无法读取设备信息服务的特征值，并使用BLE获取所有空值

Question

我正在两个不同的Android手机上设计中央和外围应用程序。我做了以下操作以添加设备信息服务及其特征

override fun onServicesDiscovered(gatt: BluetoothGatt, status: Int) {
        super.onServicesDiscovered(gatt, status)
        if (status == BluetoothGatt.GATT_SUCCESS) {
            val leServiceList: List<BluetoothGattService> = gatt.services
            for (mBluetoothGattService in leServiceList) {
                if (mBluetoothGattService.uuid.toString().equals(DEVICE_INFO_SERVICE_UUID, ignoreCase = true)) {
                    for (mBluetoothGattCharacteristic in mBluetoothGattService.characteristics) {
                        when {
                            mBluetoothGattCharacteristic.uuid.toString().equals(HARDWARE_UUID, ignoreCase = true) ->
                                Log.d(TAG, "Hardware Version : ${mBluetoothGattCharacteristic.value}")

                            mBluetoothGattCharacteristic.uuid.toString().equals(FIRMWARE_UUID, ignoreCase = true) ->
                                Log.d(TAG, "Firmware Version : ${mBluetoothGattCharacteristic.value}")
                            mBluetoothGattCharacteristic.uuid.toString().equals(MANUFACTURER_UUID, ignoreCase = true) ->
                                Log.d(TAG, "Manufacturer Name : ${mBluetoothGattCharacteristic.value}")
                        }
                    }
                }
            }
        }
    }

我正在从外围设备上阅读它。

<TextMask
        mask={[/[12]/, /\d/, /\d/, /\d/, "-", /[01]/, /\d/, "-", /[0-3]/, /\d/]}
        placeholderChar="_"
        showMask
        render={(ref, props) => (
          <Input
            name="phone"
            className="form-control"
            placeholder="Hey I am Ant design Input"
            required
            ref={ref}
            {...props}
          />
        )}
      />

但是在这里，在外围设备上发现服务后，我得到的是空值。