Using RxAndroidBle, how do I subscribe to responses from writing to a characteristic?

Question

The BLE device that I\'m connecting to emits bytes on one of its GATT characteristics in response to writes to the characteristic. Clients are supposed to enable notificatio

Answer 1

There is already a topic in which you may find some insight -> RxAndroidBle keeping a persistant connection + Write/Notification handling

This is how you could achieve the same result while using only a single .subscribe().

    connectionObservable
            .flatMap( // when the connection is available...
                    rxBleConnection -> rxBleConnection.setupNotification(AP_SCAN_DATA), // ... setup the notification...
                    (rxBleConnection, apScanDataNotificationObservable) -> Observable.combineLatest( // ... when the notification is setup...
                            rxBleConnection.writeCharacteristic(AP_SCAN_DATA, writeValue), // ... write the characteristic...
                            apScanDataNotificationObservable.first(), // ... and observe for the first notification on the AP_SCAN_DATA
                            (writtenBytes, responseBytes) -> responseBytes // ... when both will appear return just the response bytes...
                    )
            )
            .flatMap(observable -> observable) // ... flatMap the result as it is Observable...
            .first() // ... and finish after first response is received to cleanup notifications
            .observeOn(AndroidSchedulers.mainThread())
            .subscribe(
                    responseBytes -> { /* consume the response here */ },
                    throwable -> { /* handle exception */ }
            );

FYI - you should handle errors in every .subscribe() unless you're 100% sure that the Observable does not emit errors.