1

我正在尝试使用 dio 来获取 API 的用户。但是当我试图将请求转换为 dart 用户列表时它不起作用。

我的编码器和解码器类：它是从在线 json 解码器站点生成的。

List<User> userListFromJson(String str) =>
    List<User>.from(json.decode(str).map((x) => User.fromJson(x)));

User userFromJson(String str) => User.fromJson(json.decode(str));

String userToJson(User data) => json.encode(data.toJson());

class User {
  User({
    this.url,
    this.id,
    this.image,
    this.username,
    this.nid,
    this.email,
    this.password,
    this.firstName,
    this.lastName,
    this.isActive,
    this.isStaff,
    this.isAuthority,
    this.isSpecialist,
    this.isGeneralUser,
  });

  String url;
  int id;
  String image;
  String username;
  String nid;
  String email;
  String password;
  dynamic firstName;
  dynamic lastName;
  bool isActive;
  bool isStaff;
  bool isAuthority;
  bool isSpecialist;
  bool isGeneralUser;

  factory User.fromJson(Map<String, dynamic> json) => User(
        url: json["url"] == null ? null : json["url"],
        id: json["id"] == null ? null : json["id"],
        image: json["image"] == null ? null : json["image"],
        username: json["username"] == null ? null : json["username"],
        nid: json["nid"] == null ? null : json["nid"],
        email: json["email"] == null ? null : json["email"],
        password: json["password"] == null ? null : json["password"],
        firstName: json["first_name"],
        lastName: json["last_name"],
        isActive: json["is_active"],
        isStaff: json["is_staff"],
        isAuthority: json["is_authority"],
        isSpecialist: json["is_specialist"],
        isGeneralUser: json["is_general_user"],
      );

  Map<String, dynamic> toJson() => {
        "url": url == null ? null : url,
        "id": id == null ? null : id,
        "image": image == null ? null : image,
        "username": username == null ? null : username,
        "nid": nid == null ? null : nid,
        "email": email == null ? null : email,
        "first_name": firstName,
        "last_name": lastName,
        "is_active": isActive == false ? false : isActive,
        "is_staff": isStaff == false ? false : isStaff,
        "is_authority": isAuthority == false ? false : isAuthority,
        "is_specialist": isSpecialist == false ? false : isSpecialist,
        "is_general_user": isGeneralUser == false ? false : isGeneralUser,
      };
}

我的 Api Request 类返回 dio 的响应。

  Future<dio.Response> getAllUsers() async {
    return await _dio.get(
      '$baseUrl/user/list',
      options: dio.Options(
        contentType: dio.Headers.jsonContentType,
        headers: requestHeader,
      ),
    );
  }

提供者的代码，其中响应被转换和存储以供应用程序使用。

  Future<bool> fetchUsersList() async {
    var resp = await ApIService().getAllUsers();
    if (resp.statusCode == 200) {
      List rawJson = resp.data;
      var users = rawJson.map((e) => userFromJson(e)).toList();
      _setUsersList(users);
      return true;
    } else {
      _setMessage(jsonDecode(resp.data)['detail']);
      _setStatusCode(resp.statusCode);
      return false;
    }
  }

当代码运行时，它会显示如下错误：

[错误：flutter/lib/ui/ui_dart_state.cc(157)] 未处理的异常：类型 '_InternalLinkedHashMap<String, dynamic>' 不是类型 'String' 的子类型

4

1 回答 1

1 
class User {
  String url;
  int id;
  String image;
  String username;
  String nid;
  String email;
  String password;
  dynamic firstName;
  dynamic lastName;
  bool isActive;
  bool isStaff;
  bool isAuthority;
  bool isSpecialist;
  bool isGeneralUser;
  User({
    this.url,
    this.id,
    this.image,
    this.username,
    this.nid,
    this.email,
    this.password,
    this.firstName,
    this.lastName,
    this.isActive,
    this.isStaff,
    this.isAuthority,
    this.isSpecialist,
    this.isGeneralUser,
  });
  
  Map<String, dynamic> toMap() {
    return {
      'url': url,
      'id': id,
      'image': image,
      'username': username,
      'nid': nid,
      'email': email,
      'password': password,
      'firstName': firstName,
      'lastName': lastName,
      'isActive': isActive,
      'isStaff': isStaff,
      'isAuthority': isAuthority,
      'isSpecialist': isSpecialist,
      'isGeneralUser': isGeneralUser,
    };
  }

  factory User.fromMap(Map<String, dynamic> map) {
    if (map == null) return null;
  
    return User(
      url: map['url'],
      id: map['id'],
      image: map['image'],
      username: map['username'],
      nid: map['nid'],
      email: map['email'],
      password: map['password'],
      firstName: map['firstName'],
      lastName: map['lastName'],
      isActive: map['isActive'],
      isStaff: map['isStaff'],
      isAuthority: map['isAuthority'],
      isSpecialist: map['isSpecialist'],
      isGeneralUser: map['isGeneralUser'],
    );
  }

  String toJson() => json.encode(toMap());

  factory User.fromJson(String source) => User.fromMap(json.decode(source));

}

  Future<bool> fetchUsersList() async {
   List<User> _setUsersList = [];

    var resp = await ApIService().getAllUsers();
    if (resp.statusCode == 200) {
      resp.data.forEach((data) {
          User user = User.fromMap(data);
          _setUsersList.add(user);
        });
      return true;
    } else {
      _setStatusCode(resp.statusCode);
      return false;
    }
  }
于 2020-08-20T08:27:45.590 回答