用Vue来实现音乐播放器（八）：自动轮播图啊

<template>
  <div class="slider" ref="slider">
    <div class="slider-group" ref="sliderGroup">
    //要注意slot插槽里面的数据要先渲染出来
      <slot>
      </slot>
    </div>
    <div class="dots">
      <span class="dot" :class="{active: currentPageIndex === index }" v-for="(item, index) in dots" :key="index"></span>
    </div>
  </div>
</template>

<script>
  import {addClass} from ‘../../common/js/dom.js‘
  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: 1000
        },
        showDot: {
            type: Boolean,
            default: true
        },
        click: {
            type: Boolean,
            default: true
        },
        threshold: {
            type: Number,
            default: 0.3
        },
        speed: {
            type: Number,
            default: 400
        }
    },
    mounted() {
      this._setSliderWidth()
      setTimeout(() => {
        // 在初始化slider前初始化dot
        this._initDots()
        this._initSlider()
        if (this.autoPlay) {
          this._play()
        }
      }, 20)
      // 监听窗口大小改变时间
      window.addEventListener(‘resize‘, () => {
        if (!this.slider) {
          return
        }
        this._setSliderWidth(true)
        this.slider.refresh()
      })
    },
    methods:{
      _setSliderWidth(isResize) {
        this.children = this.$refs.sliderGroup.children
        let width = 0
        // slider 可见宽度
        let sliderWidth = this.$refs.slider.clientWidth
        for (let i = 0; i < this.children.length; i++) {
          let child = this.children[i]
          // 设置每个子元素的样式及高度
          addClass(child, ‘slider-item‘)
          child.style.width = sliderWidth + ‘px‘
          // 计算总宽度
          width += sliderWidth
        }
        // 循环播放首尾各加一个,因此总宽度还要加两倍的宽度
        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: {
            loop: this.loop,
            threshold: this.threshold,
            speed: this.speed
            },
            bounce: false,
            stopPropagation: true,
            click: this.click
        });
      

　　    this.slider.on("scrollEnd", this._onScrollEnd);
            this.slider.on("touchEnd", () => {
                if (this.autoPlay) {
                    this._play(); 
                }
            });
        this.slider.on("beforeScrollStart", () => {
            if (this.autoPlay) {
                clearTimeout(this.timer);
            }
            });
        },
        _onScrollEnd() {
            let pageIndex = this.slider.getCurrentPage().pageX;
            this.currentPageIndex = pageIndex; // 第一轮1（第一张图） 2 3 4 0（最后一张图索引为0 因为放在了最前面）  1 2 3 4 0 
            if (this.autoPlay) {
                this._play();
            }
        },
        _initDots() {
            this.dots = new Array(this.children.length);
        },
        _play() {
            clearTimeout(this.timer);
            this.timer = setTimeout(() => {
                this.slider.next();
            }, this.interval);
        }
    },
    watch: {
        loop() {
            this.update();
        },
        autoPlay() {
            this.update();
        },
        speed() {
            this.update();
        },
        threshold() {
            this.update();
        }
    }
  }
</script>