Nicklas Nicklas - 15 days ago 12
Android Question

ViewPager detect when user is trying to swipe out of bounds

I am using the ViewPager consisting of 6 pages to display some data. I want to be able to call a method when the user is at position 0 and tries to swipe to the right (backwards), or at position 5 and tries to swipe to the left (forward), even though no more pages exist for these directions. Is there any way I can listen for these scenarios?

Answer

Extend ViewPager and override onInterceptTouchEvent() like this:

public class CustomViewPager extends ViewPager {

    float mStartDragX;
    OnSwipeOutListener mListener;


    public void setOnSwipeOutListener(OnSwipeOutListener listener) {
        mListener = listener;
    }


    @Override
    public boolean onInterceptTouchEvent(MotionEvent ev) {
        float x = ev.getX();
        switch (ev.getAction()) {
        case MotionEvent.ACTION_DOWN:
            mStartDragX = x;
            break;
        case MotionEvent.ACTION_MOVE:
            if (mStartDragX < x && getCurrentItem() == 0) {
                mListener.onSwipeOutAtStart();
            } else if (mStartDragX > x && getCurrentItem() == getAdapter().getCount() - 1) {
                mListener.onSwipeOutAtEnd();
            }
            break;
        }
        return super.onInterceptTouchEvent(ev);
    }

    public interface OnSwipeOutListener {
        public void onSwipeOutAtStart();
        public void onSwipeOutAtEnd();
    }

}
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