Question

我的surfaceview onDraw方法有时会跳过在屏幕上绘制一些位图，一旦跳过它，它就不会再次绘制特定的位图。我的代码

public class Board extends SurfaceView implements SurfaceHolder.Callback{
 //varaibles declared here
public Board(){
    //initaializations here
    getHolder().addCallback(this);
 }
//my onDraw method
protected void onDraw(Canvas canvas){
   for(int u = 0;u<6; u++){
      ai.get(u).draw(canvas);//each of these objects draws something on the screen.
      human.get(u).draw(canvas);
   }
   postInvalidate();
 }

public void surfaceCreated(SurfaceHolder holder){
gameLoop = new GameLoop(this);
gameLoop.start();
}

onDraw（）方法在运行游戏循环的线程中每100毫秒调用一次。

public class GameLoop extends Thread{
     Board board;
     private final int DELAY = 100;
     public GameLoop(Board board){
      this.board=board;
     }

   protected void run(){
     long beforeTime,timediff,sleep;
     beforeTime = System.currentTimeMillis();
     while(running)
     {
       Canvas c = null;
       try{
           c=board.getHolder.lockCanvas();
           synchronized(board.getHolder()){
              board.onDraw(c);
          }finally{
           if(c!=null)
             board.getHolder.unlockCanvas(c);
          }
      timeDiff = System.currentTimeMillis - beforeTime;
      sleep = DELAY - timeDiff;
      if(sleep<0)
        sleep = 10;
      try{
         Thread.sleep(sleep);
      }catch(InterruptedException e){}
      beforeTime = System.currentTimeMillis();
   }
}

所以这跳过这样的事情：有时（在onDraw（）方法中）当u = 0不绘制或u = 5时，它可能是u =任何可能的值，其余的绘制，一旦它跳过每次调用onDraw方法时它都会跳过它的值。我希望我已经能够说清楚了。我很感激帮助解决这个问题。感谢

Answer 1

原样，您正在从另一个线程更新主UI线程。 Android文档表明这会导致您遇到的不可预测的行为。

考虑将AsyncTask子类化为您进行线程化。有一些例程可用于后台工作并从UI线程本身发布到主UI线程。

基本上，你在任务上调用execute，然后调用它的doInBackground例程，当它完成时，它会调用onPostExecute例程和任务结果。

这些来源应该有助于理解问题和子类AsyncTask： http://developer.android.com/guide/topics/fundamentals/processes-and-threads.html http://developer.android.com/reference/android/os/AsyncTask.html

SurfaceView onDraw会跳过绘图

1 个答案: