onCharacteristicUpdate not calling.

[karthick1611]

I'm sending some commands and write was success but not able to read the data. Here I attach my logs.

BluetoothPeripheral com.library.blenew I connected to 'GNRGYBT_HMCNF2000000' (NONE) in 0.2s 2022-12-28 17:28:40.922 3525-3525 BluetoothPeripheral com.library.blenew I discovering services of 'GNRGYBT_HMCNF2000000' with delay of 0 ms 2022-12-28 17:28:40.922 3525-3525 BluetoothGatt com.library.blenew D discoverServices() - device: 50:02:91:81:21:E6 2022-12-28 17:28:41.375 3525-3539 BluetoothGatt com.library.blenew D onConnectionUpdated() - Device=50:02:91:81:21:E6 interval=6 latency=0 timeout=500 status=0 2022-12-28 17:28:41.407 3525-3539 BluetoothPeripheral com.library.blenew I connection parameters: interval=7.5ms latency=0 timeout=5s 2022-12-28 17:28:41.612 3525-3539 BluetoothGatt com.library.blenew D onSearchComplete() = Device=50:02:91:81:21:E6 Status=0 2022-12-28 17:28:41.619 3525-3539 BluetoothPeripheral com.library.blenew I discovered 3 services for 'GNRGYBT_HMCNF2000000' 2022-12-28 17:28:41.623 3525-3525 Found com.library.blenew E Bluetooth4 2022-12-28 17:28:41.623 3525-3525 Read com.library.blenew E 6e400003-b5a3-f393-e0a9-e50e24dcca9e 2022-12-28 17:28:41.624 3525-3525 Write com.library.blenew E 6e400002-b5a3-f393-e0a9-e50e24dcca9e 2022-12-28 17:28:41.625 3525-3525 BluetoothGatt com.library.blenew D configureMTU() - device: 50:02:91:81:21:E6 mtu: 517 2022-12-28 17:28:41.630 3525-3525 BluetoothPeripheral com.library.blenew I requesting MTU of 517 2022-12-28 17:28:41.652 3525-3539 BluetoothGatt com.library.blenew D onConfigureMTU() - Device=50:02:91:81:21:E6 mtu=517 status=0 2022-12-28 17:28:41.654 3525-3525 BluetoothGatt com.library.blenew D requestConnectionPriority() - params: 1 2022-12-28 17:28:41.658 3525-3525 BluetoothPeripheral com.library.blenew I requesting connection priority HIGH 2022-12-28 17:28:41.691 3525-3539 BluetoothGatt com.library.blenew D onConnectionUpdated() - Device=50:02:91:81:21:E6 interval=36 latency=0 timeout=500 status=0 2022-12-28 17:28:41.695 3525-3539 BluetoothPeripheral com.library.blenew I connection parameters: interval=45.0ms latency=0 timeout=5s 2022-12-28 17:28:41.803 3525-3536 System com.library.blenew W A resource failed to call close. 2022-12-28 17:28:42.161 3525-3525 BluetoothGatt com.library.blenew D setCharacteristicNotification() - uuid: 6e400003-b5a3-f393-e0a9-e50e24dcca9e enable: true 2022-12-28 17:28:42.186 3525-3539 BluetoothGatt com.library.blenew D onConnectionUpdated() - Device=50:02:91:81:21:E6 interval=12 latency=0 timeout=500 status=0 2022-12-28 17:28:42.188 3525-3539 BluetoothPeripheral com.library.blenew I connection parameters: interval=15.0ms latency=0 timeout=5s 2022-12-28 17:28:42.205 3525-3525 TAG com.library.blenew E SUCCESS: Notify set to 'on' for 6e400003-b5a3-f393-e0a9-e50e24dcca9e 2022-12-28 17:28:42.228 3525-3525 BluetoothPeripheral com.library.blenew I writing <7375204d616b654c6f74734f664073> to characteristic <6e400002-b5a3-f393-e0a9-e50e24dcca9e> 2022-12-28 17:28:42.255 3525-3525 Write Success com.library.blenew I SUCCESS: Writing <7375204d616b654c6f74734f664073> to <6e400002-b5a3-f393-e0a9-e50e24dcca9e> 2022-12-28 17:33:41.021 3525-3525 ViewRootIm...nActivity] com.library.blenew I handleAppVisibility mAppVisible=true visible=false 2022-12-28 17:33:41.047 3525-3547 OpenGLRenderer com.library.blenew D setSurface called with nullptr 2022-12-28 17:33:41.048 3525-3547 OpenGLRenderer com.library.blenew D setSurface() destroyed EGLSurface 2022-12-28 17:33:41.048 3525-3547 OpenGLRenderer com.library.blenew D destroyEglSurface

[weliem]

I don't see anything strange in the logs. Are you sure the write you are doing will lead to a notification?

[karthick1611]

` val currentTimeCharacteristic = peripheral.getCharacteristic(BLUETOOTH_LE_NRF_SERVICE, readCharacteristic?.uuid!!)

if (currentTimeCharacteristic != null) peripheral.setNotify(currentTimeCharacteristic, true) `

` override fun onNotificationStateUpdate( peripheral: BluetoothPeripheral, characteristic: BluetoothGattCharacteristic, status: GattStatus ) {

            if (status == GattStatus.SUCCESS) {
                if(peripheral.isNotifying(characteristic)) {
                    Log.e("TAG", String.format("SUCCESS: Notify set to 'on' for %s", characteristic.uuid))
                    writeCharacteristic?.let { sendStringToBle(peripheral, it) }
                } else {
                    Log.e("TAG", String.format("SUCCESS: Notify set to 'off' for %s", characteristic.uuid))
                }
            } else {
                Log.e("TAG", String.format("ERROR: Changing notification state failed for %s", characteristic.uuid))
            }
        }

`

` override fun onCharacteristicWrite( peripheral: BluetoothPeripheral, value: ByteArray, characteristic: BluetoothGattCharacteristic, status: GattStatus ) {

            if (status == GattStatus.SUCCESS) {
                Log.i("Write Success", String.format("SUCCESS: Writing <%s> to <%s>", asHexString(value), characteristic.uuid))
            } else {
                Log.i("Write Failed", String.format("ERROR: Failed writing <%s> to <%s> (%s)", asHexString(value), characteristic.uuid, status))
            }
        }

`

[karthick1611]

How can I make sure that will lead to a notification?.

[karthick1611]

        override fun onCharacteristicUpdate(
            peripheral: BluetoothPeripheral,
            value: ByteArray,
            characteristic: BluetoothGattCharacteristic,
            status: GattStatus
        ) {
            if (status != GattStatus.SUCCESS) return
            val characteristicUUID = characteristic.uuid
            val parser = BluetoothBytesParser(value)
            Log.e("Response", value.decodeToString())
            if (characteristic == readCharacteristic) {
                Log.e("Response", value.decodeToString())
            }
        }

[weliem]

Whether or not a notification will happen depends on your device and the protocol it uses. You need to know the protocol in order to properly coomunicate with the device.

[karthick1611]

Thanks for the response. I figured out the issue and it's resolved. Thanks again.