Flutter封装组动画混合动画AnimatedGroup示例详解
目录
- 一、来源
- 二、AnimatedGroup使用示例:
- 三、AnimatedGroup源码
- 最后
一、来源
项目中遇到混合动画的情况,每次实现都需要生命一堆属性,让代码变得杂乱,难以维护。
参考 iOS 组动画 CAAimationGroup, 随花半天时间封装一个混合动画组件 AnimatedGroup。
此组件基于极简、高扩展、高适用的封装原则,基本满足当前项目开发。
二、AnimatedGroup使用示例:
// // AnimatedGroupDemo.dart // flutter_templet_project // // Created by shang on 12/6/21 5:52 PM. // Copyright 12/6/21 shang. All rights reserved. // import 'package:flutter/material.dart'; import 'package:flutter_templet_project/basicWidget/animated_group.dart'; class AnimatedGroupDemo extends StatefulWidget { AnimatedGroupDemo({ Key? key, this.title}) : super(key: key); final String? title; @override _AnimatedGroupDemoState createState() => _AnimatedGroupDemoState(); } class _AnimatedGroupDemoState extends State<AnimatedGroupDemo> { GlobalKey<AnimatedGroupState> _globalKey = GlobalKey(); final _animations = <AnimatedGroupItemModel>[ AnimatedGroupItemModel( tween: Tween<double>(begin: .0, end: 300.0,), begin: 0.0, end: 0.6 ), AnimatedGroupItemModel( tween: ColorTween(begin: Colors.green, end: Colors.red,), begin: 0.0, end: 0.6 ), AnimatedGroupItemModel( tween: Tween<EdgeInsets>( begin: const EdgeInsets.only(left: .0), end: const EdgeInsets.only(left: 100.0), ), begin: 0.6, end: 1.0 ), ]; @override Widget build(BuildContext context) { return Scaffold( appBar: AppBar( title: Text(widget.title ?? "$widget"), ), body: Center( child: Column( children: [ ElevatedButton( child: Text("start animation"), onPressed: (){ _globalKey.currentState?.palyeAnimations(isRemovedOnCompletion: false); }, ), Container( width: 300, height: 300, child: AnimatedGroup( key: _globalKey, duration: Duration(milliseconds: 2000), animations: _animations, child: Text("AnimatedGroupWidget 混合动画", style: TextStyle(color: Colors.white, backgroundColor: Colors.green),), builder: (BuildContext context, Widget? child, List<Animation<dynamic>> animations) { final aHeight = animations[0]; final aColor = animations[1]; final aPadding = animations[2]; return Stack( children: [ Container( alignment: Alignment.bottomCenter, padding: aPadding.value, child: Container( color: aColor.value, width: 50.0, height: aHeight.value, ), ), Center(child: child!) ], ); }, ), decoration: BoxDecoration( color: Colors.black.withOpacity(0.1), border: Border.all( color: Colors.black.withOpacity(0.5), ) ), ) ], ), ), ); } }
三、AnimatedGroup源码
// // AnimatedGroupDemo.dart // flutter_templet_project // // Created by shang on 1/19/23 8:21 AM. // Copyright 1/19/23 shang. All rights reserved. // import 'package:flutter/material.dart'; /// 混合动画回调类型 typedef AnimatedGroupBuilder = Widget Function(BuildContext context, Widget? child, List<Animation<dynamic>> animations); class AnimatedGroup extends StatefulWidget { /// 混合动画 AnimatedGroup({ Key? key, required this.animations, required this.builder, this.controller, this.duration = const Duration(milliseconds: 2000), this.child, }) : super(key: key); /// 混合动画数组 List<AnimatedGroupItemModel> animations; /// 混合动画回调 AnimatedGroupBuilder builder; /// 控制器 AnimationController? controller; /// AnimationController 控制的 duration 属性 Duration? duration; /// 不需要多次构建的部分 Widget? child; @override AnimatedGroupState createState() => AnimatedGroupState(); } /// 混合动画 State class AnimatedGroupState extends State<AnimatedGroup> with TickerProviderStateMixin { AnimationController? _controller; /// 仅限于无法满足功能时使用(透传对象, 方便二次开发) AnimationController get controller => _controller!; List<Animation<dynamic>> _animations = []; @override void initState() { _controller = widget.controller ?? AnimationController(duration: widget.duration, vsync: this); _animations = widget.animations.map((e) => e.tween.animate(_buildAnim(e.begin, e.end))).toList(); super.initState(); } @override void dispose() { _controller?.dispose(); super.dispose(); } @override Widget build(BuildContext context) { return AnimatedBuilder( animation: _controller!, child: widget.child, builder: (BuildContext context, Widget? child){ return widget.builder(context, child, _animations); } ); } /// 开始执行动画 /// /// isRemovedOnCompletion 是否单程动画 /// /// isReverse 是否逆转动画 palyeAnimations({bool isRemovedOnCompletion = true, bool isReverse = false}) async { try { if (!isReverse) { await _controller?.forward().orCancel; if (!isRemovedOnCompletion) { await _controller?.reverse().orCancel; } } else { await _controller?.reverse().orCancel; if (!isRemovedOnCompletion) { await _controller?.forward().orCancel; } } } on TickerCanceled { // the animation got canceled, probably because we were disposed }; } /// 创建动画对象 CurvedAnimation _buildAnim(double begin, double end) { return CurvedAnimation( parent: _controller!, curve: Interval( begin, end, curve: Curves.ease, ), ); } } /// 混合动画单个动画模型 class AnimatedGroupItemModel{ /// 混合动画单个动画模型 AnimatedGroupItemModel({ required this.tween, required this.begin, required this.end, }); /// 动画 Tween Tween tween; /// 动画开始时间 (0 - 1.0) double begin; /// 动画结束时间 (0 - 1.0) double end; }
最后
代码复制到项目中可直接运行;
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