Characteristic change event not received

Summary

A characteristic change event is logged but never received through the subscribed observable when a CharacteristicChangeEvent is fired while the notification is being setup

Preconditions

A RxBleDevice is connected and has a characteristic with indication property #### Steps to reproduce actual result
1. connect to a BluetoothDevice
2. setup indications

Observable.combineLatest(
connection.setupIndication(UUID.fromString(00008a82-0000-1000-8000-00805f9b34fb)),
connection.setupIndication(UUID.fromString(00008a91-0000-1000-8000-00805f9b34fb)),
(indication1, indication2) -> { return indication1;})
.flatMap(observable-> observable)
.doOnNext(bytes -> { log.d(bytes) })
.subscribe();

1. As soon as onDescriptor write is fired a onChangeEvent happens that the observable never sees

Actual result

No log

Expected result

Log of bytes

Actual Log: Galaxy s6 6.0.1

D/RxBle#Radio: FINISHED RxBleRadioOperationConnect(149819350)
 D/BluetoothGatt: onClientConnParamsChanged() - Device=98:7B:F3:6B:F9:99 interval=6 status=0
D/RxBle#Radio:   QUEUED RxBleRadioOperationServicesDiscover(8272968)
 D/RxBle#Radio:  STARTED RxBleRadioOperationServicesDiscover(8272968)
 D/BluetoothGatt: discoverServices() - device: 98:7B:F3:6B:F9:99
 D/BluetoothGatt: onSearchComplete() = Device=98:7B:F3:6B:F9:99 Status=0
D/RxBle#BluetoothGatt: onServicesDiscovered status=0
D/BluetoothGatt: setCharacteristicNotification() - uuid: 00008a82-0000-1000-8000-00805f9b34fb enable: true
 D/RxBle#Radio:   QUEUED RxBleRadioOperationDescriptorWrite(72475096)
D/RxBle#Radio: FINISHED RxBleRadioOperationServicesDiscover(8272968)
D/RxBle#Radio:  STARTED RxBleRadioOperationDescriptorWrite(72475096)
D/BluetoothGatt: onClientConnParamsChanged() - Device=98:7B:F3:6B:F9:99 interval=39 status=0
D/RxBle#BluetoothGatt: onDescriptorWrite descriptor=00002902-0000-1000-8000-00805f9b34fb status=0
**D/RxBle#BluetoothGatt: onCharacteristicChanged characteristic=00008a82-0000-1000-8000-00805f9b34fb**
D/RxBle#Radio: FINISHED RxBleRadioOperationDescriptorWrite(72475096)

[gryffindor14]

Hey @dariuszseweryn, thanks for taking a look at this. For us, yes, receiving the indication is important to the transmission.

Our use case is that when we subscribe to the characteristic it fires a characteristic change event with a value. We then write to another characteristic which causes us to receive another characteristic change event with another value that we combine into a key.

I have had better results when writing the client descriptor myself while starting to observe the change event from RxBleGattCallback.

connection.setupNotification(characteristic, NotificationSetupMode.COMPAT)
    .flatmap(observable-> Observable.combineLatest(observable, writeClientDescriptor(connection), 
          return bytes; //from observable
)

[gryffindor14]

It will require 1.2.0. I believe I posted how I got it to work in the thread. It requires setting up the notification with the NotificationCompat option. connection.setupNotification(uuid, NotificationSetupMode.COMPAT) .flatmap { notification -> return notification.mergeWith(connection.writeDescriptor(descriptor_uuid, BluetoothGattDescriptor.ENABLE_NOTIFICATIONS).ignoreElements())

note the ignoreElements() method at the end. This merges the notification byte[] stream with the descriptorWrite byte[] stream but the write for the descriptor is ignored.

combineLatest() also works as mentioned in the thread. connection.writeDescriptor is a completeable in the rxjava2 version and therefore does not emit any values. Good luck!

Griffin

On Sat, Aug 11, 2018 at 7:44 AM SogoodIT [e-mail] wrote:

@gryffindor14 https://github.com/gryffindor14 @mswokk https://github.com/mswokk i’m meet the same issue on rxandroidble version 1.1.0，can you tell me how to fix this? preferably with 1.1.0, 1.2.0 is also ok.That code is incomplete, i can’t got u well, thanks.

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