import 'dart:math';
import 'package:flutter/material.dart';
void main() {
runApp(const MyApp());
}
class MyApp extends StatelessWidget {
const MyApp({Key? key}) : super(key: key);
@override
Widget build(BuildContext context) {
return MaterialApp(
routes: {
"/": (context) => HomePage(),
},
initialRoute: "/",
);
}
}
class HomePage extends StatefulWidget {
const HomePage({Key? key}) : super(key: key);
@override
State<HomePage> createState() => _HomePageState();
}
class _HomePageState extends State<HomePage> with TickerProviderStateMixin {
late AnimationController _controller;
late CurvedAnimation _curvedAnimation;
late Animation _sizeTween;
late Animation _opacityTween;
late Animation _transformTween;
@override
void initState() {
// TODO: implement initState
super.initState();
_controller = AnimationController(
lowerBound: 0.0,
upperBound:1.0,
vsync: this,
duration: const Duration(seconds: 1),
reverseDuration: const Duration(seconds: 1));
_controller.addStatusListener((status) {
if (status == AnimationStatus.completed) {
_controller.reverse();
} else if (status == AnimationStatus.dismissed) {
_controller.forward();
}
});
_curvedAnimation = CurvedAnimation(parent: _controller, curve: Curves.easeIn);
_sizeTween = Tween(begin: 50.0, end: 100.0).animate(_curvedAnimation);
_opacityTween = Tween(begin: 0.0, end: 1.0).animate(_curvedAnimation);
_transformTween = Tween(begin: 0.0, end: pi * 2).animate(_curvedAnimation);
}
@override
Widget build(BuildContext context) {
return Scaffold(
appBar: AppBar(
title: const Text("ts"),
),
body: Center(
child: Column(
mainAxisAlignment: MainAxisAlignment.center,
children: <Widget>[
AnimatedBuilder(
animation: _controller,
builder: (context, child) {
return Opacity(
opacity: 1.0 - _opacityTween.value,
child: Transform(
transform: Matrix4.rotationZ(_transformTween.value),
alignment: Alignment.center,
child: Container(
width: _sizeTween.value,
height: _sizeTween.value,
color: Colors.red,
),
),
);
},
)
],
),
),
floatingActionButton: FloatingActionButton(
child: const Icon(Icons.play_circle),
onPressed: () {
if (_controller.isAnimating) {
_controller.stop();
} else if (_controller.status == AnimationStatus.forward){
_controller.forward();
} else if (_controller.status == AnimationStatus.reverse) {
_controller.reverse();
} else if (_controller.status == AnimationStatus.dismissed) {
_controller.forward();
} else if (_controller.status == AnimationStatus.completed) {
_controller.reverse();
}
},
),
);
}
}
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