vue下拉刷新组件的开发及slot的使用详解

<template>
	<div class="pullRefreshView" @touchmove="touchmove" @touchstart="touchstart" @touchend="touchend">
		<div ref="circleIcon" class="circle-icon">
			<div ref="circleIconInner" class="circle-icon-inner"></div>
		</div>
		<slot></slot>
	</div>
</template>

<style>
	.circle-icon{
		position: absolute;
		left: 0.625rem;
		: -1.875rem;
	}
	.circle-icon-inner{
		width: 1.5625rem;
		height: 1.5625rem;
		background-image: url('圆圈图片地址');
		background-size: cover;
	}
	.circle-rotate{
		animation: xuzhuan .8s linear infinite;
	}
	@keyframes xuzhuan{
		0%{}
		25%{}
		50%{}
		75%{}
		100%{}
	}
</style>

touchstart(evt){
	this.pullRefresh.dragStart=evt.targetTouches[0].clientY
	this.$refs.circleIcon.style.webkitTransition='none'
},

touchmove(evt){
	if(this.pullRefresh.dragStart===null){
		return
	}
	let target=evt.targetTouches[0]
	// 向上滑为正，向下拉为负
	this.pullRefresh.percentage=(this.pullRefresh.dragStart-target.clientY)/window.screen.height
	let scrollTop=document.documentElement.scrollTop || document.body.scrollTop
	if(scrollTop===0){
		//this.pullRefresh指data中的pullRefresh对象（下方有），而evt即事件event参数
		if(this.pullRefresh.percentage<0 && evt.cancelable){
			evt.preventDefault()
			this.pullRefresh.joinRefreshFlag=true
			let translateY=-this.pullRefresh.percentagethis.pullRefresh.moveCount
			if(Math.abs(this.pullRefresh.percentage)<=this.pullRefresh.dragThreshold){
				let rotate=translateY/30360
				this.$refs.circleIcon.style.webkitTransform='translate3d(0'+translateY+'px,0) rotate('+rotate+'deg)'
			}
		}else{
			if(this.pullRefresh.joinRefreshFlag===null){
				this.pullRefresh.joinRefreshFlag=false
			}
		}
	}else{
		if(this.pullRefresh.joinRefreshFlag===null){
			this.pullRefresh.joinRefreshFlag=false
		}
	}
},

touchend(evt){
	if(this.pullRefresh.percentage===0){
		return
	}
	if(Math.abs(this.pullRefresh.percentage)>this.pullRefresh.dragThreshold && this.pullRefresh.joinRefreshFlag){
		this.$emit('onRefresh')
		this.$refs.circleIconInner.classList.add('circle-rotate')
		setTimeout(()=>{
			this.$refs.circleIconInner.classList.remove('circle-rotate')
			this.$refs.circleIcon.style.webkitTransition='330ms'
			this.$refs.circleIcon.style.webkitTransform='translate3d(0,0,0) rotate(0deg)'
		},700)
	}else{
		if(this.pullRefresh.joinRefreshFlag){
			this.$refs.circleIcon.style.webkitTransition='330ms'
			this.$refs.circleIcon.style.webkitTransform='translate3d(0,0,0) rotate(0deg)'
		}
	}
	this.pullRefresh.joinRefreshFlag=null
	this.pullRefresh.dragStart=null
	this.pullRefresh.percentage=0
}

data(){
	return{
		pullRefresh:{
			dragStart:null, //开始抓取标志位
			percentage:0, //拖动量(百分比)
			dragThreshold:0.3, //临界值
			moveCount:200, //位移系数，可以调节圆形图片icon的运动速率
			joinRefreshFlag:null, //进入刷新状态的标志位（true）
		}
	}
},

<div>
	<h2>我是子组件</h2>
	<slot>只有在没有内容分发的情况下这句话才会出现</slot>
</div>

<div>
	<h1>这是父组件地盘</h1>
	<my-ponent>
		<p>这是一些初始内容</p>
		<p>这是更多的内容</p>
	</my-ponent>
</div>

<div> 
	<h1>这是父组件地盘</h1>
	<div> 
		<h2>我是子组件</h2>
		<p>这是一些初始内容</p>
		<p>这是更多的内容</p>
	</div> 
</div>