Check if an Android Recycler View is scrolled all the way down. Implementation is taken from a Fragment.

ScrollingFragment.java

private RecyclerView mRecyclerView;

@Nullable
@Override
public View onCreateView(LayoutInflater inflater, ViewGroup container, Bundle savedInstanceState) {
    View view = inflater.inflate(R.layout.fragment_view, container, false);
    mRecyclerView = (RecyclerView) view.findViewById(R.id.recycler_view);
    // ommiting other recycler view set up, such as adapter and Layout manager set up ..
    mRecyclerView.addOnScrollListener(new RecyclerView.OnScrollListener() {
        @Override
        public void onScrolled(RecyclerView recyclerView, int dx, int dy) {
            super.onScrolled(recyclerView, dx, dy);
            if (isLastItemDisplaying()) {
                // do something cool like add more items
            }
        }
    });
    return view;
}

private boolean isLastItemDisplaying() {
    RecyclerView.Adapter adapter = mRecyclerView.getAdapter();
    if (adapter != null && adapter.getItemCount() != 0) {
        int lastVisibleItemPosition = ((LinearLayoutManager) mRecyclerView.getLayoutManager()).findLastCompletelyVisibleItemPosition();
        if (lastVisibleItemPosition != RecyclerView.NO_POSITION && lastVisibleItemPosition == adapter.getItemCount() - 1) {
            return true;
        }
    }
    return false;
}