ChangeNotifierProxyProvider 2 positional argument(s) expected in the parameter 'create'

Question

void main() async {
  WidgetsFlutterBinding.ensureInitialized();

  runApp(
    MultiProvider(
      providers: [
        ChangeNotifierProvider<Auth>(
          create: (_) => Auth(),
        ),
        ChangeNotifierProxyProvider<Auth, Products>(
          create: (ctx) => Products(),
          update: (ctx, value, previousProducts) => Products(value.idToken,
              previousProducts == null ? [] : previousProducts.productsList),
        ),
      ],
      child: MyApp(),
    ),
  );
}

in this line 'create: (ctx) => Products(),' Products() expecte 2 argument and i don't know how to fix this error where Products class is like this :

class Products with ChangeNotifier {
  List<Product> productsList = [];

  final String authToken;
  Products(this.authToken, this.productsList);

Answer 1

I think add empty String and list to Products provider ,this resolves your problems. Add like this,

create:(ctx)=> Products('',[]),

Answer 2

Because your constructor requires 2 arguments, namely authToken and productsList.

You can remove the arguments from the constructor, make them nullable, or assign them default values like this:

class Products with ChangeNotifier {
  List<Product> productsList = [];

  final String authToken;
  Products({this.authToken = "someDefaultValue", this.productsList =  const []});
}