup;
 
 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.KVV;
+import de.sebse.fuplanner.tools.MainActivityListener;
-import de.sebse.fuplanner.services.KVV.types.Modules;
 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) {
+        if (mListener == null)
-            KVV kvv = ((MainActivity) getActivity()).getKVV();
+            return;
-            kvv.getModule(mItemPos, (Modules.Module module) -> {
+        mListener.getKVV().modules().gradebook().recv(mItemPos, success -> {
-                adapter.setModule(module);
+            adapter.setModule(success);
-                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);
-        }
     }
 
+    @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

@@ -1,5 +1,7 @@
 package de.sebse.fuplanner.fragments.moddetails;
 
+import android.content.Intent;
+import android.net.Uri;
 import android.util.Pair;
 import android.view.LayoutInflater;
 import android.view.View;
@@ -16,11 +18,13 @@ 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.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> {
@@ -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));
@@ -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;
@@ -116,6 +129,9 @@ class ModDetailOverviewAdapter extends RecyclerView.Adapter<RecyclerView.ViewHol
                     case ModulePart.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.mString.setText(h.mView.getResources().getString(R.string.announcements_count, getAnnounceCount()));
                         break;
@@ -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 -> {
@@ -231,6 +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

@@ -13,10 +13,8 @@ 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.KVV;
+import de.sebse.fuplanner.tools.MainActivityListener;
-import de.sebse.fuplanner.services.KVV.types.Modules;
 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
@@ -82,37 +81,45 @@ public class ModDetailOverviewFragment extends Fragment {
         return view;
     }
 
+
+
+
     private void refresh(boolean forceRefresh) {
-        if (getActivity() != null) {
+        if (mListener != null) {
-            KVV kvv = ((MainActivity) getActivity()).getKVV();
+            mListener.getKVV().modules().details().recv(mItemPos, pair -> {
-            kvv.getModule(mItemPos, (Modules.Module module) -> {
+                adapter.setModule(pair.first);
-                adapter.setModule(module);
-                kvv.getModuleDetails(module, pair -> {
-                    adapter.setModule();
                 if (pair.second)
                     swipeLayout.setRefreshing(false);
             }, error -> {
                 swipeLayout.setRefreshing(false);
                 log.e(error);
             }, forceRefresh);
-            }, 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");
+
+
         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()
+                throw new RuntimeException(context.toString() + " must implement ModDetailListener");
-                        + " 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/ModDetailResourceFragment.java

@@ -11,14 +11,14 @@ 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.Download;
+import de.sebse.fuplanner.services.KVV.ui.Download;
-import de.sebse.fuplanner.services.KVV.KVV;
 import de.sebse.fuplanner.services.KVV.types.Modules;
 import de.sebse.fuplanner.services.KVV.types.Resource;
 import de.sebse.fuplanner.tools.MainActivityListener;
@@ -40,8 +40,8 @@ public class ModDetailResourceFragment extends Fragment {
     private final Logger log = new Logger(this);
     private ModDetailResourceAdapter adapter;
     private SwipeRefreshLayout swipeLayout;
-    private MainActivityListener context;
     private Download download;
+    @Nullable private MainActivityListener mListener;
 
 
     public ModDetailResourceFragment() {
@@ -88,10 +88,8 @@ public class ModDetailResourceFragment extends Fragment {
                 if (!node.isLeaf()) {
                     // Update and toggle the node.
                     onToggle(!node.isExpand(), holder);
-                } else if(node.getContent() instanceof Resource.File) { // if leaf is file
+                } else if (node.getContent() instanceof Resource.File && ModDetailResourceFragment.this.mListener != null) { // if leaf is file
-                    KVV kvv = ModDetailResourceFragment.this.context.getKVV();
+                    ModDetailResourceFragment.this.mListener.getKVV().modules().resources().recv(mItemPos, (Modules.Module module) -> {
-                    kvv.getModule(mItemPos, (Modules.Module module) -> {
-
                         String folderName = "FU-"+module.title.replaceAll("[:*<>|/\"\\\\]", "-");
                         Resource.File file = (Resource.File) node.getContent();
                         getDownload().openDownloadDialog(file, folderName);
@@ -120,14 +118,12 @@ public class ModDetailResourceFragment extends Fragment {
         return view;
     }
 
-
-
     @Override
     public void onAttach(Context context) {
         super.onAttach(context);
         if (context instanceof MainActivityListener) {
-            this.context = ((MainActivityListener) context);
+            this.mListener = ((MainActivityListener) context);
-            this.context.addRequestPermissionsResultListener(getDownload().getRequestPermissionsResultListener(), "ModDetailResourceFragment");
+            this.mListener.addRequestPermissionsResultListener(getDownload().getRequestPermissionsResultListener(), "ModDetailResourceFragment");
         } else
             throw new RuntimeException(context.toString() + " must implement MainActivityListener");
     }
@@ -135,26 +131,22 @@ public class ModDetailResourceFragment extends Fragment {
     @Override
     public void onDetach() {
         super.onDetach();
-        this.context.removeRequestPermissionsResultListener("ModDetailResourceFragment");
+        if (this.mListener != null) {
+            this.mListener.removeRequestPermissionsResultListener("ModDetailResourceFragment");
+            this.mListener = null;
+        }
     }
 
     private void refresh(boolean forceRefresh) {
-        if (getActivity() != null) {
+        if (mListener == null)
-            KVV kvv = ((MainActivity) getActivity()).getKVV();
+            return;
-            kvv.getModule(mItemPos, (Modules.Module module) -> {
+        mListener.getKVV().modules().assignments().recv(mItemPos, success -> {
-                adapter.setModule(module);
+            adapter.setModule(success);
-                kvv.getModuleResources(module, success1 -> {
-                    adapter.setModule();
             swipeLayout.setRefreshing(false);
         }, error -> {
             swipeLayout.setRefreshing(false);
             log.e(error);
         }, forceRefresh);
-            }, error -> {
-                swipeLayout.setRefreshing(false);
-                log.e(error);
-            }, forceRefresh);
-        }
     }
 
     Download getDownload() {

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

@@ -8,6 +8,7 @@ class ModulePart {
     static final int EVENT = 4;
     static final int GRADEBOOK = 5;
     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() {

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

@@ -29,6 +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
@@ -61,6 +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

@@ -1,219 +1,47 @@
 package de.sebse.fuplanner.services.KVV;
 
 import android.content.Context;
-import android.util.Pair;
 
-import java.io.IOException;
+import org.jetbrains.annotations.NotNull;
-import java.util.ArrayList;
+
 import java.util.HashMap;
 
-import androidx.annotation.NonNull;
-import de.sebse.fuplanner.services.KVV.types.LoginToken;
-import de.sebse.fuplanner.services.KVV.types.Modules;
-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;
-
-/**
- * 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 MainActivityListener mListener;
+    private final KVVListener mListener;
-    private Logger log = new Logger(this);
+    private final Context mContext;
 
-    public KVV(Context context) {
+    public KVV(KVVListener listener, Context context) {
-        mListener = (MainActivityListener) context;
+        this.mListener = listener;
-        this.context = context;
+        this.mContext = context;
-        this.updatingList = new ArrayList<>();
     }
 
-    public boolean isLoggedIn() {
+    @NotNull
-        return this.lastToken != null;
+    public Login account() {
+        return (Login) addAndGet("account", () -> new Login(mListener, mContext));
     }
 
-    public LoginToken easyLogin() {
+    @NotNull
-        KVVLogin login = new KVVLogin(this.context);
+    public Modules modules() {
-        lastToken = login.easyLogin();
+        return (Modules) addAndGet("module", () -> new Modules(account(), mListener, mContext));
-        this.endUpdate();
-        return lastToken;
-    }
-
-    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);
-        });
-    }
-
-    public void logout() {
-        KVVModuleList modules = (KVVModuleList) addons.get("modules");
-        if (modules != null) {
-            modules.deleteModulesOffline(this.context);
-        }
-        invalidate();
-    }
-
-    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));
-    }
-
-    public void getResourceFile(final NetworkCallback<String> callback, final NetworkErrorCallback error, String filename, String url, String moduleName, boolean downloadNew){
-        getModulePart(modules -> modules.getResourceFile(callback, errorOnCallback(error),filename, url, moduleName, downloadNew));
-    }
-
-    public void testLogin(BooleanFunction callback) {
-        getLastToken(lastToken -> {
-            TestLogin.testLogin(context, lastToken, success -> callback.apply(true), error -> callback.apply(false));
-        });
     }
 
 
 
 
 
-    private void getModulePart(ModListFunction func) {
+
-        this.getLastToken(token -> {
+    @NotNull
-            KVVModuleList modules = (KVVModuleList) addons.get("modules");
+    private Object addAndGet(@NotNull String addon, @NotNull ModuleCreatorInterface creatorInterface) {
-            if (modules == null) {
+        Object o = addons.get(addon);
-                modules = new KVVModuleList(this.context, token);
+        if (o == null) {
-                addons.put("modules", modules);
+            o = creatorInterface.create();
+            addons.put(addon, o);
         }
-            func.apply(modules);
+        return o;
-        });
     }
 
-    private<T> NetworkCallback<T> saveOnCallback(KVVModuleList modules, NetworkCallback<T> callback, boolean forceRefresh){
+    private interface ModuleCreatorInterface {
-        return (success -> {
+        @NotNull Object create();
-            try {
-                modules.saveModulesOffline(this.context);
-            } catch (IOException e) {
-                e.printStackTrace();
-            }
-            if (forceRefresh)
-                mListener.onRefreshCompleted(false);
-            callback.onResponse(success);
-        });
-    }
-
-    private NetworkErrorCallback errorOnCallback(NetworkErrorCallback errorCallback){
-        return (error -> {
-            if (error.getHttpStatus() == 401 || error.getHttpStatus() == 403)
-                mListener.loginTokenInvalid(true);
-            else
-                mListener.onRefreshCompleted(true);
-            log.e(error);
-            errorCallback.onError(error);
-        });
-    }
-
-    @FunctionalInterface
-    interface ModListFunction {
-        void apply(KVVModuleList mod);
-    }
-
-    @FunctionalInterface
-    public interface BooleanFunction {
-        void apply(boolean isSuccess);
-    }
-
-    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);
-        }
     }
 }

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

@@ -1,643 +0,0 @@
-package de.sebse.fuplanner.services.KVV;
-
-import android.content.Context;
-import android.os.Build;
-import android.os.Environment;
-import android.text.Html;
-import android.text.Spanned;
-import android.util.Pair;
-
-import org.json.JSONArray;
-import org.json.JSONException;
-import org.json.JSONObject;
-
-import java.io.File;
-import java.io.FileOutputStream;
-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.AssignmentList;
-import de.sebse.fuplanner.services.KVV.types.Event;
-import de.sebse.fuplanner.services.KVV.types.EventList;
-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.Resource;
-import de.sebse.fuplanner.tools.AsyncQueue;
-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 de.sebse.fuplanner.tools.network.Result;
-
-import static de.sebse.fuplanner.services.KVV.TestLogin.testLogin;
-
-/**
- * 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();
-        }
-    }
-
-
-
-
-    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);
-            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 = 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.optString("description", "");
-                    description = String.valueOf(fromHtml(description));
-                    String id = site.getString("id");
-                    modules.addModule(semester, lvNumbers, title, lecturers, type, description, id);
-                } catch (JSONException e) {
-                    log.e("Cannot parse module! ID:", i, sites);
-                    e.printStackTrace();
-                } catch (NoSuchFieldException e) {
-                    log.e("Cannot parse module! ID:", i, sites);
-                    e.printStackTrace();
-                }
-            }
-            // Empty module *may be* because token is invalid -> check
-            if (modules.size() == 0)
-                testLogin(getContext(), token, token -> callback.onResponse(modules), errorCallback);
-            else
-                callback.onResponse(modules);
-        }, error -> errorCallback.onError(new NetworkError(101104, error.networkResponse.statusCode, "Cannot get module list!")));
-    }
-
-    void deleteModulesOffline(Context context) {
-        if (this.moduleList != null)
-            this.moduleList.delete(context);
-    }
-
-    void saveModulesOffline(Context context) throws IOException {
-        if (this.moduleList != null)
-            this.moduleList.save(context);
-    }
-
-    void getModule(String id, final NetworkCallback<Modules.Module> callback, final NetworkErrorCallback errorCallback, boolean forceRefresh) {
-        this.getModuleList(success -> {
-            callback.onResponse(success.get(id));
-        }, errorCallback, forceRefresh);
-    }
-
-
-
-
-
-
-    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();
-        }
-    }
-
-
-
-
-
-
-    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 = 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) {
-                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(getContext(), token, token -> callback.onResponse(announcements), errorCallback);
-            else
-                callback.onResponse(announcements);
-        }, error -> errorCallback.onError(new NetworkError(101203, error.networkResponse.statusCode, "Cannot get announcements!")));
-    }
-
-
-
-
-
-    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 = 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) {
-                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(getContext(), token, token -> callback.onResponse(assignments), errorCallback);
-            else
-                callback.onResponse(assignments);
-            }, error -> errorCallback.onError(new NetworkError(101303, error.networkResponse.statusCode, "Cannot get assignments!")));
-
-
-    }
-
-
-
-
-
-
-    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(getContext(), token, token -> callback.onResponse(events), errorCallback);
-            else
-                callback.onResponse(events);
-        }, error -> errorCallback.onError(new NetworkError(101403, error.networkResponse.statusCode, "Cannot get calendar entries!")));
-    }
-
-
-
-
-
-    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");
-                    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) {
-                e.printStackTrace();
-                errorCallback.onError(new NetworkError(101602, 403, "Cannot parse resources!"));
-                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 (root.size() == 0)
-                testLogin(getContext(), token, token -> callback.onResponse(root), errorCallback);
-            else
-                callback.onResponse(root);
-
-        }, error -> errorCallback.onError(new NetworkError(101603, error.networkResponse.statusCode, "Cannot get resources!")));
-
-    }
-
-    void getResourceFile(final NetworkCallback<String> callback, final NetworkErrorCallback errorCallback, String Filename, String url, String moduleName, boolean downloadNew) {
-        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() && !downloadNew) {
-                callback.onResponse(f.getPath());
-                return;
-            }
-        }
-        getResourceFileUpgrade(Filename, url , moduleName, callback, errorCallback);
-    }
-
-    private void getResourceFileUpgrade(String filename, String url , String moduleName, final NetworkCallback<String> callback, final NetworkErrorCallback errorCallback) {
-        if (token == null) {
-            errorCallback.onError(new NetworkError(101701, 500, "Currently running in offline mode!"));
-            return;
-        }
-
-        get(url, token.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){
-                testLogin(getContext(), token, token -> {
-                    if (isExternalStorageWritable()) {
-                        // try to download file again
-                        get(url, token.getCookies(), response2 -> {
-                            String path = saveFileInDownloads(filename, response2, moduleName);
-                            callback.onResponse(path);
-                        }, error -> errorCallback.onError(new NetworkError(101705, error.networkResponse.statusCode, "Cannot get file!")));
-                    } else {
-                        errorCallback.onError(new NetworkError(101703, 403, "External storage not writable!"));
-                    }
-                }, errorCallback);
-            } else if (isExternalStorageWritable()) {
-                String path = saveFileInDownloads(filename, response, 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, Result fileResult, String moduleName) {
-        // Saves file in folder: DOWNLOADS/moduleName
-        File folder = new File(Environment.getExternalStoragePublicDirectory(
-                Environment.DIRECTORY_DOWNLOADS), moduleName);
-        if (!folder.mkdirs()) {
-            log.w( "Directory not created", folder.toString());
-        }
-        String path = "";
-        try {
-            // TODO check if enough storage space is available
-            FileOutputStream out = new FileOutputStream(folder.getPath()+"/"+filename);
-            out.write(fileResult.getBytes());
-            out.close();
-            path = folder.getPath()+"/"+filename;
-        } catch (Exception e) {
-            log.w("File not saved!");
-            e.printStackTrace();
-        }
-        return path;
-    }
-
-    @SuppressWarnings("deprecation")
-    public 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);
-        }
-    }
-
-
-}

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

@@ -2,69 +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;
 
-import static de.sebse.fuplanner.services.KVV.TestLogin.testLogin;
+public class Login extends HTTPService {
+    private KVVListener mListener;
+    @Nullable private LoginToken mToken;
+    private boolean mLoginPending = false;
+    private boolean mOnlineMode = false;
 
-/**
+    Login(KVVListener listener, Context context) {
- * Created by sebastian on 24.10.17.
- */
-
-class KVVLogin extends HTTPService {
-    private LoginToken loginToken;
-
-    KVVLogin(Context context) {
         super(context);
+        this.mListener = listener;
+    }
+
+    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;
     }
 
-    LoginToken easyLogin() {
+    public boolean isOfflineStoredAvailable() {
-        return this.loginToken;
+        try {
+            LoginToken load = LoginToken.load(getContext());
+            return load != null;
+        } catch (FileNotFoundException ignored) {
+        } catch (IOException e) {
+            e.printStackTrace();
+        } catch (ClassNotFoundException e) {
+            e.printStackTrace();
+        }
+        return false;
     }
 
-    void login(String username, String password, NetworkCallback<LoginToken> callback, NetworkErrorCallback errorCallback) {
+    public boolean logout(boolean delete) {
-        if (this.loginToken != null) {
+        if (mLoginPending)
-            if (this.loginToken.getUsername().equals(username)) {
+            return false;
-                testLogin(getContext(), this.loginToken, success -> callback.onResponse(this.loginToken), error -> {
+        if (mToken == null)
-                    this.loginToken = null;
+            return true;
-                    login(username, password, callback, errorCallback);
+        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);
         });
-            } else {
-                this.loginToken = null;
-                login(username, password, callback, errorCallback);
     }
+
+
+
+    private boolean handleCallbacks() {
+        if (mToken != null) {
+            mListener.onLogin(mToken, mOnlineMode);
+            return true;
         } else {
-            doLogin(username, password, token -> {
+            mListener.onLogout();
-                this.loginToken = token;
+            return false;
-                testLogin(getContext(), this.loginToken, success -> callback.onResponse(this.loginToken), errorCallback);
-            }, errorCallback);
         }
     }
 
-    void deleteOffline() {
+    private boolean setToken(@Nullable LoginToken token, boolean enteringOnlineMode) {
-        if (this.loginToken != null)
+        if (token == null)
-            this.loginToken.delete(getContext());
+            return false;
+        boolean isOnlyRefresh = mToken != null;
+        mToken = token;
+        if (enteringOnlineMode) {
+            try {
+                mToken.save(getContext());
+            } catch (IOException e) {
+                e.printStackTrace();
+            }
+        }
+        mOnlineMode = enteringOnlineMode;
+        return isOnlyRefresh || handleCallbacks();
     }
 
-    void saveOffline() throws IOException {
+
-        if (this.loginToken != null)
+
-            this.loginToken.save(getContext());
+
-    }
 
 
 
@@ -320,5 +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/TestLogin.java

@@ -1,38 +0,0 @@
-package de.sebse.fuplanner.services.KVV;
-
-import android.content.Context;
-
-import org.json.JSONException;
-import org.json.JSONObject;
-
-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;
-
-final class TestLogin extends HTTPService {
-
-    private TestLogin(Context context) {
-        super(context);
-    }
-
-    static void testLogin(Context context, LoginToken loginToken, NetworkCallback<LoginToken> callback, NetworkErrorCallback errorCallback) {
-        new TestLogin(context).get(String.format("https://kvv.imp.fu-berlin.de/direct/profile/%s.json", loginToken.getUsername()), loginToken.getCookies(), response -> {
-            String body = response.getParsed();
-            if (body == null) {
-                errorCallback.onError(new NetworkError(100202, 403, "Testing login failed!"));
-                return;
-            }
-            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/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;
 
@@ -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;
 
@@ -15,7 +17,6 @@ public class Assignment implements Serializable {
         this.title = title;
         this.dueTime = dueTime;
         this.urls = urls;
-        //this.grade = grade;
         this.instructions = instructions;
     }
 
@@ -50,4 +51,9 @@ public class Assignment implements Serializable {
                 "\nDue date: "+getDueDate()+
                 "\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/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/Lecturer.java

@@ -8,9 +8,10 @@ public class Lecturer implements Serializable {
     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();
@@ -18,20 +19,33 @@ public class Lecturer implements Serializable {
         this.firstName = matcher.group(1);
         this.surname = matcher.group(2);
         this.mail = matcher.group(3);
+        this.isResponsible = matcher.group(4).equals("true");
     }
 
-    private String getFirstName() {
+    public String getFirstName() {
         return firstName;
     }
 
-    private String getSurname() {
+    public String getSurname() {
         return surname;
     }
 
-    private String getMail() {
+    public String getMail() {
         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()+

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

@@ -3,6 +3,7 @@ package de.sebse.fuplanner.services.KVV.types;
 import android.content.Context;
 
 import java.io.FileInputStream;
+import java.io.FileNotFoundException;
 import java.io.FileOutputStream;
 import java.io.IOException;
 import java.io.ObjectInputStream;
@@ -17,16 +18,14 @@ import androidx.annotation.Nullable;
  */
 
 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;
+    @Nullable private String fullName;
-    private String email;
+    @Nullable private String email;
-    private long saveDate = 0;
 
     public LoginToken(String username, String shibsessionKey, String shibsessionName, String JSESSIONID) {
         this.username = username;
@@ -37,17 +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);
@@ -96,8 +101,8 @@ public class LoginToken implements Serializable {
         return cookies;
     }
 
-    public boolean isSameUser(LoginToken token) {
+    public boolean isSameUser(String username) {
-        return token != null && this.getUsername().equals(token.getUsername());
+        return this.getUsername().equals(username);
     }
 
     @Override

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

@@ -2,6 +2,8 @@ package de.sebse.fuplanner.services.KVV.types;
 
 import android.content.Context;
 
+import org.jetbrains.annotations.NotNull;
+
 import java.io.FileInputStream;
 import java.io.FileOutputStream;
 import java.io.IOException;
@@ -11,6 +13,7 @@ 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;
@@ -21,16 +24,16 @@ import androidx.annotation.Nullable;
 
 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) {
+    public Modules(String username) {
-        this.token = loginToken;
+        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);
     }
@@ -66,7 +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;
@@ -84,8 +90,8 @@ public class Modules implements Iterable<Modules.Module>, Serializable {
         context.deleteFile(FILE_NAME);
     }
 
-    public LoginToken getToken() {
+    public String getUsername() {
-        return token;
+        return mUsername;
     }
 
     public void updateList(Modules modules) {
@@ -104,29 +110,25 @@ public class Modules implements Iterable<Modules.Module>, Serializable {
     }
 
     public class Module implements Serializable {
-        public final String semester;
+        @Nullable public final Semester semester;
-        final HashSet<String> lvNumber;
+        @NotNull final HashSet<String> lvNumber;
-        public final String title;
+        @NotNull public final String title;
-        final HashSet<Lecturer> lecturer;
+        @NotNull
-        public final String type;
+        public final ArrayList<Lecturer> lecturer;
-        public final String description;
+        @Nullable public final String type;
-        private final String ID;
+        @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();
                 }
@@ -136,20 +138,20 @@ 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) {
+        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) {
-            semester = semester.replace("SS", "S");
+
-            semester = semester.replaceAll("[0-9]{2}([0-9]{2})", "$1");
             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;
         }

app/src/main/java/de/sebse/fuplanner/services/KVV/types/Resource.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;
 
@@ -54,6 +56,11 @@ public abstract class Resource implements Serializable {
 
     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;
 

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 (a.getYear() == b.getYear()) {
-            if (s1type.equals(s2type))
+            if (a.getType() == b.getType())
                 return EQUAL;
-            return s1type.equals("S") ? 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) {
+    public boolean hasFilter(Modules.Module o1, Semester filter) {
-        return o1.semester.equals(filter);
+        return o1.semester != null && o1.semester.equals(filter);
     }
 }

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

@@ -1,4 +1,4 @@
-package de.sebse.fuplanner.services.KVV;
+package de.sebse.fuplanner.services.KVV.ui;
 
 import android.Manifest;
 import android.app.AlertDialog;
@@ -24,10 +24,7 @@ import de.sebse.fuplanner.tools.RequestPermissionsResultListener;
 import de.sebse.fuplanner.tools.UtilsDate;
 import de.sebse.fuplanner.tools.logging.Logger;
 
-import static android.content.Intent.normalizeMimeType;
-import static androidx.core.app.ActivityCompat.startActivityForResult;
 import static androidx.core.content.ContextCompat.checkSelfPermission;
-import static androidx.core.content.ContextCompat.startActivity;
 
 public class Download {
 
@@ -35,7 +32,6 @@ public class Download {
     private final ActivityInterface activityInterface;
     private RequestedDownload requestedDownload;
     private Logger log = new Logger(this);
-    static final int REQUEST_IMAGE_OPEN = 1;
 
 
     public Download(ContextInterface contextInterface, ActivityInterface activityInterface) {
@@ -48,19 +44,20 @@ public class Download {
     }
 
     public void openDownloadDialog(Resource.File file, String folderName) {
-        if (contextInterface.get() == null)
+        Context context = contextInterface.get();
+        if (context == null)
             return;
-        AlertDialog.Builder alertDialogBuilder = new AlertDialog.Builder(contextInterface.get());
+        AlertDialog.Builder alertDialogBuilder = new AlertDialog.Builder(context);
         File f = new File(Environment.getExternalStoragePublicDirectory(
                 Environment.DIRECTORY_DOWNLOADS)+"/"+folderName+"/"+file.getTitle());
-        Resources resources = contextInterface.get().getResources();
+        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(contextInterface.get(), file.getModifiedDate()));
+            message += resources.getString(R.string.last_modified_on, UtilsDate.getModifiedDateTime(context, file.getModifiedDate()));
         }
 
         alertDialogBuilder
@@ -82,40 +79,46 @@ public class Download {
     }
 
     private void download(Resource.File file, String folderName, boolean downloadNew){
-        if (activityInterface.get() == null) {
+        MainActivity activity = activityInterface.get();
+        if (activity == null) {
             showDownloadError();
             return;
         }
-        if (checkSelfPermission(activityInterface.get(), android.Manifest.permission.WRITE_EXTERNAL_STORAGE) == PackageManager.PERMISSION_GRANTED) {
+        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(activityInterface.get(),
+            ActivityCompat.requestPermissions(activity,
                     new String[]{Manifest.permission.WRITE_EXTERNAL_STORAGE},
                     1);
         }
     }
 
     private void downloadOrOpen(Resource.File file, String folderName, boolean downloadNew) {
-        KVV kvv = activityInterface.get().getKVV();
+        if (!isExternalStorageWritable()) {
-        if(isExternalStorageWritable()){
+            return;
-            kvv.getResourceFile(success1 -> {
+        }
-                // Downloading file failed
+        MainActivity activity = activityInterface.get();
-                if (success1.equals("")){
+        if (activity == null) {
             showDownloadError();
-                }else {
+            return;
-                    if (Regex.has("^http", success1)){
+        }
-                        Intent intent = new Intent(Intent.ACTION_VIEW, Uri.parse(success1));
+        activity.getKVV().modules().resources().file(file.getTitle(), file.getUrl(), folderName, success -> {
-                        contextInterface.get().startActivity(intent);
+            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(success1));
+                    fileOpen(new File(success));
                 }
 
             }
-            }, log::e, file.getTitle(), file.getUrl(), folderName, downloadNew);
+        }, log::e, downloadNew);
-        }
     }
 
     private void showDownloadError() {
@@ -186,7 +189,6 @@ public class Download {
     }
 
     private void fileOpen(File url){
-
         Uri uri = FileProvider.getUriForFile(contextInterface.get(), contextInterface.get().getApplicationContext().getPackageName() + ".my.provider", url);
 
         Intent intent;
@@ -235,18 +237,12 @@ public class Download {
             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.addCategory(Intent.CATEGORY_OPENABLE);
-        // Only the system receives the ACTION_OPEN_DOCUMENT, so no need to test.
-
-
-
-
         intent.addFlags(Intent.FLAG_ACTIVITY_NEW_TASK);
         contextInterface.get().startActivity(intent);
 

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

@@ -19,15 +19,12 @@ public interface MainActivityListener {
 
     GoogleAuth getGoogleAuth();
 
-    void loginTokenInvalid(boolean doLoginCheck);
-
-    void onRefreshCompleted(boolean isFailed);
-
     CanteenBrowser getCanteenBrowser();
 
+    @Deprecated
+    void onRefreshCompleted(boolean isFailed);
+
     void addRequestPermissionsResultListener(RequestPermissionsResultListener listener, String id);
 
     void removeRequestPermissionsResultListener(String id);
-
-    void refreshNavigation();
 }

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/network/HTTPService.java

@@ -17,6 +17,7 @@ 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;
 
 /**
@@ -27,34 +28,63 @@ 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.mContext = context;
         requestQueue = Volley.newRequestQueue(context, new BetterHurlStack(false));
     }
 
+    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) {
         HttpRequest request = new HttpRequest(Request.Method.GET, url, response, error) {
             @Override
             public void deliverError(VolleyError error) {
                 if (error == null) {
-                    super.deliverError(new VolleyError(new NetworkResponse(500, null, true, 0, null)));
+                    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, true, error.getNetworkTimeMs(), null)));
+                    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 {
+                        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();
@@ -109,22 +139,33 @@ public class HTTPService {
             @Override
             public void deliverError(VolleyError error) {
                 if (error == null) {
-                    super.deliverError(new VolleyError(new NetworkResponse(500, null, true, 0, null)));
+                    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, true, error.getNetworkTimeMs(), null)));
+                    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 {
+                        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 {

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

@@ -1,7 +1,6 @@
 package de.sebse.fuplanner.tools.ui;
 
 import android.view.View;
-import android.widget.ImageView;
 import android.widget.TextView;
 
 import com.cunoraz.tagview.TagView;

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

@@ -1,8 +1,6 @@
 package de.sebse.fuplanner.tools.ui;
 
 import android.view.View;
-import android.widget.ListView;
-import android.widget.TextView;
 
 import androidx.recyclerview.widget.RecyclerView;
 import de.sebse.fuplanner.R;

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

@@ -0,0 +1,26 @@
+package de.sebse.fuplanner.tools.ui;
+
+import android.view.View;
+import android.widget.ImageView;
+import android.widget.TextView;
+
+import androidx.recyclerview.widget.RecyclerView;
+import de.sebse.fuplanner.R;
+
+public class MailViewHolder extends StringViewHolder {
+    public final TextView mTitle;
+    public final TextView mSubLeft;
+    public final ImageView mIcon;
+
+    public MailViewHolder(View view) {
+        super(view);
+        mTitle = view.findViewById(R.id.title);
+        mSubLeft = view.findViewById(R.id.sub_left);
+        mIcon = view.findViewById(R.id.icon);
+    }
+
+    @Override
+    public String toString() {
+        return super.toString() + " '" + mTitle.getText() + "' '" + mSubLeft.getText() + "'";
+    }
+}

app/src/main/java/de/sebse/fuplanner/tools/ui/treeview/TreeViewAdapter.java

@@ -17,6 +17,7 @@ import androidx.recyclerview.widget.RecyclerView;
 /**
  * Created by tlh on 2016/10/1 :)
  */
+@SuppressWarnings("unused")
 public class TreeViewAdapter extends RecyclerView.Adapter<RecyclerView.ViewHolder> {
     private static final String KEY_IS_EXPAND = "IS_EXPAND";
     private final List<? extends TreeViewBinder> viewBinders;
@@ -42,7 +43,7 @@ public class TreeViewAdapter extends RecyclerView.Adapter<RecyclerView.ViewHolde
      * @param nodes 基准点
      */
     private void findDisplayNodes(List<TreeNode> nodes) {
-        for (TreeNode node : nodes) {
+        for (TreeNode<?> node : nodes) {
             displayNodes.add(node);
             if (!node.isLeaf() && node.isExpand())
                 findDisplayNodes(node.getChildList());
@@ -54,8 +55,9 @@ public class TreeViewAdapter extends RecyclerView.Adapter<RecyclerView.ViewHolde
         return displayNodes.get(position).getContent().getLayoutId();
     }
 
+    @NonNull
     @Override
-    public RecyclerView.ViewHolder onCreateViewHolder(ViewGroup parent, int viewType) {
+    public RecyclerView.ViewHolder onCreateViewHolder(@NonNull ViewGroup parent, int viewType) {
         View v = LayoutInflater.from(parent.getContext())
                 .inflate(viewType, parent, false);
         if (viewBinders.size() == 1)
@@ -68,8 +70,8 @@ public class TreeViewAdapter extends RecyclerView.Adapter<RecyclerView.ViewHolde
     }
 
     @Override
-    public void onBindViewHolder(RecyclerView.ViewHolder holder, int position, List<Object> payloads) {
+    public void onBindViewHolder(@NonNull RecyclerView.ViewHolder holder, int position, @NonNull List<Object> payloads) {
-        if (payloads != null && !payloads.isEmpty()) {
+        if (!payloads.isEmpty()) {
             Bundle b = (Bundle) payloads.get(0);
             for (String key : b.keySet()) {
                 switch (key) {
@@ -84,11 +86,9 @@ public class TreeViewAdapter extends RecyclerView.Adapter<RecyclerView.ViewHolde
     }
 
     @Override
-    public void onBindViewHolder(final RecyclerView.ViewHolder holder, int position) {
+    public void onBindViewHolder(@NonNull final RecyclerView.ViewHolder holder, int position) {
         holder.itemView.setPadding(displayNodes.get(position).getHeight() * padding, 3, 3, 3);
-        holder.itemView.setOnClickListener(new View.OnClickListener() {
+        holder.itemView.setOnClickListener(v -> {
-            @Override
-            public void onClick(View v) {
             TreeNode selectedNode = displayNodes.get(holder.getLayoutPosition());
             // Prevent multi-click during the short interval.
             try {
@@ -113,15 +113,15 @@ public class TreeViewAdapter extends RecyclerView.Adapter<RecyclerView.ViewHolde
             } else {
                 notifyItemRangeRemoved(positionStart, removeChildNodes(selectedNode, true));
             }
-            }
         });
         for (TreeViewBinder viewBinder : viewBinders) {
             if (viewBinder.getLayoutId() == displayNodes.get(position).getContent().getLayoutId())
+                //noinspection unchecked
                 viewBinder.bindView(holder, position, displayNodes.get(position));
         }
     }
 
-    private int addChildNodes(TreeNode pNode, int startIndex) {
+    private int addChildNodes(TreeNode<?> pNode, int startIndex) {
         List<TreeNode> childList = pNode.getChildList();
         int addChildCount = 0;
         for (TreeNode treeNode : childList) {
@@ -139,7 +139,7 @@ public class TreeViewAdapter extends RecyclerView.Adapter<RecyclerView.ViewHolde
         return removeChildNodes(pNode, true);
     }
 
-    private int removeChildNodes(TreeNode pNode, boolean shouldToggle) {
+    private int removeChildNodes(TreeNode<?> pNode, boolean shouldToggle) {
         if (pNode.isLeaf())
             return 0;
         List<TreeNode> childList = pNode.getChildList();
@@ -287,7 +287,7 @@ public class TreeViewAdapter extends RecyclerView.Adapter<RecyclerView.ViewHolde
         notifyDiff(temp);
     }
 
-    public void collapseBrotherNode(TreeNode pNode) {
+    public void collapseBrotherNode(TreeNode<LayoutItemType> pNode) {
         List<TreeNode> temp = backupDisplayNodes();
         if (pNode.isRoot()) {
             List<TreeNode> roots = new ArrayList<>();
@@ -301,7 +301,7 @@ public class TreeViewAdapter extends RecyclerView.Adapter<RecyclerView.ViewHolde
                     removeChildNodes(root);
             }
         } else {
-            TreeNode parent = pNode.getParent();
+            TreeNode<?> parent = pNode.getParent();
             if (parent == null)
                 return;
             List<TreeNode> childList = parent.getChildList();

app/src/main/res/drawable/ic_mail.xml

@@ -0,0 +1,9 @@
+<vector xmlns:android="http://schemas.android.com/apk/res/android"
+        android:width="40dp"
+        android:height="40dp"
+        android:viewportWidth="24.0"
+        android:viewportHeight="24.0">
+    <path
+        android:fillColor="#003366"
+        android:pathData="M20,4L4,4c-1.1,0 -1.99,0.9 -1.99,2L2,18c0,1.1 0.9,2 2,2h16c1.1,0 2,-0.9 2,-2L22,6c0,-1.1 -0.9,-2 -2,-2zM20,8l-8,5 -8,-5L4,6l8,5 8,-5v2z"/>
+</vector>

app/src/main/res/layout/activity_main.xml

@@ -10,6 +10,7 @@
 
     <include
         layout="@layout/app_bar_main"
+        android:id="@+id/app_bar_include"
         android:layout_width="match_parent"
         android:layout_height="match_parent" />
 

app/src/main/res/layout/list_all_items.xml

@@ -1,11 +1,15 @@
 <?xml version="1.0" encoding="utf-8"?>
-<RelativeLayout xmlns:android="http://schemas.android.com/apk/res/android"
+
+<androidx.cardview.widget.CardView xmlns:android="http://schemas.android.com/apk/res/android"
     xmlns:tools="http://schemas.android.com/tools"
+    android:layout_width="match_parent"
+    android:layout_height="wrap_content"
+    android:layout_margin="4dp">
+    <RelativeLayout
         android:layout_width="match_parent"
         android:layout_height="wrap_content"
         android:orientation="horizontal"
         android:padding="5dip" >
-
         <TextView
             android:id="@+id/title"
             android:layout_width="wrap_content"
@@ -48,4 +52,5 @@
             android:layout_alignParentRight="true"
             tools:text="Room 105"
             tools:ignore="RelativeOverlap" />
-</RelativeLayout>
+    </RelativeLayout>
+</androidx.cardview.widget.CardView>

app/src/main/res/layout/list_all_mails.xml

@@ -0,0 +1,45 @@
+<?xml version="1.0" encoding="utf-8"?>
+
+<androidx.cardview.widget.CardView xmlns:android="http://schemas.android.com/apk/res/android"
+    xmlns:tools="http://schemas.android.com/tools"
+    android:layout_width="match_parent"
+    android:layout_height="wrap_content"
+    android:layout_margin="4dp">
+    <RelativeLayout
+        android:layout_width="match_parent"
+        android:layout_height="wrap_content"
+        android:orientation="horizontal"
+        android:padding="5dip" >
+        <TextView
+            android:id="@+id/title"
+            android:layout_width="wrap_content"
+            android:layout_height="wrap_content"
+            android:textStyle="bold"
+            android:typeface="sans"
+            tools:text="Test this new stuff!" />
+
+        <TextView
+            android:id="@+id/sub_left"
+            android:layout_width="wrap_content"
+            android:layout_height="wrap_content"
+            android:layout_below="@id/title"
+            android:layout_marginTop="5dip"
+            android:textColor="#343434"
+            android:textSize="12sp"
+            tools:text="Peter Bauer" />
+
+        <ImageView
+            android:id="@+id/icon"
+            android:layout_width="wrap_content"
+            android:layout_height="wrap_content"
+            android:layout_alignTop="@id/title"
+            android:layout_alignBottom="@id/sub_left"
+            android:layout_alignParentEnd="true"
+            android:layout_alignParentRight="true"
+            android:layout_marginRight="10dp"
+            android:contentDescription="@string/mail_icon"
+            android:scaleType="fitCenter"
+            android:src="@drawable/ic_mail"
+            android:layout_marginEnd="10dp" />
+    </RelativeLayout>
+</androidx.cardview.widget.CardView>

app/src/main/res/values-de/strings.xml

@@ -76,4 +76,9 @@
     <string name="exam">Klausur</string>
     <string name="other">Andere</string>
     <string name="deadline">Abgabe</string>
+    <string name="winter_semester">Wintersemester %1$d/%2$d</string>
+    <string name="summer_semester">Sommersemester %1$d</string>
+    <string name="lecturers">Dozenten</string>
+    <string name="mail_icon">Mail Icon</string>
+    <string name="mail_default_text">Hallo %1$s, \n\n\n\nMit freundlichen Grüßen\n\n\n\nGesendet von der FUPlanner Android App</string>
 </resources>

app/src/main/res/values/strings.xml

@@ -84,4 +84,9 @@
     <string name="exam">Exam</string>
     <string name="other">Other</string>
     <string name="deadline">Deadline</string>
+    <string name="winter_semester">Winter Semester %1$d/%2$d</string>
+    <string name="summer_semester">Summer Semester %1$d</string>
+    <string name="lecturers">Lecturers</string>
+    <string name="mail_icon">Mail Icon</string>
+    <string name="mail_default_text">Dear %1$s, \n\n\n\nYours sincerely\n\n\n\nSend by FUPlanner Android App</string>
 </resources>