CODEWITHSUNDEEP
flutterbuilder
M Imtiaz
M Imtiaz

Reputation: 33

Flutter "ChangeNotifierProxyProvider have an error. error: "The named parameter 'builder' isn't defined. "

main.dart file ChangeNotifierProxyProvider having issues builder method is not defined.

 ChangeNotifierProxyProvider<Auth, Orders>(
      builder: (ctx, auth, previousOrders) => Orders(
        auth.token,
        auth.userId,
        previousOrders == null ? [] : previousOrders.orders,
      ),
    ),

Upvotes: 3

Views: 2161

Answers (4)

HoseinGhanbari
HoseinGhanbari

Reputation: 1143

with provider: ^5.0.0 this also should work as expected

ChangeNotifierProxyProvider<Auth, Products>(
  create: (ctx) {
    return Products();
  },
  update: (ctx, auth, prev) {
    return Products()
      ..setAuthToken(auth.token ?? '')
      ..setItems(prev?.items ?? []);
  },
),

Upvotes: 0

Arun
Arun

Reputation: 76

ChangeNotifierProxyProvider<Auth, Products>(
      create: (_) => Products('', '', []),
      update: (_, auth, prevProducts) {
        return Products(
          auth.token,
          auth.userId,
          prevProducts == null ? [] : prevProducts.items,
        );
      },
    ),

Upvotes: 6

fcidic
fcidic

Reputation: 11

ChangeNotifierProvider supported builder parameter but migration from v3.x.0 to v4.0.0+ some parameters are changed and builder is one of them.

Instead of that the initialBuilder should be replaced by create.

builder of "proxy" providers should be replaced by update

builder of classical providers should be replaced by create.

Upvotes: 1

Viren V Varasadiya
Viren V Varasadiya

Reputation: 27137

Their is no argument like builder in ChangeNotifierProxyProvider, that’s why you are getting that error.

In ChangeNotifierProxyProvider you have to provide create, update and child.

Here, in create you can create your object and in update you can specify when to change provider's value, when notifier depends on some other model.

ChangeNotifierProxyProvider<MyModel, MyChangeNotifier>(
   create: (_) => MyChangeNotifier(),
   update: (_, myModel, myNotifier) => myNotifier
       ..update(myModel),
    child: ...
);

Upvotes: 1

Related Questions