when i run my app i get this error :

Unhandled Exception: type 'Future<dynamic>' is not a subtype of type 'ProductModel'

this is occurred when i use this method:

  List<ProductModel> items2 = [];
  FetchItems2() async {
    Api ap1 = Api();
    items2.add(ap1.GetProduct());
  }

my Api class is :

class Api{
  String BasicUrl = "my link";
  var headers = {
    'Authorization':
    'some thing',
  };

   GetProduct()  async {
    final url = Uri.parse('${BasicUrl}products');

    http.Response ProResponse = await http.get(url, headers: headers);
    ProResponse.headers.addAll(headers);
    List<ProductModel> items2 = [];
    if (ProResponse.statusCode == 200) {
        var decoded = (jsonDecode(ProResponse.body));
        if (decoded.length == 0) {
          print("null2");
        } else {
          for (var i in decoded) {
            var images = (i["images"][0]["src"]);
            var id = (i["id"]);
            var description = (i["description"]);
            var price = (i["price"]);
            var regularprice = (i["regular_price"]);
            var name = (i["name"]);

            var productItem = ProductModel(
                images: images ??=
                "a link",
                name: name,
                description: description,
                price: price ?? "",
                regular_price: regularprice ?? "",
                id: id);
            items2.add(productItem);
          }
        }
        return items2;
    } else {
      print(ProResponse.reasonPhrase);
      return items2;
    }
  }

}

and finally my ProductModel class is:

class ProductModel{
  late final  int id;
  late final  String name;
  late final String regular_price;
  late final String price;
  late final String description;
  late final String images;



  ProductModel({ required this.id,required this.name,
    required this.regular_price,
    required this.price,
    required this.description,required this.images});

  factory ProductModel.fromJson(Map<String,dynamic> json){
    final name = json["name"];
    final id = json ["id"];
    final regular_price = json["regular_price"];
    final price = json["price"];
    final description = json["description"];
    final images = json["images"];
    return ProductModel(id: id, name: name,
        regular_price: regular_price,
        price: price,
        description: description, images: images);
  }
}

console says GetProduct method is dynamic and it should be the type of ProductModel and i don't know how to fix it.

note : also i tried this:

 List<ProductModel>  GetProduct()  async {

but it doesn't work. Could someone please help me please ? it's so important and i have to fix it.

CodePudding user response：

Your async functions should always return a Future. So in this instance you don't want

ProductModel GetProduct() async {}

but rather

Future<ProductModel> getProduct() async {}

And then you can load the products and add them to the list

final items2 = <ProductModel>[];
Future<void> FetchItems2() async {
  final ap1 = Api();
  final product = await ap1.getProduct();
  items2.add(product);
}

CodePudding user response：

Actually, You don't have a method type by default it will Future dynamic when it's async

• First, we will change it to Future of ProductModel
• Second, You used for loop for getting a list of data to ProductModel it is not a good practice, use the following code for returning List of ProductModel

Future GetProduct() async { final url = Uri.parse('${BasicUrl}products');

http.Response ProResponse = await http.get(url, headers: headers);
ProResponse.headers.addAll(headers);



 if (ProResponse.statusCode == 200) {
        var decoded = jsonDecode(ProResponse.body);
    if (decoded.length == 0) {
      print("null2");
    } else {
      return decoded .map((user) => ProductModel.fromJson(user)).toList(); 
      }
    }
    //return items2;
} else {
  print(ProResponse.reasonPhrase);
 // return items2;
}

}