flock 0.0.11

Coordinate Flutter widgets' states with event sourcing. What would happen if our Redux store has no reducers, no state but only actions?

example/lib/main.dart

import 'package:flock/flock.dart';
import 'package:flutter/material.dart';
import 'package:sensors/sensors.dart';

void main() => runApp(MyApp());

class MyApp extends StatelessWidget {
  // This widget is the root of your application.
  final store = createStore<AppEvent>([
    /* initial events */
  ], [
    withShakeBack(userAccelerometerEvents)
  ]);

  // withShakeBack allows you to return to previous state by shaking you device
  // The shake detection function is still quite unstable though. So please be patient.

  @override
  Widget build(BuildContext context) {
    return MaterialApp(
      title: 'Flutter Demo',
      theme: ThemeData(
        // This is the theme of your application.
        //
        // Try running your application with "flutter run". You'll see the
        // application has a blue toolbar. Then, without quitting the app, try
        // changing the primarySwatch below to Colors.green and then invoke
        // "hot reload" (press "r" in the console where you ran "flutter run",
        // or simply save your changes to "hot reload" in a Flutter IDE).
        // Notice that the counter didn't reset back to zero; the application
        // is not restarted.
        primarySwatch: Colors.blue,
      ),
      home: MyHomePage(title: 'Flutter Demo Home Page', store: store),
    );
  }
}

class MyHomePage extends StatefulWidget {
  MyHomePage({Key key, this.title, @required this.store}) : super(key: key);

  // This widget is the home page of your application. It is stateful, meaning
  // that it has a State object (defined below) that contains fields that affect
  // how it looks.

  // This class is the configuration for the state. It holds the values (in this
  // case the title) provided by the parent (in this case the App widget) and
  // used by the build method of the State. Fields in a Widget subclass are
  // always marked "final".

  final String title;
  final Store<AppEvent> store;

  @override
  _MyHomePageState createState() => _MyHomePageState();
}

class _MyHomePageState extends State<MyHomePage> {
  void _incrementCounter() {
    widget.store.dispatch(Increase());
  }

  int counter(
      int prev, EventStack<AppEvent> events, Projectable<AppEvent> store) {
    var next = prev ?? 0;
    for (final event in events) {
      if (event is Increase) next++;
      if (event is Decrease) next--;
    }
    return next;
  }

  @override
  Widget build(BuildContext context) {
    return Scaffold(
      appBar: AppBar(
        title: Text(widget.title),
      ),
      body: Center(
        child: Column(
          mainAxisAlignment: MainAxisAlignment.center,
          children: <Widget>[
            Text(
              'You have pushed the button this many times:',
            ),
            StoreBuilder(
              builder: (BuildContext context, int counter) => Text(
                    '$counter',
                    style: Theme.of(context).textTheme.display1,
                  ),
              store: widget.store,
              projector: counter,
            )
          ],
        ),
      ),
      floatingActionButton: FloatingActionButton(
        onPressed: _incrementCounter,
        tooltip: 'Increment',
        child: Icon(Icons.add),
      ), // This trailing comma makes auto-formatting nicer for build methods.
    );
  }
}

class AppEvent {}

class Increase extends AppEvent {}

class Decrease extends AppEvent {}