RK *_*ios 6 flutter flutter-animation
Flutter 没有动画网格所以，我想要实现的是像 Flutter 中的轨道一样滚动 gridview。就像下面这样。尝试使用TweenAnimationBuilder和flutter_staggered_animations: ^1.0.0打包。但无法达到预期的效果
TweenAnimationBuilder 代码是
import 'package:flutter/material.dart';
import 'dart:math' as math;
import 'package:tween_animation_check/animatedgeidView.dart';
import 'package:flutter_staggered_animations/flutter_staggered_animations.dart';
void main() {
runApp(const MyApp());
}
class MyApp extends StatelessWidget {
const MyApp({super.key});
// This widget is the root of your application.
@override
Widget build(BuildContext context) {
return MaterialApp(
title: 'Flutter Demo',
theme: ThemeData(
// This is the theme of your application.
//
// Try running your application with "flutter run". You'll see the
// application has a blue toolbar. Then, without quitting the app, try
// changing the primarySwatch below to Colors.green and then invoke
// "hot reload" (press "r" in the console where you ran "flutter run",
// or simply save your changes to "hot reload" in a Flutter IDE).
// Notice that the counter didn't reset back to zero; the application
// is not restarted.
primarySwatch: Colors.blue,
),
home: const MyHomePage(title: 'Flutter Demo Home Page'),
);
}
}
class MyHomePage extends StatefulWidget {
const MyHomePage({super.key, required this.title});
// This widget is the home page of your application. It is stateful, meaning
// that it has a State object (defined below) that contains fields that affect
// how it looks.
// This class is the configuration for the state. It holds the values (in this
// case the title) provided by the parent (in this case the App widget) and
// used by the build method of the State. Fields in a Widget subclass are
// always marked "final".
final String title;
@override
State<MyHomePage> createState() => _MyHomePageState();
}
class _MyHomePageState extends State<MyHomePage> with TickerProviderStateMixin {
int _counter = 0;
var string = [
0,
1,
2,
3,
4,
5,
6,
7,
8,
9,
10,
11,
12,
];
_onStartScroll(ScrollMetrics metrics) {
// if you need to do something at the start
}
_onUpdateScroll(ScrollMetrics metrics) {
// do your magic here to change the value
// if(spaceBetween == 30.0) return;
// spaceBetween = 30.0;
setState(() {});
}
_onEndScroll(ScrollMetrics metrics) {
// do your magic here to return the value to normal
setState(() {});
}
late final AnimationController rotationAnimationController =
AnimationController(vsync: this, duration: const Duration(seconds: 2));
ScrollController scrollController = ScrollController();
late final AnimationController _controller = AnimationController(
duration: const Duration(seconds: 1),
reverseDuration: Duration(seconds: 1),
animationBehavior: AnimationBehavior.normal,
vsync: this,
)..repeat(reverse: false);
late final Animation<double> _animation = CurvedAnimation(
parent: _controller, curve: Curves.easeIn, reverseCurve: Curves.easeIn);
void _incrementCounter() {
setState(() {
// This call to setState tells the Flutter framework that something has
// changed in this State, which causes it to rerun the build method below
// so that the display can reflect the updated values. If we changed
// _counter without calling setState(), then the build method would not be
// called again, and so nothing would appear to happen.
_counter++;
});
}
@override
void initState() {
// TODO: implement initState
super.initState();
scrollController.addListener(() {
print(scrollController.offset);
// string.forEach((element) {
// //element % 2 == 0 ?
// });
// rotationAnimationController.animateTo(scrollController.offset, duration: Duration(seconds: 3), curve: Curves.bounceIn);
// Scrollable.ensureVisible(animatedBoxKey.,curve: Curves.bounceIn, duration: Duration(seconds: 2));
});
//rotationAnimationController.animateTo(0.5);
}
@override
Widget build(BuildContext context) {
// This method is rerun every time setState is called, for instance as done
// by the _incrementCounter method above.
//
// The Flutter framework has been optimized to make rerunning build methods
// fast, so that you can just rebuild anything that needs updating rather
// than having to individually change instances of widgets.
return Scaffold(
appBar: AppBar(
// Here we take the value from the MyHomePage object that was created by
// the App.build method, and use it to set our appbar title.
title: Text(widget.title),
),
body: Center(
child: GridView.count(
crossAxisCount: 2,
crossAxisSpacing: 70,
mainAxisSpacing: 70,
reverse: true,
controller: scrollController,
children: string.map((e) {
//string.map((e) {
return TweenAnimationBuilder(
tween: Tween<double>(begin: 0.9, end: 0),
curve: Curves.easeIn,
duration: const Duration(seconds: 2),
builder: ((context, value, child) {
return Transform.translate(
filterQuality: FilterQuality.low,
offset: e.isEven ? Offset(value * e * -500, 0.0) : Offset(value * e * 500, 0.0),
child: Transform.translate(
offset: e.isEven
? Offset(0.0, value * e * -500)
: Offset(0.0, value * e * -500),
child: child,
),
);
}),
child: Container(
child: Text(e.toString()),
color: Colors.red,
height: 50,
),
);
}).toList()),
),
floatingActionButton: FloatingActionButton(
onPressed: _incrementCounter,
tooltip: 'Increment',
child: const Icon(Icons.add),
), // This trailing comma makes auto-formatting nicer for build methods.
);
}
}
挣扎了一个星期。指导我在这里做错了什么。提前致谢
小智 6
我尝试实现这种效果
特征：
限制：
演示： https: //i.stack.imgur.com/lNzvi.jpg
代码：
轨道页面.dart
class OrbitPage extends StatelessWidget {
const OrbitPage({super.key});
@override
Widget build(BuildContext context) {
return Scaffold(
backgroundColor: Colors.black26,
body: Padding(
padding: const EdgeInsets.symmetric(
vertical: 30,
),
child: OrbitView.builder(
itemCount: 10,
itemBuilder: (context, index) {
return Placeholder(
child: CircleAvatar(
child: Center(
child: Text('$index'),
),
),
);
},
),
),
);
}
}
轨道视图.dart
import 'dart:math' as math;
import 'package:flutter/material.dart';
import 'package:flutter/scheduler.dart';
class OrbitView extends StatefulWidget {
/// number of items
final int itemCount;
/// number of vertical pairs
final int viewCount;
/// aspect ratio of the child widget
final double aspectRatio;
/// margin from the edge of screen
final double edgeMargin;
/// vertical margin
final double verticalMargin;
/// this distance affect rotation angle
final double shiftDistance;
final Duration animationDuration;
final Duration animationDelay;
final Curve opacityCurve, rotationCurve, animationCurve;
final Widget Function(BuildContext, int) itemBuilder;
const OrbitView.builder({
super.key,
this.viewCount = 5,
this.aspectRatio = 1,
this.edgeMargin = 20.0,
this.verticalMargin = 35.0,
this.shiftDistance = 100.0,
this.opacityCurve = Curves.easeIn,
this.rotationCurve = Curves.linear,
this.animationCurve = Curves.easeInOutQuad,
this.animationDuration = const Duration(seconds: 2),
this.animationDelay = const Duration(seconds: 1),
required this.itemCount,
required this.itemBuilder,
});
@override
State<OrbitView> createState() => _OrbitViewState();
}
class _OrbitViewState extends State<OrbitView> {
/// to simulate infinite backwords scroll
final _initialPage = 10000;
double _currentPage = 10000.0;
bool _duringInitialAnimation = true;
late final PageController _controller;
@override
void initState() {
_controller = PageController(
initialPage: _initialPage,
viewportFraction: math.min(.25, 1 / widget.viewCount),
);
_controller.addListener(updateCurrentPage);
SchedulerBinding.instance.addPostFrameCallback((_) async {
await Future.delayed(widget.animationDelay);
await _controller.animateToPage(
_initialPage - widget.viewCount,
duration: widget.animationDuration,
curve: widget.animationCurve,
);
_duringInitialAnimation = false;
});
super.initState();
}
@override
void dispose() {
_controller.removeListener(updateCurrentPage);
_controller.dispose();
super.dispose();
}
void updateCurrentPage() {
_currentPage = _controller.page!;
}
/// for each index (page), contains the left and the right widget
Widget left(BuildContext context, int index) {
final realIndex = (2 * index) % widget.itemCount;
return widget.itemBuilder(context, realIndex);
}
/// for each index (page), contains the left and the right widget
Widget right(BuildContext context, int index) {
final realIndex = (2 * index + 1) % widget.itemCount;
return widget.itemBuilder(context, realIndex);
}
/// build the left and the right widget
Widget buildNode(int i, Widget node, bool isLeft) {
return AnimatedBuilder(
animation: _controller,
child: AspectRatio(
aspectRatio: widget.aspectRatio,
child: node,
),
builder: (context, child) {
final dist = widget.shiftDistance + widget.edgeMargin;
final diff = _calc(i, _currentPage, widget.viewCount);
/// apply the curve to the position
final transDist = dist * widget.rotationCurve.transform(diff);
/// apply the curve to the opacity
double transOpactiy = widget.opacityCurve.transform(diff);
/// for initial animation
final offset = _initialPage - widget.viewCount ~/ 2;
/// initially hide some items for the scroll animation effect
if (_duringInitialAnimation && i > offset) transOpactiy = 0;
return Positioned(
top: isLeft ? 0 : widget.verticalMargin,
left: isLeft ? -widget.shiftDistance + transDist : null,
right: isLeft ? null : -widget.shiftDistance + transDist,
bottom: isLeft ? widget.verticalMargin : 0,
child: Opacity(opacity: transOpactiy, child: child!),
);
},
);
}
@override
Widget build(BuildContext context) {
return PageView.builder(
controller: _controller,
scrollDirection: Axis.vertical,
itemBuilder: (context, index) {
return Stack(
children: [
buildNode(index, left(context, index), true),
buildNode(index, right(context, index), false),
],
);
},
);
}
}
/// this function transforms the distance between
/// the index of the current page and the other nearby pages
///
/// e.g: initially for viewCount of 3 (only display 3 pages) we have
/// i = 9998, 9999, 10000, 10000, 10001, and p is 10000
/// the first and the last should not be displayed, we can do this like this:
///
/// this function maps the i values to 2, 1, 0, 1, 2 (abs)
/// then returns 0, 1, 1, 1, 0
double _calc(int i, double p, int viewCount) {
final dist = (i - p).abs();
/// index is inside view range
if (dist <= viewCount ~/ 2) return 1;
/// index is not inside view range
/// e.g in opacity this means not visible
if (dist >= viewCount ~/ 2 + 1) return 0;
/// index is partially inside view range
/// we can use this as opacity and rotation fraction
return viewCount ~/ 2 + 1 - dist;
}
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