question: public void addPage ( @ NonNull List < MODEL > items ) { setAutoNotifyDataSetChanged ( false ) ; addAll ( items ) ; setAutoNotifyDataSetChanged ( true ) ; onNewItemsAdded ( items . size ( ) ) ; notifyItemRangeInsertedIfNeed ( size ( ) - ( items . size ( ) + getHeadersCount ( ) ) , items . size ( ) ) ; }
target:  Add new page to adapter. Call method onNewItemsAdded which check size of array and compute mAllItemsLoaded, if items.size() < mPageSize then hide bottom progress and no more show it.