Flutter: 'Null' is not a subtype of type 'String', when calling rest api-CodePudding

I would be highly grateful if the answer is in simple terms. I am a beginner.

here is my full project code: https://drive.google.com/file/d/1nj7Pj7Gzl-xVzzCm-aPRu2H1QUvdjoZB/view?usp=sharing

My error is:

E/flutter (17497): [ERROR:flutter/lib/ui/ui_dart_state.cc(209)] Unhandled Exception: type 'Null' is not a subtype of type 'String'
E/flutter (17497): #0      new Welcome.fromJson (package:getx_5_rest_api/models/product.dart:33:22)
E/flutter (17497): #1      welcomeFromJson.<anonymous closure> (package:getx_5_rest_api/models/product.dart:10:60)
E/flutter (17497): #2      MappedListIterable.elementAt (dart:_internal/iterable.dart:413:31)
E/flutter (17497): #3      ListIterator.moveNext (dart:_internal/iterable.dart:342:26)
E/flutter (17497): #4      new List.from (dart:core-patch/array_patch.dart:41:17)
E/flutter (17497): #5      welcomeFromJson (package:getx_5_rest_api/models/product.dart:10:5)
E/flutter (17497): #6      RemoteServices.fetchProducts (package:getx_5_rest_api/services/remote_service.dart:31:14)
E/flutter (17497): <asynchronous suspension>
E/flutter (17497): #7      ProductController.fetchProducts (package:getx_5_rest_api/controllers/product_controller.dart:21:20)
E/flutter (17497): <asynchronous suspension>
E/flutter (17497):

CodePudding user response：

I found your problem in the JSON response there is an image_link field but in your code inside the :

  factory Welcome.fromJson(Map<String, dynamic> json) => Welcome(
  name: json["name"],
  price: json['price'],
  imageLink: json['imageLink'].toString(),
  rating: json['rating']);

}

you are trying to get imageLink which doesn't exist in the JSON maps List, so it throws null, what exists is image_link and they are not the same so the solution is this : replace the fromJson method with this

      factory Welcome.fromJson(Map<String, dynamic> json) => Welcome(
       name: json["name"],
       price: json['price'],
       imageLink: json['image_link'].toString(),
       rating: json['rating']);
        }

it should now find it.

Hope this helps you.

CodePudding user response：

in line 22 in product model, you probably entered wrong property in the map, check the response from the API and make sure all the properties match in your fromMap() function

you should use GitHub to share your code, it'll be easier for others to help you when they can just browse the code as easy.