flutter-使用AnimationController

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

class AnimatedDemo extends StatefulWidget {
  static const String sName = 'animatedDemo';
  @override
  _AnimatedDemoState createState() => _AnimatedDemoState();
}

class _AnimatedDemoState extends State<AnimatedDemo>
    with TickerProviderStateMixin {
  AnimationController animationController;
  Animation animation;
  @override
  void initState() {
    // TODO: implement initState
    super.initState();
    animationController =
        AnimationController(vsync: this, duration: Duration(seconds: 2))
          ..addStatusListener((status) {
            if (status == AnimationStatus.completed) {
              animationController.reverse();
            } else if (status == AnimationStatus.dismissed) {
              animationController.forward();
            }
          });
    animation =
        Tween(begin: 0.0, end: 2.0 * math.pi).animate(animationController);
    animationController.forward();
  }

  @override
  void dispose() {
    // TODO: implement dispose
    super.dispose();
    animationController.dispose();
  }

  @override
  Widget build(BuildContext context) {
    return Scaffold(
      appBar: AppBar(title: Text('animated_demo')),
      body: AnimatedBuilder(
        animation: animation,
        builder: (BuildContext context, Widget child) {
          return Transform.rotate(angle: animation.value, child: child);
        },
        child: FlutterLogo(size: 60,),
      ),
    );
  }
}