main.dart

// Copyright 2014 The Flutter Authors. All rights reserved.
// Use of this source code is governed by a BSD-style license that can be
// found in the LICENSE file.

// Flutter code sample for ThemeExtension

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

void main() => runApp(const ProviderScope(
      child: App(),
    ));

class App extends StatelessWidget {
  const App({Key? key}) : super(key: key);

  @override
  Widget build(BuildContext context) {
    return const MaterialApp(
      home: HomePage(),
    );
  }
}

class HomePage extends ConsumerWidget {
  const HomePage({Key? key}) : super(key: key);

  @override
  Widget build(BuildContext context, WidgetRef ref) {
    return Scaffold(
      body: Center(
        child: ElevatedButton(
          child: const Text('Open'),
          onPressed: () => Navigator.of(context).push<void>(
            MaterialPageRoute(
              builder: (context) => const NowPage(),
            ),
          ),
        ),
      ),
    );
  }
}

final _format = DateFormat.Hms();

final nowDisposeDelay = Provider.autoDispose(
  (ref) => _format.format(DateTime.now()),
  disposeDelay: const Duration(seconds: 5),
);

final nowCacheTime = Provider.autoDispose(
  (ref) => _format.format(DateTime.now()),
  cacheTime: const Duration(seconds: 5),
);

class NowPage extends ConsumerWidget {
  const NowPage({Key? key}) : super(key: key);

  @override
  Widget build(BuildContext context, WidgetRef ref) {
    final textStyle = Theme.of(context).textTheme.headlineSmall;
    return Scaffold(
      appBar: AppBar(),
      body: Center(
        child: Column(
          crossAxisAlignment: CrossAxisAlignment.end,
          children: <Widget>[
            const SizedBox(height: 16),
            Text(
              'nowDisposeDelay: ${ref.watch(nowDisposeDelay)}',
              style: textStyle,
            ),
            const SizedBox(height: 8),
            Text(
              'nowCacheTime: ${ref.watch(nowCacheTime)}',
              style: textStyle,
            ),
          ],
        ),
      ),
    );
  }
}