Please, check out: https://github.com/leocavalcante/observable_state

Flutter-ReduRx

Flutter bindings for ReduRx.

It provides a Provider as an InheritedWidget so you can reach the ReduRx Store wherever you have a BuildContext.
It also has a Connect Widget so you can grab a few parts of the State (sub-state/props) and it will automatically recall builder whenever only this little connected part of the State has changed preventing unnecessary rebuilds.

Getting started

• Tutorial: Handling State in Flutter with ReduRx

API

Connect

• convert: State -> Props - A function used by map to transform the state in a sub-state/props.
• where: Props oldProps, Props newProps -> bool - A function to explicitly filter when the builder should be called.
• builder: Props newProps -> Widget - A function that receives the sub-state/props and returns a Widget.

Connect<State, String>(
  convert: (state) => state.title,
  where: (oldTitle, newTitle) => newTitle != oldTitle,
  builder: (title) => Text(title),
)

Example

class Example1 extends StatelessWidget {
  @override
  Widget build(BuildContext context) {
    return Scaffold(
        appBar: AppBar(
          title: Connect<AppState, String>(
            convert: (state) => state.title,
            where: (prev, next) => next != prev,
            builder: (title) {
              print('Building title: $title');
              return Text(title);
            },
          ),
        ),
        body: Center(
          child: Column(
            mainAxisAlignment: MainAxisAlignment.center,
            children: <Widget>[
              Text('You have pushed the button this many times:'),
              Connect<AppState, String>(
                convert: (state) => state.count.toString(),
                where: (prev, next) => next != prev,
                builder: (count) {
                  print('Building counter: $count');
                  return Text(count,
                      style: Theme.of(context).textTheme.display1);
                },
              ),
            ],
          ),
        ),
        floatingActionButton: FloatingActionButton(
          onPressed: () => Provider.dispatch<AppState>(context, Increment()),
          tooltip: 'Increment',
          child: Icon(Icons.add),
        ));
  }
}

Handling null values

By default, Connect will only call builder if the props aren't null, otherwise it renders an empty Container. If you want to handle null values by youself, set the nullable property to true:

Connect<State, String>(
  convert: (state) => state.title,
  where: (oldTitle, newTitle) => newTitle != oldTitle,
  builder: (title) => Text(title),
  nullable: true,
)

ConnectWidget

Behaves just like Connect but is extendable. Very useful when you see yourself in a Widget with a lot of Connects.

Example

class _Props {
  _Props({
    @required this.title,
    @required this.count,
  });

  final String title;
  final String count;
}

class Example2 extends ConnectWidget<AppState, _Props> {
  @override
  _Props convert(AppState state) {
    return _Props(title: state.title, count: state.count.toString());
  }

  @override
  Widget build(BuildContext context, _Props props) {
    return Scaffold(
      appBar: AppBar(title: Text(props.title)),
      body: Center(
        child: Column(
          mainAxisAlignment: MainAxisAlignment.center,
          children: <Widget>[
            Text('You have pushed the button this many times:'),
            Text(props.count, style: Theme.of(context).textTheme.display1),
          ],
        ),
      ),
      floatingActionButton: FloatingActionButton(
        onPressed: () => dispatch(context, Increment()),
        tooltip: 'Increment',
        child: Icon(Icons.add),
      ),
    );
  }
}

Provider

• store - A ReduRx Store.
• child - Your application's Widget.
• static dispatch<S>(BuildContext, ActionType) - Helper to call dispatch on the Provider's context Store.

Provider(
  store: Store<State>(State('Initial title')),
  child: App(),
)

Provider.dispatch<State>(context, ChangeTitle('New title'));

For a better understanding of dispatch and ActionType head to ReduRx.

Example

import 'package:flutter/material.dart' hide State;
import 'package:flutter_redurx/flutter_redurx.dart';

class State {
  State({this.title, this.count});
  final String title;
  final int count;
}

class Increment extends Action<State> {
  @override
  State reduce(State state) =>
      State(title: state.title, count: state.count + 1);
}

void main() {
  final store =
      Store<State>(State(title: 'Flutter-ReduRx Demo Title', count: 0));
  runApp(Provider(store: store, child: MyApp()));
}

class MyApp extends StatelessWidget {
  @override
  Widget build(BuildContext context) {
    return MaterialApp(
      title: 'Flutter-ReduRx Demo',
      theme: ThemeData(
        primarySwatch: Colors.pink,
      ),
      home: MyHomePage(),
    );
  }
}

class MyHomePage extends StatelessWidget {
  @override
  Widget build(BuildContext context) {
    return Scaffold(
        appBar: AppBar(
          title: Connect<State, String>(
            convert: (state) => state.title,
            where: (prev, next) => next != prev,
            builder: (title) => Text(title ?? ''),
          ),
        ),
        body: Center(
          child: Column(
            mainAxisAlignment: MainAxisAlignment.center,
            children: <Widget>[
              Text('You have pushed the button this many times:'),
              Connect<State, String>(
                convert: (state) => state.count.toString(),
                where: (prev, next) => next != prev,
                builder: (count) => Text(count ?? '',
                    style: Theme.of(context).textTheme.display1),
              ),
            ],
          ),
        ),
        floatingActionButton: FloatingActionButton(
          onPressed: () => Provider.dispatch<State>(context, Increment()),
          tooltip: 'Increment',
          child: Icon(Icons.add),
        ));
  }
}