wx.notifyBLECharacteristicValueChange({
            state: true, 
            deviceId,
            serviceId,
            characteristicId,
            success (res) {
              console.log("readStepByFive->成功:"+JSON.stringify(res))
              wx.onBLECharacteristicValueChange(function(characteristic) {
                console.log("你好");
                console.log('characteristic value comed:', characteristic)
              })
            },
            fail(res){
              console.log("readStepByFive->失败:"+JSON.stringify(res));
              that.readHRFail("读取失败");
            }

          })

对我司的一个传感器notify之后，传感器会把自身的内存数据源源传送给我(Android原生端已经实现了)。在小程序,调用了wx.notifyBLECharacteristicValueChange之后，回调了success方法，数据如下{"errno":0,"errCode":0,"errMsg":"notifyBLECharacteristicValueChange:ok"}。但是wx.onBLECharacteristicValueChange却没有源源不但返回数据是为什么呢？