flutter_bloc with flutter_hooks

main.dart

import 'package:flutter/material.dart';
import 'package:bloc/bloc.dart';
import 'package:flutter_bloc/flutter_bloc.dart';
import 'package:flutter_hooks/flutter_hooks.dart';

enum CounterEvent { increment, decrement }

class CounterBloc extends Bloc<CounterEvent, int> {
  @override
  int get initialState => 0;

  @override
  Stream<int> mapEventToState(
    CounterEvent event,
  ) async* {
    switch (event) {
      case CounterEvent.increment:
        yield currentState + 1;
        break;
      case CounterEvent.decrement:
        yield currentState - 1;
        break;
    }
  }
}

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

class MyApp extends StatelessWidget {
  @override
  Widget build(BuildContext context) {
    return MaterialApp(
      routes: {
        '/': (context) => MyPage(),
        '/details': (context) => MyDetailsPage(),
      },
      initialRoute: '/',
    );
  }
}

class MyPage extends HookWidget {
  @override
  Widget build(BuildContext context) {
    final _counterBloc = useBloc(() => CounterBloc());

    return Scaffold(
      appBar: AppBar(
        title: Text('Bloc Hook'),
        actions: <Widget>[
          IconButton(
            icon: Icon(Icons.navigate_next),
            onPressed: () {
              Navigator.of(context).pushReplacementNamed('/details');
            },
          )
        ],
      ),
      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(
              child: Icon(Icons.add),
              onPressed: () {
                _counterBloc.dispatch(CounterEvent.increment);
              },
            ),
          ),
          Padding(
            padding: EdgeInsets.symmetric(vertical: 5.0),
            child: FloatingActionButton(
              child: Icon(Icons.remove),
              onPressed: () {
                _counterBloc.dispatch(CounterEvent.decrement);
              },
            ),
          ),
        ],
      ),
    );
  }
}

class MyDetailsPage extends StatelessWidget {
  @override
  Widget build(BuildContext context) {
    return Scaffold(
      appBar: AppBar(title: Text('Details')),
      body: Center(
        child: RaisedButton(
          child: Text('Go Back'),
          onPressed: () {
            Navigator.of(context).pushReplacementNamed('/');
          },
        ),
      ),
    );
  }
}

T useBloc<T extends Bloc>(T Function() blocFactory,
    [List<Object> keys = const <dynamic>[]]) {
  return Hook.use(_BlocHook(
    blocFactory,
    keys: keys,
  ));
}

class _BlocHook<T extends Bloc> extends Hook<T> {
  final T Function() blocFactory;

  const _BlocHook(
    this.blocFactory, {
    List<Object> keys = const <dynamic>[],
  })  : assert(blocFactory != null),
        assert(keys != null),
        super(keys: keys);

  @override
  _BlocHookState<T> createState() => _BlocHookState<T>();
}

class _BlocHookState<T extends Bloc> extends HookState<T, _BlocHook<T>> {
  T bloc;

  @override
  void initHook() {
    super.initHook();
    bloc = hook.blocFactory();
  }

  @override
  T build(BuildContext context) {
    return bloc;
  }

  @override
  void dispose() {
    bloc.dispose();
    super.dispose();
  }
}