下面這個android程序我本來想按下按鈕對應的方向鍵圖片就會朝相對的方向移動。public class MySurfaceView extends SurfaceView implements Callback, Runnable {private SurfaceHolder sfh;private Paint paint;private Canvas canvas;private Thread th;private boolean flag;private Bitmap bmp = BitmapFactory.decodeResource(this.getResources(), R.drawable.android);private int left=100,top=100;public MySurfaceView(Context context) {super(context);// TODO Auto-generated constructor stubsfh = this.getHolder();sfh.addCallback(this);paint = new Paint();paint.setColor(Color.RED);setFocusable(true);}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 stubflag = true;th = new Thread(this);th.start();}public void surfaceDestroyed(SurfaceHolder holder) {// TODO Auto-generated method stub}private void myDraw() {// TODO Auto-generated method stubtry{canvas = sfh.lockCanvas();if(canvas != null){canvas.drawRGB(0, 0, 0);canvas.drawBitmap(bmp, left, top, paint);}}catch (Exception e){}finally{if(canvas != null)sfh.unlockCanvasAndPost(canvas);}}public boolean onkeyDown(int keyCode, KeyEvent event){if(keyCode == KeyEvent.KEYCODE_DPAD_UP){top-=1;}else if(keyCode == KeyEvent.KEYCODE_DPAD_DOWN){top+=1;}else if(keyCode == KeyEvent.KEYCODE_DPAD_LEFT){left-=1;}else if(keyCode == KeyEvent.KEYCODE_DPAD_RIGHT){left+=1;}return super.onKeyDown(keyCode, event);}public boolean onkeyUp(int keyCode, KeyEvent event){return super.onKeyUp(keyCode, event);}public void logic(){}public void run() {// TODO Auto-generated method stubwhile(flag){long start = System.currentTimeMillis();myDraw();logic();long end = System.currentTimeMillis();try{if(end - start < 20){Thread.sleep(20 - (end - start));}}catch(InterruptedException e){e.printStackTrace();}}}}