蓝牙小程序后台运行无法下发指令

that.data.setInter=setInterval(function(){time--;minute=parseInt(time/60);second=time%60;that.setData({minute:minute});that.setData({second:second});console.log(time);if(time==0){clearInterval(that.data.setInter)varparam=0x01;that.setData({'send[0]':param});if(that.data.write_id){dataView.setUint8(0,"0x"+send[0])//that.setData({'buffer':send[0]});console.log(send);console.log("endtime");wx.writeBLECharacteristicValue({//这里的deviceId需要在上面的getBluetoothDevices或onBluetoothDeviceFound接口中获取deviceId:that.data.deviceId,//这里的serviceId需要在上面的getBLEDeviceServices接口中获取serviceId:that.data.serviceId,//这里的characteristicId需要在上面的getBLEDeviceCharacteristics接口中获取characteristicId:that.data.write_id,//这里的value是ArrayBuffer类型value:buffer,success:function(res){console.log(send);},fail:function(res){console.log(res)},})}}},1000);