vue实现左侧固定菜单栏锚点及滚动高亮（组件封装）_vue左侧菜单栏滚动条

vue实现左侧固定菜单栏锚点及滚动高亮

先上总代码：

子组件：

<!-- LeftSidebar.vue -->
<template>
  <div class="left-sidebar">
    <a v-for="(item, index) in sidebarItems" :key="index" @click="scrollToAnchor(item.anchor)">
      <!-- 竖线 -->
      <div :class="isSelected(item.anchor) ? 'activeLine' : 'line'" />
      <!-- 图标 -->
      <img :src="isSelected(item.anchor) ? item.activeIcon : item.icon" :alt="item.label">
      <span>{{ item.label }}</span>
    </a>
  </div>
</template>

<script>
export default {
  name: 'LeftSidebar',
  props: ['selectedAnchor'],
  data() {
    return {
      sidebarItems: [
        { anchor: 'sidebar1', icon: require('@/assets/image/main/sidebarIcon/sidebar1.png'), activeIcon: require('@/assets/image/main/sidebarIcon/sidebarActive1.png'), label: '菜单1' },
        { anchor: 'sidebar2', icon: require('@/assets/image/main/sidebarIcon/sidebar2.png'), activeIcon: require('@/assets/image/main/sidebarIcon/sidebarActive2.png'), label: '菜单2' },
        { anchor: 'sidebar3', icon: require('@/assets/image/main/sidebarIcon/sidebar3.png'), activeIcon: require('@/assets/image/main/sidebarIcon/sidebarActive3.png'), label: '菜单3' },
        { anchor: 'sidebar4', icon: require('@/assets/image/main/sidebarIcon/sidebar4.png'), activeIcon: require('@/assets/image/main/sidebarIcon/sidebarActive4.png'), label: '菜单4  ' }
    }
  },
  methods: {
    scrollToAnchor(anchor) {
      // 通过方法通知父组件修改 selectedAnchor
      this.$emit('scroll-to-anchor', anchor);
    },
    isSelected(anchor) {
      // 检查当前项是否被选中
      return this.selectedAnchor === anchor;
    },
  }
}
</script>

<style lang="scss" scoped>
//根据自己需要编写样式
.left-sidebar {
  z-index: 999;
  position: fixed;
  left: 0;
  top: 50%;
  transform: translateY(-50%);
  height: 450px;
  width: 153px;
  padding: 20px 30px 20px 20px;
  gap: 10px;
  border-radius: 0 20px 20px 0;
  border: 1px solid var(--systNaNpx-text-icon-color-text-light-solid, #FFF);
  background: linear-gradient(180deg, #f0f2f6d9 0%, #fffeffd9 100%);
  box-shadow: 0 0 20px 0 #0000001a;
  display: flex;
  flex-direction: column;
  align-items: center;
  justify-content: center;

  a {
    width: 102px;
    display: flex;
    justify-content: flex-start;
    align-items: center;
    flex: 1;
    text-align: left;
    white-space: nowrap; // 防止文字换行

    .line {
      width: 1px;
      height: 60px;
      background: linear-gradient(180deg, #d9d9d900 0%, #D9D9D9 55.21%, #d9d9d900 100%);

    }

    .activeLine {
      width: 1px;
      height: 60px;
      background: linear-gradient(180deg, #1a76ff00 0%, #0D6EFF 55.21%, #2c80ff00 100%);
    }

    span {
      color: #131f31;
      font-family: "PingFang SC";
      font-size: 14px;
      font-style: normal;
      font-weight: 600;
      line-height: 24px;
      margin-left: 4px;
    }
  }
}

img {
  width: 26px;
  height: 26px;
  margin-left: 12px;
}
</style>

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父组件：

<!-- index.vue -->
<template>
<div class="sidebar" ref="sidebar1"></div>
<div class="sidebar" ref="sidebar2"></div>
<div class="sidebar" ref="sidebar3"></div>
<div class="sidebar" ref="sidebar4"></div>
<LeftSidebar :selectedAnchor="selectedAnchor" @scroll-to-anchor="scrollToAnchor" />
</template>
<script>
import LeftSidebar from '@/components/homeCops/sidebar/LeftSidebar .vue'

export default {
  components: {
    LeftSidebar
  },
  data () {
    return {
      selectedAnchor:'sidebar1'//默认高亮显示第一个
    }
  },
  mounted() {
  //经测试不同电脑监听使用的可能不成功，这里可以自行选择一个监听
  //监听当滚动条发生变化时调用handleScroll设置selectedAnchor的值并传给子组件
    window.addEventListener('scroll', this.handleScroll, true)
    window.addEventListener('onscroll', this.handleScroll, true)
    window.addEventListener('scroll', this.handleScroll.bind(this), true)
    this.$el.addEventListener('scroll', this.handleScroll.bind(this))
  },
  methods: {
    scrollToAnchor(anchor) {
      // 获取对应锚点的DOM元素
      const targetElement = this.$refs[`${anchor}`].$el
      // 如果找到目标元素，则执行滚动
      if (targetElement) {
        // smooth不生效
        targetElement.scrollIntoView({ behavior: 'auto' })
      }
    },
    handleScroll() {
      // 获取所有需要需要锚点定位的DOM元素
      const navContents = document.querySelectorAll('.sidebar') 
      const offsetTopArr = []
      navContents.forEach(item => {
        // 获取上面DOM元素距离顶部的距离
        offsetTopArr.push(item.offsetTop)   
      })
      // 获取页面滚动了距离
      const scrollTop  = document.getElementById('app').scrollTop
      let navIndex = 0//需要高亮显示的元素
      for (let n = 0; n < offsetTopArr.length; n++) {
        if (scrollTop >= offsetTopArr[n]) { 
          navIndex = n       
        }        
      }
      // 设置高亮显示
      this.selectedAnchor = `sidebar${navIndex + 1}`;
    }
  }
}
</script>
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解析：

1、实现滚动时让左侧相应的菜单高亮显示：

①首先让元素默认选中第一个，在父组件中设置一个字段表示选中第几个

data () {
    return {
      selectedAnchor:'sidebar1'
    }
  },
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②将该值传递给子组件

:selectedAnchor="selectedAnchor"
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③在子组件中接收并使用

<div :class="isSelected(item.anchor) ? 'activeLine' : 'line'" />

props: ['selectedAnchor'],

isSelected(anchor) {
      // 检查当前项是否被选中
      return this.selectedAnchor === anchor;
    },
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④在父组件编写功能代码

mounted() {
//经测试不同电脑监听使用的可能不成功，这里可以自行选择一个监听
    window.addEventListener('scroll', this.handleScroll, true)
    window.addEventListener('onscroll', this.handleScroll, true)
    window.addEventListener('scroll', this.handleScroll.bind(this), true)
    this.$el.addEventListener('scroll', this.handleScroll.bind(this))
  },
  methods: {
    handleScroll() {
      // 获取所有需要需要锚点定位的DOM元素
      const navContents = document.querySelectorAll('.sidebar') 
      const offsetTopArr = []
      navContents.forEach(item => {
        // 获取上面DOM元素距离顶部的距离
        offsetTopArr.push(item.offsetTop)   
      })
      // 获取页面滚动了距离
      const scrollTop  = document.getElementById('app').scrollTop
      let navIndex = 0//需要高亮显示的元素
      for (let n = 0; n < offsetTopArr.length; n++) {
        if (scrollTop >= offsetTopArr[n]) { 
          navIndex = n       
        }        
      }
      // 设置高亮显示
      this.selectedAnchor = `sidebar${navIndex + 1}`;
    }
  }
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到此为止以上代码实现了滚动自动选择菜单的功能

---

2、当点击左侧菜单时实现锚点跳转

①在子组件中添加点击事件，通过$emit将参数传给父组件

@click="scrollToAnchor(item.anchor)"

scrollToAnchor(anchor) {
  // 通过方法通知父组件
  this.$emit('scroll-to-anchor', anchor);
},
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②在父组件中接收子组件传递的参数，并使用scrollIntoView实现锚点功能

@scroll-to-anchor="scrollToAnchor"

scrollToAnchor(anchor) {
      // 获取对应锚点的DOM元素
      const targetElement = this.$refs[`${anchor}`].$el
      // 如果找到目标元素，则执行滚动
      if (targetElement) {
        // smooth不生效
        targetElement.scrollIntoView({ behavior: 'auto' })
      }
    },
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以上两个功能代码要结合使用，如果只使用点击功能则需要在父组件中修改selectedAnchor 的值。