refactor(flutter_login): use RepositoryProvider + dispose (#4365)

Author: yerzhant

examples/flutter_login/lib/app.dart

@@ -7,39 +7,24 @@ import 'package:flutter_login/login/login.dart';
 import 'package:flutter_login/splash/splash.dart';
 import 'package:user_repository/user_repository.dart';
 
-class App extends StatefulWidget {
+class App extends StatelessWidget {
   const App({super.key});
 
-  @override
-  State<App> createState() => _AppState();
-}
-
-class _AppState extends State<App> {
-  late final AuthenticationRepository _authenticationRepository;
-  late final UserRepository _userRepository;
-
-  @override
-  void initState() {
-    super.initState();
-    _authenticationRepository = AuthenticationRepository();
-    _userRepository = UserRepository();
-  }
-
-  @override
-  void dispose() {
-    _authenticationRepository.dispose();
-    super.dispose();
-  }
-
   @override
   Widget build(BuildContext context) {
-    return RepositoryProvider.value(
-      value: _authenticationRepository,
+    return MultiRepositoryProvider(
+      providers: [
+        RepositoryProvider(
+          create: (_) => AuthenticationRepository(),
+          dispose: (repository) => repository.dispose(),
+        ),
+        RepositoryProvider(create: (_) => UserRepository()),
+      ],
       child: BlocProvider(
         lazy: false,
-        create: (_) => AuthenticationBloc(
-          authenticationRepository: _authenticationRepository,
-          userRepository: _userRepository,
+        create: (context) => AuthenticationBloc(
+          authenticationRepository: context.read<AuthenticationRepository>(),
+          userRepository: context.read<UserRepository>(),
         )..add(AuthenticationSubscriptionRequested()),
         child: const AppView(),
       ),

packages/flutter_bloc/README.md

@@ -426,6 +426,16 @@ context.read<RepositoryA>();
 RepositoryProvider.of<RepositoryA>(context)
 ```
 
+Repositories that manage resources which must be disposed can do so via the `dispose` callback:
+
+```dart
+RepositoryProvider(
+  create: (context) => RepositoryA(),
+  dispose: (context, repository) => repository.close(),
+  child: ChildA(),
+);
+```
+
 ### MultiRepositoryProvider
 
 **MultiRepositoryProvider** is a Flutter widget that merges multiple `RepositoryProvider` widgets into one.

packages/flutter_bloc/lib/src/bloc_provider.dart

@@ -5,7 +5,7 @@ import 'package:provider/provider.dart';
 import 'package:provider/single_child_widget.dart';
 
 /// {@template bloc_provider}
-/// Takes a [Create] function that is responsible for
+/// Takes a `create` function that is responsible for
 /// creating the [Bloc] or [Cubit] and a [child] which will have access
 /// to the instance via `BlocProvider.of(context)`.
 /// It is used as a dependency injection (DI) widget so that a single instance
@@ -19,7 +19,7 @@ import 'package:provider/single_child_widget.dart';
 /// ```
 ///
 /// It automatically handles closing the instance when used with [Create].
-/// By default, [Create] is called only when the instance is accessed.
+/// By default, `create` is called only when the instance is accessed.
 /// To override this behavior, set [lazy] to `false`.
 ///
 /// ```dart
@@ -35,7 +35,7 @@ class BlocProvider<T extends StateStreamableSource<Object?>>
     extends SingleChildStatelessWidget {
   /// {@macro bloc_provider}
   const BlocProvider({
-    required Create<T> create,
+    required T Function(BuildContext context) create,
     Key? key,
     this.child,
     this.lazy = true,
@@ -52,7 +52,7 @@ class BlocProvider<T extends StateStreamableSource<Object?>>
   ///
   /// A new [Bloc] or [Cubit] should not be created in `BlocProvider.value`.
   /// New instances should always be created using the
-  /// default constructor within the [Create] function.
+  /// default constructor within the `create` function.
   ///
   /// ```dart
   /// BlocProvider.value(
@@ -76,7 +76,7 @@ class BlocProvider<T extends StateStreamableSource<Object?>>
   /// Defaults to `true`.
   final bool lazy;
 
-  final Create<T>? _create;
+  final T Function(BuildContext context)? _create;
 
   final T? _value;
 

packages/flutter_bloc/lib/src/repository_provider.dart

@@ -2,7 +2,7 @@ import 'package:flutter/widgets.dart';
 import 'package:provider/provider.dart';
 
 /// {@template repository_provider}
-/// Takes a [Create] function that is responsible for creating the repository
+/// Takes a `create` function that is responsible for creating the repository
 /// and a `child` which will have access to the repository via
 /// `RepositoryProvider.of(context)`.
 /// It is used as a dependency injection (DI) widget so that a single instance
@@ -28,14 +28,15 @@ import 'package:provider/provider.dart';
 class RepositoryProvider<T> extends Provider<T> {
   /// {@macro repository_provider}
   RepositoryProvider({
-    required Create<T> create,
+    required T Function(BuildContext context) create,
+    void Function(T value)? dispose,
     Key? key,
     Widget? child,
     bool? lazy,
   }) : super(
           key: key,
           create: create,
-          dispose: (_, __) {},
+          dispose: (_, value) => dispose?.call(value),
           child: child,
           lazy: lazy,
         );

packages/flutter_bloc/test/repository_provider_test.dart

@@ -356,5 +356,47 @@ void main() {
       final counterText = counterFinder.evaluate().first.widget as Text;
       expect(counterText.data, '0');
     });
+
+    testWidgets('calls dispose callback when disposed', (tester) async {
+      var disposeCalled = false;
+      await tester.pumpWidget(
+        MaterialApp(
+          home: Scaffold(
+            body: RepositoryProvider<Repository>(
+              create: (_) => const Repository(0),
+              dispose: (repository) {
+                disposeCalled = true;
+                expect(repository.data, equals(0));
+              },
+              child: Builder(
+                builder: (context) => Text(
+                  '${context.read<Repository>().data}',
+                  key: const Key('value_data'),
+                ),
+              ),
+            ),
+            floatingActionButton: Builder(
+              builder: (context) => FloatingActionButton(
+                onPressed: () => Navigator.of(context).pop(),
+                child: const Icon(Icons.remove),
+              ),
+            ),
+          ),
+        ),
+      );
+      final repositoryFinder = find.byKey(const Key('value_data'));
+      expect(repositoryFinder, findsOneWidget);
+
+      final repositoryText = repositoryFinder.evaluate().first.widget as Text;
+      expect(repositoryText.data, '0');
+
+      final fabFinder = find.byType(FloatingActionButton);
+      expect(fabFinder, findsOneWidget);
+
+      expect(disposeCalled, isFalse);
+      await tester.tap(fabFinder);
+      await tester.pumpAndSettle();
+      expect(disposeCalled, isTrue);
+    });
   });
 }