public override void OnScrolled(Android.Support.V7.Widget.RecyclerView recyclerView, int dx, int dy)
{
LinearLayoutManager layoutManager = (LinearLayoutManager)recyclerView.GetLayoutManager();
int firstVisible = layoutManager.FindFirstVisibleItemPosition();
int visibleCount = Math.Abs(firstVisible - layoutManager.FindLastCompletelyVisibleItemPosition());
int itemCount = recyclerView.GetAdapter().ItemCount;
if (firstVisible != _lastFirstVisible || visibleCount != _lastVisibleCount || itemCount != _lastItemCount)
{
_scrollListener.OnScroll(null, firstVisible, visibleCount, itemCount);
_lastVisibleCount = firstVisible;
_lastVisibleCount = visibleCount;
_lastItemCount = itemCount;
}
}