控制Gallery 速度

    // 实现短距离滑动
    @Override
    public boolean onFling(MotionEvent e1, MotionEvent e2, float velocityX, float velocityY) {
        int kEvent;
        if (isScrollingLeft(e1, e2)) {
            // Check if scrolling left
            kEvent = KeyEvent.KEYCODE_DPAD_LEFT;
        } else {
            // Otherwise scrolling right
            kEvent = KeyEvent.KEYCODE_DPAD_RIGHT;
        }
        onKeyDown(kEvent, null);
        return true;
    }



    private boolean isScrollingLeft(MotionEvent e1, MotionEvent e2) {
        return e2.getX() > e1.getX();
    }