我想将文本和日期保存到txt文件并加载，但收到"RangeError（index）：无效值：有效值范围为空：0英寸

void _loadNotes() async {
    var directory = await getApplicationDocumentsDirectory();
    var file = File("${directory.path}/notable.txt");
    if (!await file.exists()) {
      file.createSync();
      file.writeAsStringSync("Hello, World!#This is your first note.\n");
    }
    var contents = await file.readAsString();
    var contentsList = contents.split("\n");
    for (var i = 0; i < contentsList.length; i++) {
      var noteLine = contentsList[i].split("#");
      _notes.add(noteLine[0]);
      _noteAddedDates.add(noteLine[1]);
    }
  }
  void _saveNotes() async {
    var directory = await getApplicationDocumentsDirectory();
    var file = File("${directory.path}/notable.txt");
    var contents = "";
    for (var i = 0; i < _notes.length; i++) {
      contents += _notes[i] + "#" + _noteAddedDates[i] + "\n";
    }
    await file.writeAsString(contents);
  }