LinearLayoutManager llm = new LinearLayoutManager(context);
llm.setOrientation(LinearLayoutManager.VERTICAL);
llm.setStackFromEnd(true);
recyclerView.setLayoutManager(llm);

@Override
public void onBindViewHolder(RecyclerView.ViewHolder holder, int position) {
    if (messages.size() > 8 && position == 0 && null != mLoadMoreCallbacks) {
        mLoadMoreCallbacks.onLoadMore();
    }

@Override
public void onLoadMore() {
    // Get data from database and add into arrayList
      chatMessagesAdapter.notifyDataSetChanged();
}