@Override
        public void onScrolled(RecyclerView recyclerView, int dx, int dy) {
            final int childCount = recyclerView.getChildCount();
            if (childCount > 0) {
                View lastChild = recyclerView.getChildAt(childCount - 1);
                RecyclerView.Adapter outerAdapter = recyclerView.getAdapter();
                int lastVisible = recyclerView.getChildAdapterPosition(lastChild);
                if (lastVisible == outerAdapter.getItemCount() - 1 && hasNextPage() && canLoadNextPage()) {
                    onLoadNextPage();
                }
            }
        }
the most easy to implement {@link PickerContract.View} to show medias with google's Bottom Sheet </br>
for simplest purpose, it only support SINGLE_IMG and VIDEO Mode.
for MULTI_IMG mode, use {@link BoxingViewFragment} instead.

@author ChenSL
boxing-impl/src/main/java/com/bilibili/boxing_impl/ui/BoxingBottomSheetFragment.java