How to listen to when view pager crosses threshold to new page?

Question

When swiping on a view pager. There comes a point where when you let go, it goes to the other page instead of the original one - AKA the mid point.

ViewPager.OnPageChangeListener.onPageSelected(int position) only gets called after the select.

I want to be notified the moment the user crosses the threshold. How should I go about doing this?

Answer 1

viewPager.addOnPageChangeListener(new ViewPager.OnPageChangeListener() {
        @Override
        public void onPageScrolled(int position, float positionOffset, int positionOffsetPixels) {
            //This method will be invoked when the current page is scrolled, either as part of a
            // programmatically initiated smooth scroll or a user initiated touch scroll.
        }

        @Override
        public void onPageSelected(int position) {
            //This method will be invoked when a new page becomes selected.
        }

        @Override
        public void onPageScrollStateChanged(int state) {
            //Called when the scroll state changes.
        }
    });

for more information please refer ViewPager.addOnPageChangeListener