本文介绍了vue左右侧联动滚动的实现代码，分享给大家，具体如下：
实现功能:
布局结构:
开源滚动库:
better-scroll.js
技术要点:
1.<scroll>是对紧邻的元素生效
如:
<scroll class='foods-wrapper'> <ul class=content> <li></li> </ul> </scroll>
初始化在<ul>元素上
2.foods-wrapper的高度小于content高度时才会发生滚动
3.点击左侧菜单列表时,只需要计算右侧对应的偏移距离 或是 计算对应的移动到的元素即可
方法一: 计算移动距离, 用scrollTo()方法
for (let i = 0; i < index; i++) {
height += this.$refs.item[i].offsetHeight
}
this.$refs.foodsWrapper.scrollTo(0, -height)
方法二: 计算移动到的元素,用scrollToElement()方法
let foodsEle = this.$refs.foodsUl.getElementsByClassName('item')[index]
this.$refs.foodsWrapper.scrollToElement(foodsEle, 400)
4.滚动右侧列表时,会稍复杂一些.
4.1. 因为需要知道滚动的元素在哪个item列表区间, 因此需要计算右侧五组item距离顶部的距离
_heightArr () {
let h = 0
let list = this.$refs.item
list.forEach((item, i) => {
h += list[i].clientHeight
this.itemHeight.push(h)
})
console.log(this.itemHeight) //[0, 481, 850, 2227, 2820, 3189]
}
4.2 时时监听滚动距离
需要在<scroll>中加以下参数
其中 listenScroll probeType参数 在created中定义:
created () {
this.listenScroll = true
this.probeType = 3
}
而@scroll=scroll是在scroll.vue中代理过来的方法:
//scroll.vue
if (this.listenScroll) {
let me = this
this.scroll.on('scroll', (position) => {
me.$emit('scroll', position) //参数position: position:{x:-10, y:24}
})
}
posiiton.y就是需要实时监听的参数,即:
scroll (position) {
this.scrolly = position.y
}
其中 scrolly 需要在data中提前定义:
data () {
return {
scrolly: -1
}
}
然后在watch中监听scrolly变化即可:
watch: {
scrolly (newy) {
if (newy >= 0) this.currentIndex = 0
let itemHeight = this.itemHeight
for (let i = 0; i < itemHeight.length - 1; i++) {
let h2 = itemHeight[i]
let h3 = itemHeight[i + 1]
if (-newy >= h2 && -newy < h3) {
this.currentIndex = i
return
}
}
}
}
代码部分:
//左侧结构
<scroll class='menu-wrapper'>
<ul>
<li
v-for='(item,index) in foodsList'
:key=index
class=item
:class="{active:currentIndex === index}"
@click=selectMenu(index)
>
<span>{{item.name}}</span>
</li>
</ul>
</scroll>
//右侧结构
<scroll class='foods-wrapper' ref=foodsWrapper :listenScroll=listenScroll :probeType = 'probeType' @scroll=scroll>
<ul ref=foodsUl>
<li v-for='(item,index) in foodsList' :key=index class=item ref=item :data-index=index>
<div class=title><span class='title-name'>{{item.name}}</span><span>{{item.description}}</span></div>
<ul>
<li v-for='(food,i) in item.foods' :key=i class=food>
//.........
//略去右侧详情代码
</li>
</ul>
</li>
</ul>
</scroll>
//js部分
<script>
import Scroll from "base/scroll"
const H = 112
export default {
data () {
return {
currentIndex: 0,
offset: 0,
scrolly: -1
}
},
created () {
this.listenScroll = true
this.probeType = 3
this.itemHeight = [0]
},
mounted () {
this.$nextTick(() => {
this._heightArr()
}, 20);
},
methods: {
selectMenu (index) {
let height = 0
this.currentIndex = index
for (let i = 0; i < index; i++) {
height += this.$refs.item[i].offsetHeight
}
let foodsEle = this.$refs.foodsUl.getElementsByClassName('item')[index]
this.$refs.foodsWrapper.scrollToElement(foodsEle, 400)
// this.$refs.foodsWrapper.scrollTo(0, -height)
this.offset = height
},
scroll (position) {
this.scrolly = position.y
},
_heightArr () {
let h = 0
let list = this.$refs.item
list.forEach((item, i) => {
h += list[i].clientHeight
this.itemHeight.push(h)
})
}
},
watch: {
scrolly (newy) {
if (newy >= 0) this.currentIndex = 0
let itemHeight = this.itemHeight
for (let i = 0; i < itemHeight.length - 1; i++) {
let h2 = itemHeight[i]
let h3 = itemHeight[i + 1]
if (-newy >= h2 && -newy < h3) {
this.currentIndex = i
return
}
}
}
},
components: {
Scroll
}
}
</script>
//scroll.vue
<template>
<div ref=wrapper>
<slot></slot>
</div>
</template>
<script>
import BScroll from 'better-scroll'
export default {
props: {
probeType: {
type: Number,
default: 1//* 1 滚动的时候会派发scroll事件，会截流。 * 2 滚动的时候实时派发scroll事件，不会截流。 * 3 除了实时派发scroll事件，在swipe的情况下仍然能实时派发scroll事件
},
click: {
type: Boolean,
default: true
},
scrollX: {
type: Boolean,
default: false
},
data: {
type: Array,
default: null
},
listenScroll: {
type: Boolean,
default: false
},
},
mounted () {
this.$nextTick(() => {
this.initScroll()
}, 20)
},
methods: {
initScroll () {
if (!this.$refs.wrapper) return
this.scroll = new BScroll(this.$refs.wrapper, {
probeType: this.probeType,
click: this.click,
scrollX: this.scrollX
})
if (this.listenScroll) {
let me = this
this.scroll.on('scroll', (position) => {
me.$emit('scroll', position)
})
}
},
enable () {
this.scroll && this.scroll.enable()
},
disable () {
this.scroll && this.scroll.disable()
},
refresh () {
this.scroll && this.scroll.refresh()
},
scrollTo () {
this.scroll && this.scroll.scrollTo.apply(this.scroll, arguments)
},
scrollToElement () {
this.scroll && this.scroll.scrollToElement.apply(this.scroll, arguments)
}
},
watch: {
data () {
setTimeout(() => {
this.scroll.refresh()
}, 20)
}
}
}
</script>
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