uniapp上实现左右关联滚动

先看效果：

代码：

<template>
  <view class="container">
    
    <view class="left">
      <view
        v-for="item in leftList"
        :key="item.id"
        class="left_item"
        :class="item.id == selectedId ? 'selected' : ''"
        @click="leftItemClick(item.id)"
      >
        {{ item.title }}
      view>
    view>

    
    <view class="right">
      <view v-for="item in rightList" :key="item.id" class="right_item">
        {{ item.content }}
      view>
    view>
  view>
template>

<script>
export default {
  data() {
    return {
      leftList: [],
      rightList: [],
      selectedId: 1, //左边当前选中id
      itemTopArr: [], //右侧所有item的top数组
    };
  },
  onLoad() {
    this.initData();
    this.getItemTopArr();
  },
  //页面滚动监听
  onPageScroll(e) {
    let scrollTop = e.scrollTop;
    console.log("scrollTop = " + scrollTop);
    for (let i = 0; i < this.itemTopArr.length; i++) {
      if (scrollTop >= this.itemTopArr[i]) {
        this.selectedId = this.rightList[i].parentId;
        console.log("selectedId = " + this.selectedId);
      }
    }
  },
  methods: {
    //左侧item点击
    leftItemClick(id) {
      this.selectedId = id;

      let index = 0;
      for (let i = 0; i < this.rightList.length; i++) {
        if (this.rightList[i].parentId == id) {
          index = i;
          break;
        }
      }

      //将页面滚动到目标位置
      uni.pageScrollTo({
        scrollTop: this.itemTopArr[index],
        duration: 300, //滚动动画时长
      });
    },
    //获取右侧所有item的top数组
    getItemTopArr() {
      this.$nextTick(() => {
        const query = uni.createSelectorQuery().in(this);
        const nodesRef = query.selectAll(".right > .right_item");
        nodesRef
          .fields(
            {
              size: true,
              rect: true,
              scrollOffset: true,
            },
            (res) => {
              res.forEach((item) => {
                this.itemTopArr.push(item.top);
              });
              console.log(this.itemTopArr);
            }
          )
          .exec();
      });
    },
    //初始化数据源
    initData() {
      for (let index = 1; index < 10; index++) {
        for (let i = 1; i < 4; i++) {
          this.rightList.push({
            id: index + "-" + i,
            parentId: index,
            content: "content-" + index,
          });
        }
        this.leftList.push({
          id: index,
          title: "title-" + index,
        });
      }
    },
  },
};
script>

<style lang="scss" scoped>
.container {
  position: relative;
  min-height: 100vh;
  background: #fff;

  .left {
    position: fixed;
    width: 120px;
    height: 100%;
    min-height: 100vh;
    overflow: auto;
    float: left;
    background: #f2f2f2;

    .left_item {
      width: 100%;
      height: 60px;
      text-align: center;
      line-height: 60px;
    }

    .selected {
      background: #fff;
      font-weight: bold;
      color: #07c160;
    }
  }

  .right {
    margin-left: 120px;
    width: calc(100vw - 120px);
    overflow: auto;

    .right_item {
      width: 100%;
      height: 200px;
      text-align: center;
      line-height: 200px;
      font-size: 24px;
      border-bottom: 1px solid #ccc;
      box-sizing: border-box; //padding、border不影响元素的宽高
    }
  }
}
style>

---

官方onPageScroll方法的使用注意事项（见上图）里说不要在此方法里写复杂的交互，故将onPageScroll里的for循环改写到滚动结束执行：

<template>
  <view class="container">
    
    <view class="left">
      <view
        v-for="item in leftList"
        :key="item.id"
        class="left_item"
        :class="item.id == selectedId ? 'selected' : ''"
        @click="leftItemClick(item.id)"
      >
        {{ item.title }}
      view>
    view>

    
    <view class="right">
      <view v-for="item in rightList" :key="item.id" class="right_item">
        {{ item.content }}
      view>
    view>
  view>
template>

<script>
export default {
  data() {
    return {
      leftList: [],
      rightList: [],
      selectedId: 1, //左边当前选中id
      itemTopArr: [], //右侧所有item的top数组
      timeoutID: null,
    };
  },
  onLoad() {
    this.initData();
    this.getItemTopArr();
  },
  //页面滚动监听
  onPageScroll(e) {
    let scrollTop = e.scrollTop;
    console.log("scrollTop = " + scrollTop);

    clearTimeout(this.timeoutID);
    this.timeoutID = setTimeout(() => {
      console.log("结束滚动");

      for (let i = 0; i < this.itemTopArr.length; i++) {
        if (scrollTop >= this.itemTopArr[i]) {
          this.selectedId = this.rightList[i].parentId;
          console.log("selectedId = " + this.selectedId);
        }
      }
    }, 100);
  },
  methods: {
    //左侧item点击
    leftItemClick(id) {
      this.selectedId = id;

      let index = 0;
      for (let i = 0; i < this.rightList.length; i++) {
        if (this.rightList[i].parentId == id) {
          index = i;
          break;
        }
      }

      //将页面滚动到目标位置
      uni.pageScrollTo({
        scrollTop: this.itemTopArr[index],
        duration: 300, //滚动动画时长
        success: (res) => {
          console.log(res);
          console.log("scroll success");
        },
        fail: (err) => {
          console.log(err);
          console.log("scroll fail");
        },
      });
    },
    //获取右侧所有item的top数组
    getItemTopArr() {
      this.$nextTick(() => {
        const query = uni.createSelectorQuery().in(this);
        const nodesRef = query.selectAll(".right > .right_item");
        nodesRef
          .fields(
            {
              size: true,
              rect: true,
              scrollOffset: true,
            },
            (res) => {
              res.forEach((item) => {
                this.itemTopArr.push(item.top);
              });
              console.log(this.itemTopArr);
            }
          )
          .exec();
      });
    },
    //初始化数据源
    initData() {
      for (let index = 1; index < 10; index++) {
        for (let i = 1; i < 4; i++) {
          this.rightList.push({
            id: index + "-" + i,
            parentId: index,
            content: "content-" + index,
          });
        }
        this.leftList.push({
          id: index,
          title: "title-" + index,
        });
      }
    },
  },
};
script>

<style lang="scss" scoped>
.container {
  position: relative;
  min-height: 100vh;
  background: #fff;

  .left {
    position: fixed;
    width: 120px;
    height: 100%;
    min-height: 100vh;
    overflow: auto;
    float: left;
    background: #f2f2f2;

    .left_item {
      width: 100%;
      height: 60px;
      text-align: center;
      line-height: 60px;
    }

    .selected {
      background: #fff;
      font-weight: bold;
      color: #07c160;
    }
  }

  .right {
    margin-left: 120px;
    width: calc(100vw - 120px);
    overflow: auto;

    .right_item {
      width: 100%;
      height: 200px;
      text-align: center;
      line-height: 200px;
      font-size: 24px;
      border-bottom: 1px solid #ccc;
      box-sizing: border-box; //padding、border不影响元素的宽高
    }
  }
}
style>