onTouch（）不能画画布

Question

onDraw（画布画布）自动工作。在这个视图中，onTouch（）方法监听触摸屏幕。当我点击屏幕时，我需要重新绘制矩形，但它不绘制矩形画布。

public class Viewer extends View implements OnTouchListener{ 

    public Viewer(Context context) { 
     super(context); 

     ............. 
     .............. 
     this.setOnTouchListener(this);    
    } 

    @Override 
    public void onDraw(Canvas canvas){ 
     super .onDraw(canvas); 
     drawBackGround(imgObj.bg01, canvas);  
    } 

    @Override 
    public boolean onTouch(View v,MotionEvent event) { 
     // TODO Auto-generated method stub  

     Canvas c = new canvas(); 
     c.drawRect(.......); //<------ It's work but it isn't redraw 
     return true; 
    } 

Answer 1

试试这个，

Canvas mCanvas; 
@Override 
    public void onDraw(Canvas canvas){ 

     mCanvas = canvas; 
     drawBackGround(imgObj.bg01, mCanvas); 
     super.onDraw(mCanvas); 

    } 

    @Override 
    public boolean onTouch(View v,MotionEvent event) { 
     // TODO Auto-generated method stub  

     mCanvas.drawRect(.......); 
     invalidate(); 
     return true; 
    }