flutter：嵌套的json解析列表

Question

我试图从我的 json 代码中调用 Name 和 Fees 它是来自我的 json 主数组的嵌套数组我可以处理它的主数组但是我不能处理它的子数组

"guideExtraServices": [
      {
        "Name": "Limousine",
        "Fees": 100
      },
      {
        "Name": "Bus",
        "Fees": 10000
      },
      {
        "Name": "Mini-Bus",
        "Fees": 5000
      }
    ], 

我不能这样做，因为当我尝试调用“名称”和“费用”时出现错误

type 'List<ExtraServices>' is not a subtype of type 'String'

这是我的课程，用于映射导游数据以在列表视图中使用它

class TourGuide{
  String id;
  String name;
  String email;
  String password;
  List<ExtraServices> extraService;

  TourGuide({
      this.id,
      this.name,
      this.email,
      this.password,
    this.extraService,
  });

  TourGuide.fromJson(Map<String, dynamic> json){
    List<dynamic> extra = json['guideExtraServices'];
    List<ExtraServices> extraList = extra.map((i) => ExtraServices.fromJson(i)).toList();
id = json['id'].toString();
name = json['displayName'];
email = json['email'];
password = json['password'];
    extraService=extraList;
  }
}

这是一个额外的服务类，导游类依赖于获取子数组

   class ExtraServices{
      String name;
      double fees;
      ExtraServices({
        this.name,
        this.fees
      });

      ExtraServices.fromJson(Map<String, dynamic> json){
        name = json['Name'];
        fees = json['Fees'].toDouble();
      }
    }

我使用 for api 解码 json 的提供程序方法

 Future<dynamic> tourGuideList() async {
        _isLoading = true;
        notifyListeners();
        print('Starting request');

        http.Response response = await http.get(Environment.tourGuide,
            headers: Environment.requestHeader);
        print('Completed request');
        print('respond data : ${response.body}');

        Map<String, dynamic> res = json.decode(response.body);
        var results;
        if (res['code'] == 200) {

          print('start load tourguide');
          _tourGuide = [];
          res['message'].forEach((v) {
            _tourGuide.add(new TourGuide.fromJson(v));  
          }); 

          results = true;
        } else {
          results =
              FailedRequest(code: 400, message: res['error'], status: false);
        }
        _isLoading = false;
        notifyListeners();
        return results;
      }

我不知道为什么我有错误而且我无法修复它

Answer 1

我认为你的 json 应该是这样的：

{"guideExtraServices": [
      {
        "Name": "Limousine",
        "Fees": 100
      },
      {
        "Name": "Bus",
        "Fees": 10000
      },
      {
        "Name": "Mini-Bus",
        "Fees": 5000
      }
    ]}

尝试

// To parse this JSON data, do
//
//     final tourGuide = tourGuideFromJson(jsonString);

import 'dart:convert';

TourGuide tourGuideFromJson(String str) => TourGuide.fromJson(json.decode(str));

String tourGuideToJson(TourGuide data) => json.encode(data.toJson());

class TourGuide {
    List<GuideExtraService> guideExtraServices;

    TourGuide({
        this.guideExtraServices,
    });

    factory TourGuide.fromJson(Map<String, dynamic> json) => TourGuide(
        guideExtraServices: List<GuideExtraService>.from(json["guideExtraServices"].map((x) => GuideExtraService.fromJson(x))),
    );

    Map<String, dynamic> toJson() => {
        "guideExtraServices": List<dynamic>.from(guideExtraServices.map((x) => x.toJson())),
    };
}

class GuideExtraService {
    String name;
    int fees;

    GuideExtraService({
        this.name,
        this.fees,
    });

    factory GuideExtraService.fromJson(Map<String, dynamic> json) => GuideExtraService(
        name: json["Name"],
        fees: json["Fees"],
    );

    Map<String, dynamic> toJson() => {
        "Name": name,
        "Fees": fees,
    };
}

Answer 2

请尝试以下代码：-

首先创建模型：-

class GuideResponseModel {
  List<GuideExtraServicesModel> guideExtraServiceList;

  GuideResponseModel({
    this.guideExtraServiceList
  });

  factory GuideResponseModel.fromJson(Map<String, dynamic> parsedJson) {
    try {
      List<GuideExtraServicesModel> guideExtraServiceModelList = new List();

      if (parsedJson.containsKey('guideExtraServices')) {
        var countryList = parsedJson['guideExtraServices'] as List;
        guideExtraServiceModelList =
            countryList.map((i) => GuideExtraServicesModel.fromJson(i)).toList();
      }

      return GuideResponseModel(
        guideExtraServiceList: guideExtraServiceModelList
      );
    } catch (e) {
      return null;
    }
  }
}
class GuideExtraServicesModel {
  String name;
  int fees;

  GuideExtraServicesModel({this.name,this.fees});

  factory GuideExtraServicesModel.fromJson(Map<String, dynamic> json) {
    return GuideExtraServicesModel(name: json['Name'],fees: json['Fees']);
  }
}

第二个用户模型：-

String jsonData = '{"guideExtraServices": [{"Name": "Limousine","Fees": 100},{"Name": "Bus","Fees": 10000},{"Name": "Mini-Bus","Fees": 5000}]}';
final dynamic jsonResponse = json.decode(jsonData);
final GuideResponseModel responseModel = GuideResponseModel.fromJson(jsonResponse);
print('======${responseModel.guideExtraServiceList[0].name}----${responseModel.guideExtraServiceList[0].fees}');