I'm having trouble consuming an API. I can save data to the database, but the following error occurs:

_TypeError (type '(dynamic) => Null' is not a subtype of type '(String, dynamic) => void' of 'action')

This is a part of my repository.

  Future<MyModel?> test() async {
    .
    .
    var headerParameters = {
      "teanantId": tenantId,
      "Authorization": headerAuth,
    };
    var queryParameters = {
      'deviceId': appController.deviceId,
    };

    try {
      Response response = await dio.post(
        BASE_URL   methodPost,
        data: jsonEncode(queryParameters),
        options: Options(
            headers: headerParameters,
            contentType: 'application/json',
            responseType: ResponseType.json),
      );
      if (response.statusCode == 200) {
        var saida = MyModel.fromJson(json.decode(response.data));
        return saida;
      }
    } on DioError catch (exc) {
      throw ('Exception ${exc.message}');
    }
    return null;
  }

Here's my model.

class MyModel {

  List<Data?>? data;
  bool? success;
  int? statusCode;
  String? message;

.
.
MyModel.fromJson(Map<String, dynamic> json) {
    if (json['data'] != null) {
      data = <Data>[];
      json['data'].forEach((v) {
        data!.add(new Data.fromJson(v));
      });
    }
    success = json['success'];
    statusCode = json['statusCode'];
    message = json['message'];
  }

.
.
.
class Data {
  String? id;
  String? type;
  User? user;
  String? value;
  String? status;
  // List<Null>? errors;
  String? createdAt;
  // Null? verificationCode;
  // Null? crossValidationIdentifier;

  Data({
    this.id,
    this.type,
    this.user,
    this.value,
    this.status,
    this.createdAt,
  });

  Data.fromJson(Map<String, dynamic> json) {
    id = json['id'];
    type = json['type'];
    user = json['user'] != null ? new User.fromJson(json['user']) : null;
    value = json['value'];
    status = json['status'];

    createdAt = json['createdAt'];
  }

How can I get past this error? The error occurs in foreach.

CodePudding user response：

just decode the response.data to Map<String,dynamic>

import 'dart:convert';

....
 final post = MyModel.fromJson(json.decode(response.data));
 return post;

if your data is not list of map, then you just need to convert it from json.

Data? data;
...

MyModel.fromJson(Map<String, dynamic> json) {
    data = Data.fromJson(json.decode(json["data"]));
    success = json['success'];
    statusCode = json['statusCode'];
    message = json['message'];
  }

this will work if your data from api is a Map, not list of map.