Great article! I struggled to figure this out a few weeks back so this will definitely help people!
However I have a small issue. I have the RecyclerView under a custom toolbar and when I drag the items in the RecyclerView to the top I can drag them under my toolbar. That means I can actually drag them OUTSIDE of the RecyclerView, which is a bit strange. Do you have any idea how to stop the item from being dragged outside the RecyclerView?