[BLE] Subscription/Notification does not work

[shinyorg]

[BLE] Subscription/Notification does not work

[aritchie]

This is working fine for me using iOS nrf connect to android shiny gatt server running in the sample app. Was there an exception? Anything in the output window.

[aritchie]

Please file a reproducible case where possible. This is still in beta, so I need help, not just issues. The GATT server is not completed fully yet obviously.

[ThumbGen]

The best case possible is your own excellent Samples project:

In Sample.BlePeripherals.MainViewModel, there's

                            this.notifications = sb.AddCharacteristic
                            (
                                NotifyCharacteristicUuid,
                                cb => cb.SetNotification(cs =>
                                {
                                    var subs = cs.Characteristic.SubscribedCentrals.Count;

                                    var @event = cs.IsSubscribing ? "Subscribed" : "Unsubcribed";
                                    this.Write($"Device {cs.Peripheral.Uuid} {@event}");
                                    this.Write($"Charcteristic Subcribers: {subs}");

                                    if (subs == 0)
                                        this.StopTimer();
                                    else
                                        this.StartTimer();
                                })
                            );

Using the "Bluetooth LE Explorer" app from Windows Store I've managed to list the characteristic, it is correctly displayed as "notifiable", but attempting to subscribe to it fails. The code inside the "SetNotification" subscription handler is never called.

[fryette]

I also experienced this issue, but in my case it was incorrect configuration for device which advertise characteristic. Check is it everything OK with nrfConnect application(check it on iOS and Android store), and if even nrfConnect fail -something wrong with your BLE configuration

[ThumbGen]

I have just tried the ACR Bluetooth LE app and the problem exists there too (other apps like BLE Sim work correctly).

Reading https://stackoverflow.com/questions/17910322/android-ble-api-gatt-notification-not-received
I've noticed this sentence:

"All of the writeGattDescriptors must come first and complete before you issue any readCharacteristic calls."

No idea, I thought this might help...

[aritchie]

@ThumbGen Did you try anything from the link you provided?

[ThumbGen]

Sorry for the delayed reply, indeed it was a problem on my side.
I had to add the CCCD flag with notifications on the subscriber side; now the notifications are working and are absolutely awesome!

Thank you!

[lock]

This thread has been automatically locked since there has not been any recent activity after it was closed. Please open a new issue for related bugs.