public void addItems(int howMany){
  if (howMany > 0) {
    for (int i=lastInsertedIndex + 1; i <= lastInsertedIndex + howMany; i++) {
      items.add("Item " + i);
      notifyItemInserted(items.size() - 1);
    }
    lastInsertedIndex=lastInsertedIndex + howMany;
  }
}

public void addItems ( int howMany ) { if ( howMany > 0 ) { for ( int i = lastInsertedIndex + 1 ; i <= lastInsertedIndex + howMany ; i ++ ) { items . add ( "Item " + i ) ; notifyItemInserted ( items . size ( ) - 1 ) ; } lastInsertedIndex = lastInsertedIndex + howMany ; } }
utility method to add some rows for testing purposes . you can add rows from the toolbar menu .
