Version: 8.5.0

Working with arguments

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

In the next example to create a new instance of LoginController we needs 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/ui.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 you can create yourn own widget using PageWithArgumentsWidget class.

import 'package:flutter/material.dart';
import 'package:flutter_meedu/meedu.dart';
import 'package:flutter_meedu/ui.dart';

final loginProvider = SimpleProvider(
  (ref) => LoginController(ref.arguments),
);

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

  @override
  void onInit(RouteSettings settings) {
    /// you can use settings to get data passed as an argument
    /// using Navigator.pushName(context,'route-name', arguments: data);
    loginProvider.setArguments(settings.arguments);
  }

  @override
  Widget build(BuildContext context) {
    return Scaffold(
      .
      .
      .
    );
  }
}

success

Since flutter_meedu:^5.1.0 if you are using the meedu's router module to navigate in your app you can get your arguments without BuildContext and you can directly use them in your providers. With this you don't need a PageWithArgumentsWidget to pass route arguments to your providers.

/// also you can pass directly the route arguments to your controllers
final loginProvider = SimpleProvider(
  (_) => LoginController(router.arguments as String),
);

or

/// if you need to write unit or widget testing
/// you can use the [overrideProvider] method
setUp((){
  loginProvider.overrideProvider(
    (_) => LoginController(mockedInitialValue),
  );
});