在这个简单的示例代码中,我想同时实现淡入和淡出动画,但在这段代码中只有淡入生效而
reverse
没有生效,我该怎么做才能让它们一起生效?import 'package:flutter/material.dart';
void main()=>runApp(MaterialApp(home: FadeTransitionSample(),));
class FadeTransitionSample extends StatefulWidget {
@override
State<StatefulWidget> createState() => _Fade();
}
class _Fade extends State<FadeTransitionSample> with TickerProviderStateMixin {
AnimationController animation;
Animation<double> _fadeInFadeOut;
@override
void initState() {
super.initState();
animation = AnimationController(vsync: this, duration: Duration(seconds: 3),);
_fadeInFadeOut = Tween<double>(begin: 0.0, end: 0.1).animate(animation);
animation.addListener((){
if(animation.isCompleted){
animation.reverse();
}else{
animation.forward();
}
});
animation.repeat();
}
@override
Widget build(BuildContext context) {
return Scaffold(
body: Container(
child: Center(
child: FadeTransition(
opacity: animation,
child: Container(
color: Colors.green,
width: 100,
height: 100,
),
),
),
),
);
}
}