简单的贪吃蛇游戏

效果图:
游戏中图片
游戏失败
部分源码：
SnackView
// 屏幕的高度和宽度
    private int screenHeight;
    private int screenWidth;
    // 每个小格子的高度和宽度
    private int eachHeight;
    private int eachWidth;

    private Snack snack;
    private Food food;

    private Timer timer = new Timer();
    Handler handler = new Handler() {
        public void handleMessage(android.os.Message msg) {
            moveSnack();
            invalidate();
        }
    };

    public SnackView(Context context) {
        super(context);
        this.context = context;

        // 获得屏幕的高和宽
        DisplayMetrics metrics = new DisplayMetrics();
        WindowManager windowManager = (WindowManager) context
                .getSystemService(Context.WINDOW_SERVICE);
        windowManager.getDefaultDisplay().getMetrics(metrics);
        screenHeight = metrics.heightPixels;
        screenWidth = metrics.widthPixels;
        eachHeight = screenHeight / 32;
        eachWidth = screenWidth / 20;
        // 初始化图片
        headBitmap = BitmapFactory.decodeResource(getResources(),
                R.drawable.head);
        bodyBitmap = BitmapFactory.decodeResource(getResources(),
                R.drawable.body);
        foodBitmap = BitmapFactory.decodeResource(getResources(),
                R.drawable.food);
        this.initSnack();
        this.initFood();
        gameRun();
    }

    @Override
    protected void onDraw(Canvas canvas) {
        super.onDraw(canvas);
        Paint paint = new Paint();// 定义画笔
        paint.setColor(Color.GRAY);// 设置画笔颜色
        paint.setAntiAlias(true);// 去除锯齿
        paint.setStyle(Style.STROKE);// 设置空心实心
        paint.setTextSize(40);
        drawLines(canvas, paint);
        if(isCollide()){
            canvas.drawText("Game Over!", screenWidth/4, screenHeight/3, paint);
            timer.cancel();
        }else{
            this.drawSnack(canvas, paint);
        }
        boolean flag = IsRectCollision(snack.getHead().getPointX(), snack
                .getHead().getPointY(), eachWidth, eachHeight,
                food.getPointX(), food.getPointY(), eachWidth, eachHeight);
        if (flag) {
            food = null;
            snack.getBodyList().add(new Body());
            this.initFood();
        } else {
            this.drawFood(canvas, paint);
        }
    }

    @Override
    public boolean onTouchEvent(MotionEvent event) {
        // TODO Auto-generated method stub
        int x = (int) event.getX();
        int y = (int) event.getY();
        SnackDirection nowDir = snack.getSnackDirection();
        int m = -800 * x + 800 * 480 - 480 * y;
        int n = 800 * x - 480 * y;
        if ((m > 0 && n > 0) && (nowDir != SnackDirection.DOWN)) {
            snack.setSnackDirection(SnackDirection.UP);
        } else if ((m > 0 && n < 0) && (nowDir != SnackDirection.RIGHT)) {
            snack.setSnackDirection(SnackDirection.LEFT);
        } else if ((m < 0 && n > 0) && (nowDir != SnackDirection.LEFT)) {
            snack.setSnackDirection(SnackDirection.RIGHT);
        } else if ((m < 0 && n < 0) && (nowDir != SnackDirection.UP)) {
            snack.setSnackDirection(SnackDirection.DOWN);
        }
        return super.onTouchEvent(event);
    }

    public void gameRun() {
        timer.scheduleAtFixedRate(new TimerTask() {

            @Override
            public void run() {
                // TODO Auto-generated method stub
                handler.obtainMessage().sendToTarget();
            }
        }, 100, 400);
    }

    /*
     * 画网格线
     */
    public void drawLines(Canvas canvas, Paint paint) {
        int startX = 0, startY = 0;
        for (int i = 0; i < 100; i++) {
            canvas.drawLine(0, startY, screenWidth, startY, paint);
            startY = startY + eachHeight;
        }
        for (int i = 0; i < 100; i++) {
            canvas.drawLine(startX, 0, startX, screenHeight, paint);
            startX = startX + eachWidth;
        }
        canvas.drawLine(0, 0, screenWidth, screenHeight, paint);
        canvas.drawLine(0, screenHeight, screenWidth, 0, paint);
    }

    // 初始化蛇
    public void initSnack() {
        List<Body> bodies = new ArrayList<Body>();
        Head head = new Head(eachWidth * 2, eachHeight * 2, headBitmap);
        Body body1 = new Body(eachWidth * 1, eachHeight * 2, bodyBitmap);
        Body body2 = new Body(eachWidth * 0, eachHeight * 2, bodyBitmap);
        bodies.add(body1);
        bodies.add(body2);
        snack = new Snack(head, bodies, SnackDirection.RIGHT);
    }

    // 画蛇
    public void drawSnack(Canvas canvas, Paint paint) {
        canvas.drawBitmap(headBitmap, snack.getHead().getPointX(), snack
                .getHead().getPointY(), paint);
        for (int i = 0; i < snack.getBodyList().size(); i++) {
            canvas.drawBitmap(bodyBitmap, snack.getBodyList().get(i)
                    .getPointX(), snack.getBodyList().get(i).getPointY(), paint);
        }
    }

    // 改变蛇身的位置
    public void changSnackPosition(int pointX, int pointY) {
        for (int i = snack.getBodyList().size() - 1; i > 0; i--) {
            snack.getBodyList().get(i)
                    .setPointX(snack.getBodyList().get(i - 1).getPointX());
            snack.getBodyList().get(i)
                    .setPointY(snack.getBodyList().get(i - 1).getPointY());
        }
        snack.getBodyList().get(0).setPointX(snack.getHead().getPointX());
        snack.getBodyList().get(0).setPointY(snack.getHead().getPointY());
    }

    // 移动蛇
    public void moveSnack() {
        int nowPointX = snack.getHead().getPointX();
        int nowPointY = snack.getHead().getPointY();
        if (snack.getSnackDirection() == SnackDirection.RIGHT) {
            changSnackPosition(nowPointX, nowPointY);
            if (nowPointX >= screenWidth - eachWidth) {
                snack.getHead().setPointX(0);
            } else {
                snack.getHead().setPointX(nowPointX + eachWidth);
            }
        } else if (snack.getSnackDirection() == SnackDirection.DOWN) {
            changSnackPosition(nowPointX, nowPointY);
            if (nowPointY >= screenHeight - eachHeight) {
                snack.getHead().setPointY(0);
            } else {
                snack.getHead().setPointY(nowPointY + eachHeight);
            }
        } else if (snack.getSnackDirection() == SnackDirection.LEFT) {
            changSnackPosition(nowPointX, nowPointY);
            if (nowPointX <= 0) {
                snack.getHead().setPointX(screenWidth - eachWidth);
            } else {
                snack.getHead().setPointX(nowPointX - eachWidth);
            }
        } else if (snack.getSnackDirection() == SnackDirection.UP) {
            changSnackPosition(nowPointX, nowPointY);
            if (nowPointY <= 0) {
                snack.getHead().setPointY(screenHeight - eachHeight);
            } else {
                snack.getHead().setPointY(nowPointY - eachHeight);
            }
        }
    }

    // 初始化food
    public void initFood() {
        int x = new Random().nextInt(20);
        int y = new Random().nextInt(30);
        food = new Food(eachWidth * x, eachHeight * y, foodBitmap);
    }

    // 在界面上画出Food
    public void drawFood(Canvas canvas, Paint paint) {
        if (food != null) {
            canvas.drawBitmap(foodBitmap, food.getPointX(), food.getPointY(),
                    paint);
        }
    }

    /**
     * 矩形碰撞检测 参数为x,y,width,height
     * 
     * @param x1
     *            第一个矩形的x
     * @param y1
     *            第一个矩形的y
     * @param w1
     *            第一个矩形的w
     * @param h1
     *            第一个矩形的h
     * @param x2
     *            第二个矩形的x
     * @param y2
     *            第二个矩形的y
     * @param w2
     *            第二个矩形的w
     * @param h2
     *            第二个矩形的h
     * @return 是否碰撞
     */
    public boolean IsRectCollision(int x1, int y1, int w1, int h1, int x2,
            int y2, int w2, int h2) {

        if (x2 > x1 && x2 >= x1 + w1) {
            return false;
        } else if (x2 < x1 && x2 <= x1 - w2) {
            return false;
        } else if (y2 > y1 && y2 >= y1 + h1) {
            return false;
        } else if (y2 < y1 && y2 <= y1 - h2) {
            return false;
        } else {
            return true;
        }
    }

    //检测蛇头是否与蛇身碰撞
    public boolean isCollide() {
        boolean flag = false;
        for (int i = 0; i < snack.getBodyList().size(); i++) {
            flag = IsRectCollision(snack.getHead().getPointX(), snack.getHead()
                    .getPointY(), eachWidth, eachHeight, snack.getBodyList()
                    .get(i).getPointX(),
                    snack.getBodyList().get(i).getPointY(), eachWidth,
                    eachHeight);
            if(flag){
                break;
            }
        }
        return flag;
    }

}