@Override
  void saveState(Bundle outState) {
    super.saveState(outState);

    int[] rows = new int[mOldNotes.size()];
    int[] cols = new int[mOldNotes.size()];
    String[] notes = new String[mOldNotes.size()];

    int i = 0;
    for (NoteEntry ne : mOldNotes) {
      rows[i] = ne.rowIndex;
      cols[i] = ne.colIndex;
      notes[i] = ne.note.serialize();
      i++;
    }

    outState.putIntArray("rows", rows);
    outState.putIntArray("cols", cols);
    outState.putStringArray("notes", notes);
  }