[英]Flutter, Transform.scale with Duration?
嗨,我正在寻找一个示例 Transform.scale with Duration(milliseconds: 300..)
我可以看看例子吗?
我搜索过没有例子
Flutter 中有两种动画:隐式和显式。 在您的情况下,您似乎想要一个隐式小部件来为某物的比例变化设置动画。 幸运的是,有一个为您准备的小部件,称为AnimatedScale
。 如果这适合您的需要,您应该更喜欢使用该小部件。 如果没有,例如,如果您想应用其他更高级的转换,您可以尝试将Transform
小部件与TweenAnimationBuilder
一起使用,以保持在“隐式动画”中。 这样您就可以避免处理AnimationController
,并且可以使您的代码简洁。
完整示例,将main.dart
替换为以下代码以运行它。 单击该按钮将在 1.0x 和 5.0x 比例之间切换 Flutter 徽标:
import 'package:flutter/material.dart';
void main() {
runApp(MyApp());
}
class MyApp extends StatelessWidget {
@override
Widget build(BuildContext context) {
return MaterialApp(
home: MyHomePage(),
);
}
}
class MyHomePage extends StatefulWidget {
@override
_MyHomePageState createState() => _MyHomePageState();
}
class _MyHomePageState extends State<MyHomePage> {
bool _big = false;
@override
Widget build(BuildContext context) {
return Scaffold(
appBar: AppBar(
title: Text('Flutter Demo'),
),
body: Center(
child: Column(
mainAxisAlignment: MainAxisAlignment.spaceEvenly,
children: [
AnimatedScale(
duration: Duration(seconds: 1),
scale: _big ? 5.0 : 1.0,
child: FlutterLogo(),
),
ElevatedButton(
child: Text('change size'),
onPressed: () => setState(() => _big = !_big),
),
],
),
),
);
}
}
你可以这样使用
class TransformWithDuration extends StatefulWidget {
final Widget child;
final void Function()? onTap;
final void Function()? onLongTap;
const TransformWithDuration({Key? key, required this.child, this.onTap, this.onLongTap}) : super(key: key);
@override
_TransformWithDurationState createState() => _TransformWithDurationState();
}
class _TransformWithDurationState extends State<TransformWithDuration>
with TickerProviderStateMixin {
double squareScaleA = 1;
late AnimationController _controllerA;
@override
void initState() {
_controllerA = AnimationController(
vsync: this,
lowerBound: 0.94,
upperBound: 1.0,
value: 1,
duration: Duration(milliseconds: 200),
);
_controllerA.addListener(() {
setState(() {
squareScaleA = _controllerA.value;
});
});
_controllerA.drive(CurveTween(curve: Curves.fastOutSlowIn));
super.initState();
}
@override
Widget build(BuildContext context) {
return GestureDetector(
behavior: HitTestBehavior.translucent,
onTap: () {
_controllerA.reverse();
if (widget.onTap != null) widget.onTap!();
},
onTapDown: (dp) {
_controllerA.reverse();
},
onTapUp: (dp) {
Timer(Duration(milliseconds: 150), () {
_controllerA.fling();
});
},
onTapCancel: () {
_controllerA.fling();
},
onLongPress: () {
if (widget.onLongTap != null) widget.onLongTap!();
},
child: Transform.scale(
scale: squareScaleA,
child: widget.child,
),
);
}
@override
void dispose() {
_controllerA.dispose();
super.dispose();
}
}
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