Question

我正在尝试解析来自Web服务的响应，并以表格形式将其显示出来。以下是我的回复

{
    "success": true,
    "data": [{
            "id": 5,
            "roll_no": "R1005",
            "user_id": "5"
        },
        {
            "id": 6,
            "roll_no": "R1006",
            "user_id": "6"
        },
        {
            "id": 7,
            "roll_no": "R1007",
            "user_id": "7"
        },
        {
            "id": 8,
            "roll_no": "R1008",
            "user_id": "8"
        }
    ]
}

当我试图将上述json解析为表格时，我只能打印成功一词

Map<String, dynamic> response = await AppHttp().getApi(donationListURL);
donationListlModel = DonationListlModel.fromJson(response);

和

DonationListlModel.fromJson(Map<String, dynamic> json) {
    success = json['success'];
    print('donation list model success $success');

    data = json['data'] != null ? new Data.fromJson(json['data']) : null;
  }

这是我收到的错误消息- type 'List<dynamic>' is not a subtype of type 'Data'

以下是我的模型文件

class DonationListlModel {
  bool success;
  Data data;

  DonationListlModel({this.success, this.data});

  DonationListlModel.fromJson(Map<String, dynamic> json) {
    success = json['success'];
    print('donation list model success $success');

    data = json['data'] != null ? new Data.fromJson(json['data']) : null;
  }

  Map<String, dynamic> toJson() {
    final Map<String, dynamic> data = new Map<String, dynamic>();
    data['success'] = this.success;
    if (this.data != null) {
      data['data'] = this.data.toJson();
    }
    print('donation list model data $data');
    return data;
  }
}

class Data {
  String id;
  String rollNo;
  String userId;

  Data(
      {this.id,
      this.rollNo,
      this.userId,
      this.parentId});

  Data.fromJson(Map<String, dynamic> json) {
    id = json['id'];
    rollNo = json['roll_no'];
    userId = json['user_id'];
    parentId = json['parent_id'];
  }

  Map<String, dynamic> toJson() {
    final Map<String, dynamic> data = new Map<String, dynamic>();
    data['id'] = this.id;
    data['roll_no'] = this.rollNo;
    data['user_id'] = this.userId;
    data['parent_id'] = this.parentId;
    
    print('donation list model data toJSON $data');
    return data;
  }
}

什么是错误

Answer 1

在您的JSON中，“数据”是List个对象中的Data个。因此，您需要将数据变量的数据类型更改为List<Data>，如下所示

class DonationListlModel {
  bool success;
  List<Data> data;

  DonationListlModel({this.success, this.data});

  DonationListlModel.fromJson(Map<String, dynamic> json) {
    success = json['success'];
    print('donation list model success $success');

    if (this.data != null) {
      json['data'] = this.data.map((v) => v.toJson()).toList();
    }
  }

  Map<String, dynamic> toJson() {
    final Map<String, dynamic> data = new Map<String, dynamic>();
    data['success'] = this.success;
    if (this.data != null) {
      data['data'] = this.data.map((v) => v.toJson()).toList();
    }
    print('donation list model data $data');
    return data;
  }
}

class Data {
  String id;
  String rollNo;
  String userId;

  Data(
      {this.id,
        this.rollNo,
        this.userId});

  Data.fromJson(Map<String, dynamic> json) {
    id = json['id'];
    rollNo = json['roll_no'];
    userId = json['user_id'];
  }

  Map<String, dynamic> toJson() {
    final Map<String, dynamic> data = new Map<String, dynamic>();
    data['id'] = this.id;
    data['roll_no'] = this.rollNo;
    data['user_id'] = this.userId;

    print('donation list model data toJSON $data');
    return data;
  }
}

错误-'List <dynamic>'不是'Data'类型的子类型

1 个答案: