code: public int getItemPosition(int id) {
          for(int index = getCount()-1; index >= 0; index--) {
              TwinTextItem item = getItem(index);
              if(item.getId() == id)
                  return index;
          }
          return -1;
      }
docs: Finds a spinner item's position in the data set by its id value (excluding any temporary selection).
  @param id The id of the item to search.
  @return The position of the specified TwinTextItem, or -1 if no item with the given id was found.