const IScroll = require('iscroll')
const VIScroll = {
 install: function (Vue, options) {
 Vue.directive('iscroll', {
 inserted: function (el, binding, vnode) {
 let callBack
 let iscrollOptions = options
 <!--vue組件中綁定的兩個(gè)參數(shù) option、instance-->
 const option = binding.value && binding.value.option
 const func = binding.value && binding.value.instance
 // 判斷輸入?yún)?shù)
 const optionType = option ? [].toString.call(option) : undefined
 const funcType = func ? [].toString.call(func) : undefined
 // 兼容 google 瀏覽器拖動(dòng)
 el.addEventListener('touchmove', function (e) {
  e.preventDefault()
 })
 // 將參數(shù)配置到new IScroll(el, iscrollOptions)中
 if (optionType === '[object Object]') {
  iscrollOptions = option
 }
 if (funcType === '[object Function]') {
  callBack = func
 }
 // 使用vnode綁定iscroll是為了讓iscroll對(duì)象能夠夸狀態(tài)傳遞，避免iscroll重復(fù)建立
 // 這里面跟官方網(wǎng)站 const myScroll = new IScroll('#wrapper'，option) 初始化一樣
 vnode.scroll = new IScroll(el, iscrollOptions)
 // 如果指令傳遞函數(shù)進(jìn)來(lái)，把iscroll實(shí)例傳遞出去
 if (callBack) callBack(vnode.scroll)
 },
 componentUpdated: function (el, binding, vnode, oldVnode) {
 // 將scroll綁定到新的vnode上，避免多次綁定
 vnode.scroll = oldVnode.scroll
 // 使用 settimeout 讓refresh跳到事件流結(jié)尾，保證refresh時(shí)數(shù)據(jù)已經(jīng)更新完畢
 setTimeout(() => {
  vnode.scroll.refresh()
 }, 0)
 },
 unbind: function (el, binding, vnode, oldVnode) {
 // 解除綁定時(shí)要把iscroll銷毀
 vnode.scroll = oldVnode.scroll
 vnode.scroll.destroy()
 vnode.scroll = null
 }
 })
 }
}
module.exports = VIScroll

import Vue from 'vue'
import App from './App.vue'
import "./assets/reset.css"
// 加載scroll指令
import VIscroll from './directive/vIscroll'
Vue.use(VIscroll)
Vue.config.productionTip = false

new Vue({
 render: h => h(App),
}).$mount('#app')

<template>
 <div class="tab-container">
 <div
  class="scroll-container"
  v-iscroll="{
  option: iscrollConf,
  instance: getIscroll
  }"
  ref="scrollContainer"
 >
  <ul
  class="tab-li-container"
  ref="tabLiContainer"
  >
  <li
   class="tab-li-item"
   v-for="(item, index) in list"
   :key="item.id"
   :id="item.id"
   ref="tabItem"
   @click="tabEvent(item, index)"
  >
   <div
   class="item"
   :class="{
    'item-active': currentId == item.id
   }"
   >{{item.num}}</div>
  </li>
  </ul>
 </div>
 <div
  class="tab-left"
  @click="tabBtnEvent('left')"
 ><</div>
 <div
  class="tab-right"
  @click="tabBtnEvent('right')"
 >></div>
 </div>
</template>
<script>
export default {
 props: ['list'],
 data () {
 return {
  iscrollConf: {
  bounce: true,
  mouseWheel: true,
  click: true,
  scrollX: true,
  scrollY: false
  },
  currentId: null,
  currentIndex: 0,
  myScroll: null
 }
 },
 mounted () {
 this.$refs.tabLiContainer.style.width = this.$refs.tabItem[0].offsetWidth * this.list.length + 'px'
 this.$nextTick(() => {
  this.myScroll.refresh()
 })
 },
 methods: {
 tabEvent (item, currentIndex) {
  <!--點(diǎn)擊某個(gè)li 按鈕事件處理邏輯-->
 },
 tabBtnEvent (direction) {
  <!--左右切換邏輯事件-->
 },
 getIscroll (iscroll) {
  this.myScroll = iscroll
 }
 },
 watch: {
 list: {
  handler (l) {
  this.currentId = l[0].id
  },
  immediate: true,
  deep: true
 }
 }
}
</script>
<style scoped>
// 樣式
</style>

tabEvent (item, currentIndex) {
 this.currentId = item.id
 this.currentIndex = currentIndex
 <!--這里實(shí)現(xiàn)按鈕始終居中顯示，暫時(shí)省略，下面補(bǔ)充-->
 ...
 <!--傳給豎向滾動(dòng)組件-->
 this.$emit("switchTab", this.currentId, this.currentIndex)
},

<template>
 <div id="app">
 <TabList
  :list="list"
  @switchTab="switchTab"
 ></TabList>
 <!-- v-iscroll="defalutOption" -->
 <div
  v-iscroll="{
  option: defalutOption,
  instance: getIscroll
  }"
  class="tab-content-container"
  ref="detailItemContainer"
 >
  <ul class="tab-list-container">
  <li
   v-for="item in list"
   :key="item.id"
   class="list-item"
   ref="detailItem"
  >
   <div>{{item.value}}</div>
  </li>
  </ul>
 </div>
 </div>
</template>

<script>
import TabList from './components/tabList.vue'

export default {
 name: 'App',
 components: {
 TabList,
 },
 data () {
 return {
  list: [
  { id: 1, value: '這是第1題', num: 1 },
  <!--...省略數(shù)據(jù)展示-->
  { id: 16, value: '這是第16題', num: 16 }
  ],
  defalutOption: {
  bounce: true,
  mouseWheel: true,
  click: true,
  scrollX: false,
  scrollY: true
  },
  myScroll: null
 }
 },
 methods: {
 switchTab (currentId, currentIndex) {
  <!--對(duì)選中的當(dāng)前項(xiàng)，這里就是“3”按鈕對(duì)應(yīng)的“這是第3題”，求出它距離父元素的上邊距offsetTop值-->
  const offsetTop = this.$refs.detailItem[currentIndex].offsetTop
  <!--滾動(dòng)的范圍不能超過(guò)這個(gè)滾動(dòng)體的底部，這里面用到iscroll的屬性maxScrollY-->
  const y = offsetTop >= Math.abs(this.myScroll.maxScrollY) ? this.myScroll.maxScrollY : -offsetTop
  <!--調(diào)用iscroll的方法進(jìn)行滾動(dòng)到相應(yīng)的位置-->
  this.myScroll.scrollTo(0, y)
 },
 <!--獲取實(shí)例-->
 getIscroll (iscroll) {
  this.myScroll = iscroll
 }
 }
}
</script>
<style scoped>
<!--樣式-->
...
</style>

this.$refs.tabItem[this.currentIndex].scrollIntoView({
 behavior: "smooth",
 inline: "center",
 block: 'nearest'
})

tabBtnEvent (direction) {
 const max = this.$refs.tabItem.length
 if (direction === 'left' && this.currentIndex > 0) {
 this.currentIndex--
 }
 if (direction === 'right' && this.currentIndex < max - 1) {
 this.currentIndex++
 }
 <!--調(diào)用單擊按鈕事件-->
 this.tabEvent(this.$refs.tabItem[this.currentIndex], this.currentIndex)
},

tabEvent (item, currentIndex) {
 this.currentId = item.id
 this.currentIndex = currentIndex
 // 獲取滾動(dòng)容器的長(zhǎng)度的一半，即中間點(diǎn)
 const scrollContainerHalfWidth = this.$refs.scrollContainer.offsetWidth / 2
 // 獲取單個(gè)item的一半長(zhǎng)度
 const tabItemHalfWidth = this.$refs.tabItem[currentIndex].offsetWidth / 2
 // 求取插值，就是開(kāi)始到中間開(kāi)始位置的距離
 const halfDistance = scrollContainerHalfWidth - tabItemHalfWidth
 // 求取當(dāng)前item的相對(duì)總長(zhǎng)度的偏移量
 const currentItemOffsetLeft = this.$refs.tabItem[currentIndex].offsetLeft
 // scroll 移動(dòng)到中間的值
 const x = halfDistance - currentItemOffsetLeft
 this.myScroll.scrollTo(x, 0)
 this.$emit("switchTab", this.currentId, this.currentIndex)
},