flutter入门到放弃5

json数据格式转换

• 使用json_serializable库

1. pubspec.yaml文件中添加依赖

dependencies:
  json_annotation: ^4.4.0

dev_dependencies:
  build_runner: ^2.1.4
  json_serializable: ^6.7.1

2. 使用@JsonSerializable注解标记类

import 'package:json_annotation/json_annotation.dart';

import '../dio/HttpState.dart';
part 'BaseResponse.g.dart';

@JsonSerializable(genericArgumentFactories: true)
class BaseResponse<T> {
  int status = 0;
  T? data;
  String? title;

  BaseResponse({
    required this.data,
    required this.status,
    required this.title,
  });

  bool isSuccess() {
    return status == HttpState.SUCCESS;
  }

  String getMessageAndCodeWithEmpty() {
    if (title == null) {
      return "";
    } else {
      return "${title!}:$status";
    }
  }

  factory BaseResponse.fromJson(
    Map<String, dynamic> json,
    T Function(dynamic json) fromJsonT,
  ) =>
      _$BaseResponseFromJson<T>(json, fromJsonT);

  Map<String, dynamic> toJson(Object? Function(T value) toJsonT) =>
      _$BaseResponseToJson<T>(this, toJsonT);
}

3. 运行以下命令生成序列化文件
   flutter pub run build_runner build
4. 导入生成一个名为xx.g.dart的文件
5. 泛型处理

part 'UserInfo.g.dart';
 @JsonSerializable(explicitToJson: true)
class UserInfo {
  String? name;
  int age = 0;
  String? email;

  UserInfo({
    required this.name,
    required this.age,
    required this.email,
  });

  factory UserInfo.fromJson(Map<String, dynamic> json) =>
      _$UserInfoFromJson(json);

  Map<String, dynamic> toJson() => _$UserInfoToJson(this);
}

BaseResponse和UserInfo中的factory直接调用xx.g.dart文件

测试

  void _checkJson(){
    String jsonString = '{"status":200,"data":{"name":"张三","age":18}}';
    Map<String,dynamic> jsonData = json.decode(jsonString);
    BaseResponse<UserInfo>? response = BaseResponse<UserInfo>.fromJson(jsonData, (json) => UserInfo.fromJson(json));
    Log.e("用户名称：${response.data?.name}");
  }