Flutter 我怎样才能做一个；“出现”；颤振中的文本动画？
我希望实现material.io页面中显示的行为： 第一次显示文本时，文本会进行很好的转换Flutter 我怎样才能做一个；“出现”；颤振中的文本动画？,flutter,Flutter,我希望实现material.io页面中显示的行为： 第一次显示文本时，文本会进行很好的转换 如何在颤振中实现这一点？您可以编写如下小部件： import 'dart:async'; import 'package:flutter/material.dart'; class ShowUp extends StatefulWidget { final Widget child; final int delay; ShowUp({@required this.child, this.
如何在颤振中实现这一点？您可以编写如下小部件：
import 'dart:async';
import 'package:flutter/material.dart';
class ShowUp extends StatefulWidget {
final Widget child;
final int delay;
ShowUp({@required this.child, this.delay});
@override
_ShowUpState createState() => _ShowUpState();
}
class _ShowUpState extends State<ShowUp> with TickerProviderStateMixin {
AnimationController _animController;
Animation<Offset> _animOffset;
@override
void initState() {
super.initState();
_animController =
AnimationController(vsync: this, duration: Duration(milliseconds: 500));
final curve =
CurvedAnimation(curve: Curves.decelerate, parent: _animController);
_animOffset =
Tween<Offset>(begin: const Offset(0.0, 0.35), end: Offset.zero)
.animate(curve);
if (widget.delay == null) {
_animController.forward();
} else {
Timer(Duration(milliseconds: widget.delay), () {
_animController.forward();
});
}
}
@override
void dispose() {
super.dispose();
_animController.dispose();
}
@override
Widget build(BuildContext context) {
return FadeTransition(
child: SlideTransition(
position: _animOffset,
child: widget.child,
),
opacity: _animController,
);
}
}
int delayAmount = 500;
...........
...........
...........
Column(
children: <Widget>[
ShowUp(
child: Text("The first texto to be shown"),
delay: delayAmount,
),
ShowUp(
child: Text("The text below the first"),
delay: delayAmount + 200,
),
ShowUp(
child: Column(
children: <Widget>[
Text("Texts together 1"),
Text("Texts together 2"),
Text("Texts together 3"),
],
),
delay: delayAmount + 400,
),
],
),
导入'dart:async'；
进口“包装：颤振/材料.省道”；
类ShowUp扩展了StatefulWidget{
最后一个孩子；
最终整数延迟；
显示（{@required this.child，this.delay}）；
@凌驾
_ShowUpState createState（）=>\u ShowUpState（）；
}
类_ShowUpState使用TickerProviderStateMixin扩展状态{
AnimationController\u AnimationController；
动画;；
@凌驾
void initState（）{
super.initState（）；
_动物控制器=
AnimationController（vsync:this，duration:duration（毫秒：500））；
最终曲线=
曲线动画（曲线：Curves.Decreate，父对象：_animController）；
_动物补偿=
吐温（开始：常数偏移（0.0,0.35），结束：偏移.0）
.制作（曲线）动画；
if（widget.delay==null）{
_animController.forward（）；
}否则{
计时器（持续时间（毫秒：widget.delay），（）{
_animController.forward（）；
});
}
}
@凌驾
无效处置（）{
super.dispose（）；
_animController.dispose（）；
}
@凌驾
小部件构建（构建上下文）{
返回衰减转换(
子：幻灯片转换(
位置：，
child:widget.child，
),
不透明度：，
);
}
}
import 'dart:async';
import 'package:flutter/material.dart';
class ShowUp extends StatefulWidget {
final Widget child;
final int delay;
ShowUp({@required this.child, this.delay});
@override
_ShowUpState createState() => _ShowUpState();
}
class _ShowUpState extends State<ShowUp> with TickerProviderStateMixin {
AnimationController _animController;
Animation<Offset> _animOffset;
@override
void initState() {
super.initState();
_animController =
AnimationController(vsync: this, duration: Duration(milliseconds: 500));
final curve =
CurvedAnimation(curve: Curves.decelerate, parent: _animController);
_animOffset =
Tween<Offset>(begin: const Offset(0.0, 0.35), end: Offset.zero)
.animate(curve);
if (widget.delay == null) {
_animController.forward();
} else {
Timer(Duration(milliseconds: widget.delay), () {
_animController.forward();
});
}
}
@override
void dispose() {
super.dispose();
_animController.dispose();
}
@override
Widget build(BuildContext context) {
return FadeTransition(
child: SlideTransition(
position: _animOffset,
child: widget.child,
),
opacity: _animController,
);
}
}
int delayAmount = 500;
...........
...........
...........
Column(
children: <Widget>[
ShowUp(
child: Text("The first texto to be shown"),
delay: delayAmount,
),
ShowUp(
child: Text("The text below the first"),
delay: delayAmount + 200,
),
ShowUp(
child: Column(
children: <Widget>[
Text("Texts together 1"),
Text("Texts together 2"),
Text("Texts together 3"),
],
),
delay: delayAmount + 400,
),
],
),
int delayAmount=500；
...........
...........
...........
纵队(
儿童：[
展示(
子项：文本（“要显示的第一个文本”），
延迟：延迟金额，
),
展示(
子项：文本（“第一个下面的文本”），
延迟：延迟金额+200，
),
展示(
子：列(
儿童：[
正文（“正文合1”），
文本（“合并文本2”），
文本（“文本加在一起3”），
],
),
延迟：延迟金额+400，
),
],
),
请注意，这个“展示”小部件可以制作任何东西的动画，而不仅仅是文本。有一个现有的程序包需要它，它基于下面的实现 这是一个提供此动画的通用小部件。您所要做的就是将您的小部件（是的，任何小部件）包装在SlideFadeTransition小部件中，瞧 它提供了很多控制。例如，可以控制动画的数量、速度、方向、延迟甚至曲线
///Wrapper class to implement slide and fade animations at the same time to
///a given element. Wrap the widget that you wish to appear with slide-fade
///transition in this class.
import 'dart:async';
import 'package:flutter/material.dart';
enum Direction { vertical, horizontal }
class SlideFadeTransition extends StatefulWidget {
///The child on which to apply the given [SlideFadeTransition]
final Widget child;
///The offset by which to slide and [child] into view from [Direction].
///Defaults to 0.2
final double offset;
///The curve used to animate the [child] into view.
///Defaults to [Curves.easeIn]
final Curve curve;
///The direction from which to animate the [child] into view. [Direction.horizontal]
///will make the child slide on x-axis by [offset] and [Direction.vertical] on y-axis.
///Defaults to [Direction.vertical]
final Direction direction;
///The delay with which to animate the [child]. Takes in a [Duration] and
/// defaults to 0.0 seconds
final Duration delayStart;
///The total duration in which the animation completes. Defaults to 800 milliseconds
final Duration animationDuration;
SlideFadeTransition({
@required this.child,
this.offset = 0.2,
this.curve = Curves.easeIn,
this.direction = Direction.vertical,
this.delayStart = const Duration(seconds: 0),
this.animationDuration = const Duration(milliseconds: 800),
});
@override
_SlideFadeTransitionState createState() => _SlideFadeTransitionState();
}
class _SlideFadeTransitionState extends State<SlideFadeTransition>
with SingleTickerProviderStateMixin {
Animation<Offset> _animationSlide;
AnimationController _animationController;
Animation<double> _animationFade;
@override
void initState() {
super.initState();
_animationController = AnimationController(
vsync: this,
duration: widget.animationDuration,
);
//configure the animation controller as per the direction
if (widget.direction == Direction.vertical) {
_animationSlide =
Tween<Offset>(begin: Offset(0, widget.offset), end: Offset(0, 0))
.animate(CurvedAnimation(
curve: widget.curve,
parent: _animationController,
));
} else {
_animationSlide =
Tween<Offset>(begin: Offset(widget.offset, 0), end: Offset(0, 0))
.animate(CurvedAnimation(
curve: widget.curve,
parent: _animationController,
));
}
_animationFade =
Tween<double>(begin: -1.0, end: 1.0).animate(CurvedAnimation(
curve: widget.curve,
parent: _animationController,
));
Timer(widget.delayStart, () {
_animationController.forward();
});
}
@override
Widget build(BuildContext context) {
return FadeTransition(
opacity: _animationFade,
child: SlideTransition(
position: _animationSlide,
child: widget.child,
),
);
}
}
///同时实现幻灯片和淡入淡出动画的包装器类
///给定的元素。用幻灯片淡入淡出包装您希望显示的小部件
///这门课的过渡。
导入“dart:async”；
进口“包装：颤振/材料.省道”；
枚举方向{垂直，水平}
类SlideFadeTransition扩展StatefulWidget{
///要对其应用给定[SlideFadeTransition]的子项
最后一个孩子；
///从[方向]滑动和[子]到视图的偏移量。
///默认值为0.2
最终双偏移量；
///用于在视图中设置[子对象]动画的曲线。
///默认为[Curves.easeIn]
最终曲线；
///将[子对象]设置为视图动画的方向。[方向.水平]
///将使子对象在x轴上滑动[offset]，在y轴上滑动[Direction.vertical]。
///默认为[方向.垂直]
最终方向；
///设置[child]动画的延迟时间为[Duration]，并且
///默认值为0.0秒
最终持续时间延迟开始；
///动画完成的总持续时间。默认为800毫秒
最终持续时间动画持续时间；
幻灯片格式转换({
@需要这个孩子，
该偏移量=0.2，
this.curve=Curves.easeIn，
this.direction=direction.vertical，
this.delayStart=常数持续时间（秒：0），
this.animationDuration=常量持续时间（毫秒：800），
});
@凌驾
_SlideFadeTransitionState createState（）=>\u SlideFadeTransitionState（）；
}
类SlideFadeTransitionState扩展了状态
使用SingleTickerProviderStateMixin{
动画_animationSlide；
AnimationController _AnimationController；
动画-动画淡入淡出；
@凌驾
void initState（）{
super.initState（）；
_animationController=animationController(
vsync:这个,，
持续时间：widget.animationDuration，
);
//根据方向配置动画控制器
if（widget.direction==direction.vertical）{
_动画幻灯片=
Tween（开始：偏移量（0，widget.Offset），结束：偏移量（0，0））
.动画（曲线动画）(
曲线：widget.curve，
父项：_animationController，
));
}否则{
_动画幻灯片=
Tween（开始：偏移量（widget.Offset，0），结束：偏移量（0，0））
.动画（曲线动画）(
曲线：widget.curve，
父项：_animationController，
));
}
_动画淡入淡出=
吐温（开始：-1.0，结束：1.0）。动画（曲线动画）(
曲线：widget.curve，
父项：_animationController，
));
计时器（widget.delayStart，（）{
_animationController.forward（）；
});
}
@凌驾
小部件构建（构建上下文）{
返回衰减转换(
不透明度：_animationFade，
子：幻灯片转换(
位置：_animationSlide，
child:widget.child，
),
);
}
}
import 'dart:async';
import 'package:flutter/material.dart';
void main() => runApp(MyApp());
class MyApp extends StatelessWidget {
@override
Widget build(BuildContext context) {
return MaterialApp(
title: 'Show up Demo',
theme: ThemeData(
primarySwatch: Colors.blue,
),
home: MyHomePage(title: 'Show up Demo'),
);
}
}
class MyHomePage extends StatefulWidget {
MyHomePage({Key key, this.title}) : super(key: key);
final String title;
@override
_MyHomePageState createState() => _MyHomePageState();
}
class _MyHomePageState extends State<MyHomePage> {
@override
Widget build(BuildContext context) {
return Scaffold(
appBar: AppBar(
title: Text(widget.title),
),
body: Center(
child: Column(
mainAxisAlignment: MainAxisAlignment.center,
children: <Widget>[
SlideFadeTransition(
child: Text(
'You have pushed the button this many times:',
),
),
SlideFadeTransition(
delayStart: Duration(milliseconds: 800),
child: Text(
'0',
style: Theme.of(context).textTheme.display1,
),
),
],
),
),
floatingActionButton: FloatingActionButton(
onPressed: () {
setState(() {});
},
tooltip: 'Animate',
child: Icon(Icons.add),
),
);
}
}
///Wrapper class to implement slide and fade animations at the same time to
///a given element. Wrap the widget that you wish to appear with slide-fade
///transition in this class.
enum Direction { vertical, horizontal }
class SlideFadeTransition extends StatefulWidget {
///The child on which to apply the given [SlideFadeTransition]
final Widget child;
///The offset by which to slide and [child] into view from [Direction].
///Defaults to 1.0
final double offset;
///The curve used to animate the [child] into view.
///Defaults to [Curves.easeIn]
final Curve curve;
///The direction from which to animate the [child] into view. [Direction.horizontal]
///will make the child slide on x-axis by [offset] and [Direction.vertical] on y-axis.
///Defaults to [Direction.vertical]
final Direction direction;
///The delay with which to animate the [child]. Takes in a [Duration] and
/// defaults to 0.0 seconds
final Duration delayStart;
///The total duration in which the animation completes. Defaults to 800 milliseconds
final Duration animationDuration;
SlideFadeTransition({
@required this.child,
this.offset = 1.0,
this.curve = Curves.easeIn,
this.direction = Direction.vertical,
this.delayStart = const Duration(seconds: 0),
this.animationDuration = const Duration(milliseconds: 800),
});
@override
_SlideFadeTransitionState createState() => _SlideFadeTransitionState();
}
class _SlideFadeTransitionState extends State<SlideFadeTransition>
with SingleTickerProviderStateMixin {
Animation<Offset> _animationSlide;
AnimationController _animationController;
Animation<double> _animationFade;
@override
void initState() {
super.initState();
_animationController = AnimationController(
vsync: this,
duration: widget.animationDuration,
);
//configure the animation controller as per the direction
if (widget.direction == Direction.vertical) {
_animationSlide =
Tween<Offset>(begin: Offset(0, widget.offset), end: Offset(0, 0))
.animate(CurvedAnimation(
curve: widget.curve,
parent: _animationController,
));
} else {
_animationSlide =
Tween<Offset>(begin: Offset(widget.offset, 0), end: Offset(0, 0))
.animate(CurvedAnimation(
curve: widget.curve,
parent: _animationController,
));
}
_animationFade =
Tween<double>(begin: -1.0, end: 1.0).animate(CurvedAnimation(
curve: widget.curve,
parent: _animationController,
));
Timer(widget.delayStart, () {
_animationController.forward();
});
}
@override
void dispose() {
_animationController.dispose();
super.dispose();
}
@override
Widget build(BuildContext context) {
return FadeTransition(
opacity: _animationFade,
child: SlideTransition(
position: _animationSlide,
child: widget.child,
),
);
}
}
导入'dart:async'；
进口“包装：颤振/材料.省道”；
void main（）=>runApp（MyApp（））；
类MyApp扩展了无状态小部件{
@凌驾
小部件构建（构建上下文）