android 游戏 让人物动起来

public class MySurfaceView extends SurfaceView implements Callback, Runnable {
private SurfaceHolder sfh;
private Paint paint;
private Thread th;
private boolean flag;
private Canvas canvas;
private int screenW, screenH;
//机器人位图
private Bitmap bmpRobot;
//机器人的方向常量
private final int DIR_LEFT = 0;
private final int DIR_RIGHT = 1;
//机器人当前的方向(默认朝右方向)
private int dir = DIR_RIGHT;
//动作帧下标
private int currentFrame;
//机器人的X,Y位置
private int robot_x, robot_y;
//处理按键卡现象
private boolean isUp, isDown, isLeft, isRight;

/**
* 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);
bmpRobot = BitmapFactory.decodeResource(this.getResources(), R.drawable.robot);
}

/**
* SurfaceView视图创建，响应此函数
*/
@Override
public void surfaceCreated(SurfaceHolder holder) {
screenW = this.getWidth();
screenH = this.getHeight();
flag = true;
//实例线程
th = new Thread(this);
//启动线程
th.start();
}

/**
*
* @param currentFrame 绘制帧
* @param frameW
*          每帧的高
* @param frameH
*          每帧的高
* @param canvas
*          画布实例
* @param paint
*           画笔实例
*/
public void drawFrame(int currentFrame, Canvas canvas, Paint paint) {
int frameW = bmpRobot.getWidth() / 6;
int frameH = bmpRobot.getHeight() / 2;
//得到位图的列数
int col = bmpRobot.getWidth() / frameW;
//得到当前帧相对于位图的X坐标
int x = currentFrame % col * frameW;
//得到当前帧相对于位图的Y坐标
int y = currentFrame / col * frameH;
canvas.save();
//设置一个宽高与机器人每帧相同大小的可视区域
canvas.clipRect(robot_x, robot_y, robot_x + bmpRobot.getWidth() / 6, robot_y + bmpRobot.getHeight() / 2);
if (dir == DIR_LEFT) {//如果是向左侧移动
//镜像操作
canvas.scale(-1, 1, robot_x - x + bmpRobot.getWidth() / 2, robot_y - y + bmpRobot.getHeight() / 2);
}
//robot_x 按下后的位置 减去原来的机器人x 的位置   y 同理
canvas.drawBitmap(bmpRobot, robot_x - x, robot_y - y, paint);
canvas.restore();
}

/**
* 游戏绘图
*/
public void myDraw() {
try {
canvas = sfh.lockCanvas();
if (canvas != null) {
canvas.drawColor(Color.BLACK);
drawFrame(currentFrame, canvas, paint);
}
} catch (Exception e) {
// TODO: handle exception
} finally {
if (canvas != null)
sfh.unlockCanvasAndPost(canvas);
}
}

@Override
public boolean onKeyMultiple(int keyCode, int repeatCount, KeyEvent event) {
Log.e("", "aaaaaaa");
return super.onKeyMultiple(keyCode, repeatCount, event);
}

/**
* 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) {
if (keyCode == KeyEvent.KEYCODE_DPAD_UP) {
isUp = true;
}
if (keyCode == KeyEvent.KEYCODE_DPAD_DOWN) {
isDown = true;
}
if (keyCode == KeyEvent.KEYCODE_DPAD_LEFT) {
isLeft = true;
dir = DIR_LEFT;
}
if (keyCode == KeyEvent.KEYCODE_DPAD_RIGHT) {
isRight = true;
dir = DIR_RIGHT;
}
return super.onKeyDown(keyCode, event);
}

@Override
public boolean onKeyUp(int keyCode, KeyEvent event) {
if (keyCode == KeyEvent.KEYCODE_DPAD_UP) {
isUp = false;
}
if (keyCode == KeyEvent.KEYCODE_DPAD_DOWN) {
isDown = false;
}
if (keyCode == KeyEvent.KEYCODE_DPAD_LEFT) {
isLeft = false;
}
if (keyCode == KeyEvent.KEYCODE_DPAD_RIGHT) {
isRight = false;
}
return super.onKeyUp(keyCode, event);
}

/**
* 游戏逻辑
*/
private void logic() {
if (isUp) {
robot_y -= 5;
}
if (isDown) {
robot_y += 5;
}
if (isLeft) {
robot_x -= 5;
}
if (isRight) {
robot_x += 5;
}
currentFrame++;
if (currentFrame >= 12) {
currentFrame = 0;
}
}

@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;
}
}