<template> 
 <div class="progress-bar" ref="progressBar" @click="progressClick"> 
  <div class="bar-inner"> 
   <div class="progress" ref="progress"></div> 
   <div class="progress-btn-wrapper"ref="progressBtn" 
      @touchstart.prevent = "progressTouchStart" 
      @touchmove.prevent = "progressTouchMove" 
      @touchend = "progressTouchEnd" 
   > 
    <div class="progress-btn"></div> 
   </div> 
  </div> 
 </div> 
</template> 
 
<script type="text/ecmascript-6"> 
 // 进度条按钮宽度,由于style中没有设置width,因此只能用clientWidth获取 
 export default { 
  data() { 
   return { 
    btnWidth: { 
     type: Number, 
     default: 0 
    }, 
    touchInfo: { 
     initiated: false 
    } 
   } 
  }, 
  props: { 
   percent: { 
    type: Number, 
    default: 0 
   } 
  }, 
  mounted() { 
   this.btnWidth = document.getElementsByClassName('progress-btn')[0].clientWidth 
  }, 
  methods: { 
   // 点击按钮 
   progressTouchStart(e) { 
    // 记录touch事件已经初始化 
    this.touchInfo.initiated = true 
    // 点击位置 
    this.touchInfo.startX = e.touches[0].pageX 
    // 点击时进度条长度 
    this.touchInfo.left = this.$refs.progress.clientWidth 
   }, 
   // 开始移动 
   progressTouchMove(e) { 
    if (!this.touchInfo.initiated) { 
     return 
    } 
    // 计算移动距离 
    const moveX = e.touches[0].pageX - this.touchInfo.startX 
    // 设置偏移值 
    const offsetWidth = Math.min(Math.max(0, this.touchInfo.left + moveX), 
     this.$refs.progressBar.clientWidth - this.btnWidth) 
    this._setOffset(offsetWidth) 
   }, 
   // 移动结束 
   progressTouchEnd(e) { 
    this.touchInfo.initiated = false 
    // 向父组件派发事件,传递当前百分比值 
    this._triggerPercent() 
   }, 
   // 进度条点击事件 
   progressClick(e) { 
    console.log('clikc') 
    // 设置进度条及按钮偏移 
    this._setOffset(e.offsetX) 
    // 通知父组件播放进度变化 
    this._triggerPercent() 
   }, 
   _triggerPercent() { 
    const barWidth = this.$refs.progressBar.clientWidth - this.btnWidth 
    const percent = Math.min(1, this.$refs.progress.clientWidth / barWidth) 
    this.$emit('percentChange', percent) 
   }, 
   // 设置偏移 
   _setOffset(offsetWidth) { 
    // 设置进度长度随着百分比变化 
    this.$refs.progress.style.width = `${offsetWidth}px` 
    // 设置按钮随着百分比偏移 
    this.$refs.progressBtn.style.transform = `translate3d(${offsetWidth}px, 0, 0)` 
   } 
  }, 
  watch: { 
   // 监听歌曲播放百分比变化 
   percent(newPercent, oldPercent) { 
    if (newPercent > 0 && !this.touchInfo.initiated) { 
     // 进度条总长度 
     const barWidth = this.$refs.progressBar.clientWidth - this.btnWidth 
     const offsetWidth = barWidth * newPercent 
     // 设置进度条及按钮偏移 
     this._setOffset(offsetWidth) 
    } 
   } 
  } 
 } 
</script> 
 
<style lang="stylus" rel="stylesheet/stylus"> 
 @import "~common/stylus/variable.styl" 
 
 .progress-bar 
  height 0.5rem 
  .bar-inner 
   position relative 
   top 0.2rem 
   height 0.08rem 
   background rgba(0, 0, 0, 0.3) 
   .progress 
    position absolute 
    height 100% 
    background $color-theme 
   .progress-btn-wrapper 
    position absolute 
    left -0.25rem 
    top -0.25rem 
    width 0.5rem 
    height 0.5rem 
    .progress-btn 
     position relative 
     top 0.12rem 
     left 0.12rem 
     box-sizing border-box 
     width 0.32rem 
     height 0.32rem 
     border 0.06rem solid $color-text 
     border-radius 50% 
     background $color-theme 
</style> 

<div class="progress-wrapper"> 
 <span class="time time-l">{{formatTime(currentTime)}}</span> 
 <div class="progress-bar-wrapper"> 
  <progress-bar :percent="percent" @percentChange="setProgress"></progress-bar> 
 </div> 
 <span class="time time-r">{{formatTime(currentSong.duration)}}</span> 
</div> 

// 计算百分比 
percent() { 
 return Math.min(1, this.currentTime / this.currentSong.duration) 
} 

// 设置进度 
  setProgress(percent) { 
   // 根据子组件传过来的百分比设置播放进度 
   this.$refs.audio.currentTime = this.currentSong.duration * percent 
   // 拖动后设置歌曲播放 
   if (!this.playing) { 
    this.togglePlaying() 
   } 
  }, 

.progress-wrapper 
     display flex 
     .time 
      font-size 0.24rem 
      &.time-l 
       position absolute 
       bottom 1.62rem 
       left 1rem 
      &.time-r 
       position absolute 
       bottom 1.62rem 
       right 1rem 
     .progress-bar-wrapper 
      position absolute 
      bottom 1.5rem 
      left 1.7rem 
      width 4.2rem