重新堆叠是组件最后一个功能，同时也是最重要和复杂的功能。在我们的代码里，stack-item的排序依赖绑定:style的transformIndex和transform函数，函数里判定的条件是currentPage，那是不是改变currentPage，让其+1，即可完成重新堆叠呢？
答案没有那么简单，因为我们滑出是动画效果，会进行300ms的时间，而currentPage变化引起的重排，会立即变化，打断动画的进行。因此我们需要先修改transform函数的排序条件，后改变currentPage。
#### 具体实现
修改transform函数排序条件
让currentPage+1
添加onTransitionEnd事件，在滑出结束后，重新放置stack列表中
代码如下：
<template> <ul> <li v-for="(item, index) in pages" :style="[transformIndex(index),transform(index)]" @touchmove.stop.capture="touchmove" @touchstart.stop.capture="touchstart" @touchend.stop.capture="touchend" @mousedown.stop.capture="touchstart" @mouseup.stop.capture="touchend" @mousemove.stop.capture="touchmove" @webkit-transition-end="onTransitionEnd" @transitionend="onTransitionEnd" > <img :src="item.src"> </li> </ul> </template> <script> export default { props: { // pages数据包含基础的图片数据 pages: { type: Array, default: [] } }, data () { return { // basicdata数据包含组件基本数据 basicdata: { start: {}, // 记录起始位置 end: {}, // 记录终点位置 currentPage: 0 // 默认首图的序列 }, // temporaryData数据包含组件临时数据 temporaryData: { poswidth: '', // 记录位移 posheight: '', // 记录位移 lastPosWidth: '', // 记录上次最终位移 lastPosHeight: '', // 记录上次最终位移 tracking: false, // 是否在滑动，防止多次操作，影响体验 animation: false, // 首图是否启用动画效果，默认为否 opacity: 1, // 记录首图透明度 swipe: false // onTransition判定条件 } } }, methods: { touchstart (e) { if (this.temporaryData.tracking) { return } // 是否为touch if (e.type === 'touchstart') { if (e.touches.length > 1) { this.temporaryData.tracking = false return } else { // 记录起始位置 this.basicdata.start.t = new Date().getTime() this.basicdata.start.x = e.targetTouches[0].clientX this.basicdata.start.y = e.targetTouches[0].clientY this.basicdata.end.x = e.targetTouches[0].clientX this.basicdata.end.y = e.targetTouches[0].clientY } // pc操作 } else { this.basicdata.start.t = new Date().getTime() this.basicdata.start.x = e.clientX this.basicdata.start.y = e.clientY this.basicdata.end.x = e.clientX this.basicdata.end.y = e.clientY } this.temporaryData.tracking = true this.temporaryData.animation = false }, touchmove (e) { // 记录滑动位置 if (this.temporaryData.tracking && !this.temporaryData.animation) { if (e.type === 'touchmove') { this.basicdata.end.x = e.targetTouches[0].clientX this.basicdata.end.y = e.targetTouches[0].clientY } else { this.basicdata.end.x = e.clientX this.basicdata.end.y = e.clientY } // 计算滑动值 this.temporaryData.poswidth = this.basicdata.end.x - this.basicdata.start.x this.temporaryData.posheight = this.basicdata.end.y - this.basicdata.start.y } }, touchend (e) { this.temporaryData.tracking = false this.temporaryData.animation = true // 滑动结束，触发判断 // 简单判断滑动宽度超出100像素时触发滑出 if (Math.abs(this.temporaryData.poswidth) >= 100) { // 最终位移简单设定为x轴200像素的偏移 let ratio = Math.abs(this.temporaryData.posheight / this.temporaryData.poswidth) this.temporaryData.poswidth = this.temporaryData.poswidth >= 0 ? this.temporaryData.poswidth + 200 : this.temporaryData.poswidth - 200 this.temporaryData.posheight = this.temporaryData.posheight >= 0 ? Math.abs(this.temporaryData.poswidth * ratio) : -Math.abs(this.temporaryData.poswidth * ratio) this.temporaryData.opacity = 0 this.temporaryData.swipe = true // 记录最终滑动距离 this.temporaryData.lastPosWidth = this.temporaryData.poswidth this.temporaryData.lastPosHeight = this.temporaryData.posheight // currentPage+1 引发排序变化 this.basicdata.currentPage += 1 // currentPage切换，整体dom进行变化，把第一层滑动置零 this.$nextTick(() => { this.temporaryData.poswidth = 0 this.temporaryData.posheight = 0 this.temporaryData.opacity = 1 }) // 不满足条件则滑入 } else { this.temporaryData.poswidth = 0 this.temporaryData.posheight = 0 this.temporaryData.swipe = false } }, onTransitionEnd (index) { // dom发生变化后，正在执行的动画滑动序列已经变为上一层 if (this.temporaryData.swipe && index === this.basicdata.currentPage - 1) { this.temporaryData.animation = true this.temporaryData.lastPosWidth = 0 this.temporaryData.lastPosHeight = 0 this.temporaryData.swipe = false } }, // 非首页样式切换 transform (index) { if (index > this.basicdata.currentPage) { let style = {} let visible = 3 let perIndex = index - this.basicdata.currentPage // visible可见数量前滑块的样式 if (index <= this.basicdata.currentPage + visible - 1) { style['opacity'] = '1' style['transform'] = 'translate3D(0,0,' + -1 * perIndex * 60 + 'px' + ')' style['zIndex'] = visible - index + this.basicdata.currentPage style['transitionTimingFunction'] = 'ease' style['transitionDuration'] = 300 + 'ms' } else { style['zIndex'] = '-1' style['transform'] = 'translate3D(0,0,' + -1 * visible * 60 + 'px' + ')' } return style // 已滑动模块释放后 } else if (index === this.basicdata.currentPage - 1) { let style = {} // 继续执行动画 style['transform'] = 'translate3D(' + this.temporaryData.lastPosWidth + 'px' + ',' + this.temporaryData.lastPosHeight + 'px' + ',0px)' style['opacity'] = '0' style['zIndex'] = '-1' style['transitionTimingFunction'] = 'ease' style['transitionDuration'] = 300 + 'ms' return style } }, // 首页样式切换 transformIndex (index) { // 处理3D效果 if (index === this.basicdata.currentPage) { let style = {} style['transform'] = 'translate3D(' + this.temporaryData.poswidth + 'px' + ',' + this.temporaryData.posheight + 'px' + ',0px)' style['opacity'] = this.temporaryData.opacity style['zIndex'] = 10 if (this.temporaryData.animation) { style['transitionTimingFunction'] = 'ease' style['transitionDuration'] = 300 + 'ms' } return style } } } } </script>
ok~ 完成了上面的四步，堆叠组件的基本功能就已经实现，快来看看效果吧
堆叠滑动效果已经出来了，但是探探在体验上，还增加了触碰角度偏移，以及判定滑出面积比例
角度偏移的原理，是在用户每次进行touch时，记录用户触碰位置，计算出最大的偏移角度，在滑动出现位移时，线性增加角度以至最大的偏移角度。
使用在stack中具体要做的是：
touchmove中计算出所需角度和方向
touchend及onTransitionEnd中将角度至零
判定滑出面积比例，主要通过偏移量计算出偏移面积，从而得到面积比例，完成判断
完整的代码和demo可以在 github 上查看源码，这里就不贴出来了
谢谢大家看完这篇文章，喜欢可以在github上给个:star:️ ，最后祝大家在探探上都能找到前女友:green_heart:
总结