android 游戏 自定义动画 动态位图

public class MySurfaceView extends SurfaceView implements Callback, Runnable {
    private SurfaceHolder sfh;
    private Paint paint;
    private Thread th;
    private boolean flag;
    private Canvas canvas;
    // 声明一张波浪位图
    private Bitmap bmp;
    // 声明波浪图的X,Y坐标
    private int bmpX, bmpY;

    /** * SurfaceView初始化函数 */
    public MySurfaceView(Context context) {
        super(context);
        sfh = this.getHolder();
        sfh.addCallback(this);
        paint = new Paint();
        paint.setColor(Color.WHITE);
        paint.setAntiAlias(true);
        setFocusable(true);
    }

    /** * SurfaceView视图创建，响应此函数 */
    @Override
    public void surfaceCreated(SurfaceHolder holder) {
        bmp = BitmapFactory.decodeResource(this.getResources(),
                R.drawable.water);
        // 让位图初始化X坐标正好充满屏幕
        bmpX = -bmp.getWidth() + this.getWidth();
        // 让位图绘制在的最下方，且图片Y坐标正好是（屏幕高-图片高）
        bmpY = this.getHeight() - bmp.getHeight();
        flag = true;
        // 实例线程
        th = new Thread(this);
        // 启动线程
        th.start();
    }

    /** * 游戏绘图 */
    public void myDraw() {
        try {
            canvas = sfh.lockCanvas();
            if (canvas != null) {
                canvas.drawColor(Color.WHITE);
                canvas.drawBitmap(bmp, bmpX, bmpY, new Paint());
            }
        } catch (Exception e) {
            // TODO: handle exception
        } finally {
            if (canvas != null)
                sfh.unlockCanvasAndPost(canvas);
        }
    }

    /** * 触屏事件监听 */
    @Override
    public boolean onTouchEvent(MotionEvent event) {
        return true;
    }

    /** * 按键事件监听 */
    @Override
    public boolean onKeyDown(int keyCode, KeyEvent event) {
        return super.onKeyDown(keyCode, event);
    }

    /** * 游戏逻辑 */
    private void logic() {
        bmpX += 5;
    }

    @Override
    public void run() {
        while (flag) {
            long start = System.currentTimeMillis();
            myDraw();
            logic();
            long end = System.currentTimeMillis();
            try {
                if (end - start < 50) {
                    Thread.sleep(50 - (end - start));
                }
            } catch (InterruptedException e) {
                e.printStackTrace();
            }
        }
    }

    /** * SurfaceView视图状态发生改变，响应此函数 */
    @Override
    public void surfaceChanged(SurfaceHolder holder, int format, int width,
            int height) {
    }

    /** * SurfaceView视图消亡时，响应此函数 */
    @Override
    public void surfaceDestroyed(SurfaceHolder holder) {
        flag = false;
    }
}