HarmonyOS鸿蒙Next中ble订阅蓝牙低功耗设备的特征值变化事件BLECharacteristicChange，发送指令并操作成功后，没有得到设备的回调

HarmonyOS鸿蒙Next中ble订阅蓝牙低功耗设备的特征值变化事件BLECharacteristicChange，发送指令并操作成功后，没有得到设备的回调 以下是大致的代码流程：

let descriptors: Array<ble.BLEDescriptor> = [];
let bufferDesc = new ArrayBuffer(8);
let descV = new Uint8Array(bufferDesc);
descV[0] = 0x00;
descV[1] = 0xaa;
descV[2] = 0xbb;
descV[3] = 0xcc;
// 模拟数据
let descriptor: ble.BLEDescriptor = {
  serviceUuid: 'xxxxxx00-aaaa-bbbb-cccc-dddddddddddd',
  characteristicUuid: 'xxxxxx02-aaaa-bbbb-cccc-dddddddddddd',
  descriptorUuid: '00002902-0000-1000-8000-00805F9B34FB',
  descriptorValue: bufferDesc
};
descriptors[0] = descriptor;
let bufferCCC = new ArrayBuffer(8);
let cccV = new Uint8Array(bufferCCC);
cccV[0] = 0x00;
cccV[1] = 0xaa;
cccV[2] = 0xbb;
cccV[3] = 0xcc;
cccV[4] = 0xdd;

let characteristic: ble.BLECharacteristic = {
  serviceUuid: 'xxxxxx00-aaaa-bbbb-cccc-dddddddddddd',
  characteristicUuid: 'xxxxxx01-aaaa-bbbb-cccc-dddddddddddd',
  characteristicValue: bufferCCC,
  descriptors: descriptors
};

// 创建客户端
gattClient = ble.createGattClientDevice(myDevice.deviceId);
try {
  gattClient.on('BLEConnectionStateChange', (state: ble.BLEConnectionChangeState) => {
    console.info('订阅连接状态变化事件 bluetooth connect state changed');
    let connectState: ble.ProfileConnectionState = state.state;
    console.info('连接状态:' + connectState);
    // 已连接状态，进行以下操作
    if (connectState === 2) {
      // 服务发现
      gattClient.getServices()
        .then((result: Array<ble.GattService>) => {
          console.info('服务发现 getServices successfully:' + JSON.stringify(result));

          // 设置特征值变化通知能力
          try {
            // enable入参: true表示启用，false表示禁用
            gattClient.setCharacteristicChangeNotification(characteristic, true, (err: BusinessError, data) => {
              if (err) {
                console.error('特征值变化通知 setCharacteristicChangeNotification callback failed');
              } else {
                console.info('特征值变化通知 setCharacteristicChangeNotification callback successful --', data);

                try {
                  // 订阅特征值变化事件通知
                  // 需要先调用 setCharacteristicChangeNotification 接口
                  // 或 setCharacteristicChangeIndication 接口才能接收服务端的通知。
                  gattClient.on('BLECharacteristicChange', (characteristicChangeReq: ble.BLECharacteristic) => {
                    let serviceUuids: string = characteristicChangeReq.serviceUuid;
                    let characteristicUuids: string = characteristicChangeReq.characteristicUuid;
                    let values: Uint8Array = new Uint8Array(characteristicChangeReq.characteristicValue);
                    console.log('订阅特征值变化事件', serviceUuids, characteristicUuids, values)
                  })
                } catch (err) {
                  console.error('订阅特征值变化事件 errCode: ' + (err as BusinessError).code + ', errMessage: ' + (err as BusinessError).message);
                }
              }
            });
          } catch (err) {
            console.error('特征值变化通知 errCode: ' + (err as BusinessError).code + ', errMessage: ' + (err as BusinessError).message);
          }

        }).catch((err: BusinessError) => {
          console.error('服务发现 getServices failed:' + JSON.stringify(err));
        })
    }
  });
  // 发起ble连接
  try {
    gattClient.connect();
  } catch (err) {
    console.error('发起ble建立连接 errCode: ' + (err as BusinessError).code + ', errMessage: ' + (err as BusinessError).message);
  }
} catch (err) {
  console.error('订阅连接状态变化事件: ' + (err as BusinessError).code + ', errMessage: ' + (err as BusinessError).message)
}

// 写入特征值 发送指令
try {
  const TAG: string = '写入特征值 GattClientManager';
  console.warn('character', JSON.stringify(characteristic))
  gattClient.writeCharacteristicValue(characteristic, ble.GattWriteType.WRITE, (err) => {
    if (err) {
      console.error(TAG, 'errCode: ' + (err as BusinessError).code + ', errMessage: ' + (err as BusinessError).message);
      return;
    }
    console.info(TAG, 'writeCharacteristicValue success');
  });
} catch (err) {
  console.error('errCode: ' + (err as BusinessError).code + ', errMessage: ' + (err as BusinessError).message);
}

以下是**gattClient.getServices()**拿到的数据：

[
  {
    "serviceUuid":"xxxxxx00-aaaa-bbbb-cccc-dddddddddddd",
    "isPrimary":true,
    "characteristics":[
      {
        "characteristicUuid":"xxxxxx01-aaaa-bbbb-cccc-dddddddddddd",
        "serviceUuid":"xxxxxx00-aaaa-bbbb-cccc-dddddddddddd",
        "characteristicValue":{},
        "properties":{
          "write":true,
          "writeNoResponse":true,
          "read":false,
          "notify":false,
          "indicate":false
        },
        "descriptors":[]
      },
      {
        "characteristicUuid":"xxxxxx02-aaaa-bbbb-cccc-dddddddddddd",
        "serviceUuid":"xxxxxx00-aaaa-bbbb-cccc-dddddddddddd",
        "characteristicValue":{},
        "properties":{
           "write":false,
           "writeNoResponse":false,
           "read":true,
           "notify":true,
           "indicate":false
         },
       "descriptors":[
         {
           "descriptorUuid":"00002902-0000-1000-8000-00805F9B34FB",
           "characteristicUuid":"xxxxxx02-aaaa-bbbb-cccc-dddddddddddd",
           "serviceUuid":"xxxxxx00-aaaa-bbbb-cccc-dddddddddddd",
           "descriptorValue":{}
         }
       ]
      }
    ],
    "includeServices":[]
  }
]

我是通过gattClient.getServices()获取的数据，然后去手动编写最开始的characteristic、descriptor等数据，然后再发送请求。

蓝牙设备能够正常进行ble连接，发送的指令也能够正常的执行，但是就是无法获取设备的回调。

gattClient.setCharacteristicChangeNotification方法的回调没有报错，应该是正常设置了特征值变化通知能力，**gattClient.on(‘BLECharacteristicChange’)**方法也没有报错，但是没有任何反应。请问为什么无法获取设备的回调呢？