Scrolling to last item of a recyclerview with a collapsing toolbar

The problem is that getNestedScrollingParentForType(type) in NestedScrollingChildHelper#dispatchNestedScroll returns null for the non-touch scroll, so scrolling is not dispatched when it is done programmatically.

So we need to enable that before scrolling programmatically:

if (!recyclerView.hasNestedScrollingParent(ViewCompat.TYPE_NON_TOUCH)) {
    recyclerView.startNestedScroll(View.SCROLL_AXIS_VERTICAL,ViewCompat.TYPE_NON_TOUCH);
}
// now smooth scroll your recycler view programmatically here. 

A fix for this problem would be to collapse the toolbar before scrolling to the given position. This can be done by adding app_bar_layout.setExpanded(false) before scrollToPosition.