구현

도메인

class Counter {
  int _value = 0;

  int get value => _value;

  void increment() {
    _value++;
  }
}

컨트롤러

import 'package:flutter/material.dart';
import 'package:stateManagement/domain/counter.dart';

class CounterController extends ChangeNotifier {
  CounterController(Counter counter) : this._counter = counter;
  Counter _counter;

  void increment() {
    this._counter.increment();
    notifyListeners();
  }

  int getCount() {
    return this._counter.value;
  }
}

Component

CountText

class CountText extends StatelessWidget {
  const CountText(this._count);
  final int _count;

  @override
  Widget build(BuildContext context) {
    return Center(
      child: Column(
        mainAxisAlignment: MainAxisAlignment.center,
        children: <Widget>[
          Text(
            'You have pushed the button this many times:',
          ),
          Text(
            _count.toString(),
            style: Theme.of(context).textTheme.headline4,
          ),
        ],
      ),
    );
  }
}

IncrementButton

typedef void Increment();

class IncrementButton extends StatelessWidget {
  const IncrementButton(this._increment);

  final Increment _increment;

  @override
  Widget build(BuildContext context) {
    return FloatingActionButton(
      onPressed: this._increment,
      tooltip: 'Increment',
      child: Icon(Icons.add),
    );
  }
}

페이지

import 'package:flutter/material.dart';
import 'package:flutter_riverpod/flutter_riverpod.dart';
// import counter.dart
// import counter_controller.dart
// import count_text.dart
// import increment_button.dart

class CounterPage extends StatelessWidget {
  CounterPage(this._title);
  final String _title;
  final counterProvider = ChangeNotifierProvider<CounterController>(
      (_) => CounterController(Counter()));

  @override
  Widget build(BuildContext context) {
    return Scaffold(
        appBar: AppBar(
          title: Text(this._title),
        ),
        body: Center(
          child: Column(
            mainAxisAlignment: MainAxisAlignment.center,
            children: <Widget>[
              Consumer(
                builder: (_, watch, __) =>
                    CountText(watch(counterProvider).getCount()),
              )
            ],
          ),
        ),
        floatingActionButton: IncrementButton(context.read(counterProvider).increment));
  }
}

앱

import 'package:flutter/material.dart';
import 'package:flutter_riverpod/flutter_riverpod.dart';
// import counter_page.dart;

class RiverpodTestApp extends StatelessWidget {
  // This widget is the root of your application.
  @override
  Widget build(BuildContext context) {
    return ProviderScope(
      child: MaterialApp(
        title: 'CounterApp',
        theme: ThemeData(
          // This is the theme of your application.
          primarySwatch: Colors.orange,
          // This makes the visual density adapt to the platform that you run
          // the app on. For desktop platforms, the controls will be smaller and
          // closer together (more dense) than on mobile platforms.
          visualDensity: VisualDensity.adaptivePlatformDensity,
        ),
        home: CounterPage('Counter'),
      ),
    );
  }
}

Main

import 'package:flutter/material.dart';
// import riverpod_test.dart

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

요약