/**
  * When a user selects an item: - If it's a directory, load that directory. - If it's a file, open
  * the SheetMusicActivity.
  */
 @Override
 protected void onListItemClick(ListView parent, View view, int position, long id) {
   super.onListItemClick(parent, view, position, id);
   FileUri file = (FileUri) this.getListAdapter().getItem(position);
   if (file.isDirectory()) {
     this.loadDirectory(file.getUri().getPath());
     return;
   } else {
     ChooseSongActivity.openFile(file);
   }
 }