詳解vue之better-scroll實現輪播圖和頁面滾動

(該方法只針對移動端使用效果較好，PC端不推薦，使用的版本是[email protected]，其他版本會出錯)

1.安裝better-scroll

在根目錄中package.json的dependencies中添加：

"better-scroll": "^0.1.15"

然後 npm i 安裝。

2.封裝代碼

將better-scroll封裝成兩個基礎組件slider和scroll放於src/base文件夾中。
slider.vue 代碼

<template>
  <div class="slider" ref="slider">
    <div class="slider-group" ref="sliderGroup">
      <slot>
      </slot>
    </div>
    <div class="dots">
      <span class="dot" :class="{active: currentPageIndex === index }" v-for="(item, index) in dots"></span>
    </div>
  </div>
</template>

<script>
  import {addClass} from '../common/js/dom'
  import BScroll from 'better-scroll'
  export default{
    data() {
      return {
        dots:[],
        currentPageIndex: 0
      }
    },
    props:{
      loop:{
        type:Boolean,
        default:true
      },
      autoPlay:{
        type:Boolean,
        default:true
      },
      interval:{
        type: Number,
        default:4000
      }
    },
    mounted() {
      this._setSliderWidth()
      setTimeout(() => {
        // 在初始化slider前初始化dot
        this._initDots()
        this._initSlider()
        if (this.autoPlay) {
          this._play()
        }
      }, 20)
      // 監聽窗口大小改變時間
      window.addEventListener('resize', () => {
        if (!this.slider) {
          return
        }
        this._setSliderWidth(true)
        this.slider.refresh()
      })
    },
    methods:{
      _setSliderWidth(isResize) {
        this.children = this.$refs.sliderGroup.children
        let width = 0
        // slider 可見寬度
        let sliderWidth = this.$refs.slider.clientWidth
        for (let i = 0; i < this.children.length; i++) {
          let child = this.children[i]
          // 設置每個子元素的樣式及高度
          addClass(child, 'slider-item')
          child.style.width = sliderWidth + 'px'
          // 計算總寬度
          width += sliderWidth
        }
        // 循環播放首尾各加一個,因此總寬度還要加兩倍的寬度
        if (this.loop && !isResize) {
          width += 2 * sliderWidth
        }
        this.$refs.sliderGroup.style.width = width + 'px'
      },
      _initSlider() {
        this.slider = new BScroll(this.$refs.slider, {
          scrollX: true,
          scrollY: false,
          momentum: false,
          snap: true,
          snapLoop: this.loop,
          snapThreshold: 0.3,
          snapSpeed: 400,
          // click:true
        })
        // 監聽滾動結束時間獲取pageX
        this.slider.on('scrollEnd', () => {
          let pageIndex = this.slider.getCurrentPage().pageX
          if (this.loop) {
            // 由於bscroll循環播放首尾各加一個,因此索引-1
            pageIndex -= 1
          }
          this.currentPageIndex = pageIndex
          if (this.autoPlay) {
            this._play()
          }
        })
        this.slider.on('beforeScrollStart', () => {
          if (this.autoPlay) {
            clearTimeout(this.timer)
          }
        })
      },
      _initDots() {
        // 長度爲n的空數組
        this.dots = new Array(this.children.length)
      },
      _play() {
        // currentPageIndex爲不含首尾副本的索引，因此若有循環要+2
        let pageIndex = this.currentPageIndex + 1
        if (this.loop) {
          pageIndex += 1
        }
        this.timer = setTimeout(() => {
          this.slider.goToPage(pageIndex, 0, 400)
        }, this.interval)
      }
    },
    // 生命週期destroyed銷燬清除定時器，有利於內存釋放
    destroyed() {
      clearTimeout(this.timer)
    },
  }
</script>
<style scoped>
  .slider{
    min-height: 1px;
    position: relative;
  }

  .slider-group{
    position: relative;
    overflow: hidden;
    white-space: nowrap;
  }

  .slider-item{
    float: left;
    box-sizing: border-box;
    overflow: hidden;
    text-align: center;
    height: 150px;
    overflow: hidden;
  }

  .slider-item a{
    display: block;
    width: 100%;
    overflow: hidden;
    text-decoration: none;
  }


  .slider-item img{
    display: block;
    width: 100%;
  }

  .dots{
    position: absolute;
    right: 0;
    left: 0;
    bottom: 12px;
    text-align: center;
    font-size: 0;
  }

  .dot{
    display: inline-block;
    margin: 0 4px;
    width: 8px;
    height: 8px;
    border-radius: 50%;
    background: red;
  }

  .active{
    width: 20px;
    border-radius: 5px;
  }
</style>

該代碼引用common/js/dom.js中的addClass()方法爲每個輪播圖添加一個slider-item類，dom.js代碼如下：

export function hasClass (el, className) {
  // 開始或空白字符+類名+空白字符或結束
  let reg = new RegExp('(^|\\s)' + className + '(\\s|$)')
  // 測試元素是否有該類名，返回布爾值
  return reg.test(el.className)
}

export function addClass (el, className) {
  if (hasClass(el, className)) {
    return
  }
// 以空白符爲切割位置切割生成新數組
  let newClass = el.className.split(' ')
// 數組中加入新類名
  newClass.push(className)
// 將數組元素放入一個字符串，以空白符間隔
  el.className = newClass.join(' ')
}

scroll.vue代碼

<template>
  <div ref="wrapper">
    <slot></slot>
  </div>
</template>

<script>
  import BScroll from 'better-scroll'

  export default {
    props: {
      probeType: {
        type: Number,
        default: 1
      },
      click: {
        type: Boolean,
        default: true
      },
      listenScroll: {
        type: Boolean,
        default: false
      },
      object: {
        type: Object,
        default: null
      },
      data: {
        type: Array,
        default: null
      },
      string: {
        type: String,
        default: ''
      },
      pullup: {
        type: Boolean,
        default: false
      },
      beforeScroll: {
        type: Boolean,
        default: false
      },
      refreshDelay: {
        type: Number,
        default: 20
      }
    },
    mounted() {
      setTimeout(() => {
        this._initScroll()
      }, 20)
    },
    methods: {
      _initScroll() {
        if (!this.$refs.wrapper) {
          return
        }
        this.scroll = new BScroll(this.$refs.wrapper, {
          probeType: this.probeType,
          click: this.click
        })

        if (this.listenScroll) {
          let me = this
          // pos爲位置參數
          this.scroll.on('scroll', (pos) => {
            me.$emit('scroll', pos)
          })
        }

        if (this.pullup) {
          this.scroll.on('scrollEnd', () => {
            if (this.scroll.y <= (this.scroll.maxScrollY + 50)) {
              this.$emit('scrollToEnd')
            }
          })
        }

        if (this.beforeScroll) {
          this.scroll.on('beforeScrollStart', () => {
            this.$emit('beforeScroll')
          })
        }
      },
      disable() {
        this.scroll && this.scroll.disable()
      },
      enable() {
        this.scroll && this.scroll.enable()
      },
      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.refresh()
        }, this.refreshDelay)
      },
      string() {
        setTimeout(() => {
          this.refresh()
        }, this.refreshDelay)
      },
      object() {
        setTimeout(() => {
          this.refresh()
        }, this.refreshDelay)
      }
    }
  }
</script>
<style>
</style>

3.使用封裝組件

使用這兩個組件的頁面組件home.vue 代碼如下：

<template>
    <div>
    <scroll :data="su" class="scroll">
        <div>
            <div class="slider-wrapper">
                <slider>
                    <div v-for='item in slider'>
                        <a href="">
                            <img :src="item.url" alt="">
                        </a>
                    </div>
                </slider>
            </div>
            <ul v-for='item in su'>
                <li>{{item}}</li>
            </ul>
        </div>
    </scroll>
    </div>
</template>
<script>
    import Slider from '../base/slider'
    import Scroll from '../base/scroll'
export default {
    data () {
        return {
            slider: [
                {url: 'http://upload-images.jianshu.io/upload_images/7932253-54c81df0beed405b.jpg?imageMogr2/auto-orient/strip%7CimageView2/2/w/1080/q/50'},
                {url: 'https://y.gtimg.cn/music/photo_new/T003R720x288M000004ERTpn1UBu2f.jpg?max_age=2592000&max_age=2592000'},
                {url: 'https://y.gtimg.cn/music/photo_new/T003R720x288M00000077s7P0HaZpc.jpg?max_age=2592000&max_age=2592000'},
                {url: 'https://y.gtimg.cn/music/photo_new/T003R720x288M000001QL1Si05yMPq.jpg?max_age=2592000&max_age=2592000'},
                {url: 'https://y.gtimg.cn/music/photo_new/T003R720x288M000002ke7OC3ooZ5g.jpg?max_age=2592000&max_age=2592000'},
            ],
            su:[1,2,3,4,5,6,7,8,9,10,1,2,3,4,2,3,5,8,7,4,]
        }
    },
    methods: {
    },
    components: {
        Slider,
        Scroll
    }
}
</script>
<style>
.slider-wrapper{
    width: 100%;
    position: relative;
    overflow: hidden;
}
.scroll{
    height: 500px;
}
</style>

注意點：

• slider組件的父元素必須給他一個100%的寬度且定義overflow:hidden，否則整個頁面會被撐開，整個頁面都能橫向滾動
• scroll組件在引用時必須給他一個固定高度。只有擁有固定高度纔會發生滾動。

效果圖如下：