code: public void selectTemporary(TwinTextItem item) {
          // if we just want to clear the selection:
          if(item == null) {
              setSelection(getLastItemPosition());
              // the call is passed on to the adapter in setSelection.
              return;
          }
          PickerSpinnerAdapter adapter = (PickerSpinnerAdapter) getAdapter();
          // pass on the call to the adapter (just stores the item):
          adapter.selectTemporary(item);
          final int tempItemPosition = adapter.getCount();
          if(getSelectedItemPosition() == tempItemPosition) {
              // this is quite a hack, first reset the position to 0 but intercept the callback,
              // then redo the selection:
              setSelectionQuietly(0);
          }
          super.setSelection(tempItemPosition);
          // during initialization the system might check our selected position and reset it,
          // thus we need to check after the message queue has been settled
          if (!restoreTemporarySelection) {
              restoreTemporarySelection = true;
              post(new Runnable() {
                  @Override
                  public void run() {
                      if (restoreTemporarySelection) {
                          restoreTemporarySelection = false;
                          reselectTemporaryItem = false;
                          final int tempItemPosition = getAdapter().getCount();
                          if (getSelectedItemPosition() != tempItemPosition)
                              superSetSelection(tempItemPosition);
                      }
                  }
              });
          }
      }
docs: Push an item to be selected, but not shown in the dropdown menu. This is similar to calling
  setText(item.toString()) if a Spinner had such a method.
  @param item The item to select, or null to remove any temporary selection.