[Interest] Crash in iOS 12 when Accessibility is ON

maitai maitai at virtual-winds.org
Fri Oct 26 10:09:47 CEST 2018

Hi Robert,
Thanks for the support.
Backtrace is joined, as seen from xcode.


Le 26-10-2018 09:27, coroberti . a écrit :
> Hi Philippe,
> Just voted for it.
> If you run the app from debugger and trigger the menu's action to 
> reproduce,
> which backtrace stack of functions you see there?
> Kind regards,
> Robert Iakobashvili
> ............................
> On Fri, Oct 26, 2018 at 10:01 AM maitai <maitai at virtual-winds.org> 
> wrote:
>> Hello,
>> There has been already 2 bug reports for that (QTBUG-70909 and
>> QTBUG-70683), but it is not yet fixed and I am looking for a 
>> workaround,
>> since lot of my users are complaining.
>> To make a long story short, iOS 12 is crashing in UIAccessibility
>> _axuiElementForNotificationData when for instance Speak Screen is ON.
>> This is because Qt doesn't check that the list of Accessibility items 
>> is
>> empty, as I understood.
>> A workaround has been proposed, which consists in putting a non empty
>> title to the main window. That is indeed OK for a QML application, but
>> our app is still pure QWidget-based. Putting a title in MainWindow 
>> duly
>> fixed the crash at startup, but now it only crashes later, whenever 
>> the
>> user triggers a QAction from a QMenu. It crashes at the same place in
>> UIAccessibility.
>> I have tried many things with no success, including:
>> - Add some setAccessibilityName etc in some relevant objects,
>> - In qappdelegate settings some flags supposed to ignore 
>> Accessibility,
>> such as [aView setIsAccessibilityElement:NO]; and [aView
>> accessibilityElementsHidden:YES];
>> - I even tried to override some QIOS functions but did not succeed.
>> Someone suggested to just add a dummy Accessibility item, so the list
>> won't be empty. I have no idea how to do that.
>> I have of course tried 5.9.7 and 5.11.2, no luck.
>> If someone has some advices or ideas...
>> Thanks
>> Philippe Lelong
>> _______________________________________________
>> Interest mailing list
>> Interest at qt-project.org
>> http://lists.qt-project.org/mailman/listinfo/interest
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