examples/api/lib/widgets/inherited_notifier/inherited_notifier.0.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 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(),
        ],
      ),
    );
  }
}