有人能帮帮我吗？我已经被困在这里好几天了，然后被困在这里。我添加了List duplicateItems = [];接下来的问题是：无法将“List”类型的值赋给“List”类型的变量。尝试改变变量的类型，或者将右边的类型强制转换为'List'

class _view_problemState extends State<view_problem> {
  List<problemModel> problemlist = [];
  StreamController _streamController = StreamController();
  Future getAllProblem() async {
    problemlist = await problemcontrollers().getProblem();
    _streamController.sink.add(problemlist);
  }

  @override
  void initState() {
    // TODO: implement initState
   Timer.periodic(Duration(seconds: 1), (timer) {
      getAllProblem();
    });
    super.initState();
  }

  void _filterSearch(String query) {
    List<String> duplicateItems = [];
    setState(() {
      problemlist = duplicateItems
          .where((problemlist) =>
              problemlist.toLowerCase().contains(query.toLowerCase()))
          .toList();
    });
  }