做的是定位当前位置并且显示行动轨迹，存放轨迹polyline的数据console可以看到数据但是在地图上面只显示当前定位不显示轨迹

onLoad: function (options) {
    console.log(options.id)
    var that = this;
    wx.request({
      url: 'http://。。。。。。:8000/position/findTheConcreteTrace/' + app.globalData.userid + '/' + options.id,
      method: 'GET',
      header: {
        'content-type': 'application/json'
      },
      success: function (res) {
        that.setData({
          position: res.data
        })
        console.log('position',that.data.position)
        var lengthOfRes = res.data.length;
        console.log('len',lengthOfRes)
        for(var i=0;i<lengthOfRes;i++){
          that.data.positionArr[i]={
            latitude:that.data.position[i].latitude,
            longitude:that.data.position[i].longitude
          }
        }
          
      }
    })
    that.mapLoad();
    console.log('long',that.data.longitude)
  },


  mapLoad: function () {
    qqmapsdk = new QQMapWX({
      key: '。。。。。。。。。。'
    });
    this.mapCtx = wx.createMapContext('myMap');
    wx.getLocation({
      type:'gcj02',
      success:(res)=>{
        console.log('dingwei',res)
        this.setData({
          longitude:res.longitude,
          latitude:res.latitude
        })
      }
    });
    this.drawline();
    //隐藏定位中信息进度
    wx.hideLoading()
  },


  drawline:function(){
    let that=this;
    console.log('su',that.data.positionArr)
    let polyline = [{
      points: that.data.positionArr,
      color: '#00ff00',
      width: 5,
    }];
    that.setData({
      polyline: polyline
    });
    console.log('polyline',that.data.polyline)
  }

<map id="map" class="maMap" subkey="。。。。。。。" longitude="{{longitude}}" latitude="{{latitude}}" markers="{{markers}}" polyline="{{polyline}}" show-location>
</map>