No notification data in Write/Notification set-up

问题

After doing my best to understand all the magic in RxJava and the excellent rxandrodible library I'm stuck! The last thing that I need to fix is to setup a write/Notification link in which I write a value - a single value - and after that subscribe to a specific characteristic.

I've used the following code - as considered best practice (?) - but it doesen't actually result in any data on the soundTV.

connectionSubscription = device.establishConnection(false)
                    .flatMap( // when the connection is available...
                            rxBleConnection -> rxBleConnection.setupNotification(RX_CHAR_UUID), // ... setup the notification...
                            (rxBleConnection, apScanDataNotificationObservable) -> Observable.combineLatest( // ... when the notification is setup...
                                    rxBleConnection.writeCharacteristic(TX_CHAR_UUID, new byte[]{SOUND}).toObservable(), // ... write the characteristic...
                                    apScanDataNotificationObservable.take(1),// ... 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<byte[]>...// ... and finish after first response is received to cleanup notifications
                    .take(1)
                    .observeOn(AndroidSchedulers.mainThread())
                    .subscribe(
                            responseBytes -> {
                                soundTV.setText(new String(responseBytes));
                            },
                            throwable -> {
                                soundTV.setText(throwable.toString());}
                    );

There is no data written by the subscription to the give TextView, and I can't find anything that goes wrong.

If I just setup the notifications, without combining it with the write, everything works as it should.

Any suggestions on how to make it work?

---

The code example used gives only one response. What I was looking for was a write and a subscription that was ongoing. I didn't realize that the take(1) call actually made a difference, thought it was a clean-up in the complex call structure.

Sorry! This works as intended for me:

    connectionSubscription = device.establishConnection(false)
                    .flatMap( // when the connection is available...
                            rxBleConnection -> rxBleConnection.setupNotification(RX_CHAR_UUID), // ... setup the notification...
                            (rxBleConnection, apScanDataNotificationObservable) -> Observable.combineLatest( // ... when the notification is setup...
                                    rxBleConnection.writeCharacteristic(TX_CHAR_UUID, new byte[]{SOUND}).toObservable(), // ... write the characteristic...
                                    apScanDataNotificationObservable,// ... 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<byte[]>...// ... and finish after first response is received to cleanup notifications
                    .observeOn(AndroidSchedulers.mainThread())
                    .subscribe(
                            responseBytes -> {
                                soundTV.setText(new String(responseBytes));
                            },
                            throwable -> {
                                soundTV.setText(throwable.toString());}
                    ); 

来源：https://stackoverflow.com/questions/52916457/no-notification-data-in-write-notification-set-up