https://github.com/mono0926/bloc_provider
Provides bloc to descendant widget (O(1)), and the bloc is disposed appropriately by state that the bloc_provider holds internally.
https://github.com/mono0926/bloc_provider
bloc business-logic-component dart flutter inherited-widget lifecycle
Last synced: 9 months ago
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Provides bloc to descendant widget (O(1)), and the bloc is disposed appropriately by state that the bloc_provider holds internally.
- Host: GitHub
- URL: https://github.com/mono0926/bloc_provider
- Owner: mono0926
- License: mit
- Created: 2018-11-29T06:52:27.000Z (over 7 years ago)
- Default Branch: main
- Last Pushed: 2022-08-16T00:54:48.000Z (over 3 years ago)
- Last Synced: 2025-04-07T19:21:17.113Z (11 months ago)
- Topics: bloc, business-logic-component, dart, flutter, inherited-widget, lifecycle
- Language: Dart
- Homepage: https://pub.dev/packages/bloc_provider
- Size: 278 KB
- Stars: 115
- Watchers: 12
- Forks: 17
- Open Issues: 4
-
Metadata Files:
- Readme: README.md
- Changelog: CHANGELOG.md
- License: LICENSE
Awesome Lists containing this project
README
# bloc_provider [](https://codemagic.io/apps/5c07297ae5d85c000decbd7a/5c0b461ee3b238001782269a/latest_build)
Provides BLoC(Business Logic Component) to descendant widget (O(1)), and the bloc is disposed automatically by the state which the bloc_provider holds internally.
## Recommended other packages
`bloc_provider` was one of the good choice for BLoC pattern until early 2019, but I now recommend to use these instead.
- [provider](https://pub.dev/packages/provider)
- [disposable_provider](https://pub.dev/packages/disposable_provider)
- Thin wrapper of Provider and it calls dispose automatically.
- [bloc](https://pub.dev/packages/bloc)
- [riverpod](https://pub.dev/packages/riverpod)
`bloc_provider` will now be minimally maintained.
## Usage
#### 1. Define some BLoC like this:
```dart
class CounterBloc implements Bloc {
final _countController = BehaviorSubject.seeded(0);
final _incrementController = PublishSubject();
CounterBloc() {
_incrementController
.scan((sum, _v, _i) => sum + 1, 0)
.pipe(_countController);
}
ValueStream get count => _countController;
Sink get increment => _incrementController.sink;
@override
void dispose() async {
await _incrementController.close();
await _countController.close();
}
}
```
#### 2. Provide the bloc by using BlocProvider and access the bloc at subtree:
```dart
void main() => runApp(
// Create and provide the bloc.
BlocProvider(
creator: (_context, _bag) => CounterBloc(),
child: App(),
),
);
class App extends StatelessWidget {
@override
Widget build(BuildContext context) {
// Access the bloc with O(1) computation complexity.
final bloc = BlocProvider.of(context);
return MaterialApp(
home: Scaffold(
body: Center(
child: StreamBuilder(
stream: bloc.count,
initialData: bloc.count.value,
builder: (context, snap) => Text(
'count: ${snap.data}',
style: Theme.of(context).textTheme.title,
),
),
),
floatingActionButton: FloatingActionButton(
child: const Icon(Icons.add),
onPressed: () => bloc.increment.add(null),
),
),
);
}
}
```
- Computational complexity of `of` method, which is used for accessing the bloc is `O(1)`.
- `of` method can be also called at [State](https://docs.flutter.io/flutter/widgets/State-class.html)'s [initState](https://docs.flutter.io/flutter/widgets/State/initState.html).
- Provided bloc will be disposed when the inner state is disposed 👍
## Examples
- https://github.com/mono0926/bloc_provider/tree/master/example
- [mono0926/wdb106-flutter](https://github.com/mono0926/wdb106-flutter)
- [TaskShare/taskshare-flutter](https://github.com/TaskShare/taskshare-flutter)
## Technical explanation
- [Flutter の BLoC(Business Logic Component)のライフサイクルを正確に管理して提供する Provider パッケージの解説](https://medium.com/flutter-jp/bloc-provider-70e869b11b2f)
- Japanese only, currently🙇🇯🇵
## Features and bugs
Please file feature requests and bugs at the [issue tracker][tracker].
[tracker]: https://github.com/mono0926/bloc_provider/issues