1.开发原因
在项目中经常需要一个需要一个树状框架，这是非常常见的控件。不过可能是谷歌考虑到android是手机系统，界面宽度有限，所以只提供了只有二级的ExpandableListView。虽然这个控件可以满足很多需求，但是无数级的树在某些情况下还是需要的，所以我花了一天时间（大部分时间都在调试动画去了，不过现在动画还有点问题，具体原因不明。。如果某位大神能找到原因灰常感谢）。

2.原理

网上很多都是扩展listview实现的，不过listview貌似不支持复杂控件的事件？而且做动画也不方便，所有我决定扩展linearlayout，在里面增加子节点的方式实现。

3.代码

TreeView.java:

public class TreeView extends LinearLayout{

//    private List<TreeItem> items;
    private List<TreeItem> sortedItems;
    private int animTime;

    public TreeView(Context context, AttributeSet attrs) {
        super(context, attrs);
        setOrientation(LinearLayout.VERTICAL);
    }
    /**
     * initialize data,you must make sure that each item has parent except the top ones.
     * @param items the data to show
     * @param index the index of the tree to insert to
     * @param viewHeight each view\'s height
     * @param animTime if you want expand animation,
     * you can set the time(ms) of animation,otherwise you can set 0.
     *
     */
    public void initData(List<TreeItem> items,int index){

        if(items==null||items.size()==0){
            return ;
        }

        sortItemList(items);

        int size=sortedItems.size();

        initAddIndex=index<0?-Integer.MAX_VALUE:index;

        for (int i=0;i<size;i++) {
            TreeItem item=sortedItems.get(i);
            recuseShow(item);
        }

    }

    private boolean isAnim=false;
    /**
     * 这个方法还有很 严重的bug，无法使用。。
     * 设置为0则关闭动画
     * @param animTime
     */
    public void enabledAnim(int animTime) {
        if(animTime<0){
            isAnim=false;
            return ;
        }
        this.animTime=animTime;
        isAnim=true;
    }

    private int initAddIndex;

    private void recuseShow(TreeItem item){
        View view=item.getView();
        addView(view,initAddIndex);
        if(item.getParent()!=null){
            view.setVisibility(View.GONE);
            item.isShow=false;
        }else {
            view.setVisibility(View.VISIBLE);
            item.isShow=true;
        }
        initAddIndex++;
        List<TreeItem> childrens=item.getChildrens();
        if(childrens.size()>0){
            for (TreeItem it : childrens) {
                recuseShow(it);
            }
        }
    }

    @Override
    public void onWindowFocusChanged(boolean hasWindowFocus) {
        super.onWindowFocusChanged(hasWindowFocus);
        if(hasWindowFocus){

        }
    }

   private void sortItemList(List<TreeItem> items) {
       //把items按照层级关系存放，sortedItems只存放顶层的item
       sortedItems=new ArrayList<TreeItem>(5);
       for (TreeItem item : items) {
           if(item.getParent()==null){
               sortedItems.add(item);
           }else {
               item.getParent().getChildrens().add(item);
           }
       }

   }

  
   private int viewIndex=0;
   private int animHeight=0;
   private void addChild(TreeItem item,boolean isRecurse){
       if(item.getChildrens().size()>0){
           List<TreeItem> list=item.getChildrens();
           for (TreeItem it :    list) {
               View view=it.getView();
               if(it.isShow){
                   continue;
               }
               viewIndex++;
               view.setVisibility(View.VISIBLE);
               it.isShow=true;
               if(isAnim){
                   animHeight-=it.getViewHeight();
               }
               it.nextIsExpand=true;
               if(isRecurse){
                   addChild(it,true);
               }
           }
       }
   }
   private int removeCount=0;
   private synchronized void removeChild(TreeItem item,boolean isRecurse){
       if(item.getChildrens().size()>0){
           List<TreeItem> list=item.getChildrens();
           for (TreeItem it :    list) {
               View view=it.getView();
               if(!it.isShow){
                   continue;
               }
//                removeViewAt(viewIndex);

               TranslateAnimation ta=new TranslateAnimation(0, 0, 0, 0);
               ta.setFillAfter(true);
               ta.setDuration(1000);
               view.startAnimation(ta);
//                viewIndex++;
               removeCount++;
               it.isShow=false;
               view.setVisibility(View.GONE);
               if(isAnim){
                   animHeight+=it.getViewHeight();
               }
               if(isRecurse){
                   removeChild(it,true);
               }
           }
       }
   }

   private void animAdd(){
       TranslateAnimation ta=new TranslateAnimation(
               Animation.ABSOLUTE, 0,
               Animation.ABSOLUTE, 0,
               Animation.ABSOLUTE, animHeight,
               Animation.ABSOLUTE, 0);
       ta.setFillBefore(true);
//        ta.setFillAfter(false);
       ta.setDuration(animTime);

       for (int i = viewIndex+1; i < getChildCount(); i++) {
           View view=getChildAt(i);
           view.startAnimation(ta);
       }
       animHeight=0;
   }
   private void animRemove(){
       TranslateAnimation ta=new TranslateAnimation(
               Animation.ABSOLUTE, 0,
               Animation.ABSOLUTE, 0,
               Animation.ABSOLUTE, animHeight,
               Animation.ABSOLUTE, 0);
       ta.setFillAfter(false);
       ta.setFillBefore(true);
       ta.setDuration(animTime);

       int startAnimIndex;
       startAnimIndex=viewIndex+1;
       for (int i = startAnimIndex; i < getChildCount(); i++) {
           View view=getChildAt(i);

           view.startAnimation(ta);
       }
       animHeight=0;
   }
   public void expand(TreeItem item){
       viewIndex=indexOfChild(item.getView());
       addChild(item,false);
       if(isAnim){
           animAdd();
       }
   }
  

   public void expandAllChildren(TreeItem item) {
       viewIndex=indexOfChild(item.getView());
       addChild(item,true);
       if(isAnim){
           animAdd();
       }
   }

   public void expandAll(){
       if(sortedItems==null){
           return ;
       }
       for (TreeItem item : sortedItems) {
           expandAllChildren(item);
       }
   }

   public void contractAllChildren(TreeItem item) {
       viewIndex=indexOfChild(item.getView())+1;
       removeChild(item,true);
       if(isAnim){
           animRemove();
       }
   }

   public void contractAll(){
       if(sortedItems==null){
           return ;
       }
       for (TreeItem item : sortedItems) {
           contractAllChildren(item);
       }
   }

   public void bind(TreeItem item) {
       if(item.nextIsExpand){
           expand(item);
       }else {
           contractAllChildren(item);
       }
       item.nextIsExpand=!item.nextIsExpand;
   } 
}