flutter - Flutter Futurebuilder在显示快照数据值时显示错误

Question

我在应用程序中使用Future builder，并且工作正常，但是当数据加载以及当我在Text小部件中显示它时，它显示此错误

Class '_InternalLinkedHashMap<String, dynamic>' has no instance getter 'approved_value'.
Receiver: _LinkedHashMap len:31
Tried calling: approved_value

我的密码

class _ClaimsScreenState extends State<ClaimsScreen> {
  @override
  initState() {
    super.initState();
    doSomeAsyncStuff();
  }

  Future<List> doSomeAsyncStuff() async {
    final storage = new FlutterSecureStorage();
    String value = await storage.read(key: 'health_card');
    print(value);

    String url2 =
        'api.com';

    final response2 = await http.get(url2);
    var Data = json.decode(response2.body);
    print(Data);
    var DisplayData = Data["records"];

    return DisplayData;
  }

  @override
  Widget build(BuildContext context) {
    return Scaffold(
      appBar: AppBar(
        centerTitle: true,
        title: Text('IGI GENERAL INSURANCE'),
      ),
      body: FutureBuilder<List>(
          future: doSomeAsyncStuff(),
          builder: (BuildContext context, AsyncSnapshot<List> snapshot) {
            if (snapshot.hasData) {
              print('ss');
              print(snapshot.data);
              return ListView.builder(
                  itemCount: snapshot.data.length,
                  itemBuilder: (BuildContext context, int index) {
                    return Card(
                      child: Column(
                        children: <Widget>[
                          Row(
                            children: <Widget>[
                              Row(
                                children: <Widget>[
                                  Text('Approved Value:'),
                                  Text(snapshot.data[index].approved_value)
                                ],
                              ),
                              Row(
                                children: <Widget>[
                                  Text('Patient Name:'),
                                  Text(snapshot.data[index].patient_name)
                                ],
                              )
                            ],
                          ),
                          Row(
                            children: <Widget>[
                              Row(
                                children: <Widget>[
                                  Text('Claimed Value:'),
                                  Text(snapshot.data[index].claimed_value)
                                ],
                              ),
                              Row(
                                children: <Widget>[
                                  Text('status:'),
                                  Text(snapshot.data[index].patient_name)
                                ],
                              )
                            ],
                          )
                        ],
                      ),
                    );
                  });
            } else if (snapshot.hasError) {
              return Padding(
                padding: const EdgeInsets.only(top: 16),
                child: Text('Error: ${snapshot.error}'),
              );
            } else {
              return Padding(
                padding: EdgeInsets.only(top: 16),
                child: Text('Awaiting result...'),
              );
            }
          }),
    );
  }
}

我在 future builder 中使用listview构建器，因为值在数组中，并且需要在文本小部件中全部显示
我不确定为什么如果我在文本小部件中显示值然后删除显示值时删除它的工作正常，为什么显示此错误。

Answer 1

snapshot.data[index]返回一个Map。 Map类没有approved_value setter/getter 。您可能打算改用snapshot.data[index]['approved_value']。