clock_animation.dart

// Copyright (c) 2019, the Dart project authors.  Please see the AUTHORS file
// for details. All rights reserved. Use of this source code is governed by a
// BSD-style license that can be found in the LICENSE file.

import 'package:flutter/material.dart';
import 'dart:math' as math;

void main() => runApp(MyApp());

class MyApp extends StatelessWidget {
  @override
  Widget build(BuildContext context) {
    return MaterialApp(
      title: 'Flutter Demo',
      debugShowCheckedModeBanner: false,
      theme: ThemeData(
        primarySwatch: Colors.blue,
      ),
      home: MainPage(),
    );
  }
}

class MainPage extends StatefulWidget {
  @override
  _MainPageState createState() => _MainPageState();
}

class _MainPageState extends State<MainPage>
    with SingleTickerProviderStateMixin {
  AnimationController _controller;

  void start() async {
    var position = 0;
    while (mounted) {
      position++;
      _controller.animateTo(
        position.toDouble(),
        curve: Curves.ease,
        duration: const Duration(milliseconds: 200),
      );
      await Future.delayed(const Duration(seconds: 1));
    }
  }
  
  @override
  void initState() {
    super.initState();
    _controller = AnimationController.unbounded(vsync: this);
    start();
  }

  @override
  Widget build(BuildContext context) {
    return Scaffold(
      appBar: AppBar(),
      body: Center(
        child: AnimatedBuilder(
          animation: _controller,
          builder: (_, child) {
            return Transform.rotate(
              angle: _controller.value * (math.pi / 8),
              child: child,
            );
          },
          child: Container(height: 200, width: 200, color: Colors.orangeAccent),
        ),
      ),
    );
  }
}