ViewPager2.PageTransformer A PageTransformer is invoked whenever a visible/attached page is scrolled. 


CompositePageTransformer Allows for combining multiple ViewPager2.PageTransformer objects. 
MarginPageTransformer Adds space between pages via the ViewPager2.PageTransformer API. 
ViewPager2 ViewPager2 replaces ViewPager, addressing most of its predecessor’s pain-points, including right-to-left layout support, vertical orientation, modifiable Fragment collections, etc. 
ViewPager2.OnPageChangeCallback Callback interface for responding to changing state of the selected page.