code: public boolean addItems(Collection<? extends T> items) {
          if (mListItems.addAll(items)) {
              notifyDataSetChanged();
              return true;
          }
          return false;
      }
docs: Append a collection of items and refresh the {@code AdapterView} by calling
  {@code notifyDataSetChanged()}.
  
  @param items collection of items to append
  @return true if any data was modified by this operation, false otherwise.