Resource 1st version... Visible

.idea/misc.xml

@@ -25,5 +25,5 @@
       </value>
     </option>
   </component>
-  <component name="ProjectRootManager" version="2" languageLevel="JDK_1_8" default="true" project-jdk-name="1.8 (2)" project-jdk-type="JavaSDK" />
+  <component name="ProjectRootManager" version="2" languageLevel="JDK_1_8" project-jdk-name="1.8" project-jdk-type="JavaSDK" />
 </project>

.idea/modules.xml

@@ -2,7 +2,7 @@
 <project version="4">
   <component name="ProjectModuleManager">
     <modules>
-      <module fileurl="file://$PROJECT_DIR$/.idea/FUPlanner.iml" filepath="$PROJECT_DIR$/.idea/FUPlanner.iml" />
+      <module fileurl="file://$PROJECT_DIR$/FUPlanner.iml" filepath="$PROJECT_DIR$/FUPlanner.iml" />
       <module fileurl="file://$PROJECT_DIR$/app/app.iml" filepath="$PROJECT_DIR$/app/app.iml" />
     </modules>
   </component>

.idea/vcs.xml

@@ -1,7 +1,6 @@
 <?xml version="1.0" encoding="UTF-8"?>
 <project version="4">
   <component name="VcsDirectoryMappings">
-    <mapping directory="" vcs="Git" />
     <mapping directory="$PROJECT_DIR$" vcs="Git" />
   </component>
 </project>

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

@@ -38,6 +38,8 @@ class ModDetailAdapter extends FragmentStatePagerAdapter {
                 return ModDetailEventFragment.newInstance(mItemPos);
             case ModulePart.GRADEBOOK:
                 return ModDetailGradebookFragment.newInstance(mItemPos);
+            case ModulePart.RESOURCES:
+                return ModDetailResourceFragment.newInstance(mItemPos);
             default:
                 return null;
         }
@@ -57,6 +59,8 @@ class ModDetailAdapter extends FragmentStatePagerAdapter {
                 return this.mContext.getResources().getString(R.string.events);
             case ModulePart.GRADEBOOK:
                 return this.mContext.getResources().getString(R.string.gradebook);
+            case ModulePart.RESOURCES:
+                return this.mContext.getResources().getString(R.string.resourcen);
             default:
                 return "";
         }

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

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

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

@@ -0,0 +1,132 @@
+package de.sebse.fuplanner.fragments.moddetails;
+
+
+import android.content.Context;
+import android.os.Bundle;
+import android.support.annotation.NonNull;
+import android.support.v4.app.Fragment;
+import android.support.v4.widget.SwipeRefreshLayout;
+import android.support.v7.widget.LinearLayoutManager;
+import android.support.v7.widget.RecyclerView;
+import android.view.LayoutInflater;
+import android.view.View;
+import android.view.ViewGroup;
+import android.widget.ImageView;
+
+import java.util.Arrays;
+
+import de.sebse.fuplanner.MainActivity;
+import de.sebse.fuplanner.R;
+import de.sebse.fuplanner.services.KVV.KVV;
+import de.sebse.fuplanner.services.KVV.types.Modules;
+import de.sebse.fuplanner.tools.logging.Logger;
+import de.sebse.fuplanner.tools.ui.treeview.DirectoryNodeBinder;
+import de.sebse.fuplanner.tools.ui.treeview.FileNodeBinder;
+import de.sebse.fuplanner.tools.ui.treeview.TreeNode;
+import de.sebse.fuplanner.tools.ui.treeview.TreeViewAdapter;
+
+/**
+ * A simple {@link Fragment} subclass.
+ * Use the {@link ModDetailResourceFragment#newInstance} factory method to
+ * create an instance of this fragment.
+ */
+public class ModDetailResourceFragment extends Fragment {
+    private static final String ARG_POSITION = "itemPosition";
+
+    private String mItemPos;
+    private final Logger log = new Logger(this);
+    private ModDetailResourceAdapter adapter;
+    private SwipeRefreshLayout swipeLayout;
+
+
+    public ModDetailResourceFragment() {
+        // Required empty public constructor
+    }
+
+    /**
+     * Use this factory method to create a new instance of
+     * this fragment using the provided parameters.
+     *
+     * @param itemPosition Item position in module list.
+     * @return A new instance of fragment ModDetailAnnounceFragment.
+     */
+    public static ModDetailResourceFragment newInstance(String itemPosition) {
+        ModDetailResourceFragment fragment = new ModDetailResourceFragment();
+        Bundle args = new Bundle();
+        args.putString(ARG_POSITION, itemPosition);
+        fragment.setArguments(args);
+        return fragment;
+    }
+
+    @Override
+    public void onCreate(Bundle savedInstanceState) {
+        super.onCreate(savedInstanceState);
+        if (getArguments() != null) {
+            mItemPos = getArguments().getString(ARG_POSITION);
+        }
+    }
+
+    @Override
+    public View onCreateView(@NonNull LayoutInflater inflater, ViewGroup container,
+                             Bundle savedInstanceState) {
+        // Inflate the layout for this fragment
+        View view = inflater.inflate(R.layout.fragment_recycler_view, container, false);
+        // Set the adapter
+        Context context = view.getContext();
+        RecyclerView recyclerView = view.findViewById(R.id.list);
+        recyclerView.setLayoutManager(new LinearLayoutManager(context));
+
+        adapter = new ModDetailResourceAdapter(Arrays.asList(new FileNodeBinder(), new DirectoryNodeBinder()));
+        adapter.setOnTreeNodeListener(new TreeViewAdapter.OnTreeNodeListener() {
+            @Override
+            public boolean onClick(TreeNode node, RecyclerView.ViewHolder holder) {
+                if (!node.isLeaf()) {
+                    //Update and toggle the node.
+                    onToggle(!node.isExpand(), holder);
+//                    if (!node.isExpand())
+//                        adapter.collapseBrotherNode(node);
+                }
+                return false;
+            }
+
+            @Override
+            public void onToggle(boolean isExpand, RecyclerView.ViewHolder holder) {
+                DirectoryNodeBinder.ViewHolder dirViewHolder = (DirectoryNodeBinder.ViewHolder) holder;
+                final ImageView ivArrow = dirViewHolder.getIvArrow();
+                int rotateDegree = isExpand ? 90 : -90;
+                ivArrow.animate().rotationBy(rotateDegree)
+                        .start();
+            }
+        });
+
+        recyclerView.setAdapter(adapter);
+
+        // Getting SwipeContainerLayout
+        swipeLayout = view.findViewById(R.id.swipe_container);
+        // Adding Listener
+        swipeLayout.setOnRefreshListener(() -> refresh(true));
+        refresh(false);
+
+        return view;
+    }
+
+    private void refresh(boolean forceRefresh) {
+        if (getActivity() != null) {
+            KVV kvv = ((MainActivity) getActivity()).getKVV();
+            kvv.getModule(mItemPos, (Modules.Module module) -> {
+                adapter.setModule(module);
+                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);
+        }
+    }
+
+}

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

@@ -7,7 +7,8 @@ class ModulePart {
     static final int ASSIGNMENT = 3;
     static final int EVENT = 4;
     static final int GRADEBOOK = 5;
-    private static final int[] pages = new int[]{OVERVIEW, ANNOUNCEMENT, ASSIGNMENT, EVENT, GRADEBOOK};
+    static final int RESOURCES = 6;
+    private static final int[] pages = new int[]{OVERVIEW, ANNOUNCEMENT, ASSIGNMENT, EVENT, GRADEBOOK, RESOURCES};
 
     static int getPageCount() {
         return pages.length;

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

@@ -3,6 +3,9 @@ package de.sebse.fuplanner.services.KVV.types;
 import java.io.Serializable;
 import java.util.ArrayList;
 
+import de.sebse.fuplanner.tools.ui.treeview.Dir;
+import de.sebse.fuplanner.tools.ui.treeview.TreeNode;
+
 
 public abstract class Resource implements Serializable {
 
@@ -47,9 +50,9 @@ public abstract class Resource implements Serializable {
         return visible;
     }
 
+    public abstract TreeNode getTreeNode();
+
     public static class File extends Resource {
-
-
         private final String type;
 
         public File(String author, String title, long modifiedDate, String url, boolean visible, String container, String type) {
@@ -67,6 +70,11 @@ public abstract class Resource implements Serializable {
                     ", type='" + type + '\'' +
                     '}';
         }
+
+        @Override
+        public TreeNode getTreeNode() {
+            return new TreeNode<>(new de.sebse.fuplanner.tools.ui.treeview.File(title));
+        }
     }
 
     public static class Folder extends Resource{
@@ -99,6 +107,15 @@ public abstract class Resource implements Serializable {
                     ", childs='" + childs + '\'' +
                     '}';
         }
+
+        @Override
+        public TreeNode getTreeNode() {
+            TreeNode<Dir> dir = new TreeNode<>(new Dir(title));
+            for (Resource res: childs) {
+                dir.addChild(res.getTreeNode());
+            }
+            return dir;
+        }
     }
 }
 

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

@@ -0,0 +1,21 @@
+package de.sebse.fuplanner.tools.ui.treeview;
+
+
+import de.sebse.fuplanner.R;
+
+/**
+ * Created by tlh on 2016/10/1 :)
+ */
+
+public class Dir implements LayoutItemType {
+    public String dirName;
+
+    public Dir(String dirName) {
+        this.dirName = dirName;
+    }
+
+    @Override
+    public int getLayoutId() {
+        return R.layout.item_dir;
+    }
+}

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

@@ -0,0 +1,55 @@
+package de.sebse.fuplanner.tools.ui.treeview;
+
+import android.view.View;
+import android.widget.ImageView;
+import android.widget.TextView;
+
+import de.sebse.fuplanner.R;
+
+/**
+ * Created by tlh on 2016/10/1 :)
+ */
+
+public class DirectoryNodeBinder extends TreeViewBinder<DirectoryNodeBinder.ViewHolder> {
+    @Override
+    public ViewHolder provideViewHolder(View itemView) {
+        return new ViewHolder(itemView);
+    }
+
+    @Override
+    public void bindView(ViewHolder holder, int position, TreeNode node) {
+        holder.ivArrow.setRotation(0);
+        holder.ivArrow.setImageResource(R.drawable.ic_keyboard_arrow_right_black_18dp);
+        int rotateDegree = node.isExpand() ? 90 : 0;
+        holder.ivArrow.setRotation(rotateDegree);
+        Dir dirNode = (Dir) node.getContent();
+        holder.tvName.setText(dirNode.dirName);
+        if (node.isLeaf())
+            holder.ivArrow.setVisibility(View.INVISIBLE);
+        else holder.ivArrow.setVisibility(View.VISIBLE);
+    }
+
+    @Override
+    public int getLayoutId() {
+        return R.layout.item_dir;
+    }
+
+    public static class ViewHolder extends TreeViewBinder.ViewHolder {
+        private ImageView ivArrow;
+        private TextView tvName;
+
+        public ViewHolder(View rootView) {
+            super(rootView);
+            this.ivArrow = (ImageView) rootView.findViewById(R.id.iv_arrow);
+            this.tvName = (TextView) rootView.findViewById(R.id.tv_name);
+        }
+
+        public ImageView getIvArrow() {
+            return ivArrow;
+        }
+
+        public TextView getTvName() {
+            return tvName;
+        }
+    }
+}

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

@@ -0,0 +1,21 @@
+package de.sebse.fuplanner.tools.ui.treeview;
+
+
+import de.sebse.fuplanner.R;
+
+/**
+ * Created by tlh on 2016/10/1 :)
+ */
+
+public class File implements LayoutItemType {
+    public String fileName;
+
+    public File(String fileName) {
+        this.fileName = fileName;
+    }
+
+    @Override
+    public int getLayoutId() {
+        return R.layout.item_file;
+    }
+}

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

@@ -0,0 +1,38 @@
+package de.sebse.fuplanner.tools.ui.treeview;
+
+import android.view.View;
+import android.widget.TextView;
+
+import de.sebse.fuplanner.R;
+
+/**
+ * Created by tlh on 2016/10/1 :)
+ */
+
+public class FileNodeBinder extends TreeViewBinder<FileNodeBinder.ViewHolder> {
+    @Override
+    public ViewHolder provideViewHolder(View itemView) {
+        return new ViewHolder(itemView);
+    }
+
+    @Override
+    public void bindView(ViewHolder holder, int position, TreeNode node) {
+        File fileNode = (File) node.getContent();
+        holder.tvName.setText(fileNode.fileName);
+    }
+
+    @Override
+    public int getLayoutId() {
+        return R.layout.item_file;
+    }
+
+    public class ViewHolder extends TreeViewBinder.ViewHolder {
+        public TextView tvName;
+
+        public ViewHolder(View rootView) {
+            super(rootView);
+            this.tvName = (TextView) rootView.findViewById(R.id.tv_name);
+        }
+
+    }
+}

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

@@ -0,0 +1,9 @@
+package de.sebse.fuplanner.tools.ui.treeview;
+
+/**
+ * Created by tlh on 2016/10/1 :)
+ */
+
+public interface LayoutItemType {
+    int getLayoutId();
+}

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

@@ -0,0 +1,149 @@
+package de.sebse.fuplanner.tools.ui.treeview;
+
+import android.support.annotation.NonNull;
+
+import java.util.ArrayList;
+import java.util.List;
+
+/**
+ * Created by tlh on 2016/10/1 :)
+ */
+
+public class TreeNode<T extends LayoutItemType> implements Cloneable {
+    private T content;
+    private TreeNode parent;
+    private List<TreeNode> childList;
+    private boolean isExpand;
+    private boolean isLocked;
+    //the tree high
+    private int height = UNDEFINE;
+
+    private static final int UNDEFINE = -1;
+
+    public TreeNode(@NonNull T content) {
+        this.content = content;
+        this.childList = new ArrayList<>();
+    }
+
+    public int getHeight() {
+        if (isRoot())
+            height = 0;
+        else if (height == UNDEFINE)
+            height = parent.getHeight() + 1;
+        return height;
+    }
+
+    public boolean isRoot() {
+        return parent == null;
+    }
+
+    public boolean isLeaf() {
+        return childList == null || childList.isEmpty();
+    }
+
+    public void setContent(T content) {
+        this.content = content;
+    }
+
+    public T getContent() {
+        return content;
+    }
+
+    public List<TreeNode> getChildList() {
+        return childList;
+    }
+
+    public void setChildList(List<TreeNode> childList) {
+        this.childList.clear();
+        for (TreeNode treeNode : childList) {
+            addChild(treeNode);
+        }
+    }
+
+    public TreeNode addChild(TreeNode node) {
+        if (childList == null)
+            childList = new ArrayList<>();
+        childList.add(node);
+        node.parent = this;
+        return this;
+    }
+
+    public boolean toggle() {
+        isExpand = !isExpand;
+        return isExpand;
+    }
+
+    public void collapse() {
+        if (isExpand) {
+            isExpand = false;
+        }
+    }
+
+    public void collapseAll() {
+        if (childList == null || childList.isEmpty()) {
+            return;
+        }
+        for (TreeNode child : this.childList) {
+            child.collapseAll();
+        }
+    }
+
+    public void expand() {
+        if (!isExpand) {
+            isExpand = true;
+        }
+    }
+
+    public void expandAll() {
+        expand();
+        if (childList == null || childList.isEmpty()) {
+            return;
+        }
+        for (TreeNode child : this.childList) {
+            child.expandAll();
+        }
+    }
+
+    public boolean isExpand() {
+        return isExpand;
+    }
+
+    public void setParent(TreeNode parent) {
+        this.parent = parent;
+    }
+
+    public TreeNode getParent() {
+        return parent;
+    }
+
+    public TreeNode<T> lock() {
+        isLocked = true;
+        return this;
+    }
+
+    public TreeNode<T> unlock() {
+        isLocked = false;
+        return this;
+    }
+
+    public boolean isLocked() {
+        return isLocked;
+    }
+
+    @Override
+    public String toString() {
+        return "TreeNode{" +
+                "content=" + this.content +
+                ", parent=" + (parent == null ? "null" : parent.getContent().toString()) +
+                ", childList=" + (childList == null ? "null" : childList.toString()) +
+                ", isExpand=" + isExpand +
+                '}';
+    }
+
+    @Override
+    protected TreeNode<T> clone() throws CloneNotSupportedException {
+        TreeNode<T> clone = new TreeNode<>(this.content);
+        clone.isExpand = this.isExpand;
+        return clone;
+    }
+}

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

@@ -0,0 +1,320 @@
+package de.sebse.fuplanner.tools.ui.treeview;
+
+import android.os.Bundle;
+import android.support.annotation.NonNull;
+import android.support.annotation.Nullable;
+import android.support.v7.util.DiffUtil;
+import android.support.v7.widget.RecyclerView;
+import android.view.LayoutInflater;
+import android.view.View;
+import android.view.ViewGroup;
+
+import java.util.ArrayList;
+import java.util.Iterator;
+import java.util.List;
+
+/**
+ * Created by tlh on 2016/10/1 :)
+ */
+public class TreeViewAdapter extends RecyclerView.Adapter<RecyclerView.ViewHolder> {
+    private static final String KEY_IS_EXPAND = "IS_EXPAND";
+    private final List<? extends TreeViewBinder> viewBinders;
+    private List<TreeNode> displayNodes;
+    private int padding = 30;
+    private OnTreeNodeListener onTreeNodeListener;
+    private boolean toCollapseChild;
+
+    public TreeViewAdapter(List<? extends TreeViewBinder> viewBinders) {
+        this(null, viewBinders);
+    }
+
+    public TreeViewAdapter(List<TreeNode> nodes, List<? extends TreeViewBinder> viewBinders) {
+        displayNodes = new ArrayList<>();
+        if (nodes != null)
+            findDisplayNodes(nodes);
+        this.viewBinders = viewBinders;
+    }
+
+    /**
+     * 从nodes的结点中寻找展开了的非叶结点，添加到displayNodes中。
+     *
+     * @param nodes 基准点
+     */
+    private void findDisplayNodes(List<TreeNode> nodes) {
+        for (TreeNode node : nodes) {
+            displayNodes.add(node);
+            if (!node.isLeaf() && node.isExpand())
+                findDisplayNodes(node.getChildList());
+        }
+    }
+
+    @Override
+    public int getItemViewType(int position) {
+        return displayNodes.get(position).getContent().getLayoutId();
+    }
+
+    @Override
+    public RecyclerView.ViewHolder onCreateViewHolder(ViewGroup parent, int viewType) {
+        View v = LayoutInflater.from(parent.getContext())
+                .inflate(viewType, parent, false);
+        if (viewBinders.size() == 1)
+            return viewBinders.get(0).provideViewHolder(v);
+        for (TreeViewBinder viewBinder : viewBinders) {
+            if (viewBinder.getLayoutId() == viewType)
+                return viewBinder.provideViewHolder(v);
+        }
+        return viewBinders.get(0).provideViewHolder(v);
+    }
+
+    @Override
+    public void onBindViewHolder(RecyclerView.ViewHolder holder, int position, List<Object> payloads) {
+        if (payloads != null && !payloads.isEmpty()) {
+            Bundle b = (Bundle) payloads.get(0);
+            for (String key : b.keySet()) {
+                switch (key) {
+                    case KEY_IS_EXPAND:
+                        if (onTreeNodeListener != null)
+                            onTreeNodeListener.onToggle(b.getBoolean(key), holder);
+                        break;
+                }
+            }
+        }
+        super.onBindViewHolder(holder, position, payloads);
+    }
+
+    @Override
+    public void onBindViewHolder(final RecyclerView.ViewHolder holder, int position) {
+        holder.itemView.setPadding(displayNodes.get(position).getHeight() * padding, 3, 3, 3);
+        holder.itemView.setOnClickListener(new View.OnClickListener() {
+            @Override
+            public void onClick(View v) {
+                TreeNode selectedNode = displayNodes.get(holder.getLayoutPosition());
+                // Prevent multi-click during the short interval.
+                try {
+                    long lastClickTime = (long) holder.itemView.getTag();
+                    if (System.currentTimeMillis() - lastClickTime < 500)
+                        return;
+                } catch (Exception e) {
+                    holder.itemView.setTag(System.currentTimeMillis());
+                }
+                holder.itemView.setTag(System.currentTimeMillis());
+
+                if (onTreeNodeListener != null && onTreeNodeListener.onClick(selectedNode, holder))
+                    return;
+                if (selectedNode.isLeaf())
+                    return;
+                // This TreeNode was locked to click.
+                if (selectedNode.isLocked()) return;
+                boolean isExpand = selectedNode.isExpand();
+                int positionStart = displayNodes.indexOf(selectedNode) + 1;
+                if (!isExpand) {
+                    notifyItemRangeInserted(positionStart, addChildNodes(selectedNode, positionStart));
+                } else {
+                    notifyItemRangeRemoved(positionStart, removeChildNodes(selectedNode, true));
+                }
+            }
+        });
+        for (TreeViewBinder viewBinder : viewBinders) {
+            if (viewBinder.getLayoutId() == displayNodes.get(position).getContent().getLayoutId())
+                viewBinder.bindView(holder, position, displayNodes.get(position));
+        }
+    }
+
+    private int addChildNodes(TreeNode pNode, int startIndex) {
+        List<TreeNode> childList = pNode.getChildList();
+        int addChildCount = 0;
+        for (TreeNode treeNode : childList) {
+            displayNodes.add(startIndex + addChildCount++, treeNode);
+            if (treeNode.isExpand()) {
+                addChildCount += addChildNodes(treeNode, startIndex + addChildCount);
+            }
+        }
+        if (!pNode.isExpand())
+            pNode.toggle();
+        return addChildCount;
+    }
+
+    private int removeChildNodes(TreeNode pNode) {
+        return removeChildNodes(pNode, true);
+    }
+
+    private int removeChildNodes(TreeNode pNode, boolean shouldToggle) {
+        if (pNode.isLeaf())
+            return 0;
+        List<TreeNode> childList = pNode.getChildList();
+        int removeChildCount = childList.size();
+        displayNodes.removeAll(childList);
+        for (TreeNode child : childList) {
+            if (child.isExpand()) {
+                if (toCollapseChild)
+                    child.toggle();
+                removeChildCount += removeChildNodes(child, false);
+            }
+        }
+        if (shouldToggle)
+            pNode.toggle();
+        return removeChildCount;
+    }
+
+    @Override
+    public int getItemCount() {
+        return displayNodes == null ? 0 : displayNodes.size();
+    }
+
+    public void setPadding(int padding) {
+        this.padding = padding;
+    }
+
+    public void ifCollapseChildWhileCollapseParent(boolean toCollapseChild) {
+        this.toCollapseChild = toCollapseChild;
+    }
+
+    public void setOnTreeNodeListener(OnTreeNodeListener onTreeNodeListener) {
+        this.onTreeNodeListener = onTreeNodeListener;
+    }
+
+    public interface OnTreeNodeListener {
+        /**
+         * called when TreeNodes were clicked.
+         * @return weather consume the click event.
+         */
+        boolean onClick(TreeNode node, RecyclerView.ViewHolder holder);
+
+        /**
+         * called when TreeNodes were toggle.
+         * @param isExpand the status of TreeNodes after being toggled.
+         */
+        void onToggle(boolean isExpand, RecyclerView.ViewHolder holder);
+    }
+
+    public void refresh(List<TreeNode> treeNodes) {
+        displayNodes.clear();
+        findDisplayNodes(treeNodes);
+        notifyDataSetChanged();
+    }
+
+    public Iterator<TreeNode> getDisplayNodesIterator() {
+        return displayNodes.iterator();
+    }
+
+    private void notifyDiff(final List<TreeNode> temp) {
+        DiffUtil.DiffResult diffResult = DiffUtil.calculateDiff(new DiffUtil.Callback() {
+            @Override
+            public int getOldListSize() {
+                return temp.size();
+            }
+
+            @Override
+            public int getNewListSize() {
+                return displayNodes.size();
+            }
+
+            // judge if the same items
+            @Override
+            public boolean areItemsTheSame(int oldItemPosition, int newItemPosition) {
+                return TreeViewAdapter.this.areItemsTheSame(temp.get(oldItemPosition), displayNodes.get(newItemPosition));
+            }
+
+            // if they are the same items, whether the contents has bean changed.
+            @Override
+            public boolean areContentsTheSame(int oldItemPosition, int newItemPosition) {
+                return TreeViewAdapter.this.areContentsTheSame(temp.get(oldItemPosition), displayNodes.get(newItemPosition));
+            }
+
+            @Nullable
+            @Override
+            public Object getChangePayload(int oldItemPosition, int newItemPosition) {
+                return TreeViewAdapter.this.getChangePayload(temp.get(oldItemPosition), displayNodes.get(newItemPosition));
+            }
+        });
+        diffResult.dispatchUpdatesTo(this);
+    }
+
+    private Object getChangePayload(TreeNode oldNode, TreeNode newNode) {
+        Bundle diffBundle = new Bundle();
+        if (newNode.isExpand() != oldNode.isExpand()) {
+            diffBundle.putBoolean(KEY_IS_EXPAND, newNode.isExpand());
+        }
+        if (diffBundle.size() == 0)
+            return null;
+        return diffBundle;
+    }
+
+    // For DiffUtil, if they are the same items, whether the contents has bean changed.
+    private boolean areContentsTheSame(TreeNode oldNode, TreeNode newNode) {
+        return oldNode.getContent() != null && oldNode.getContent().equals(newNode.getContent())
+                && oldNode.isExpand() == newNode.isExpand();
+    }
+
+    // judge if the same item for DiffUtil
+    private boolean areItemsTheSame(TreeNode oldNode, TreeNode newNode) {
+        return oldNode.getContent() != null && oldNode.getContent().equals(newNode.getContent());
+    }
+
+    /**
+     * collapse all root nodes.
+     */
+    public void collapseAll() {
+        // Back up the nodes are displaying.
+        List<TreeNode> temp = backupDisplayNodes();
+        //find all root nodes.
+        List<TreeNode> roots = new ArrayList<>();
+        for (TreeNode displayNode : displayNodes) {
+            if (displayNode.isRoot())
+                roots.add(displayNode);
+        }
+        //Close all root nodes.
+        for (TreeNode root : roots) {
+            if (root.isExpand())
+                removeChildNodes(root);
+        }
+        notifyDiff(temp);
+    }
+
+    @NonNull
+    private List<TreeNode> backupDisplayNodes() {
+        List<TreeNode> temp = new ArrayList<>();
+        for (TreeNode displayNode : displayNodes) {
+            try {
+                temp.add(displayNode.clone());
+            } catch (CloneNotSupportedException e) {
+                temp.add(displayNode);
+            }
+        }
+        return temp;
+    }
+
+    public void collapseNode(TreeNode pNode) {
+        List<TreeNode> temp = backupDisplayNodes();
+        removeChildNodes(pNode);
+        notifyDiff(temp);
+    }
+
+    public void collapseBrotherNode(TreeNode pNode) {
+        List<TreeNode> temp = backupDisplayNodes();
+        if (pNode.isRoot()) {
+            List<TreeNode> roots = new ArrayList<>();
+            for (TreeNode displayNode : displayNodes) {
+                if (displayNode.isRoot())
+                    roots.add(displayNode);
+            }
+            //Close all root nodes.
+            for (TreeNode root : roots) {
+                if (root.isExpand() && !root.equals(pNode))
+                    removeChildNodes(root);
+            }
+        } else {
+            TreeNode parent = pNode.getParent();
+            if (parent == null)
+                return;
+            List<TreeNode> childList = parent.getChildList();
+            for (TreeNode node : childList) {
+                if (node.equals(pNode) || !node.isExpand())
+                    continue;
+                removeChildNodes(node);
+            }
+        }
+        notifyDiff(temp);
+    }
+
+}

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

@@ -0,0 +1,23 @@
+package de.sebse.fuplanner.tools.ui.treeview;
+
+import android.support.annotation.IdRes;
+import android.support.v7.widget.RecyclerView;
+import android.view.View;
+
+
+public abstract class TreeViewBinder<VH extends RecyclerView.ViewHolder> implements LayoutItemType {
+    public abstract VH provideViewHolder(View itemView);
+
+    public abstract void bindView(VH holder, int position, TreeNode node);
+
+    public static class ViewHolder extends RecyclerView.ViewHolder {
+        public ViewHolder(View rootView) {
+            super(rootView);
+        }
+
+        protected <T extends View> T findViewById(@IdRes int id) {
+            return (T) itemView.findViewById(id);
+        }
+    }
+
+}

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

@@ -0,0 +1,24 @@
+<?xml version="1.0" encoding="utf-8"?>
+<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
+    android:layout_width="match_parent"
+    android:layout_height="wrap_content"
+    xmlns:tools="http://schemas.android.com/tools">
+
+    <ImageView
+        android:id="@+id/iv_arrow"
+        android:layout_width="18dp"
+        android:layout_height="18dp"
+        android:layout_gravity="center_vertical"
+        android:src="@drawable/ic_keyboard_arrow_right_black_18dp" />
+
+    <TextView
+        android:id="@+id/tv_name"
+        android:layout_width="match_parent"
+        android:layout_height="wrap_content"
+        android:layout_marginLeft="5dp"
+        android:drawableLeft="@drawable/ic_folder_light_blue_700_24dp"
+        android:drawablePadding="10dp"
+        android:gravity="center_vertical"
+        tools:text="@string/app_name"
+        android:textSize="18sp" />
+</LinearLayout>

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

@@ -0,0 +1,16 @@
+<?xml version="1.0" encoding="utf-8"?>
+<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
+android:layout_width="match_parent"
+android:layout_height="wrap_content"
+xmlns:tools="http://schemas.android.com/tools">
+<TextView
+    android:id="@+id/tv_name"
+    android:layout_marginLeft="23dp"
+    android:drawableLeft="@drawable/ic_insert_drive_file_light_blue_700_24dp"
+    android:drawablePadding="10dp"
+    android:gravity="center_vertical"
+    tools:text="@string/app_name"
+    android:textSize="18sp"
+    android:layout_width="match_parent"
+    android:layout_height="match_parent" />
+</LinearLayout>