There is a model

class DataModel {
  String name;
  String img;
  int price;
  int people;
  int stars;
  String description;
  String location;

  DataModel({
    required this.name,
    required this.img,
    required this.price,
    required this.people,
    required this.stars,
    required this.description,
    required this.location,
  });

  factory DataModel.fromJson(Map<String, dynamic> json) {
    return DataModel(
      name: json['name'],
      img: json['img'],
      price: json['price'],
      people: json['people'],
      stars: json['stars'],
      description: json['description,'],
      location: json['location'],
    );
  }
}

and a function where I get null

import 'dart:convert';
import 'package:flutter_cubit/services/data_model.dart';
import 'package:http/http.dart' as http;

class DataServices {
  String baseUrl = 'http://******';

  Future<List<DataModel>> getInfo() async {
    String apiUrl = '/****';
    http.Response res = await http.get(Uri.parse(baseUrl   apiUrl));
    try {
      print('response status:${res.statusCode}');

      if (res.statusCode == 200) {
        print('----------1');
        List<dynamic> list = json.decode(res.body);
        print(list[0]); // only first imem just for example the data isn't empty
        print('----------2');

        // the error is on the next line
        List<DataModel> result = list.map((e) => DataModel.fromJson(e)).toList();
 
        print('----------3');
        print(result);
        return result;
      } else {
        return <DataModel>[];
      }
    } catch (e) {
      print(e);
      return <DataModel>[];
    }
  }
}

The output from the above function

I/flutter ( 6979): response status:200
I/flutter ( 6979): ----------1
I/flutter ( 6979): {id: 1, name: British Columbia, description: This 134 kilometers Highway 99 trail gives you a taste of the Canada mountains, from Horseshoe Bay in the north of Vancouver to Pemberton. , price: 1276, stars: 4, people: 5, selected_people: 5, img: images/f9d4b5e088c7bc70b7bbd51cd89e71b6.jpeg, location: Canada, British Columbia, created_at: 2021-11-17T10:09:08.000000Z, updated_at: 2021-11-19T13:39:55.000000Z}
I/flutter ( 6979): ----------2
I/flutter ( 6979): type 'Null' is not a subtype of type 'String'

Why do I get null on error-line of the code?

the original json from api

[
   {
      "id":1,
      "name":"British Columbia",
      "description":"This 134 kilometers Highway 99 trail gives you a taste of the Canada mountains, from Horseshoe Bay in the north of Vancouver to Pemberton. ",
      "price":1276,
      "stars":4,
      "people":5,
      "selected_people":5,
      "img":"images\/f9d4b5e088c7bc70b7bbd51cd89e71b6.jpeg",
      "location":"Canada, British Columbia",
      "created_at":"2021-11-17T10:09:08.000000Z",
      "updated_at":"2021-11-19T13:39:55.000000Z"
   },
   {
      "id":2,
      "name":"Icefields",
      "description":"This stretches for a straight 234 kilometers from Banff to Jasper. The Icefields Parkway offers you the picturesque panorama of Alberta\u2019s most talked about mountain vistas. ",
      "price":2153,
      "stars":5,
      "people":5,
      "selected_people":3,
      "img":"images\/1a2d25d3c5ea7912982e37b8005bbebe.jpeg",
      "location":"Icefields, Alberta",
      "created_at":"2021-11-17T10:10:43.000000Z",
      "updated_at":"2021-11-19T14:18:09.000000Z"
   },
   {
      "id":3,
      "name":"Moraine Lake",
      "description":"Moraine Lake is yet another astonishing geographical location that you cannot afford to miss out on if you\u2019re traveling along the Icefields Parkway. ",
      "price":3456,
      "stars":3,
      "people":5,
      "selected_people":4,
      "img":"images\/9a4079ae9e67ca51b9fdf4670a5795f4.jpeg",
      "location":"Moraine Lake, Alberta",
      "created_at":"2021-11-17T10:16:31.000000Z",
      "updated_at":"2021-11-19T13:40:36.000000Z"
   },
   {
      "id":4,
      "name":"Ontario",
      "description":"If you\u2019re in Canada and if you\u2019re a sucker for mountains, Killarney Provincial Park in Ontario is your best catch for Canada mountains near Toronto. ",
      "price":3312,
      "stars":4,
      "people":5,
      "selected_people":3,
      "img":"images\/24fe838b325456a0ca7fc2249409de3f.jpeg",
      "location":"Killarney Provincial Park",
      "created_at":"2021-11-17T10:18:46.000000Z",
      "updated_at":"2021-11-19T13:40:44.000000Z"
   },
   {
      "id":5,
      "name":"Gaza",
      "description":"Dome of the rock the beautiful and amazing human made architectural.",
      "price":10,
      "stars":5,
      "people":5,
      "selected_people":4,
      "img":"images\/9aaf2377eb3e0978ecb0e17717579a2b.jpg",
      "location":"Palestine, Gaza",
      "created_at":"2021-12-08T12:29:53.000000Z",
      "updated_at":"2021-12-08T12:29:53.000000Z"
   }
]

CodePudding user response：

There is a mistake in your factory Constructor

  factory DataModel.fromJson(Map<String, dynamic> json) {
    return DataModel(
      name: json['name'],
      img: json['img'],
      price: json['price'],
      people: json['people'],
      stars: json['stars'],
      description: json['description,'], //Here; You added a comma.
      location: json['location'],
    );
  }

Use this:

  factory DataModel.fromJson(Map<String, dynamic> json) {
    return DataModel(
      name: json['name'],
      img: json['img'],
      price: json['price'],
      people: json['people'],
      stars: json['stars'],
      description: json['description'], //Comma removed.
      location: json['location'],
    );
  }