手势识别

public class ViewFlipperDemo extends Activity implements OnGestureListener,OnTouchListener{
    private ViewFlipper mFlipper;
    GestureDetector mGestureDetector;
    private int mCurrentLayoutState;
    private static final int FLING_MIN_DISTANCE = 100;
    private static final int FLING_MIN_VELOCITY = 200;

    @Override
    public void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.main);
//        mFlipper = (ViewFlipper) findViewById(R.id.flipper);
        //注册一个用于手势识别的类
        mGestureDetector = new GestureDetector(this);
        //给mFlipper设置一个listener
        mFlipper.setOnTouchListener(this);
        mCurrentLayoutState = 0;
        //允许长按住ViewFlipper,这样才能识别拖动等手势
        mFlipper.setLongClickable(true);
    }

    /**
     * 此方法在本例中未用到，可以指定跳转到某个页面
     * @param switchTo
     */
    public void switchLayoutStateTo(int switchTo) {
        while (mCurrentLayoutState != switchTo) {
            if (mCurrentLayoutState > switchTo) {
                mCurrentLayoutState--;
                mFlipper.setInAnimation(inFromLeftAnimation());
                mFlipper.setOutAnimation(outToRightAnimation());
                mFlipper.showPrevious();
            } else {
                mCurrentLayoutState++;
                mFlipper.setInAnimation(inFromRightAnimation());
                mFlipper.setOutAnimation(outToLeftAnimation());
                mFlipper.showNext();
            }

        }
        ;
    }

    /**
     * 定义从右侧进入的动画效果
     * @return
     */
    protected Animation inFromRightAnimation() {
        Animation inFromRight = new TranslateAnimation(
                Animation.RELATIVE_TO_PARENT, +1.0f,
                Animation.RELATIVE_TO_PARENT, 0.0f,
                Animation.RELATIVE_TO_PARENT, 0.0f,
                Animation.RELATIVE_TO_PARENT, 0.0f);
        inFromRight.setDuration(500);
        inFromRight.setInterpolator(new AccelerateInterpolator());
        return inFromRight;
    }

    /**
     * 定义从左侧退出的动画效果
     * @return
     */
    protected Animation outToLeftAnimation() {
        Animation outtoLeft = new TranslateAnimation(
                Animation.RELATIVE_TO_PARENT, 0.0f,
                Animation.RELATIVE_TO_PARENT, -1.0f,
                Animation.RELATIVE_TO_PARENT, 0.0f,
                Animation.RELATIVE_TO_PARENT, 0.0f);
        outtoLeft.setDuration(500);
        outtoLeft.setInterpolator(new AccelerateInterpolator());
        return outtoLeft;
    }

    /**
     * 定义从左侧进入的动画效果
     * @return
     */
    protected Animation inFromLeftAnimation() {
        Animation inFromLeft = new TranslateAnimation(
                Animation.RELATIVE_TO_PARENT, -1.0f,
                Animation.RELATIVE_TO_PARENT, 0.0f,
                Animation.RELATIVE_TO_PARENT, 0.0f,
                Animation.RELATIVE_TO_PARENT, 0.0f);
        inFromLeft.setDuration(500);
        inFromLeft.setInterpolator(new AccelerateInterpolator());
        return inFromLeft;
    }

    /**
     * 定义从右侧退出时的动画效果
     * @return
     */
    protected Animation outToRightAnimation() {
        Animation outtoRight = new TranslateAnimation(
                Animation.RELATIVE_TO_PARENT, 0.0f,
                Animation.RELATIVE_TO_PARENT, +1.0f,
                Animation.RELATIVE_TO_PARENT, 0.0f,
                Animation.RELATIVE_TO_PARENT, 0.0f);
        outtoRight.setDuration(500);
        outtoRight.setInterpolator(new AccelerateInterpolator());
        return outtoRight;
    }

    public boolean onDown(MotionEvent e) {
        // TODO Auto-generated method stub
        return false;
    }

    /*
     * 用户按下触摸屏、快速移动后松开即触发这个事件
     * e1：第1个ACTION_DOWN MotionEvent
     * e2：最后一个ACTION_MOVE MotionEvent
     * velocityX：X轴上的移动速度，像素/秒
     * velocityY：Y轴上的移动速度，像素/秒
     * 触发条件 ：
     * X轴的坐标位移大于FLING_MIN_DISTANCE，且移动速度大于FLING_MIN_VELOCITY个像素/秒
     */
    public boolean onFling(MotionEvent e1, MotionEvent e2, float velocityX,
            float velocityY) {
        if (e1.getX() - e2.getX() > FLING_MIN_DISTANCE
                && Math.abs(velocityX) > FLING_MIN_VELOCITY) {
            // 当像左侧滑动的时候
            //设置View进入屏幕时候使用的动画
            mFlipper.setInAnimation(inFromRightAnimation());
            //设置View退出屏幕时候使用的动画
            mFlipper.setOutAnimation(outToLeftAnimation());
            mFlipper.showNext();
        } else if (e2.getX() - e1.getX() > FLING_MIN_DISTANCE
                && Math.abs(velocityX) > FLING_MIN_VELOCITY) {
            // 当像右侧滑动的时候
            mFlipper.setInAnimation(inFromLeftAnimation());
            mFlipper.setOutAnimation(outToRightAnimation());
            mFlipper.showPrevious();
        }
        return false;
    }

    public void onLongPress(MotionEvent e) {
        // TODO Auto-generated method stub

    }

    public boolean onScroll(MotionEvent e1, MotionEvent e2, float distanceX,
            float distanceY) {
        return false;
    }

    public void onShowPress(MotionEvent e) {
        // TODO Auto-generated method stub

    }

    public boolean onSingleTapUp(MotionEvent e) {
        // TODO Auto-generated method stub
        return false;
    }
    public boolean onTouch(View v, MotionEvent event) {
        // 一定要将触屏事件交给手势识别类去处理（自己处理会很麻烦的）
        return mGestureDetector.onTouchEvent(event);
    }
}