@Override public void toggleSelection(Photo photo){
  if (selectedPhotos.contains(photo.getPath())) {
    selectedPhotos.remove(photo.getPath());
  }
 else {
    selectedPhotos.add(photo.getPath());
  }
}

@ Override public void toggleSelection ( Photo photo ) { if ( selectedPhotos . contains ( photo . getPath ( ) ) ) { selectedPhotos . remove ( photo . getPath ( ) ) ; } else { selectedPhotos . add ( photo . getPath ( ) ) ; } }
toggle the selection status of the item at a given position
