Version: 3.x.x

Working with arguments

Some times you need to pass a initial values to your SimpleNotifier or StateNotifier in that cases you can sue the setArguments method of your provider.

In the next example to create a new instance of LoginController we need a initial email value

class LoginController extends StateNotifier<LoginState> {
  LoginController(String initialEmail)
      : super(
          LoginState(email: initialEmail, password: ''),
        );
}

Next you can use the ref parameter of your callback generator to get the arguments passed in the initState method.

final loginProvider = StateProvider<LoginController, LoginState>(
  (ref) => LoginController(ref.arguments ?? ''),
);


class LoginPage extends StatefulWidget {
  const LoginPage({Key? key}) : super(key: key);

  @override
  _LoginPageState createState() => _LoginPageState();
}

class _LoginPageState extends State<LoginPage> {
  @override
  void initState() {
    super.initState();
    // you must set your arguments
    // before call loginProvider.read or before use watch(loginProvider)
    loginProvider.setArguments("initial@email.com");
  }

  @override
  Widget build(BuildContext context) {
    // YOUR CODE HERE
  }
}

WARNING

If you are using ModalRoute.of(context) in your build method or in the routes parameter of one MaterialApp to get arguments that was passed by Navigator.push, Navigator.pushName, etc and next you use Navigator.pushNamedAndRemoveUntil or Navigator.pushNameAndRemoveUntil to navigate to a new Route removing multiples routes from the Stack the ModalRoute.of(context) will rebuild the route before remove it and it could be a problem with a provider because that could be recreated a disposed provider.

In that cases you could use the PageWithArguments widget to avoid the recreation of a disposed provider.

import 'package:flutter/material.dart';
import 'package:flutter_meedu/page.dart';

class ProductDetail extends StatelessWidget {
  const ProductDetail({Key? key}) : super(key: key);

  @override
  Widget build(BuildContext context) {
    return PageWithArguments(
      onReady: (RouteSettings settings) {
        final arguments = settings.arguments;
        productProvider.setArguments(arguments);
      },
     builder: (context) => Scaffold(...) ,
    );
  }
}


// or in your MaterialApp
MaterialApp(
  initialRoute: Routes.SPLASH,
  navigatorObservers: [
    router.observer,
  ],
  routes: {
    'product-detail': (_) => PageWithArguments(
      onReady: (RouteSettings settings) {
         final arguments = settings.arguments;
         tabsProvider.setArguments(arguments);
      },
      builder: (_) => ProductPage(),
    ),
  },
) 