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// 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({Key? key}) : super(key: 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({
Key? key,
AnimationController? notifier,
required Widget child,
}) : super(key: key, notifier: notifier, child: child);
static double of(BuildContext context) {
return context
.dependOnInheritedWidgetOfExactType<SpinModel>()!
.notifier!
.value;
}
}
class Spinner extends StatelessWidget {
const Spinner({Key? key}) : super(key: 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({Key? key}) : super(key: key);
@override
State<MyStatefulWidget> createState() => _MyStatefulWidgetState();
}
/// AnimationControllers 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(),
],
),
);
}
}