2

I am trying to set up notifications using RxAndroidBle, however when the connection to the peripheral is lost, the notification that I set up needs to be created again. I am creating notifications like so:

connectionObservable
                .flatMap(rxBleConnection -> rxBleConnection.setupNotification(characteristicUuid))
                .doOnNext(notificationObservable -> runOnUiThread(this::notificationHasBeenSetUp))
                .flatMap(notificationObservable -> notificationObservable)
                .retryWhen(errors -> errors.flatMap(error -> {
                    if (error instanceof BleDisconnectedException) {
                        Log.d("Retry", "Retrying");
                        return Observable.just(null);
                    }
                    return Observable.error(error);
                }))
                .observeOn(AndroidSchedulers.mainThread())
                .subscribe(this::onNotificationReceived, this::onNotificationSetupFailure);

This code is the same as the RxAndroidBle sample located here(See onNotifyClick()) except I added a .retryWhen() block to retry connecting when a connection is lost. The notification is successfully set up upon establishing connection, and onNotificationReceived() is called. This will sometimes reconnects several times before I am repeatedly failing to connect, and setCharacteristicNotification() is repeatedly called.

This is a portion of the logs showing the problem I am running into:

12-12 11:36:23.420 10841-10841/com.polidea.rxandroidble.sample I/CharacteristicOperationExampleActivity: Hey, connection has been established!
12-12 11:36:23.441 10841-10860/com.polidea.rxandroidble.sample D/BluetoothGatt: onConnectionUpdated() - Device=F9:A1:74:C0:09:3A interval=36 latency=0 timeout=500 status=0
12-12 11:36:24.819 10841-10841/com.polidea.rxandroidble.sample D/BluetoothGatt: setCharacteristicNotification() - uuid: 00002a19-0000-1000-8000-00805f9b34fb enable: true
12-12 11:36:24.823 10841-10841/com.polidea.rxandroidble.sample D/RxBle#ConnectionOperationQueue:   QUEUED DescriptorWriteOperation(204891860)
12-12 11:36:24.825 10841-10887/com.polidea.rxandroidble.sample D/RxBle#ConnectionOperationQueue:  STARTED DescriptorWriteOperation(204891860)
12-12 11:36:24.889 10841-10859/com.polidea.rxandroidble.sample D/RxBle#BluetoothGatt$1: onDescriptorWrite descriptor=00002902-0000-1000-8000-00805f9b34fb status=0
12-12 11:36:24.893 10841-10841/com.polidea.rxandroidble.sample D/Notifications: Notifications set up
12-12 11:36:24.893 10841-10887/com.polidea.rxandroidble.sample D/RxBle#ConnectionOperationQueue: FINISHED DescriptorWriteOperation(204891860)
12-12 11:36:26.252 10841-10860/com.polidea.rxandroidble.sample D/RxBle#BluetoothGatt$1: onCharacteristicChanged characteristic=00002a19-0000-1000-8000-00805f9b34fb
12-12 11:36:26.814 10841-10851/com.polidea.rxandroidble.sample I/zygote64: Compiler allocated 6MB to compile void android.view.ViewRootImpl.performTraversals()
12-12 11:36:27.681 10841-10859/com.polidea.rxandroidble.sample D/BluetoothGatt: onConnectionUpdated() - Device=F9:A1:74:C0:09:3A interval=24 latency=1 timeout=75 status=0
12-12 11:36:28.271 10841-10860/com.polidea.rxandroidble.sample D/RxBle#BluetoothGatt$1: onCharacteristicChanged characteristic=00002a19-0000-1000-8000-00805f9b34fb
12-12 11:36:28.401 10841-10851/com.polidea.rxandroidble.sample I/zygote64: Do full code cache collection, code=103KB, data=93KB
12-12 11:36:28.402 10841-10851/com.polidea.rxandroidble.sample I/zygote64: After code cache collection, code=101KB, data=74KB
12-12 11:36:30.261 10841-10859/com.polidea.rxandroidble.sample D/RxBle#BluetoothGatt$1: onCharacteristicChanged characteristic=00002a19-0000-1000-8000-00805f9b34fb
12-12 11:36:32.271 10841-10860/com.polidea.rxandroidble.sample D/RxBle#BluetoothGatt$1: onCharacteristicChanged characteristic=00002a19-0000-1000-8000-00805f9b34fb
12-12 11:36:34.283 10841-10859/com.polidea.rxandroidble.sample D/RxBle#BluetoothGatt$1: onCharacteristicChanged characteristic=00002a19-0000-1000-8000-00805f9b34fb
12-12 11:36:34.657 10841-10851/com.polidea.rxandroidble.sample I/zygote64: Do partial code cache collection, code=125KB, data=99KB
12-12 11:36:34.657 10841-10851/com.polidea.rxandroidble.sample I/zygote64: After code cache collection, code=125KB, data=99KB
12-12 11:36:34.658 10841-10851/com.polidea.rxandroidble.sample I/zygote64: Increasing code cache capacity to 512KB
12-12 11:36:36.323 10841-10860/com.polidea.rxandroidble.sample D/RxBle#BluetoothGatt$1: onCharacteristicChanged characteristic=00002a19-0000-1000-8000-00805f9b34fb
12-12 11:36:38.273 10841-10859/com.polidea.rxandroidble.sample D/RxBle#BluetoothGatt$1: onCharacteristicChanged characteristic=00002a19-0000-1000-8000-00805f9b34fb
12-12 11:36:40.311 10841-10860/com.polidea.rxandroidble.sample D/RxBle#BluetoothGatt$1: onCharacteristicChanged characteristic=00002a19-0000-1000-8000-00805f9b34fb
12-12 11:36:41.846 10841-10859/com.polidea.rxandroidble.sample D/BluetoothGatt: onClientConnectionState() - status=19 clientIf=6 device=F9:A1:74:C0:09:3A
12-12 11:36:41.854 10841-10859/com.polidea.rxandroidble.sample D/RxBle#BluetoothGatt$1: onConnectionStateChange newState=0 status=19
12-12 11:36:41.873 10841-10859/com.polidea.rxandroidble.sample D/BluetoothGatt: setCharacteristicNotification() - uuid: 00002a19-0000-1000-8000-00805f9b34fb enable: false
12-12 11:36:41.879 10841-10859/com.polidea.rxandroidble.sample D/RxBle#ConnectionOperationQueue:   QUEUED DescriptorWriteOperation(54354895)
12-12 11:36:41.884 10841-10887/com.polidea.rxandroidble.sample D/RxBle#ConnectionOperationQueue:  STARTED DescriptorWriteOperation(54354895)
12-12 11:36:41.885 10841-10859/com.polidea.rxandroidble.sample D/Retry: Retrying
12-12 11:36:41.895 10841-10859/com.polidea.rxandroidble.sample D/BluetoothGatt: setCharacteristicNotification() - uuid: 00002a19-0000-1000-8000-00805f9b34fb enable: true
12-12 11:36:41.900 10841-10859/com.polidea.rxandroidble.sample D/RxBle#ConnectionOperationQueue:   QUEUED DescriptorWriteOperation(254074559)
12-12 11:36:41.902 10841-10887/com.polidea.rxandroidble.sample D/RxBle#ConnectionOperationQueue: FINISHED DescriptorWriteOperation(54354895)
12-12 11:36:41.904 10841-10859/com.polidea.rxandroidble.sample D/BluetoothGatt: setCharacteristicNotification() - uuid: 00002a19-0000-1000-8000-00805f9b34fb enable: false
12-12 11:36:41.904 10841-10887/com.polidea.rxandroidble.sample D/RxBle#ConnectionOperationQueue:  STARTED DescriptorWriteOperation(254074559)
12-12 11:36:41.909 10841-10859/com.polidea.rxandroidble.sample D/RxBle#ConnectionOperationQueue:   QUEUED DescriptorWriteOperation(231910737)
12-12 11:36:41.914 10841-10859/com.polidea.rxandroidble.sample D/Retry: Retrying
12-12 11:36:41.916 10841-10887/com.polidea.rxandroidble.sample D/RxBle#ConnectionOperationQueue: FINISHED DescriptorWriteOperation(254074559)
12-12 11:36:41.918 10841-10887/com.polidea.rxandroidble.sample D/RxBle#ConnectionOperationQueue:  STARTED DescriptorWriteOperation(231910737)
12-12 11:36:41.923 10841-10859/com.polidea.rxandroidble.sample D/BluetoothGatt: setCharacteristicNotification() - uuid: 00002a19-0000-1000-8000-00805f9b34fb enable: true
12-12 11:36:41.926 10841-10859/com.polidea.rxandroidble.sample D/RxBle#ConnectionOperationQueue:   QUEUED DescriptorWriteOperation(48916564)
12-12 11:36:41.928 10841-10859/com.polidea.rxandroidble.sample D/BluetoothGatt: setCharacteristicNotification() - uuid: 00002a19-0000-1000-8000-00805f9b34fb enable: false
12-12 11:36:41.935 10841-10859/com.polidea.rxandroidble.sample D/RxBle#ConnectionOperationQueue:   QUEUED DescriptorWriteOperation(258401717)
12-12 11:36:41.935 10841-10887/com.polidea.rxandroidble.sample D/RxBle#ConnectionOperationQueue: FINISHED DescriptorWriteOperation(231910737)
12-12 11:36:41.937 10841-10859/com.polidea.rxandroidble.sample D/Retry: Retrying
12-12 11:36:41.937 10841-10887/com.polidea.rxandroidble.sample D/RxBle#ConnectionOperationQueue:  STARTED DescriptorWriteOperation(48916564)
12-12 11:36:41.941 10841-10859/com.polidea.rxandroidble.sample D/BluetoothGatt: setCharacteristicNotification() - uuid: 00002a19-0000-1000-8000-00805f9b34fb enable: true
12-12 11:36:41.947 10841-10887/com.polidea.rxandroidble.sample D/RxBle#ConnectionOperationQueue: FINISHED DescriptorWriteOperation(48916564)
12-12 11:36:41.947 10841-10859/com.polidea.rxandroidble.sample D/RxBle#ConnectionOperationQueue:   QUEUED DescriptorWriteOperation(261960698)
12-12 11:36:41.948 10841-10887/com.polidea.rxandroidble.sample D/RxBle#ConnectionOperationQueue:  STARTED DescriptorWriteOperation(258401717)
12-12 11:36:41.949 10841-10859/com.polidea.rxandroidble.sample D/BluetoothGatt: setCharacteristicNotification() - uuid: 00002a19-0000-1000-8000-00805f9b34fb enable: false
12-12 11:36:41.952 10841-10859/com.polidea.rxandroidble.sample D/RxBle#ConnectionOperationQueue:   QUEUED DescriptorWriteOperation(184043911)
12-12 11:36:41.955 10841-10859/com.polidea.rxandroidble.sample D/RxBle#ConnectionOperationQueue$2:  REMOVED DescriptorWriteOperation(261960698)
12-12 11:36:41.957 10841-10887/com.polidea.rxandroidble.sample D/RxBle#ConnectionOperationQueue: FINISHED DescriptorWriteOperation(258401717)
12-12 11:36:41.957 10841-10859/com.polidea.rxandroidble.sample D/Retry: Retrying
12-12 11:36:41.958 10841-10887/com.polidea.rxandroidble.sample D/RxBle#ConnectionOperationQueue:  STARTED DescriptorWriteOperation(184043911)
12-12 11:36:41.961 10841-10859/com.polidea.rxandroidble.sample D/BluetoothGatt: setCharacteristicNotification() - uuid: 00002a19-0000-1000-8000-00805f9b34fb enable: true
12-12 11:36:41.964 10841-10859/com.polidea.rxandroidble.sample D/RxBle#ConnectionOperationQueue:   QUEUED DescriptorWriteOperation(233807588)
12-12 11:36:41.966 10841-10859/com.polidea.rxandroidble.sample D/BluetoothGatt: setCharacteristicNotification() - uuid: 00002a19-0000-1000-8000-00805f9b34fb enable: false
12-12 11:36:41.969 10841-10859/com.polidea.rxandroidble.sample D/RxBle#ConnectionOperationQueue:   QUEUED DescriptorWriteOperation(92084997)
12-12 11:36:41.970 10841-10887/com.polidea.rxandroidble.sample D/RxBle#ConnectionOperationQueue: FINISHED DescriptorWriteOperation(184043911)
12-12 11:36:41.970 10841-10859/com.polidea.rxandroidble.sample D/RxBle#ConnectionOperationQueue$2:  REMOVED DescriptorWriteOperation(233807588)
12-12 11:36:41.972 10841-10859/com.polidea.rxandroidble.sample D/Retry: Retrying
12-12 11:36:41.973 10841-10887/com.polidea.rxandroidble.sample D/RxBle#ConnectionOperationQueue:  STARTED DescriptorWriteOperation(92084997)
12-12 11:36:41.975 10841-10859/com.polidea.rxandroidble.sample D/BluetoothGatt: setCharacteristicNotification() - uuid: 00002a19-0000-1000-8000-00805f9b34fb enable: true
12-12 11:36:41.978 10841-10859/com.polidea.rxandroidble.sample D/RxBle#ConnectionOperationQueue:   QUEUED DescriptorWriteOperation(4571907)
12-12 11:36:41.979 10841-10859/com.polidea.rxandroidble.sample D/BluetoothGatt: setCharacteristicNotification() - uuid: 00002a19-0000-1000-8000-00805f9b34fb enable: false
12-12 11:36:41.982 10841-10859/com.polidea.rxandroidble.sample D/RxBle#ConnectionOperationQueue:   QUEUED DescriptorWriteOperation(85913073)
12-12 11:36:41.983 10841-10887/com.polidea.rxandroidble.sample D/RxBle#ConnectionOperationQueue: FINISHED DescriptorWriteOperation(92084997)
12-12 11:36:41.984 10841-10859/com.polidea.rxandroidble.sample D/RxBle#ConnectionOperationQueue$2:  REMOVED DescriptorWriteOperation(4571907)
12-12 11:36:41.985 10841-10887/com.polidea.rxandroidble.sample D/RxBle#ConnectionOperationQueue:  STARTED DescriptorWriteOperation(85913073)
12-12 11:36:41.986 10841-10859/com.polidea.rxandroidble.sample D/Retry: Retrying
12-12 11:36:41.989 10841-10859/com.polidea.rxandroidble.sample D/BluetoothGatt: setCharacteristicNotification() - uuid: 00002a19-0000-1000-8000-00805f9b34fb enable: true
12-12 11:36:41.991 10841-10859/com.polidea.rxandroidble.sample D/RxBle#ConnectionOperationQueue:   QUEUED DescriptorWriteOperation(44454620)
12-12 11:36:41.993 10841-10859/com.polidea.rxandroidble.sample D/BluetoothGatt: setCharacteristicNotification() - uuid: 00002a19-0000-1000-8000-00805f9b34fb enable: false
12-12 11:36:41.995 10841-10859/com.polidea.rxandroidble.sample D/RxBle#ConnectionOperationQueue:   QUEUED DescriptorWriteOperation(260032157)
12-12 11:36:41.996 10841-10887/com.polidea.rxandroidble.sample D/RxBle#ConnectionOperationQueue: FINISHED DescriptorWriteOperation(85913073)
12-12 11:36:41.997 10841-10859/com.polidea.rxandroidble.sample D/RxBle#ConnectionOperationQueue$2:  REMOVED DescriptorWriteOperation(44454620)
12-12 11:36:41.998 10841-10859/com.polidea.rxandroidble.sample D/Retry: Retrying
12-12 11:36:41.998 10841-10887/com.polidea.rxandroidble.sample D/RxBle#ConnectionOperationQueue:  STARTED DescriptorWriteOperation(260032157)
12-12 11:36:42.001 10841-10859/com.polidea.rxandroidble.sample D/BluetoothGatt: setCharacteristicNotification() - uuid: 00002a19-0000-1000-8000-00805f9b34fb enable: true
12-12 11:36:42.003 10841-10859/com.polidea.rxandroidble.sample D/RxBle#ConnectionOperationQueue:   QUEUED DescriptorWriteOperation(205319160)
12-12 11:36:42.005 10841-10859/com.polidea.rxandroidble.sample D/BluetoothGatt: setCharacteristicNotification() - uuid: 00002a19-0000-1000-8000-00805f9b34fb enable: false
12-12 11:36:42.007 10841-10859/com.polidea.rxandroidble.sample D/RxBle#ConnectionOperationQueue:   QUEUED DescriptorWriteOperation(141963529)
12-12 11:36:42.007 10841-10887/com.polidea.rxandroidble.sample D/RxBle#ConnectionOperationQueue: FINISHED DescriptorWriteOperation(260032157)
12-12 11:36:42.009 10841-10859/com.polidea.rxandroidble.sample D/Retry: Retrying
12-12 11:36:42.010 10841-10887/com.polidea.rxandroidble.sample D/RxBle#ConnectionOperationQueue:  STARTED DescriptorWriteOperation(205319160)
12-12 11:36:42.012 10841-10859/com.polidea.rxandroidble.sample D/BluetoothGatt: setCharacteristicNotification() - uuid: 00002a19-0000-1000-8000-00805f9b34fb enable: true
12-12 11:36:42.014 10841-10859/com.polidea.rxandroidble.sample D/RxBle#ConnectionOperationQueue:   QUEUED DescriptorWriteOperation(207186388)
12-12 11:36:42.016 10841-10859/com.polidea.rxandroidble.sample D/BluetoothGatt: setCharacteristicNotification() - uuid: 00002a19-0000-1000-8000-00805f9b34fb enable: false
12-12 11:36:42.019 10841-10859/com.polidea.rxandroidble.sample D/RxBle#ConnectionOperationQueue:   QUEUED DescriptorWriteOperation(12579274)
12-12 11:36:42.020 10841-10887/com.polidea.rxandroidble.sample D/RxBle#ConnectionOperationQueue: FINISHED DescriptorWriteOperation(205319160)
12-12 11:36:42.020 10841-10859/com.polidea.rxandroidble.sample D/RxBle#ConnectionOperationQueue$2:  REMOVED DescriptorWriteOperation(207186388)
12-12 11:36:42.021 10841-10859/com.polidea.rxandroidble.sample D/Retry: Retrying
12-12 11:36:42.022 10841-10887/com.polidea.rxandroidble.sample D/RxBle#ConnectionOperationQueue:  STARTED DescriptorWriteOperation(141963529)
12-12 11:36:42.024 10841-10859/com.polidea.rxandroidble.sample D/BluetoothGatt: setCharacteristicNotification() - uuid: 00002a19-0000-1000-8000-00805f9b34fb enable: true
12-12 11:36:42.027 10841-10859/com.polidea.rxandroidble.sample D/RxBle#ConnectionOperationQueue:   QUEUED DescriptorWriteOperation(227068595)
12-12 11:36:42.029 10841-10859/com.polidea.rxandroidble.sample D/BluetoothGatt: setCharacteristicNotification() - uuid: 00002a19-0000-1000-8000-00805f9b34fb enable: false
12-12 11:36:42.031 10841-10859/com.polidea.rxandroidble.sample D/RxBle#ConnectionOperationQueue:   QUEUED DescriptorWriteOperation(34646817)
12-12 11:36:42.032 10841-10887/com.polidea.rxandroidble.sample D/RxBle#ConnectionOperationQueue: FINISHED DescriptorWriteOperation(141963529)
12-12 11:36:42.033 10841-10859/com.polidea.rxandroidble.sample D/RxBle#ConnectionOperationQueue$2:  REMOVED DescriptorWriteOperation(227068595)
12-12 11:36:42.034 10841-10859/com.polidea.rxandroidble.sample D/Retry: Retrying
12-12 11:36:42.034 10841-10887/com.polidea.rxandroidble.sample D/RxBle#ConnectionOperationQueue:  STARTED DescriptorWriteOperation(12579274)
12-12 11:36:42.037 10841-10859/com.polidea.rxandroidble.sample D/BluetoothGatt: setCharacteristicNotification() - uuid: 00002a19-0000-1000-8000-00805f9b34fb enable: true
12-12 11:36:42.040 10841-10859/com.polidea.rxandroidble.sample D/RxBle#ConnectionOperationQueue:   QUEUED DescriptorWriteOperation(200262604)
12-12 11:36:42.041 10841-10859/com.polidea.rxandroidble.sample D/BluetoothGatt: setCharacteristicNotification() - uuid: 00002a19-0000-1000-8000-00805f9b34fb enable: false
12-12 11:36:42.044 10841-10859/com.polidea.rxandroidble.sample D/RxBle#ConnectionOperationQueue:   QUEUED DescriptorWriteOperation(3707597)
12-12 11:36:42.044 10841-10887/com.polidea.rxandroidble.sample D/RxBle#ConnectionOperationQueue: FINISHED DescriptorWriteOperation(12579274)
12-12 11:36:42.046 10841-10859/com.polidea.rxandroidble.sample D/RxBle#ConnectionOperationQueue$2:  REMOVED DescriptorWriteOperation(200262604)
12-12 11:36:42.046 10841-10887/com.polidea.rxandroidble.sample D/RxBle#ConnectionOperationQueue:  STARTED DescriptorWriteOperation(34646817)
12-12 11:36:42.047 10841-10859/com.polidea.rxandroidble.sample D/Retry: Retrying
12-12 11:36:42.050 10841-10859/com.polidea.rxandroidble.sample D/BluetoothGatt: setCharacteristicNotification() - uuid: 00002a19-0000-1000-8000-00805f9b34fb enable: true
12-12 11:36:42.053 10841-10859/com.polidea.rxandroidble.sample D/RxBle#ConnectionOperationQueue:   QUEUED DescriptorWriteOperation(115232257)
12-12 11:36:42.054 10841-10859/com.polidea.rxandroidble.sample D/BluetoothGatt: setCharacteristicNotification() - uuid: 00002a19-0000-1000-8000-00805f9b34fb enable: false
12-12 11:36:42.056 10841-10887/com.polidea.rxandroidble.sample D/RxBle#ConnectionOperationQueue: FINISHED DescriptorWriteOperation(34646817)
12-12 11:36:42.056 10841-10859/com.polidea.rxandroidble.sample D/RxBle#ConnectionOperationQueue:   QUEUED DescriptorWriteOperation(187740798)
12-12 11:36:42.058 10841-10887/com.polidea.rxandroidble.sample D/RxBle#ConnectionOperationQueue:  STARTED DescriptorWriteOperation(3707597)
12-12 11:36:42.058 10841-10859/com.polidea.rxandroidble.sample D/RxBle#ConnectionOperationQueue$2:  REMOVED DescriptorWriteOperation(115232257)
12-12 11:36:42.060 10841-10859/com.polidea.rxandroidble.sample D/Retry: Retrying
12-12 11:36:42.064 10841-10859/com.polidea.rxandroidble.sample D/BluetoothGatt: setCharacteristicNotification() - uuid: 00002a19-0000-1000-8000-00805f9b34fb enable: true
12-12 11:36:42.067 10841-10859/com.polidea.rxandroidble.sample D/RxBle#ConnectionOperationQueue:   QUEUED DescriptorWriteOperation(8463785)
12-12 11:36:42.067 10841-10887/com.polidea.rxandroidble.sample D/RxBle#ConnectionOperationQueue: FINISHED DescriptorWriteOperation(3707597)
12-12 11:36:42.069 10841-10859/com.polidea.rxandroidble.sample D/BluetoothGatt: setCharacteristicNotification() - uuid: 00002a19-0000-1000-8000-00805f9b34fb enable: false
12-12 11:36:42.070 10841-10887/com.polidea.rxandroidble.sample D/RxBle#ConnectionOperationQueue:  STARTED DescriptorWriteOperation(187740798)
12-12 11:36:42.072 10841-10859/com.polidea.rxandroidble.sample D/RxBle#ConnectionOperationQueue:   QUEUED DescriptorWriteOperation(22091834)
12-12 11:36:42.077 10841-10859/com.polidea.rxandroidble.sample D/RxBle#ConnectionOperationQueue$2:  REMOVED DescriptorWriteOperation(8463785)

As seen in the logs, a connection is established successfully, and I receive a few characteristic change notifications; however after I lose connection and retry connecting, I am setting up the characteristic notifications again and then immediately disconnecting.

My goal is to be able to simulate a long running continuous connection to a bluetooth device. While the connection is active, I need to be able to get characteristic notifications. If using retryWhen() is not the correct way to reconnect and set up notifications, then what would be a better solution?

user3370201
  • 59
  • 9

1 Answers1

1

Apparently there is a problem with ConnectionSharingAdapter that does not properly release RxBleConnection after an exception was emitted from RxBleDevice.establishConnection().

Using the plain RxJava API should do the trick:

subscription = rxBleDevice.establishConnection()
            .flatMap(rxBleConnection -> rxBleConnection.setupNotification(characteristicUuid))
            .doOnNext(notificationObservable -> runOnUiThread(this::notificationHasBeenSetUp))
            .flatMap(notificationObservable -> notificationObservable)
            .retryWhen(errors -> errors.flatMap(error -> {
                if (error instanceof BleDisconnectedException) {
                    Log.d("Retry", "Retrying");
                    return Observable.just(null);
                }
                return Observable.error(error);
            }))
            .observeOn(AndroidSchedulers.mainThread())
            .subscribe(this::onNotificationReceived, this::onNotificationSetupFailure);

One just need to unsubscribe the subscription when the connection is no longer needed. It is also possible to unsubscribe from the upstream by using .takeUntil(Observable) just before the .subscribe() function that would have roughly the same effect.

Edit: If one needs to share the same connection between more than one place in the code one would need to share the same Observable. Although it is possible to achieve it with ConnectionSharingAdapter it seems that is a bug as mentioned above. A drop-in replacement could be a ReplayingShare operator.

Alternatively one could rearrange the flow so it could be achieved with a single .subscribe(). There is a good (though advanced) talk about it Managing State with RxJava by Jake Wharton.

Dariusz Seweryn
  • 3,212
  • 2
  • 14
  • 21
  • This seems to work fine if I only want to have one connection to a single device. Is there a method in which I can retry if I want to have another connection to the same device? The goal would be to keep maintaining both connections at the same time. – user3370201 Dec 18 '17 at 18:52
  • You cannot have two connections to the same device at the same time. There can be only one at any given moment. You can still share it. It seems that you have more requirements and code than you have written in the original post. – Dariusz Seweryn Dec 18 '17 at 19:04
  • My last comment may have been a bit misworded. I meant to ask if I have a shared connection used in two different places, and the connection drops, how am I supposed to retry correctly? For example, going back to the sample that I referenced in the original post, if I wanted the connection created in `onConnectToggleClick()` to reconnect on disconnect, and for the notifications set up in `onNotifyClick()` to also be resetup if the connection drops, how should I do this? – user3370201 Dec 18 '17 at 20:07
  • I have edited the answer. There seems to be a drop-in replacement for `ConnectionSharingAdapter` and a good talk on how one could get rid of the need for one. – Dariusz Seweryn Dec 19 '17 at 10:17
  • @DariuszSeweryn i've tried to adapt your answer to have a backoff retry mechanism (i.e. max # of retries and time off between each -- something like https://pastebin.com/hr91kykU) but i end up running into a fatal exception (https://pastebin.com/KkK9Akd2). any ideas how best to achieve this? – takecare Nov 12 '18 at 15:16
  • You probably would like to read the [FAQ about UndeliverableException](https://github.com/Polidea/RxAndroidBle/wiki/FAQ:-UndeliverableException) – Dariusz Seweryn Nov 12 '18 at 16:08