Skip to content
Generic BloC provider implementation
Branch: master
Clone or download
Latest commit e026e94 Apr 26, 2019

README.md

generic_bloc_provider

Build Status License: MIT Pub

A generic BloC Provider for your Flutter apps.

Getting Started

All your BloCs must extend the Bloc abstract class. This means that all of them should have a dispose method that will be executed whenever the life of the BloC comes to an end.

In this method, you should take care of closing all the sinks and resources.

Example of how to use it:

void main() => runApp(MyApp());

class MyApp extends StatelessWidget {
  @override
  Widget build(BuildContext context) {
    return BlocProvider(
      bloc: AppBloc(),
      child: MaterialApp(
        title: 'Yo Sleep',
        home: MainPage(),
        initialRoute: 'main',
        routes: {
          'main': (context) => MainPage(),
        },
      ),
    );
  }
}

class MainPage extends StatelessWidget {
  @override
  Widget build(BuildContext context) {
    final appBloc = BlocProvider.of<AppBloc>(context);
    return Scaffold(
      body: SafeArea(
        child: Column(
          children: <Widget>[
            Header(),
            RecordList(appBloc),
          ],
        ),
      ),
    );
  }
}

Attaching your context to the InheritedWidget

The BlocProvider class depends on InheritedWidget. Whenever you want to get your BloC, you can decide wether to attach the context of your widget to the InheritedWidget or not.

In order to control this behavior, the static method of has an optional boolean argument (which is true by default) which determines wether your context will be attached or not.

Basically, if you don't provide it or you just set it to true, inheritFromWidgetOfExactType will be used. If you set it to false then ancestorInheritedElementForWidgetOfExactType will be used instead.

Customizing the update policy

If you want to change the way updateShouldNotify behaves you have the option to provide a custom anonymous function to the BlocProvider constructor.

You will notice that there's an argument called updateShouldNotifyOverride which accepts a function receiving a BloC and the internal InheritedWidget:

bool Function(T bloc, _BlocProvider oldWidget);

This is the default implementation of the updateShouldNotify method:

@override
  bool updateShouldNotify(_BlocProvider oldWidget) =>
      updateShouldNotifyOverride != null
          ? updateShouldNotifyOverride(bloc, oldWidget)
          : oldWidget.bloc != bloc;
You can’t perform that action at this time.