缩放动画和渐显渐隐动画
import 'package:flutter/material.dart';
import 'animation7.dart';
//通用‘切换动画’组件
//AnimatedSwitcher
class AnimatedSwitcherCounterRoute extends StatefulWidget {
const AnimatedSwitcherCounterRoute({
Key key}) : super(key: key);
@override
_AnimatedSwitcherCounterRouteState createState() =>
_AnimatedSwitcherCounterRouteState();
}
class _AnimatedSwitcherCounterRouteState
extends State<AnimatedSwitcherCounterRoute> {
int _count = 0;
@override
Widget build(BuildContext context) {
return Center(
child: Column(
mainAxisAlignment: MainAxisAlignment.center,
children: <Widget>[
AnimatedSwitcher(
//当child发生变化时(类型或key不同),旧child执行隐藏动画,新child执行显示动画
duration: const Duration(milliseconds: 500),
//transitionBuilder决定动画效果
transitionBuilder: (Widget child,Animation<double> animation){