Flutter实现红包动画效果的示例代码
作者:天选的打工人
这篇文章主要为大家详细介绍了如何利用Flutter实现红包的动画效果,文中的示例代码讲解详细,具有一定的借鉴价值,感兴趣的小伙伴可以了解一下
前言
红包动画效果实现,如图:
该效果的实现难道其实比较简单,就是基础的平移、旋转和缩放动画,但比较麻烦的就是需要写很多小动画组合,共由11个小动画组合而成。
动画拆解
红包显示动画
红包显示时的动画,由0到1的放大。
late AnimationController controller; late Animation<double> animation; ///红包展开动画 controller = AnimationController( duration: const Duration(milliseconds: 200), vsync: this); WidgetsBinding.instance.addPostFrameCallback((timeStamp) { controller.forward(); }); animation = Tween(begin: 0.0, end: 1.0).animate(controller);
红包未开前,平移动画
红包未开前,整体微微上下平移
late AnimationController bgController; late Animation<Offset> bgAnimation; ///红包背景上下平移动画 bgController = AnimationController( duration: const Duration(milliseconds: 1000), vsync: this) ..repeat(reverse: true); bgAnimation = Tween<Offset>(begin: Offset.zero, end: const Offset(0.0, -10)) .animate(bgController);
红包未开前,”开“按钮缩放动画
"开"按钮缩放动画,由1到0.8,动画循环执行。
late AnimationController openBtController; late Animation<double> openBtAnimation; ///红包未开时,按钮缩放动画 openBtController = AnimationController( duration: const Duration(milliseconds: 1000), vsync: this) ..repeat(reverse: true); openBtAnimation = Tween(begin: 1.0, end: 0.8).animate(openBtController);
红包开启后,背景光显示动画
开红包后,会显示背景光
late AnimationController openLightScaleController; late Animation<double> openLightScaleAnimation; ///开红包后,显示背景光 openLightScaleController = AnimationController( duration: const Duration(milliseconds: 200), vsync: this); openLightScaleAnimation = Tween(begin: 0.4, end: 1.0).animate(openLightScaleController);
红包开启后,背景光放大动画
开红包后,背景光微微放大1.2倍,动画循环执行。
late AnimationController lightScaleController; late Animation<double> lightScaleAnimation; ///背景光放大动画,只放大1.2倍 lightScaleController = AnimationController( duration: const Duration(milliseconds: 1000), vsync: this) ..repeat(reverse: true); lightScaleAnimation = Tween(begin: 1.0, end: 1.2).animate(lightScaleController);
红包开启后,背景光旋转动画
开红包后,背景光微微旋转,只旋转0.02的弧度,动画循环执行。
late AnimationController lightRotateController; late Animation<double> lightRotateAnimation; ///背景光旋转动画,微微旋转,只旋转0.02的弧度 lightRotateController = AnimationController( duration: const Duration(milliseconds: 1000), vsync: this) ..repeat(reverse: true); lightRotateAnimation = Tween(begin: 0.0, end: 0.02).animate(lightRotateController);
红包开启后,新背景放大动画
开红包后,原红包背景缩小至不见,新红包背景显示
late AnimationController openController; late Animation<double> openAnimation; ///开红包 背景放大动画 openController = AnimationController( duration: const Duration(milliseconds: 200), vsync: this); openAnimation = Tween(begin: 0.4, end: 1.0).animate(openController);
红包开启后,新背景平移动画
开红包后,新背景也微微上下平移
late AnimationController openBgController; late Animation<Offset> openBgAnimation; ///红包背景上下平移动画 openBgController = AnimationController( duration: const Duration(milliseconds: 1000), vsync: this) ..repeat(reverse: true); openBgAnimation = Tween<Offset>(begin: Offset.zero, end: const Offset(0.0, -10)) .animate(openBgController);
红包开启后,”立即使用“按钮缩放动画
开红包后,”立即使用“按钮缩放动画,由1到0.9,动画循环执行。
late AnimationController useBtController; late Animation<double> useBtAnimation; ///立即使用按钮缩放动画 useBtController = AnimationController( duration: const Duration(milliseconds: 1000), vsync: this) ..repeat(reverse: true); useBtAnimation = Tween(begin: 1.0, end: 0.9).animate(useBtController);
红包开启后,金额显示的卡片上移动画
开红包后,显示金额的卡片上移
late final AnimationController offsetTopController; late final Animation<Offset> offsetTopAnimation; ///卡片上移动画 offsetTopController = AnimationController( duration: const Duration(milliseconds: 500), vsync: this, ); offsetTopAnimation = Tween<Offset>( begin: const Offset(0, 0.6), end: const Offset(0, 0), ).animate(CurvedAnimation( parent: offsetTopController, curve: Curves.easeInOutCubic, ));
红包开启后,金额显示的动画
开红包后,金额会从某个数值自增至实际金额数值
late AnimationController priceController; late Animation<double> priceAnimation; ///金额变换效果 price = widget.price; double startPrice = 0; if (price <= 100) { ///小于100的金额从0开始自增 startPrice = 0; } else { ///大于100的金额对半开始自增 startPrice = price / 2; } priceController = AnimationController( duration: const Duration(milliseconds: 600), vsync: this); priceAnimation = Tween(begin: startPrice, end: price).animate(priceController);
资源文件
class ImageAssets{ static const String homeIcRed1Webp = 'assets/home/ic-red-1.webp'; static const String homeIcRedBgWebp = 'assets/home/ic-red-bg.webp'; static const String homeIcRedLightWebp = 'assets/home/ic-red-light.webp'; static const String homeIcRedOpenWebp = 'assets/home/ic-red-open.webp'; static const String homeIcRed2BgWebp = 'assets/home/ic-red2-bg.webp'; static const String homeIcRed2BottomWebp = 'assets/home/ic-red2-bottom.webp'; static const String homeIcRed2BtWebp = 'assets/home/ic-red2-bt.webp'; static const String homeIcRed2TopBgWebp = 'assets/home/ic-red2-top-bg.webp'; static const String homeIcRed2TopWebp = 'assets/home/ic-red2-top.webp'; static const String homeIcCloseWhiteWebp = 'assets/home/ic-close-white.webp'; }
homeIcRedBgWebp :
homeIcRed1Webp:
homeIcRedLightWebp:
homeIcRedOpenWebp:
homeIcRed2BgWebp:
homeIcRed2BottomWebp:
homeIcRed2BtWebp:
homeIcRed2TopBgWebp:
homeIcRed2TopWebp:
完整代码
项目用到了GetX,需要注意导入。
import 'package:flutter/material.dart'; import 'package:get/get.dart'; ///新人红包 class RedEnvelopeDialog extends StatefulWidget { double price; RedEnvelopeDialog({Key? key, required this.price}) : super(key: key); @override _PageState createState() => _PageState(); } class _PageState extends State<RedEnvelopeDialog> with TickerProviderStateMixin { double width = 0; double height = 0; double openSize = 0; double btBgTopMargin = 0; double openBgBottomMargin = 0; double openBgTopMargin = 0; double openTopBgHeight = 0; double openBottomBgHeight = 0; double openTopBgBottomMargin = 0; double moveHeight = 0; double openHeight = 0; double useBtWidth = 0; late AnimationController controller; late Animation<double> animation; late AnimationController openBtController; late Animation<double> openBtAnimation; late AnimationController lightScaleController; late Animation<double> lightScaleAnimation; late AnimationController lightRotateController; late Animation<double> lightRotateAnimation; late AnimationController openLightScaleController; late Animation<double> openLightScaleAnimation; late AnimationController bgController; late Animation<Offset> bgAnimation; late AnimationController openController; late Animation<double> openAnimation; late AnimationController openBgController; late Animation<Offset> openBgAnimation; late AnimationController useBtController; late Animation<double> useBtAnimation; late final AnimationController offsetTopController; late final Animation<Offset> offsetTopAnimation; late AnimationController priceController; late Animation<double> priceAnimation; RxBool showOpen = false.obs; double price = 0; @override void initState() { super.initState(); ///根据设计稿比例计算实际数值 width = Get.width - 100; height = (332 / 273) * width; openSize = (78 / 332) * height; btBgTopMargin = (20 / 332) * height; openHeight = (332 / 273) * width; openBgBottomMargin = (12 / 273) * width; openBgTopMargin = (50 / 273) * width; openTopBgHeight = (194 / 273) * width; openBottomBgHeight = (189 / 273) * width; openTopBgBottomMargin = (138 / 273) * width; moveHeight = (143 / 273) * width; useBtWidth = (178 / 273) * width; ///红包展开动画 controller = AnimationController( duration: const Duration(milliseconds: 200), vsync: this); WidgetsBinding.instance.addPostFrameCallback((timeStamp) { controller.forward(); }); animation = Tween(begin: 0.0, end: 1.0).animate(controller); ///开按钮缩放动画 openBtController = AnimationController( duration: const Duration(milliseconds: 1000), vsync: this) ..repeat(reverse: true); openBtAnimation = Tween(begin: 1.0, end: 0.8).animate(openBtController); ///背景光显示动画 openLightScaleController = AnimationController( duration: const Duration(milliseconds: 200), vsync: this); openLightScaleAnimation = Tween(begin: 0.4, end: 1.0).animate(openLightScaleController); ///背景光放大动画,只放大1.2倍 lightScaleController = AnimationController( duration: const Duration(milliseconds: 1000), vsync: this) ..repeat(reverse: true); lightScaleAnimation = Tween(begin: 1.0, end: 1.2).animate(lightScaleController); ///背景光旋转动画,微微旋转,只旋转0.02的弧度 lightRotateController = AnimationController( duration: const Duration(milliseconds: 1000), vsync: this) ..repeat(reverse: true); lightRotateAnimation = Tween(begin: 0.0, end: 0.02).animate(lightRotateController); ///红包背景上下平移动画 bgController = AnimationController( duration: const Duration(milliseconds: 1000), vsync: this) ..repeat(reverse: true); bgAnimation = Tween<Offset>(begin: Offset.zero, end: const Offset(0.0, -10)) .animate(bgController); ///开红包 背景放大动画 openController = AnimationController( duration: const Duration(milliseconds: 200), vsync: this); openAnimation = Tween(begin: 0.4, end: 1.0).animate(openController); ///开红包背景上下平移动画 openBgController = AnimationController( duration: const Duration(milliseconds: 1000), vsync: this) ..repeat(reverse: true); openBgAnimation = Tween<Offset>(begin: Offset.zero, end: const Offset(0.0, -10)) .animate(openBgController); ///开按钮缩放动画 useBtController = AnimationController( duration: const Duration(milliseconds: 1000), vsync: this) ..repeat(reverse: true); useBtAnimation = Tween(begin: 1.0, end: 0.9).animate(useBtController); ///卡片上移动画 offsetTopController = AnimationController( duration: const Duration(milliseconds: 500), vsync: this, ); offsetTopAnimation = Tween<Offset>( begin: const Offset(0, 0.6), end: const Offset(0, 0), ).animate(CurvedAnimation( parent: offsetTopController, curve: Curves.easeInOutCubic, )); ///金额变换效果 price = widget.price; double startPrice = 0; if (price <= 100) { ///小于100的金额从0开始自增 startPrice = 0; } else { ///大于100的金额对半开始自增 startPrice = price / 2; } priceController = AnimationController( duration: const Duration(milliseconds: 600), vsync: this); priceAnimation = Tween(begin: startPrice, end: price).animate(priceController); } @override void dispose() { controller.dispose(); openBtController.dispose(); lightScaleController.dispose(); lightRotateController.dispose(); openLightScaleController.dispose(); bgController.dispose(); openController.dispose(); openBgController.dispose(); useBtController.dispose(); offsetTopController.dispose(); priceController.dispose(); super.dispose(); } @override Widget build(BuildContext context) { return Material( color: Colors.transparent, child: Stack( alignment: Alignment.center, children: [ Column( mainAxisSize: MainAxisSize.min, crossAxisAlignment: CrossAxisAlignment.center, mainAxisAlignment: MainAxisAlignment.center, children: [ Stack( alignment: Alignment.center, children: [ ///背景光 Obx( () => Visibility( visible: showOpen.value, child: AnimatedBuilder( animation: openLightScaleAnimation, builder: (context, child) { return Transform.scale( scale: openLightScaleAnimation.value, child: AnimatedBuilder( animation: lightScaleAnimation, builder: (context, child) { return Transform.scale( scale: lightScaleAnimation.value, child: AnimatedBuilder( animation: lightRotateAnimation, builder: (context, child) { return Transform.rotate( angle: lightRotateAnimation.value, child: Image.asset( ImageAssets.homeIcRedLightWebp, width: double.infinity, fit: BoxFit.fitWidth, ), ); }, ), ); }, ), ); }, ), ), ), ///开红包前 AnimatedBuilder( animation: animation, builder: (context, child) { return Transform.scale( scale: animation.value, child: Container( margin: EdgeInsets.all(50), child: AnimatedBuilder( animation: bgAnimation, builder: (context, child) { return Transform.translate( offset: bgAnimation.value, child: Stack( children: [ Image.asset( ImageAssets.homeIcRedBgWebp, width: double.infinity, fit: BoxFit.fitWidth, ), SizedBox( height: height, width: width, child: Column( children: [ Expanded( child: Column( mainAxisAlignment: MainAxisAlignment.center, children: [ Text( "新人见面礼", style: TextStyle( fontSize: 30, color: const Color( 0xFFFFDC81)), ), SizedBox( height: 10, ), Text( "$priceRellyStr元", style: TextStyle( fontSize: 30, color: const Color( 0xFFFFBB81)), ), SizedBox( height: 5, ), Container( padding: EdgeInsets.symmetric( horizontal: 12, vertical: 4), decoration: BoxDecoration( color: const Color( 0xFFDC1215), borderRadius: BorderRadius .circular(6), ), child: Text( "无门槛", style: TextStyle( fontSize: 15, color: const Color( 0xFFFF862F)), ), ) ], ), flex: 173, ), Expanded( child: Stack( alignment: Alignment.topCenter, children: [ Container( height: double.infinity, alignment: Alignment .bottomCenter, margin: EdgeInsets.only( bottom: 20), child: Text( "新人专享\u3000福利大派送", style: TextStyle( fontSize: 14, color: const Color( 0xFFFF6571)), ), ), Padding( padding: EdgeInsets.only( top: btBgTopMargin), child: Image.asset( ImageAssets .homeIcRed1Webp, width: double.infinity, fit: BoxFit.fitWidth, ), ), GestureDetector( child: AnimatedBuilder( animation: openBtAnimation, builder: (context, child) { return Transform .scale( scale: openBtAnimation .value, child: Image.asset( ImageAssets .homeIcRedOpenWebp, width: openSize, height: openSize, ), ); }, ), onTap: () { controller.reverse(); showOpen.value = true; openController .forward(); openLightScaleController .forward(); offsetTopController .forward() .whenComplete(() => offsetTopController .stop()); priceController .forward() .whenComplete(() => priceController .stop()); }, ) ], ), flex: 159, ) ], ), ) ], ), ); }, ), )); }), ///开红包后 Obx(() => Visibility( visible: showOpen.value, child: AnimatedBuilder( animation: openAnimation, builder: (context, child) { return Transform.scale( scale: openAnimation.value, child: AnimatedBuilder( animation: openBgAnimation, builder: (context, child) { return Transform.translate( offset: openBgAnimation.value, child: Container( height: openHeight, margin: EdgeInsets.all(50), child: Stack( alignment: Alignment.bottomCenter, children: [ Padding( padding: EdgeInsets.only( bottom: openBgBottomMargin, top: openBgTopMargin), child: Image.asset( ImageAssets .homeIcRed2BgWebp, width: double.infinity, fit: BoxFit.fitWidth, ), ), Padding( padding: EdgeInsets.only( bottom: openTopBgBottomMargin), child: SlideTransition( position: offsetTopAnimation, child: Stack( alignment: Alignment.center, children: [ Image.asset( ImageAssets .homeIcRed2TopBgWebp, height: openTopBgHeight, fit: BoxFit.fitWidth, ), Container( height: openTopBgHeight, width: double .infinity, alignment: Alignment .center, child: Column( mainAxisAlignment: MainAxisAlignment .center, crossAxisAlignment: CrossAxisAlignment .center, children: [ Expanded( child: Column( children: [ Stack( alignment: Alignment.center, children: [ Image.asset( ImageAssets.homeIcRed2TopWebp, height: (30 / 273) * width, fit: BoxFit.fitHeight, ), Container( width: (184 / 273) * width, alignment: Alignment.center, padding: EdgeInsets.symmetric(horizontal: 8), child: Text( "开门红包", style: TextStyle( fontSize: 16, color: const Color(0xFFBA683D), ), maxLines: 1, overflow: TextOverflow.ellipsis, ), ) ], ), Expanded( child: Container( alignment: Alignment.center, child: Row( crossAxisAlignment: CrossAxisAlignment.end, mainAxisAlignment: MainAxisAlignment.center, children: [ AnimatedBuilder( animation: priceController, builder: (BuildContext context, Widget? child) { return Text( priceStr, style: TextStyle(fontSize: 48, color: const Color(0xFFF30313), height: 1, fontWeight: FontWeight.bold), ); }, ), Text( '元', style: TextStyle(fontSize: 20, height: 2, color: Color(0xFF141414)), ) ], ), )) ], ), flex: 128, ), Expanded( child: Column( children: [ Expanded( child: Container( alignment: Alignment.bottomCenter, child: Text("永久有效", textAlign: TextAlign.center, style: TextStyle( fontSize: 12, color: const Color(0xFF8A8A8A), height: 1, )), ), flex: 2, ), Expanded( child: const SizedBox(), flex: 3, ) ], ), flex: 65, ) ], )) ], )), ), Image.asset( ImageAssets .homeIcRed2BottomWebp, width: double.infinity, fit: BoxFit.fitWidth, ), Column( children: [ Expanded( child: const SizedBox(), flex: 143, ), Expanded( child: Container( alignment: Alignment.center, child: Column( mainAxisAlignment: MainAxisAlignment .center, children: [ SizedBox( height: 20), AnimatedBuilder( animation: useBtAnimation, builder: (context, child) { return Transform.scale( scale: useBtAnimation.value, child: GestureDetector( onTap: () { //todo 点击事件 }, child: Stack( alignment: Alignment.center, children: [ Image.asset( ImageAssets.homeIcRed2BtWebp, width: useBtWidth, fit: BoxFit.fitWidth, ), Text("立即领取", style: TextStyle(fontSize: 16, color: const Color(0xFFFFF0E1))), ], ))); }), SizedBox( height: ((30 / 273) * width), ), Text( "可在“我的-优惠券”中查看", style: TextStyle( fontSize: 12, color: const Color( 0xFFFF6571)), ), ], )), flex: 189, ), ], ) ], ), )); })); }))) ], ) ], ), //关闭按钮 GestureDetector( onTap: () { Get.back(); }, child: Container( margin: EdgeInsets.only(bottom: height * 1.5, left: width), child: Image.asset( ImageAssets.homeIcCloseWhiteWebp, width: 21, height: 21, ), )) ], ), ); } ///金额数值变化 String get priceStr { if (price % 1 == 0) { return (priceAnimation.value.toInt()).toString(); } else { return priceAnimation.value.toStringAsFixed(2); } } ///小数据点后没有尾数则不显示 String get priceRellyStr { if (price % 1 == 0) { return (price.toInt()).toString(); } else { String pr = price.toStringAsFixed(2); if (pr.endsWith("0")) { return pr.substring(0, pr.length - 1); } return price.toStringAsFixed(2); } } }
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