Flutter 正在从Json文件获取数据，但映射不起作用

我有一个从JSON文件获取数据的列表，我想通过映射在GridView中显示它，GridView项将根据我的JSON文件展开，但我得到了一个错误，即类型“\u InternalLinkedHashMap”不是类型“int”的子类型。 Json文件链接在这里

---

您在解析json时遇到问题。我已经为它添加了一个数据类，请立即尝试

    import 'dart:convert';
    import 'package:flutter/services.dart';
    import 'package:flutter/material.dart';
    import 'package:http/http.dart' as http;
    import 'package:percent_indicator/percent_indicator.dart';
    import 'dart:async';
    import 'package:sweetalert/sweetalert.dart';

    void main() => runApp(News1());
    List data = [];

    class News1 extends StatelessWidget {
    @override
    Widget build(BuildContext context) {
        return MaterialApp(
        title: "Flutter",
        debugShowCheckedModeBanner: false,
        home: HomePage(),
        );
    }
    }

    class HomePage extends StatefulWidget {
    @override
    _HomePageState createState() => _HomePageState();
    }

    class _HomePageState extends State<HomePage> {

    List<Data> dataList = List();

    @override
    void initState() {
        fetchData();
        Timer(
            Duration(seconds: 3),
                () => Navigator.push(
            context,
            MaterialPageRoute(
                builder: (context) => showdata(),
            ),
            ));
        super.initState();
    }

    void fetchData() async {
        final response =
        await http.get('http://salterz.com/ukjalsa_data/directions.json');

        if (response.statusCode == 200) {
        setState(() {

            dataList.addAll(Data.fromMapList(json.decode(response.body)));
            print(dataList.length);
        });
        }
    }

    @override
    Widget build(BuildContext context) {
        SystemChrome.setPreferredOrientations(
            [DeviceOrientation.landscapeLeft, DeviceOrientation.landscapeRight]);

        return Scaffold(
            body: Center(
                child: Column(
                mainAxisAlignment: MainAxisAlignment.center,
                children: <Widget>[
                    CircularPercentIndicator(
                        radius: 130.0,
                        animation: true,
                        progressColor: Colors.green,
                        animationDuration: 3000,
                        lineWidth: 15.0,
                        percent: 1.0,
                        center: new Text(
                        "Loading",
                        style: new TextStyle(fontWeight: FontWeight.bold, fontSize: 20.0),
                        )),
                    Text('Please wait News are Loading'),
                ],
                )));
    }
    }

    class showdata extends StatefulWidget {
    @override
    _showdataState createState() => _showdataState();
    }

    class _showdataState extends State<showdata> {
    @override
    Widget build(BuildContext context) {
        return Scaffold(
            body: GridView.count(
            crossAxisCount: 2,
            children: data.map((TransID){
                return  Card(
                margin: EdgeInsets.all(20),
                child: InkWell(
                    onTap: () {
                    print('Card tapped.');
                    },
                    child: Container(
                    margin: EdgeInsets.all(10),
                    width: 300,
                    height: 100,
                    child: Text(data[TransID].Head),
                    ),
                ),
                );
            }).toList(),
            ));
    }
    }

这是您的数据类

    class Data {
    int _transID;
    String _head;
    String _imgUrl;
    String _description;
    String _mapLink;

    static Data fromMap(Map<String, dynamic> map) {
        Data data = new Data();
        data._transID = map['TransID'];
        data._head = map['Head'];
        data._imgUrl = map['ImgUrl'];
        data._description = map['Description'];
        data._mapLink = map['MapLink'];

        return data;
    }


    static List<Data> fromMapList(dynamic mapList) {
        List<Data> list = new List(mapList.length);
        for (int i = 0; i < mapList.length; i++) {
        list[i] = fromMap(mapList[i]);
        }
        return list;
    }
    }

---

请看我已经打印了该列表，您将看到数组4的大小作为响应，现在您可以根据需要使用。Amit非常感谢，但我不理解为什么此列表没有显示在我的应用程序中。请帮助我您实际需要如何处理该列表，您想在listview或其他任何位置显示该数据？我想在网格视图中显示它。但知道问题解决了很多很多，谢谢你，埃米特，继续祝福

    class Data {
    int _transID;
    String _head;
    String _imgUrl;
    String _description;
    String _mapLink;

    static Data fromMap(Map<String, dynamic> map) {
        Data data = new Data();
        data._transID = map['TransID'];
        data._head = map['Head'];
        data._imgUrl = map['ImgUrl'];
        data._description = map['Description'];
        data._mapLink = map['MapLink'];

        return data;
    }


    static List<Data> fromMapList(dynamic mapList) {
        List<Data> list = new List(mapList.length);
        for (int i = 0; i < mapList.length; i++) {
        list[i] = fromMap(mapList[i]);
        }
        return list;
    }
    }