QT iOS BLE Issue

[BTSTOnline]

Anyone have any thoughts on why I would be getting this when using BLE on iOS?

[qt.bluetooth.ios] can not discover service details in the current state, QLowEnergyController::DiscoveredState is expected
[CoreBluetooth] XPC connection invalid

Latest iOS, latest XCode, latest Qt/QtCreator...

Source code in Creator, opening project in XCode and running on device. This used to work a couple months ago on 5.12... but not working on 5.14.

Ideas?

[VladoV]

Hi,

I noticed similar behaviour on both ios and osx, I also upgraded to qt5.14.
It seems the QLowEnergyController::DiscoveredState comes when QLowEnergyController::discoveryFinished is emitted. My code discovered service details already in serviceDiscovered's handler, which seems caused the described scenario.

In the slot attached to QLowEnergyController::serviceDiscovered I remember the discovered service uuids in vector of uuis like this
mServiceUUids.push_back(serviceUUid); // std::vector<QBluetoothUuid> mServiceUUids declared in header file

then in the slot attached to QLowEnergyController::discoveryFinished loop through the mServiceUUids and do service details discovery.

Seems to work for me even though it is more a workaround. I need to study what is the proper way to do it.

[BTSTOnline]

Yeah, this seems to be a workaround, but it works for me well enough to utilize in my project!

Thanks @VladoV , much appreciated!

[AlexBlasche]

The issue was resolved by https://codereview.qt-project.org/c/qt/qtconnectivity/+/313077. Thank you for pointing it out. In particular the workaround highlighted the problem.