android canvas.drawbitmap（）圖像不斷重複

我在android上製作了一個遊戲，其中一個圖像和你必須拖動它並移動它。但是，當我拖動它的圖像被拖動的路徑上創建了幾個圖像。請看我的代碼和幫助android canvas.drawbitmap（）圖像不斷重複

package com.saad.alien; 

import android.app.Activity; 
import android.content.Context; 
import android.graphics.Bitmap; 
import android.graphics.BitmapFactory; 
import android.graphics.Canvas; 
import android.graphics.RectF; 
import android.os.Bundle; 
import android.view.MotionEvent; 
import android.view.SurfaceHolder; 
import android.view.SurfaceView; 
import android.view.View; 
import android.view.View.OnTouchListener; 

public class Game extends Activity implements OnTouchListener { 

    CustomView Cview; 
    float x, y, left = 0, top = 0, right = 0, bottom = 0; 
    float dx, dy; 
    Bitmap man; 
    int done = 0; 
    RectF rman = new RectF(50, 50, 150, 150); 

    @Override 
    protected void onCreate(Bundle savedInstanceState) { 
     // TODO Auto-generated method stub 
     super.onCreate(savedInstanceState); 

     Cview = new CustomView(this); 
     Cview.setOnTouchListener(this); 
     x = 50; 
     y = 600; 
     dx = dy = 0; 

     man = BitmapFactory.decodeResource(getResources(), R.drawable.man); 

     setContentView(Cview); 
    } 

    @Override 
    protected void onPause() { 
     // TODO Auto-generated method stub 
     super.onPause(); 
     Cview.pause(); 
    } 

    @Override 
    protected void onResume() { 
     // TODO Auto-generated method stub 
     super.onResume(); 
     Cview.resume(); 
    } 

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

     try { 
      Thread.sleep(50); 
     } catch (InterruptedException e) { 
      // TODO Auto-generated catch block 
      e.printStackTrace(); 
     } 

     // x = event.getX(); 
     // y = event.getY(); 
     switch (event.getAction()) { 

     case MotionEvent.ACTION_DOWN: 
      dx = event.getX(); 
      dy = event.getY(); 
      float length = x + man.getWidth(); 
      float height = y + man.getHeight(); 
      if (dx > x && dx < length && dy > y && dy < height) { 
       done = 1; 
      } 
      break; 
     case MotionEvent.ACTION_MOVE: 
      if (done == 1) { 
       x = event.getX(); 
       y = event.getY(); 
      } 
      break; 
     case MotionEvent.ACTION_UP: 
      if (done == 1) { 
       x = event.getX(); 
       y = event.getY(); 
       done = 0; 
      } 
      break; 
     } 

     return true; 
    } 

    public class CustomView extends SurfaceView implements Runnable { 

     SurfaceHolder ourHolder; 
     Thread ourThread = null; 
     boolean isRunning = false; 

     public CustomView(Context context) { 
      super(context); 
      ourHolder = getHolder(); 
     } 

     public void pause() { 
      isRunning = false; 
      while (true) { 
       try { 
        ourThread.join(); 
       } catch (InterruptedException e) { 
        // TODO Auto-generated catch block 
        e.printStackTrace(); 
       } 
       break; 
      } 
      ourThread = null; 
     } 

     public void resume() { 
      isRunning = true; 
      ourThread = new Thread(this); 
      ourThread.start(); 
     } 

     public void run() { 
      while (isRunning) { 
       if (!ourHolder.getSurface().isValid()) 
        continue; 

       Canvas can = ourHolder.lockCanvas(); 
       left = x; 
       right = (x + man.getWidth()); 
       top = y; 
       bottom = (y + man.getHeight()); 
       rman.set(left, top, right, bottom); 
       can.drawBitmap(man, null, rman, null); 
       ourHolder.unlockCanvasAndPost(can); 

      } 

     } 

    } 

}

來源

2013-01-10 user1750990

我想你需要http://stackoverflow.com/questions/5729377/android-canvas-how-do-i-clear-delete-contents-of- a-canvas-bitmaps-livin。檢查答案。 –

您需要在繪製之前在每一幀清除畫布。

舉例來說，像這樣：

Canvas.drawColor(Color.BLACK)

來源

2013-01-10 13:29:40 fiddler

canvas.drawColor（Color.TRANSPARENT，PorterDuff.Mode.CLEAR）;可能會給你更好的表現。 – slott

android canvas.drawbitmap（）圖像不斷重複

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