dart - 'String' 不是 'int' flutter 的子类型

Question

这是我的第一个 flutter JSON 示例，我尝试从 json 链接获取数据并将标题显示为 ListView

我用了这个code写我的一些变化.. 在链接中他有 results array 在我的我没有所以我离开了 data = resBody[""]; 是空的吗？

另外，我在 flutter HTTP 请求中遇到了这个错误，我真的不知道该怎么办

有什么帮助吗？

Dart Error: Unhandled exception:
 type 'String' is not a subtype of type 'int' of 'index'

这是我的代码

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

    void main() {
      runApp(MaterialApp(
    home: ToDo(),
  ));
}

class ToDo extends StatefulWidget {
  @override
  ToDoState createState() => ToDoState();
}

class ToDoState extends State<ToDo> {
  final String url = "https://jsonplaceholder.typicode.com/todos";
  List data;

  Future<String> getTitle() async {
    var res = await http
        .get(Uri.encodeFull(url), headers: {"Accept": "application/json"});

    setState(() {
      var resBody = json.decode(res.body);
      data = resBody[" "];
    });

    return "Success!";
  }

  @override
  Widget build(BuildContext context) {
    return Scaffold(
      appBar: AppBar(
        title: Text("Title List"),
        backgroundColor: Colors.amber,
      ),
      body: ListView.builder(
        itemCount: data == null ? 0 : data.length,
        itemBuilder: (BuildContext context, int index) {
          return new Container(
            child: Center(
              child: Column(
                crossAxisAlignment: CrossAxisAlignment.stretch,
                children: <Widget>[
                  Card(
                    child: Container(
                        padding: EdgeInsets.all(15.0),
                        child: Row(
                          children: <Widget>[
                            Text("Title: "),
                            Text(data[index]["title"],
                                style: TextStyle(
                                    fontSize: 18.0, color: Colors.black87)),
                          ],
                        )),
                  ),
                ],
              ),
            ),
          );
        },
      ),
    );
  }

  @override
  void initState() {
    super.initState();
    this.getTitle();
  }
}

Answer 1

您的 getTitle 方法需要更改为以下内容:

Future<String> getTitle() async {
    var res = await http
        .get(Uri.encodeFull(url), headers: {"Accept": "application/json"});

    setState(() {
      var resBody = json.decode(res.body);
      data = resBody; //This line changed from data = resBody[" "];
    });

    return "Success!";
}