<template>
  <div class="music-list">
    <div
      class="back"
    >
      <i class="icon-back"></i>
    </div>
    <h1 class="title">{{ title }}</h1>
    <div
      class="bg-image"
      :style="bgImageStyle"
      ref="bgImage"
    >
      <div
        class="filter"
      ></div>
    </div>
    <scroll
      class="list"
      :style="scrollStyle"
    >
      <div class="song-list-wrapper">
        <song-list
          :songs="songs"
        ></song-list>
      </div>
    </scroll>
  </div>
</template>

<script>
  import SongList from '@/components/base/song-list/song-list'
  import Scroll from "@/components/base/scroll/scroll";
  // import { mapActions, mapState } from 'vuex'

  // const RESERVED_HEIGHT = 40

  export default {
    name: 'music-list',
    components: {
      SongList,
      Scroll
    },
    props: {
      songs: {
        type: Array,
        default() {
          return []
        }
      },
      title: String,
      pic: String,
      loading: Boolean,
      noResultText: {
        type: String,
        default: '抱歉，没有找到可播放的歌曲'
      },
      rank: Boolean
    },
    data() {
      return {
        imageHeight: 0
      }
    },
    mounted() {
      console.log('ref---', this.$refs.bgImage.clientHeight)
      this.imageHeight = this.$refs.bgImage.clientHeight
    },
    computed: {
      bgImageStyle() {
        return {
          backgroundImage: `url(${this.pic})`
        }
      },
      scrollStyle() {
        return {top: `${this.imageHeight}`}
      }
    }
  }
</script>

<style lang="scss" scoped>
  .music-list {
    position: relative;
    height: 100%;
    .back {
      position: absolute;
      top: 0;
      left: 6px;
      z-index: 20;
      transform: translateZ(2px);
      .icon-back {
        display: block;
        padding: 10px;
        font-size: $font-size-large-x;
        color: $color-theme;
      }
    }
    .title {
      position: absolute;
      top: 0;
      left: 10%;
      width: 80%;
      z-index: 20;
      transform: translateZ(2px);
      @include no-wrap();
      text-align: center;
      line-height: 40px;
      font-size: $font-size-large;
      color: $color-text;
    }
    .bg-image {
      position: relative;
      width: 100%;
      transform-origin: top;
      background-size: cover;
      .play-btn-wrapper {
        position: absolute;
        bottom: 20px;
        z-index: 10;
        width: 100%;
        .play-btn {
          box-sizing: border-box;
          width: 135px;
          padding: 7px 0;
          margin: 0 auto;
          text-align: center;
          border: 1px solid $color-theme;
          color: $color-theme;
          border-radius: 100px;
          font-size: 0;
        }
        .icon-play {
          display: inline-block;
          vertical-align: middle;
          margin-right: 6px;
          font-size: $font-size-medium-x;
        }
        .text {
          display: inline-block;
          vertical-align: middle;
          font-size: $font-size-small;
        }
      }
      .filter {
        position: absolute;
        top: 0;
        left: 0;
        width: 100%;
        height: 100%;
        background: rgba(7, 17, 27, 0.4);
      }
    }
    .list {
      position: absolute;
      bottom: 0;
      width: 100%;
      z-index: 0;
      .song-list-wrapper {
        padding: 20px 30px;
        background: $color-background;
      }
    }
  }
</style>

然后在mounted里面打印：

this.$refs.bgImage.clientHeight

打印结果为0
所以动态获取图片高度为0，导致图片没高度，出不来，老师有什么办法处理吗？