viper 0.0.4

An elegant way to adapt VIPER architecture into Flutter project.

example/lib/main.dart

import 'package:flutter/material.dart' hide Router;
import 'package:viper/viper.dart';

abstract class MyHomeView extends View {
  BehaviorSubject<int> get counter;

  Stream<void> get incrementButtonDidTap;
}

class CounterInteractor extends Interactor {
  var _counter = 0;

  int get counter => _counter;

  Stream<int> increment() {
    _counter++;
    return Stream.value(_counter);
  }
}

class MyHomeRouter extends Router {}

class MyHomePresenter extends Presenter<MyHomeView, MyHomeRouter> {
  late final counterInteractor = CounterInteractor();

  @override
  void onReady() {
    super.onReady();

    MergeStream([
      view.stateDidInit
        .map((event) => counterInteractor.counter),
      view.incrementButtonDidTap
        .flatMap((value) => counterInteractor.increment())
    ])
        .bind(view.counter)
        .addTo(disposeBag);

  }
}

class MyHomeModule extends Module<MyHomeView, MyHomePresenter, MyHomeRouter> {
  @override
  final presenter = MyHomePresenter();

  @override
  final router = MyHomeRouter();

  @override
  Widget build(BuildContext context) {
    return MyHomeViewImpl();
  }
}

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

class MyApp extends StatelessWidget {
  // This widget is the root of your application.
  @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: MyHomeModule(),
    );
  }
}

class MyHomeViewImpl extends StatefulWidget {
  MyHomeViewImpl({Key? key}) : 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".

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

class _MyHomeViewImplState extends ViewState<MyHomeViewImpl, MyHomeModule> implements MyHomeView {
  @override
  final counter = BehaviorSubject<int>.seeded(0);

  @override
  BehaviorSubject<void> incrementButtonDidTap = BehaviorSubject();

  @override
  Widget build(BuildContext context) {
    // This method is rerun every time setState is called, for instance as done
    // by the _incrementCounter method above.
    //
    // The Flutter framework has been optimized to make rerunning build methods
    // fast, so that you can just rebuild anything that needs updating rather
    // than having to individually change instances of widgets.
    return Scaffold(
      appBar: AppBar(
        // Here we take the value from the MyHomePage object that was created by
        // the App.build method, and use it to set our appbar title.
        title: Text("Example"),
      ),
      body: Center(
        // Center is a layout widget. It takes a single child and positions it
        // in the middle of the parent.
        child: Column(
          // Column is also a layout widget. It takes a list of children and
          // arranges them vertically. By default, it sizes itself to fit its
          // children horizontally, and tries to be as tall as its parent.
          //
          // Invoke "debug painting" (press "p" in the console, choose the
          // "Toggle Debug Paint" action from the Flutter Inspector in Android
          // Studio, or the "Toggle Debug Paint" command in Visual Studio Code)
          // to see the wireframe for each widget.
          //
          // Column has various properties to control how it sizes itself and
          // how it positions its children. Here we use mainAxisAlignment to
          // center the children vertically; the main axis here is the vertical
          // axis because Columns are vertical (the cross axis would be
          // horizontal).
          mainAxisAlignment: MainAxisAlignment.center,
          children: <Widget>[
            Text(
              'You have pushed the button this many times:',
            ),
            StreamSelector<int>(
              stream: counter,
              builder: (_, counter, __) => Text(
                '$counter',
                style: Theme.of(context).textTheme.headline4,
              ),
            ),
          ],
        ),
      ),
      floatingActionButton: FloatingActionButton(
        onPressed: () => incrementButtonDidTap.add(null),
        tooltip: 'Increment',
        child: Icon(Icons.add),
      ), // This trailing comma makes auto-formatting nicer for build methods.
    );
  }
}