gistfile1.txt

import 'package:flutter/material.dart';
import 'package:provider/provider.dart';
import 'package:rxdart/rxdart.dart';

void main() {
  runApp(MyApp());
}

class MyApp extends StatelessWidget {
  // This widget is the root of your application.
  @override
  Widget build(BuildContext context) {
    return MultiProvider(
      providers: [
        Provider<Store>(
          lazy: false,
          create: (context) => Store(),
        ),
        Provider<SeededStore>(
          lazy: false,
          create: (context) => SeededStore(),
        ),
        StreamProvider<SeededCount>(
          create: (context) =>
              Provider.of<SeededStore>(context, listen: false).counter,
        ),
        StreamProvider<Count>(
          create: (context) =>
              Provider.of<Store>(context, listen: false).counter,
        ),
      ],
      child: MaterialApp(
        home: BehaviourSubjectExample(),
      ),
    );
  }
}

//UI
class BehaviourSubjectExample extends StatelessWidget {
  @override
  Widget build(BuildContext context) {
    return Scaffold(
      body: Column(
        mainAxisAlignment: MainAxisAlignment.center,
        children: <Widget>[
          ListTile(
            title: Text("Counter"),
            onTap: () => Navigator.push(
                context, MaterialPageRoute(builder: (context) => CountPage())),
          ),
          ListTile(
            title: Text("Seeded Counter"),
            onTap: () => Navigator.push(context,
                MaterialPageRoute(builder: (context) => SeededCountPage())),
          ),
        ],
      ),
    );
  }
}

class SeededCountPage extends StatelessWidget {
  @override
  Widget build(BuildContext context) {
    return Consumer<SeededCount>(
      builder: (_, count, __) {
        if (count == null) {
          print(" SEEDED COUNT IS NULL");
          return Container();
        }
        return Scaffold(
          body: Center(
            child: Text(count.counter.toString()),
          ),
          floatingActionButton: FloatingActionButton(
            child: Icon(Icons.add),
            onPressed: () => IncreaseCount.of(context).increaseSeededCount(),
          ),
        );
      },
    );
  }
}

class CountPage extends StatelessWidget {
  @override
  Widget build(BuildContext context) {
    return Consumer<Count>(
      builder: (_, count, __) {
        if (count == null) {
          print(" COUNT IS NULL");
          return Container();
        }
        return Scaffold(
          body: Center(
            child: Text(count.counter.toString()),
          ),
          floatingActionButton: FloatingActionButton(
            child: Icon(Icons.add),
            onPressed: () => IncreaseCount.of(context).increaseCount(),
          ),
        );
      },
    );
  }
}

//Stores
class SeededStore {
  BehaviorSubject<SeededCount> counter = BehaviorSubject.seeded(SeededCount(0));
  void dispose() => counter.close();

  void increaseSeededCount() {
    counter.add(SeededCount(counter.value.counter + 1));
  }
}

class Store {
  BehaviorSubject<Count> counter = BehaviorSubject();
  void dispose() => counter.close();

  Store() {
    Future.delayed(Duration(milliseconds: 300), () {
      counter.add(Count(0));
    });
  }

  void increaseCount() {
    counter.add(Count(counter.value.counter + 1));
  }
}

//Observables
class SeededCount {
  final int counter;
  SeededCount(this.counter);
}

class Count {
  final int counter;
  Count(this.counter);
}

//Action
class IncreaseCount {
  final Store _store;
  final SeededStore _seededStore;

  IncreaseCount(this._store, this._seededStore);

  factory IncreaseCount.of(BuildContext context) => IncreaseCount(
        Provider.of(context, listen: false),
        Provider.of(context, listen: false),
      );

  void increaseCount() => _store.increaseCount();
  void increaseSeededCount() => _seededStore.increaseSeededCount();
}