微信小程序地图(map)组件点击(tap)获取经纬度的方法

微信小程序中使用地图(map)组件，通过点击(tap)获取经纬度，按照官方的回应，暂时是没法做到的，从地图组件API多有残缺判断，怀疑是个实习生干的...

做个变通，适用性有限，请大家参考。基本思路就是在地图上铺满一层marker，从而通过点击marker获得经纬度。

<map id="map" longitude="102.324520" latitude="40.099994" scale="4" bindcontroltap="controltap" polygons="{{polygons}}" bindregionchange="regionchange" markers="{{markers}}" bindmarkertap="markertap" show-location style="width: 100％; height: 700px;"></map>

const app = getApp()
const markersize = 30
function range(start, edge, step) {
for (var ret = [];
 (edge - start) * step > 0; start += step) {
 ret.push(start);
}
return ret;
}
function markers(northeast, southwest, scale, width, height) {
const markerslng = (northeast.longitude - southwest.longitude) * markersize / width
const markerslat = (northeast.latitude - southwest.latitude) * markersize / height
const maxlon = northeast.longitude
const minlon = southwest.longitude
const maxlat = northeast.latitude
const minlat = southwest.latitude
const lons = range(minlon, maxlon, markerslng)
const lats = range(minlat, maxlat, markerslat)
let _markers = []
lons.forEach((lon, i) => {
 lats.forEach((lat, j) => {
  _markers.push({
   id: lon + ',' + lat,
   latitude: lat,
   longitude: lon,
   iconPath: '/marker.png',
   alpha: 0.1, //将图片设置为透明,通过开发者工具看不出效果,但真机是有效果的
   width: markersize,
   height: markersize
  })
 })
})
return _markers
}
Page({
data: {
 polygons: [],
 controls: [{
  id: 1,
  position: {
   left: 0,
   top: 300 - 50,
   width: 50,
   height: 50
  },
  clickable: true
 }],
 markers: []
},
createMarkers() {
this.mapCtx = wx.createMapContext('map')
 const query = wx.createSelectorQuery()
 const map = query.select('#map').boundingClientRect()
let that = this
that.mapCtx.getRegion({
  success(res1) {
   that.mapCtx.getScale({
    success(res2) {
     query.exec((res) => {
      let width = res[0].width;
      let height = res[0].height;
      let _markers = markers(res1.northeast, res1.southwest, res2.scale, width, height)
      that.data.markers = _markers
      that.setData(that.data)
     })
    }
   })
  }
 })
},
regionchange(e) {
 this.createMarkers()
},
markertap(e) {
 console.log(e.markerId)
},
controltap(e) {
 console.log(e.controlId)
},
onReady(e) {
 this.createMarkers()
}
})

效果如图

来源：https://segmentfault.com/a/1190000017821849