没有为 Dart 中的类型定义 getter 'fromJson'答案

【问题标题】：The getter 'fromJson' isn't defined for the type in Dart没有为 Dart 中的类型定义 getter 'fromJson'
【发布时间】：2021-10-06 04:37:17
【问题描述】：

我正在学习flutter，尝试使用Getx的GetConnectCustom configuration，

当尝试为默认请求设置 defaultDecoder 时，它会报错：

The getter 'fromJson' isn't defined for the type 'Resp'.
Try importing the library that defines 'fromJson', correcting the name to the name of an existing getter, or defining a getter or field named 'fromJson'.dart"

如何解决这个错误？

这是我的代码：

import 'package:get/get.dart';

class AuthService extends GetConnect {
  @override
  void onInit() {
    // All request will pass to jsonEncode so CasesModel.fromJson()

    httpClient.defaultDecoder = Resp.fromJson;
    httpClient.baseUrl = 'http://localhost/app_api/auth';

   
  }

  Future<Response<Map<String, dynamic>>> getCaptcha(String mobile) =>
      get("get_captcha");
}

class Resp {
  final int Errcode;
  final String Errmsg;
  final Map<String, dynamic> Data;

  Resp(this.Errcode, this.Errmsg, this.Data);

  factory Resp.fromJson(Map<String, dynamic> json) {
    return Resp(json["errcode"], json["errmsg"], json["data"]);
  }
}

【问题讨论】：

通过添加解决 httpClient.defaultDecoder = (json) => Resp.fromJson(json);

标签： flutter dart flutter-getx

【解决方案1】：

检查这个 https://gist.github.com/eduardoflorence/d918d05ad71175b52c2aca95588c305d

class CityModel {
  CityModel({
    required this.abbreviation,
    required this.name,
  });

  String abbreviation;
  String name;

  factory CityModel.fromJson(Map<String, dynamic> json) => CityModel(
        abbreviation: json["sigla"],
        name: json["nome"],
      );

  static List<CityModel> listFromJson(list) => List<CityModel>.from(list.map((x) => CityModel.fromJson(x)));
}

然后
httpClient.defaultDecoder = CityModel.listFromJson;

【讨论】：