球没有在与SurfaceView的页面中显示。为什么？

Question

我想编写一个程序，通过SurfaceView在屏幕上移动一个球，并更改drawCircle（）方法的X参数，但程序不会在屏幕上显示任何内容，只会显示一个黑色页面。

这是我的代码。

TestsSurface.java：

public class TestSurface extends SurfaceView implements SurfaceHolder.Callback{ 
SurfaceHolder surfaceHolder; 

public TestSurface(Context context) { 
    super(context); 
    // TODO Auto-generated constructor stub 
    getHolder().addCallback(this); 
} 

public void surfaceChanged(SurfaceHolder holder, int format, int width, 
     int height) { 
    // TODO Auto-generated method stub 

} 

public void surfaceCreated(SurfaceHolder holder) { 
    // TODO Auto-generated method stub 
    Thread thread=new Thread(); 
    thread.start(); 
} 

public void surfaceDestroyed(SurfaceHolder holder) { 
    // TODO Auto-generated method stub 

} 

public void drawing(Canvas canvas){ 
    drawingShape(canvas); 
} 
int x=100; 
public void drawingShape(Canvas canvas){ 
    canvas.drawColor(Color.BLACK); 
    Paint paint=new Paint(); 
    paint.setColor(Color.RED); 
    canvas.drawCircle(x, 100, 50, paint); 
    x+=2; 
} 

public void run(){ 
    Canvas canvas; 
    while(true){ 
     canvas=null; 
     try{ 
      synchronized(surfaceHolder){ 
       canvas=getHolder().lockCanvas(); 
       drawing(canvas); 
      } 
     }finally{ 
      if(canvas!=null) 
       getHolder().unlockCanvasAndPost(canvas); 
     } 
    } 
} 
} 

MainActivity.java：

public class MainActivity extends Activity { 

@Override 
public void onCreate(Bundle savedInstanceState){ 
    super.onCreate(savedInstanceState); 
    TestSurface test=new TestSurface(this); 
    setContentView(test); 

} 
} 

什么是我的问题吗？

Answer 1

你的变量surfaceHolder决不会在通话设置为synchronized()

考虑增加：

surfaceHolder = getHolder(); 

...您的构造函数。

编辑按的评论如下::

Thread thread = new Thread(new Runnable() { 
    public void run() { 
    Canvas canvas; 
    while(true){ 
     canvas=null; 
     try{ 
     synchronized(surfaceHolder){ 
      canvas=getHolder().lockCanvas(); 
      drawing(canvas); 
     } 
     }finally{ 
     if(canvas!=null) 
      getHolder().unlockCanvasAndPost(canvas); 
     } 
     Thread.Sleep(1000); 
    } 
    } 
}).start();