Question

我正在尝试使用以下代码在活动中向右或向左滑动手势来启动活动：

gestureDetector = new GestureDetectorCompat(this, new GestureDetector.SimpleOnGestureListener(){
    private static final int SWIPE_THRESHOLD = 50;
    private static final int SWIPE_VELOCITY_THRESHOLD = 0;

    @Override
    public boolean onDown(MotionEvent e) {
        return true;
    }

    @Override
    public boolean onFling(MotionEvent event1, MotionEvent event2, float velocityX, float velocityY) {
        //user will move forward through messages on fling up or left
        boolean forward = false;
        //user will move backward through messages on fling down or right
        boolean backward = false;

        //calculate the change in X position within the fling gesture
        float horizontalDiff = event2.getX() - event1.getX();
        //calculate the change in Y position within the fling gesture
        float verticalDiff = event2.getY() - event1.getY();

        float absHDiff = Math.abs(horizontalDiff);
        float absVDiff = Math.abs(verticalDiff);
        float absVelocityX = Math.abs(velocityX);
        float absVelocityY = Math.abs(velocityY);

        if(absHDiff > absVDiff && absHDiff > SWIPE_THRESHOLD && absVelocityX > SWIPE_VELOCITY_THRESHOLD){
            //move forward or backward
            if(horizontalDiff>0) backward=true;
            else forward=true;
        }
        else if(absVDiff > SWIPE_THRESHOLD && absVelocityY > SWIPE_VELOCITY_THRESHOLD){
            if(verticalDiff>0) backward=true;
            else forward=true;
        }

        //user is cycling forward through messages
        if(forward){
            //check current message is not at end of array, increment or set back to start
            swipeTo(SWIPE_LEFT);
        }
        //user is cycling backwards through messages
        else if(backward){
            //check that current message is not at start of array, decrement or set to last message
            swipeTo(SWIPE_RIGHT);
        }

        //return super.onFling(event1, event2, velocityX, velocityY);
        return true;
    }

});

如何在滑动垂直（从上到下或从下到上）时禁用操作？

SWIPE_LEFT和SWIPE_RIGHT只是类成员常量，值分别为1和2。

提前致谢。

Answer 1

我认为你应该检测到absVelocityY的高值。如果该值太高，则表示垂直投掷。在这些情况下，请勿启动新的Activity。

使用GestureDetectorCompat禁用上下滑动滑动手势

1 个答案: