Vue实现详情页Header渐隐渐现效果

<template>
  <div>
    <div class="box"></div>

    <!-- header-icon -->
    <div class="header-abs" v-show="visiableAbs">
      <div class="header-abs-back">&lt;</div>
    </div>

    <!-- header-bar -->
    <div class="header-fixed" v-show="!visiableAbs" :style="opacityStyle">
      <div class="header-icons">&lt;</div>
      <div class="header-title">标题</div>
      <div class="header-icons"></div>
    </div>
  </div>
</template>

<script>
  export default {
    data() {
      return {
        visiableAbs: true,
        opacityStyle: {
          opacity: 0
        }
      }
    },
    methods: {
      handleScroll() {
        const top = document.documentElement.scrollTop || document.body.scrollTop
        if (top > 60) {
          let opacity = top / 140
          opacity = opacity > 1 ? 1 : opacity
          this.opacityStyle = {
            opacity
          }
          this.visiableAbs = false
        } else {
          this.visiableAbs = true
        }
      }
    },
    mounted() {
      window.addEventListener('scroll', this.handleScroll)
    },
    unmounted() {
      window.removeEventListener('scroll', this.handleScroll)
    }
  }
</script>

<style scoped>
  .box {
    height: 1000px;
    background-color: #fff;
  }

  .header-abs {
    position: absolute;
    left: 10px;
    top: 10px;
    width: 40px;
    height: 40px;
    line-height: 40px;
    border-radius: 20px;
    text-align: center;
    border-radius: 40%;
    background: rgba(0, 0, 0, .8)
  }

  .header-abs-back {
    color: #fff;
    font-size: 20px;
  }

  .header-fixed {
    z-index: 2;
    display: flex;
    position: fixed;
    top: 0;
    left: 0;
    right: 0;
    height: 40px;
    line-height: 40px;
    text-align: center;
    color: #fff;
    background: #000;
    font-size: 16px;
  }

  .header-icons {
    width: 50px;
    height: 100%;
    font-size: 22px;
  }

  .header-title {
    flex: 1;
    overflow: hidden;
    text-overflow: ellipsis;
    display: -webkit-box;
    -webkit-line-clamp: 1;
    -webkit-box-orient: vertical;
  }
</style>