思路：将标记物固定在地图正中间，地图拖动结束后，获取地图中心位置的经纬度信息

html代码

<view style="width: 100%;height: 60vh;posotion: relative">
      <map id="map" style="width: 100%;height: 60vh;" :latitude="latitude" :longitude="longitude" show-location @regionchange="regionchange"></map>
        <image :src="addrType=='load'?'../../static/choose/load.png':'../../static/choose/unload.png'" mode="aspectFill" class="position-logo"></image>
        <view class="addr-info">
          <view class="addr-info-text">{{addr}}</view>
          <view class="triple"></view>
       </view>
    </view>

css代码

.position-logo {
    position: absolute;
    width: 77rpx;
    height: 77rpx;
    top: calc(30vh - 35rpx);
    left: 50%;
    transform: translate(-50%, -50%);
  }
  .addr-info {
    padding: 19rpx 26rpx;
    background-color: rgba(0, 0, 0, 0.66);
    box-shadow: 0rpx 0rpx 10rpx 0rpx rgba(0,0,0,0.66);
    opacity: 0.8;
    border-radius: 12rpx;
    position: absolute;
    top: calc(30vh - 130rpx);
    left: 50%;
    transform: translate(-50%, -50%);
    white-space: nowrap;
    .addr-info-text {
      font-size: 30rpx;
      font-weight: 500;
      color: #FFFFFF;
    }
    .triple {
      position: absolute;
      width: 0%;
      height: 0%;
      border: 15rpx solid transparent;
      border-top-color: rgba(0, 0, 0, 0.66);
      opacity: 0.8;
      bottom: -29rpx;
      left: 50%;
      transform: translateX(-50%);
    }
  }

js代码

(小程序解析经纬度获取地址信息需申请腾讯地图key并下载SDK文件)

const QQMapWX = require('@/common/qqmap-wx-jssdk.js');  // 引入sdk文件

// 页面加载时创建并使用
onLoad(){
  this.qqMapSdk = new QQMapWX({key: 'xxxxxxx'}); // 需填入申请的key
}

// 获取中心点位置
      getCenterLatLong(){
        let mapCtx = uni.createMapContext('map', this)
        mapCtx.getCenterLocation({
          success: (res) => {
            this.latitude = res.latitude
            this.longitude = res.longitude
            this.formatLocation(res.latitude, res.longitude)
            this.$forceUpdate()
          },
          fail: (res) => {
            console.log('失败',res)
          }
        })
      },
      // 转换城市
      formatLocation(latitude, longitude) {
        this.qqMapSdk.reverseGeocoder({
          location: {
            latitude,
            longitude
          },
          success: (res) => {
            this.addr = res.result.address_reference.landmark_l2.title
            this.address = res.result.address
          }
        })
      },
      // 地图区域发生改变
      regionchange(e){
        if(e.type==='end'){
          this.getCenterLatLong()
        }
      },