I am trying to build a BLE Gatt Server with multiple custom services and multiple characteristics.
To begin with I used the Google Example: https://github.com/androidthings/sample-bluetooth-le-gattserver/tree/master/kotlin
This was straight forward and worked very well. I modified the UUIDs to fit mine and I could receive notifications and write to the chars with no problem.
This is where I define the services and chars:
fun createTimeService(): BluetoothGattService {
val service = BluetoothGattService(TIME_SERVICE,
BluetoothGattService.SERVICE_TYPE_PRIMARY)
// Current Time characteristic
val currentTime = BluetoothGattCharacteristic(CURRENT_TIME,
//Read-only characteristic, supports notifications
BluetoothGattCharacteristic.PROPERTY_READ or BluetoothGattCharacteristic.PROPERTY_NOTIFY,
BluetoothGattCharacteristic.PERMISSION_READ)
val configDescriptor = BluetoothGattDescriptor(CLIENT_CONFIG,
//Read/write descriptor
BluetoothGattDescriptor.PERMISSION_READ or BluetoothGattDescriptor.PERMISSION_WRITE)
currentTime.addDescriptor(configDescriptor)
// Local Time Information characteristic
val localTime = BluetoothGattCharacteristic(LOCAL_TIME_INFO,
BluetoothGattCharacteristic.PROPERTY_WRITE,
BluetoothGattCharacteristic.PERMISSION_WRITE)
service.addCharacteristic(currentTime)
service.addCharacteristic(localTime)
return service
}
fun createSerialService(): BluetoothGattService {
val service = BluetoothGattService(serialPortServiceID,
BluetoothGattService.SERVICE_TYPE_PRIMARY)
val serialData = BluetoothGattCharacteristic(serialDataCharacteristicID,
BluetoothGattCharacteristic.PROPERTY_WRITE,
BluetoothGattCharacteristic.PERMISSION_WRITE)
service.addCharacteristic(serialData)
return service
}
And here I am applying them to my server:
private fun startServer() {
bluetoothGattServer = bluetoothManager.openGattServer(this, gattServerCallback)
bluetoothGattServer?.addService(TimeProfile.createTimeService())
?: Log.w(TAG, "Unable to create GATT server")
bluetoothGattServer?.addService(TimeProfile.createSerialService())
?: Log.w(TAG, "Unable to create GATT server")
// Initialize the local UI
updateLocalUi(System.currentTimeMillis())
}
I would expect that everything would be working like before after adding the second service. But now if I try to write/subscribe to any of the characteristics (doesn't matter in which service) I just receive this:
W/BluetoothGattServer: onCharacteristicWriteRequest() no char for handle 42
W/BluetoothGattServer: onDescriptorWriteRequest() no desc for handle 43