在flutter中使用listview搜索数据时出错

class SearchExample extends StatefulWidget {
  @override
  _SearchExampleState createState() => _SearchExampleState();
}

class _SearchExampleState extends State<SearchExample> {
  List<String> _data = ['apple', 'banana', 'cherry', 'date'];
  List<String> _filteredData = [];
  String _searchText = '';

  @override
  void initState() {
    super.initState();
    _filteredData = _data;
  }

  void _onSearchChanged(String value) {
    setState(() {
      _searchText = value;
      _filteredData = _data.where((item) => item.contains(value)).toList();
    });
  }

  @override
  Widget build(BuildContext context) {
    return Column(
      children: [
        TextField(
          onChanged: _onSearchChanged,
          decoration: InputDecoration(labelText: 'Search'),
        ),
        Expanded(
          child: ListView.builder(
            itemCount: _filteredData.length,
            itemBuilder: (context, index) {
              return ListTile(title: Text(_filteredData[index]));
            },
          ),
        ),
      ],
    );
  }
}

void _onSearchChanged(String value) {
  setState(() {
    _searchText = value;
    if (value.isEmpty) {
      _filteredData = _data;
    } else {
      _filteredData = _data.where((item) => item.toLowerCase().contains(value.toLowerCase())).toList();
    }
  });
}

IndexedListView.builder(
  indexGetter: (index) => _filteredData[index].hashCode,
  itemCount: _filteredData.length,
  itemBuilder: (context, index) {
    return ListTile(title: Text(_filteredData[index]));
  },
)

Future<void> _loadData() async {
  // 模拟异步数据加载
  await Future.delayed(Duration(seconds: 2));
  setState(() {
    _data = ['apple', 'banana', 'cherry', 'date'];
    _filteredData = _data;
  });
}

@override
void initState() {
  super.initState();
  _loadData();
}