| // 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 [InheritedNotifier]. |
| |
| import 'dart:math' as math; |
| |
| import 'package:flutter/material.dart'; |
| |
| void main() => runApp(const MyApp()); |
| |
| class MyApp extends StatelessWidget { |
| const MyApp({super.key}); |
| |
| static const String _title = 'Flutter Code Sample'; |
| |
| @override |
| Widget build(BuildContext context) { |
| return const MaterialApp( |
| title: _title, |
| home: MyStatefulWidget(), |
| ); |
| } |
| } |
| |
| class SpinModel extends InheritedNotifier<AnimationController> { |
| const SpinModel({ |
| super.key, |
| super.notifier, |
| required super.child, |
| }); |
| |
| static double of(BuildContext context) { |
| return context |
| .dependOnInheritedWidgetOfExactType<SpinModel>()! |
| .notifier! |
| .value; |
| } |
| } |
| |
| class Spinner extends StatelessWidget { |
| const Spinner({super.key}); |
| |
| @override |
| Widget build(BuildContext context) { |
| return Transform.rotate( |
| angle: SpinModel.of(context) * 2.0 * math.pi, |
| child: Container( |
| width: 100, |
| height: 100, |
| color: Colors.green, |
| child: const Center( |
| child: Text('Whee!'), |
| ), |
| ), |
| ); |
| } |
| } |
| |
| class MyStatefulWidget extends StatefulWidget { |
| const MyStatefulWidget({super.key}); |
| |
| @override |
| State<MyStatefulWidget> createState() => _MyStatefulWidgetState(); |
| } |
| |
| /// [AnimationController]s can be created with `vsync: this` because of |
| /// [TickerProviderStateMixin]. |
| class _MyStatefulWidgetState extends State<MyStatefulWidget> |
| with TickerProviderStateMixin { |
| late AnimationController _controller; |
| |
| @override |
| void initState() { |
| super.initState(); |
| _controller = AnimationController( |
| duration: const Duration(seconds: 10), |
| vsync: this, |
| )..repeat(); |
| } |
| |
| @override |
| void dispose() { |
| _controller.dispose(); |
| super.dispose(); |
| } |
| |
| @override |
| Widget build(BuildContext context) { |
| return SpinModel( |
| notifier: _controller, |
| child: Row( |
| mainAxisAlignment: MainAxisAlignment.spaceAround, |
| children: const <Widget>[ |
| Spinner(), |
| Spinner(), |
| Spinner(), |
| ], |
| ), |
| ); |
| } |
| } |