Flutter 如何从 json 数据创建列表答案

【问题标题】：Flutter how to create a list from a json dataFlutter 如何从 json 数据创建列表
【发布时间】：2020-10-19 20:15:57
【问题描述】：

按照在线示例，我有以下代码：将一些 json 数据制作成一个列表，但问题是数据是映射字符串形式

 Future<List<Phone>> getData() async {
    http.Response response = await http.get(
        Uri.encodeFull("http://chicken20.pythonanywhere.com/user"),
        headers: {"Accept": "application/json"});
    /*setState(() {
      phone = json.decode(response.body);
      print (phone[0]);
    });*/

    List<Phone> users = (json.decode(response.body) as List)
        .map((data) =>Phone.fromJson(data))
        .toList();
return users;
  }

我的 json 文件

{"user":[{"email":"iot3@iot.com","id":1,"password":"1234","username":"med"},{"email":"firas.slimene@gmail.com","id":2,"password":"123456789","username":"firas_96"},{"email":"ahmedmattousii77@gmail.com","id":3,"password":"07495074","username":"ahmed"},{"email":"feharou@gmail.com","id":6,"password":"1234","username":"wajdi hassyaoui"},{"email":"matt@gmail.com","id":7,"password":"1234","username":"matt"}]}

错误

 [ERROR:flutter/lib/ui/ui_dart_state.cc(157)] Unhandled Exception: type '_InternalLinkedHashMap<String, dynamic>' is not a subtype of type 'List<dynamic>' in type cast

型号类电话{ 用户用户；

  Phone({this.user});

  Phone.fromJson(Map<String, dynamic> json) {
    user = json['user'] != null ? new User.fromJson(json['user']) : null;
   
  }

  Map<String, dynamic> toJson() {
    final Map<String, dynamic> data = new Map<String, dynamic>();
    if (this.user != null) {
      data['user'] = this.user.toJson();
     


    }
    return data;
  }
}

class User{
  String email;
  String password;

  User({this.email,this.password});

  User.fromJson(Map<String, dynamic> json) {
    email = json['email'];
    password=json['password'];
  }

  Map<String, dynamic> toJson() {
    final Map<String, dynamic> data = new Map<String, dynamic>();
    data['email'] = this.email;
    data['password'] = this.password;
    return data;
  }
}

我需要一些帮助，谢谢

【问题讨论】：

标签： flutter dart

【解决方案1】：

你得到的json的'user'对象中的用户列表

Future<List<Phone>> getData() async {
    http.Response response = await http.get(
        Uri.encodeFull("http://chicken20.pythonanywhere.com/user"),
        headers: {"Accept": "application/json"});
    /*setState(() {
      phone = json.decode(response.body);
      print (phone[0]);
    });*/

    List<Phone> users = (json.decode(response.body)['user'] as List)
        .map((data) =>Phone.fromJson(data))
        .toList();
    return users;
}

【讨论】：