一步步实现这个炫酷的树状节点图自定义控件

Posted 怪兽N

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本文介绍了我实现自定义树状节点图控件的原理及一些效果展示,欢迎交流
Tree View; Mind map; Think map; tree map; 树状图;思维导图;

文章目录

简介

github连接: https://github.com/guaishouN/android-tree-view.git

目前没发现比较好的android树状图开源控件,于是决定自己写一个开源控件,对比了一下市面上关于思维导图或者树状图显示(如xMind,mind master等)的app,本文开源框架并不逊色。实现这个树状图过程中主要综合应用了很多自定义控件关键知识点,比如自定义ViewGroup的步骤、触摸事件的处理、动画使用、Scroller及惯性滑动、ViewDragHelper的使用等等。主要实现了下面几个功能点。

  • 丝滑的跟随手指放缩,拖动,及惯性滑动

  • 自动动画回归屏幕中心

  • 支持子节点复杂布局自定义,并且节点布局点击事件与滑动不冲突

  • 节点间的连接线自定义

  • 可删除动态节点

  • 可动态添加节点

  • 支持拖动调整节点关系

  • 增删、移动结构添加动画效果

效果展示

基础----连接线, 布局, 自定义节点View

添加

删除

拖动节点编辑书树状图结构

放缩拖动不影响点击

放缩拖动及适应窗口

使用步骤

下面说明中Animal类是仅仅用于举例的bean

public class Animal 
    public int headId;
    public String name;

按照以下四个步骤使用该开源控件

1 通过继承 TreeViewAdapter实现节点数据与节点视图的绑定

public class AnimalTreeViewAdapter extends TreeViewAdapter<Animal> 
    private DashLine dashLine =  new DashLine(Color.parseColor("#F06292"),6);
    @Override
    public TreeViewHolder<Animal> onCreateViewHolder(@NonNull ViewGroup viewGroup, NodeModel<Animal> node) 
        //TODO in inflate item view
        NodeBaseLayoutBinding nodeBinding = NodeBaseLayoutBinding.inflate(LayoutInflater.from(viewGroup.getContext()),viewGroup,false);
        return new TreeViewHolder<>(nodeBinding.getRoot(),node);
    

    @Override
    public void onBindViewHolder(@NonNull TreeViewHolder<Animal> holder) 
        //TODO get view and node from holder, and then control your item view
        View itemView = holder.getView();
        NodeModel<Animal> node = holder.getNode();
		...
    

    @Override
    public Baseline onDrawLine(DrawInfo drawInfo) 
        // TODO If you return an BaseLine, line will be draw by the return one instead of TreeViewLayoutManager's
		// if(...)
        //   ...
        // 	 return dashLine;
   		// 
        return null;
    

2 配置LayoutManager。主要设置布局风格(向右展开或垂直向下展开)、父节点与子节点的间隙、子节点间的间隙、节点间的连线(已经实现了直线、光滑曲线、虚线、根状线,也可通过BaseLine实现你自己的连线)

int space_50dp = 50;
int space_20dp = 20;
//choose a demo line or a customs line. StraightLine, PointedLine, DashLine, SmoothLine are available.
Baseline line =  new DashLine(Color.parseColor("#4DB6AC"),8);
//choose layoout manager. VerticalTreeLayoutManager,RightTreeLayoutManager are available.
TreeLayoutManager treeLayoutManager = new RightTreeLayoutManager(this,space_50dp,space_20dp,line);

3 把Adapter和LayoutManager设置到你的树状图

...
treeView = findViewById(R.id.tree_view);   
TreeViewAdapter adapter = new AnimlTreeViewAdapter();
treeView.setAdapter(adapter);
treeView.setTreeLayoutManager(treeLayoutManager);
...

4 设置节点数据

//Create a TreeModel by using a root node.
NodeModel<Animal> node0 = new NodeModel<>(new Animal(R.drawable.ic_01,"root"));
TreeModel<Animal> treeModel = new TreeModel<>(root);

//Other nodes.
NodeModel<Animal> node1 = new NodeModel<>(new Animal(R.drawable.ic_02,"sub0"));
NodeModel<Animal> node2 = new NodeModel<>(new Animal(R.drawable.ic_03,"sub1"));
NodeModel<Animal> node3 = new NodeModel<>(new Animal(R.drawable.ic_04,"sub2"));
NodeModel<Animal> node4 = new NodeModel<>(new Animal(R.drawable.ic_05,"sub3"));
NodeModel<Animal> node5 = new NodeModel<>(new Animal(R.drawable.ic_06,"sub4"));


//Build the relationship between parent node and childs,like:
//treeModel.add(parent, child1, child2, ...., childN);
treeModel.add(node0, node1, node2);
treeModel.add(node1, node3, node4);
treeModel.add(node2, node5);

//finally set this treeModel to the adapter
adapter.setTreeModel(treeModel);

实现基本的布局流程

这里涉及View自定义的基本三部曲onMeasureonLayoutonDrawonDispatchDraw, 其中我把onMeasureonLayout布局的交给了一个特定的类LayoutManager处理,并且把节点的子View生成及绑定交给Adapter处理,在onDispatchDraw中画节点的连线也交给Adapter处理。这样可以极大地方便使用者自定义连线及节点View,甚至是自定义LayoutManager。另外在onSizeChange中记录控件的大小。

这几个关键点的流程是onMeasure->onLayout->onSizeChanged->onDrawonDispatchDraw

    private TreeViewHolder<?> createHolder(NodeModel<?> node) 
        int type = adapter.getHolderType(node);
		...
        //node 子View创建交给adapter
        return adapter.onCreateViewHolder(this, (NodeModel)node);
    
	/**
    * 初始化添加NodeView
    **/
	private void addNodeViewToGroup(NodeModel<?> node) 
        TreeViewHolder<?> treeViewHolder = createHolder(node);
        //node 子View绑定交给adapter
        adapter.onBindViewHolder((TreeViewHolder)treeViewHolder);
		...
    
	...
    @Override
    protected void onMeasure(int widthMeasureSpec, int heightMeasureSpec) 
        TreeViewLog.e(TAG,"onMeasure");
        final int size = getChildCount();
        for (int i = 0; i < size; i++) 
            measureChild(getChildAt(i), widthMeasureSpec, heightMeasureSpec);
        
        if(MeasureSpec.getSize(widthMeasureSpec)>0 && MeasureSpec.getSize(heightMeasureSpec)>0)
            winWidth  = MeasureSpec.getSize(widthMeasureSpec);
            winHeight = MeasureSpec.getSize(heightMeasureSpec);
        
        if (mTreeLayoutManager != null && mTreeModel != null) 
            mTreeLayoutManager.setViewport(winHeight,winWidth);
            //交给LayoutManager测量
            mTreeLayoutManager.performMeasure(this);
            ViewBox viewBox = mTreeLayoutManager.getTreeLayoutBox();
            drawInfo.setSpace(mTreeLayoutManager.getSpacePeerToPeer(),mTreeLayoutManager.getSpaceParentToChild());
            int specWidth = MeasureSpec.makeMeasureSpec(Math.max(winWidth, viewBox.getWidth()), MeasureSpec.EXACTLY);
            int specHeight = MeasureSpec.makeMeasureSpec(Math.max(winHeight,viewBox.getHeight()),MeasureSpec.EXACTLY);
            setMeasuredDimension(specWidth,specHeight);
        else
            super.onMeasure(widthMeasureSpec, heightMeasureSpec);
        
    


    @Override
    protected void onLayout(boolean changed, int l, int t, int r, int b) 
        TreeViewLog.e(TAG,"onLayout");
        if (mTreeLayoutManager != null && mTreeModel != null) 
            //交给LayoutManager布局
            mTreeLayoutManager.performLayout(this);
        
    

    @Override
    protected void onSizeChanged(int w, int h, int oldw, int oldh) 
        super.onSizeChanged(w, h, oldw, oldh);
        //记录初始大小
        viewWidth = w;
        viewHeight = h;
        drawInfo.setWindowWidth(w);
        drawInfo.setWindowHeight(h);
        //记录适应窗口的scale
        fixWindow();
    

    @Override
    protected void dispatchDraw(Canvas canvas) 
        super.dispatchDraw(canvas);
        if (mTreeModel != null) 
            drawInfo.setCanvas(canvas);
            drawTreeLine(mTreeModel.getRootNode());
        
    
    /**
     * 绘制树形的连线
     * @param root root node
     */
    private void drawTreeLine(NodeModel<?> root) 
        LinkedList<? extends NodeModel<?>> childNodes = root.getChildNodes();
        for (NodeModel<?> node : childNodes) 
			...
            //画连线交给adapter或mTreeLayoutManager处理
            BaseLine adapterDrawLine = adapter.onDrawLine(drawInfo);
            if(adapterDrawLine!=null)
                adapterDrawLine.draw(drawInfo);
            else
                mTreeLayoutManager.performDrawLine(drawInfo);
            
            drawTreeLine(node);
        
    

实现自由放缩及拖动

这部分是核心点,乍一看很简单,不就是处理下dispaTouchEventonInterceptTouchEventonTouchEvent就可以了吗?没错是都是在这几个函数中处理,但是要知道以下这几个难点:

  1. 这个自定义控件要放缩或移动过程中,通过onTouchEvent中MotionEvent.getX()拿到的触摸事件也是放缩后触点相对父View的位置,而getRaw又不是所有SDK版本都支持的,因为不能获取稳定的触点数据,所以可能放缩会出现震动的现象
  2. 这个树状图自定义控件子节点View也是ViewGroup,至少拖动放缩不能影响子节点View里的控件点击事件
  3. 另外还要考虑,回归屏幕中心控制、增删节点要稳定目标节点View显示、反变换获取View相对屏幕位置等, 实现放缩及拖动时的触点跟随

对于问题1,可以再加一层一样大小的ViewGroup(其实就是GysoTreeView,它是一个壳)用来接收触摸事件,这样因为这个接收触摸事件的ViewGroup是大小是稳定的,所以拦截的触摸要是稳定的。里面的treeViewContainer是真正的树状图ViewGroup容器。

    public GysoTreeView(@NonNull Context context, @Nullable AttributeSet attrs, int defStyleAttr) 
        super(context, attrs, defStyleAttr);
        LayoutParams layoutParams = new LayoutParams(LayoutParams.MATCH_PARENT,LayoutParams.MATCH_PARENT);
        setClipChildren(false);
        setClipToPadding(false);
        treeViewContainer = new TreeViewContainer(getContext());
        treeViewContainer.setLayoutParams(layoutParams);
        addView(treeViewContainer);
        treeViewGestureHandler = new TouchEventHandler(getContext(), treeViewContainer);
        treeViewGestureHandler.setKeepInViewport(false);

        //set animate default
        treeViewContainer.setAnimateAdd(true);
        treeViewContainer.setAnimateRemove(true);
        treeViewContainer.setAnimateMove(true);
    

    @Override
    public void requestDisallowInterceptTouchEvent(boolean disallowIntercept) 
        super.requestDisallowInterceptTouchEvent(disallowIntercept);
        this.disallowIntercept = disallowIntercept;
        TreeViewLog.e(TAG, "requestDisallowInterceptTouchEvent:"+disallowIntercept);
    

    @Override
    public boolean onInterceptTouchEvent(MotionEvent event) 
        TreeViewLog.e(TAG, "onInterceptTouchEvent: "+MotionEvent.actionToString(event.getAction()));
        return (!disallowIntercept && treeViewGestureHandler.detectInterceptTouchEvent(event)) || super.onInterceptTouchEvent(event);
    

    @Override
    public boolean onTouchEvent(MotionEvent event) 
        TreeViewLog.e(TAG, "onTouchEvent: "+MotionEvent.actionToString(event.getAction()));
        return !disallowIntercept && treeViewGestureHandler.onTouchEvent(event);
    

TouchEventHandler用来处理触摸事件,有点像SDK提供的ViewDragHelper判断是否需要拦截触摸事件,并处理放缩、拖动及惯性滑动。判断是不是滑动了一小段距离,是那么拦截

    /**
     * to detect whether should intercept the touch event
     * @param event event
     * @return true for intercept
     */
    public boolean detectInterceptTouchEvent(MotionEvent event)
        final int action = event.getAction() & MotionEvent.ACTION_MASK;
        onTouchEvent(event);
        if (action == MotionEvent.ACTION_DOWN)
            preInterceptTouchEvent = MotionEvent.obtain(event);
            mIsMoving = false;
        
        if (action == MotionEvent.ACTION_CANCEL || action == MotionEvent.ACTION_UP) 
            mIsMoving = false;
        
        //如果滑动大于mTouchSlop,则触发拦截
        if(action == MotionEvent.ACTION_MOVE && mTouchSlop < calculateMoveDistance(event, preInterceptTouchEvent))
            mIsMoving = true;
        
        return mIsMoving;
    

    /**
     * handler the touch event, drag and scale
     * @param event touch event
     * @return true for has consume
     */
    public boolean onTouchEvent(MotionEvent event) 
        mGestureDetector.onTouchEvent(event);
        //Log.e(TAG, "onTouchEvent:"+event);
        int action =  event.getAction() & MotionEvent.ACTION_MASK;
        switch (action) 
            case MotionEvent.ACTION_DOWN:
                mode = TOUCH_MODE_SINGLE;
                preMovingTouchEvent = MotionEvent.obtain(event);
                if(mView instanceof TreeViewContainer)
                    minScale = ((TreeViewContainer)mView).getMinScale();
                
                if(flingX!=null)
                    flingX.cancel();
                
                if(flingY!=null)
                    flingY.cancel();
                
                break;
            case MotionEvent.ACTION_UP:
                mode = TOUCH_MODE_RELEASE;
                break;
            case MotionEvent.ACTION_POINTER_UP:
            case MotionEvent.ACTION_CANCEL:
                mode = TOUCH_MODE_UNSET;
                break;
            case MotionEvent.ACTION_POINTER_DOWN:
                mode++;
                if (mode >= TOUCH_MODE_DOUBLE)
                    scaleFactor = preScaleFactor = mView.getScaleX();
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