flutter_bloc_pattern #

Base class, BLoC provider and rxdart builder for BLoC pattern in Flutter.

Getting Started #

1. Add this to your package's pubspec.yaml file #

dependencies:
  flutter_bloc_pattern: <latest_version>

2. Implements BaseBloc #

import 'package:disposebag/disposebag.dart';
import 'package:flutter_bloc_pattern/flutter_bloc_pattern.dart';
import 'package:rxdart_ext/rxdart_ext.dart';

class MyBloc implements BaseBloc {
  StateStream<String> get stream;

  @override
  void dispose() {}
}

3. Consume BLoC #

 final bloc = BlocProvider.of<MyBloc>(context);
 return RxStreamBuilder<String>(
  stream: bloc.stream,
  builder: (context, state) {
    return ...;
  },
);

Example: A port of the standard "Counter Button" example from Flutter #

1. File counter_bloc.dart #

import 'dart:async';

import 'package:disposebag/disposebag.dart';
import 'package:flutter_bloc_pattern/flutter_bloc_pattern.dart';
import 'package:rxdart_ext/rxdart_ext.dart';

class CounterBloc extends DisposeCallbackBaseBloc {
  /// Inputs
  final VoidAction increment;

  /// Outputs
  final StateStream<int> state;

  CounterBloc._({
    required VoidAction dispose,
    required this.increment,
    required this.state,
  }) : super(dispose);

  factory CounterBloc() {
    final incrementController = StreamController<void>();

    final state$ = incrementController.stream
        .scan<int>((acc, _, __) => acc + 1, 0)
        .publishState(0);

    return CounterBloc._(
      dispose: DisposeBag([incrementController, state$.connect()]).dispose,
      increment: incrementController.addNull,
      state: state$,
    );
  }
}

2. File main.dart #

import 'package:example/bloc.dart';
import 'package:flutter/material.dart';
import 'package:flutter_bloc_pattern/flutter_bloc_pattern.dart';

class TextCounter1 extends StatelessWidget {
  const TextCounter1({super.key});

  @override
  Widget build(BuildContext context) {
    final bloc = BlocProvider.of<CounterBloc>(context);

    return RxStreamBuilder<int>(
      stream: bloc.state,
      builder: (context, state) {
        return Text(
          'COUNTER 1: $state',
          style: Theme.of(context).textTheme.titleLarge,
        );
      },
    );
  }
}

class IncrementButton extends StatelessWidget {
  const IncrementButton({super.key});

  @override
  Widget build(BuildContext context) {
    final bloc = context.bloc<CounterBloc>();

    return FloatingActionButton(
      onPressed: bloc.increment,
      tooltip: 'Increment',
      child: const Icon(Icons.add),
    );
  }
}