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                import 'package:flutter/material.dart';

void main() {

class MyApp extends StatelessWidget {
  Widget build(BuildContext context) {
    return MaterialApp(
      theme: ThemeData(primaryColor:,
      home: const MyHomePage(),

class MyHomePage extends StatelessWidget {
  const MyHomePage({Key key}) : super(key: key);
  Widget build(BuildContext context) {
    return const Scaffold(
      body: Center(child: RotatedLogo(size: 200)),

class RotatedLogo extends StatefulWidget {
  const RotatedLogo({
    Key key,
    this.size = 50,
    this.duration = const Duration(seconds: 1),
  }) : super(key: key);
  final double size;
  final Duration duration;
  _RotatedLogoState createState() => _RotatedLogoState();

class _RotatedLogoState extends State<RotatedLogo> with SingleTickerProviderStateMixin {
 AnimationController controller;

  void initState() {
    controller = AnimationController(vsync: this, duration: widget.duration);

  void dispose() {

  Widget build(BuildContext context) {
    return RotationTransition(
      /// repeat を呼ぶだけ
      turns: controller..repeat(),
      child: FlutterLogo(size: widget.size),