question: private void initSelectPosition ( int position ) { if ( mSelectMode == ISelectable . SELECT_MODE_SINGLE ) { if ( mSelectedPosition == ISelectable . INVALID_POSITION ) { mSelectedPosition = position ; } } else if ( mSelectMode == ISelectable . SELECT_MODE_MULTI ) { if ( ! mSelectedPositions . contains ( position ) ) mSelectedPositions . add ( position ) ; } else { throw new RuntimeException ( ) ; } }
target:  this will only called once. 