code: private int getPositionForId(final long itemId) {
          View v = getViewForId(itemId);
          if (v == null) {
              return AdapterView.INVALID_POSITION;
          } else {
              return mWrapper.getPositionForView(v);
          }
      }
docs: Retrieves the position in the list corresponding to itemId.
  
  @return the position of the item in the list, or {@link android.widget.AdapterView#INVALID_POSITION} if the {@code View} corresponding to the id was not found.