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@felangel felangel/main.dart
Created Dec 22, 2018

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Sharing Bloc Across Routes
import 'dart:async';
import 'package:flutter/material.dart';
import 'package:bloc/bloc.dart';
import 'package:flutter_bloc/flutter_bloc.dart';
class SimpleBlocDelegate extends BlocDelegate {
@override
void onTransition(Transition transition) {
print(transition.toString());
}
}
void main() {
BlocSupervisor().delegate = SimpleBlocDelegate();
runApp(MyApp());
}
class MyApp extends StatefulWidget {
@override
State<StatefulWidget> createState() => MyAppState();
}
class MyAppState extends State<MyApp> {
final CounterBloc _counterBloc = CounterBloc();
@override
Widget build(BuildContext context) {
return BlocProvider<CounterBloc>(
bloc: _counterBloc,
child: MaterialApp(
title: 'Flutter Demo',
routes: {
'/': (BuildContext context) => CounterPage(),
'/otherCounter': (BuildContext context) => OtherCounterPage(),
},
initialRoute: '/',
),
);
}
@override
void dispose() {
_counterBloc.dispose();
super.dispose();
}
}
class CounterPage extends StatelessWidget {
@override
Widget build(BuildContext context) {
final CounterBloc _counterBloc = BlocProvider.of<CounterBloc>(context);
return Scaffold(
appBar: AppBar(
title: Text('Counter'),
actions: <Widget>[
IconButton(
icon: Icon(Icons.navigate_next),
onPressed: () {
Navigator.of(context).pushNamed('/otherCounter');
},
)
],
),
body: BlocBuilder<CounterEvent, int>(
bloc: _counterBloc,
builder: (BuildContext context, int count) {
return Center(
child: Text(
'$count',
style: TextStyle(fontSize: 24.0),
),
);
},
),
floatingActionButton: Column(
crossAxisAlignment: CrossAxisAlignment.end,
mainAxisAlignment: MainAxisAlignment.end,
children: <Widget>[
Padding(
padding: EdgeInsets.symmetric(vertical: 5.0),
child: FloatingActionButton(
heroTag: 0,
child: Icon(Icons.add),
onPressed: () {
_counterBloc.dispatch(Increment());
},
),
),
Padding(
padding: EdgeInsets.symmetric(vertical: 5.0),
child: FloatingActionButton(
heroTag: 1,
child: Icon(Icons.remove),
onPressed: () {
_counterBloc.dispatch(Decrement());
},
),
),
],
),
);
}
}
class OtherCounterPage extends StatelessWidget {
@override
Widget build(BuildContext context) {
final CounterBloc _counterBloc = BlocProvider.of<CounterBloc>(context);
return Scaffold(
appBar: AppBar(title: Text('Other Counter Page')),
body: BlocBuilder<CounterEvent, int>(
bloc: _counterBloc,
builder: (BuildContext context, int count) {
return Center(
child: Text(
'$count',
style: TextStyle(fontSize: 24.0),
),
);
},
),
floatingActionButton: Column(
crossAxisAlignment: CrossAxisAlignment.end,
mainAxisAlignment: MainAxisAlignment.end,
children: <Widget>[
Padding(
padding: EdgeInsets.symmetric(vertical: 5.0),
child: FloatingActionButton(
heroTag: 2,
child: Icon(Icons.add),
onPressed: () {
_counterBloc.dispatch(Increment());
},
),
),
Padding(
padding: EdgeInsets.symmetric(vertical: 5.0),
child: FloatingActionButton(
heroTag: 3,
child: Icon(Icons.remove),
onPressed: () {
_counterBloc.dispatch(Decrement());
},
),
),
],
),
);
}
}
abstract class CounterEvent {}
class Increment extends CounterEvent {
@override
String toString() => 'Increment';
}
class Decrement extends CounterEvent {
@override
String toString() => 'Decrement';
}
class CounterBloc extends Bloc<CounterEvent, int> {
@override
int get initialState => 0;
@override
Stream<int> mapEventToState(int currentState, CounterEvent event) async* {
if (event is Increment) {
yield currentState + 1;
}
if (event is Decrement) {
yield currentState - 1;
}
}
}
@ThinkDigitalSoftware

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commented Dec 22, 2018

@felangel, I haven't had to use this yet, but why is it an issue sharing a bloc across routes?

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