比如我单击按钮 开启后台位置监控调用,再单击关闭后台监控,现在的问题是 开了然后关,再开发现onLocationChange事件触发2次,再关再开就会出现3,4,5次.这是如何避免 //开启后台获取地理位置坐标   async enableLocationUpdateBackground() {     const that = this;     wx.startLocationUpdateBackground({        success:async res=> {         //console.log('开启后台定位', res)         Notify({           type: 'success',           message: '开启上报定位信息'         });         //开始记录         const userId = wx.getStorageSync('userId');         const openId = wx.getStorageSync('openid');         const userInfo = this.data.userInfo;         const startloc = await that.getLocation();         const startaddress = await that.reverseGeocoder({           latitude: startloc.latitude,           longitude: startloc.longitude         });         that.addTrackPath({           "UserId": userId,           "TrackingDateTime": moment().format("YYYY-MM-DDTHH:mm:ss.SSS[Z]"),           "BeginDateTime": moment().format("YYYY-MM-DDTHH:mm:ss.SSS[Z]"),           "Location": JSON.stringify(startloc),           "latitude": startloc.latitude,           "longitude": startloc.longitude,           "Address": startaddress.result.address,           "OpenId": openId,           "NickName": userInfo.nickName,           "AvatarUrl": userInfo.avatarUrl,         })         wx.onLocationChange(           async res => {             //console.log('onLocationChange', res)             const loc = await that.reverseGeocoder({               latitude: res.latitude,               longitude: res.longitude             });             //console.log(loc)             that.addTrackPath({               "UserId": userId,               "TrackingDateTime": moment().format("YYYY-MM-DDTHH:mm:ss.SSS[Z]"),               "Location": JSON.stringify(res),               "latitude": res.latitude,               "longitude": res.longitude,               "Address": loc.result.address,               "OpenId": openId,               "NickName": userInfo.nickName,               "AvatarUrl": userInfo.avatarUrl,             })           });       },       fail(res) {         that.setData({           enable: false         })         console.log('开启后台定位失败', res)         Notify({           type: 'danger',           message: '开启定位失败'         });         Dialog.alert({           message: '请转到设置位置信息[使用小程序期间和离开小程序后]',         }).then(() => {           wx.navigateTo({             url: '../manage/index',           })         });                 },       complete: function (res) {         // console.log('开启后台定位.complete', res)         // wx.openSetting({         //   success(res) {         //     console.log(res.authSetting)         //     res.authSetting = {         //       "scope.userInfo": true,         //       "scope.userLocation": true         //     }         //   }         // })       },     });   },   //关闭后台获取地理坐标   disableLocationUpdateBackground() {     const that = this;     wx.stopLocationUpdate({       complete: async (res) => {         wx.offLocationChange(res=>{                    })         //结束记录         const userId = wx.getStorageSync('userId');         const openId = wx.getStorageSync('openid');         const userInfo = this.data.userInfo;         const endloc = await that.getLocation();         const endaddress = await that.reverseGeocoder({           latitude: endloc.latitude,           longitude: endloc.longitude         });         that.addTrackPath({           "UserId": userId,           "TrackingDateTime": moment().format("YYYY-MM-DDTHH:mm:ss.SSS[Z]"),           "EndDateTime": moment().format("YYYY-MM-DDTHH:mm:ss.SSS[Z]"),           "Location": JSON.stringify(endloc),           "latitude": endloc.latitude,           "longitude": endloc.longitude,           "Address": endaddress.result.address,           "OpenId": openId,           "NickName": userInfo.nickName,           "AvatarUrl": userInfo.avatarUrl,         })         Notify({           type: 'primary',           message: '停止上报定位信息'         });       },     })   },