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iOS WTArchitectView crash when back pressed (after dealloc uiviewcontroller)

Hi Team,

We have iOS cordova sample project and we made same changes to create a demo for poi based solution. It uses storyboard, Everything is fine here. 

Now we works for integrate sample demo to our native application.

WTArhitectView works fine on uiviewcontroller, we see all pois, everything fine here. but when we pressed back button from navigation bar, application crashes after uiviewcontroller dealloc method.

here is log:

*** Terminating app due to uncaught exception 'NSInternalInconsistencyException', reason: 'An instance 0x7fcfe30cf230 of class AVPlayer was deallocated while key value observers were still registered with it. Current observation info: <NSKeyValueObservationInfo 0x7fcfe392dac0> (

<NSKeyValueObservance 0x7fcfe392da60: Observer: 0x7fcfe3928140, Key path: status, Options: <New: YES, Old: NO, Prior: NO> Context: 0x0, Property: 0x7fcfe392d730>


*** First throw call stack:


0   CoreFoundation                      0x000000010ba03d85 __exceptionPreprocess + 165

1   libobjc.A.dylib                     0x000000010b47edeb objc_exception_throw + 48

2   CoreFoundation                      0x000000010ba03cbd +[NSException raise:format:] + 205

3   Foundation                          0x00000001074acd41 NSKVODeallocate + 294

4   libobjc.A.dylib                     0x000000010b492afe _ZN11objc_object17sidetable_releaseEb + 232

5   WikitudeSDK                         0x00000001053d316e -[WTVideoReader .cxx_destruct] + 43

6   libobjc.A.dylib                     0x000000010b47d7bb _ZL27object_cxxDestructFromClassP11objc_objectP10objc_class + 127

7   libobjc.A.dylib                     0x000000010b488332 objc_destructInstance + 93

8   CoreFoundation                      0x000000010ba0cf76 -[NSObject(NSObject) __dealloc_zombie] + 150

9   libobjc.A.dylib                     0x000000010b492afe _ZN11objc_object17sidetable_releaseEb + 232

10  libobjc.A.dylib                     0x000000010b47d7bb _ZL27object_cxxDestructFromClassP11objc_objectP10objc_class + 127

11  libobjc.A.dylib                     0x000000010b488332 objc_destructInstance + 93

12  CoreFoundation                      0x000000010ba0cf76 -[NSObject(NSObject) __dealloc_zombie] + 150

13  libobjc.A.dylib                     0x000000010b492afe _ZN11objc_object17sidetable_releaseEb + 232

14  WikitudeSDK                         0x0000000104be0e88 -[WTARchitectManager .cxx_destruct] + 26

15  libobjc.A.dylib                     0x000000010b47d7bb _ZL27object_cxxDestructFromClassP11objc_objectP10objc_class + 127

16  libobjc.A.dylib                     0x000000010b488332 objc_destructInstance + 93

17  CoreFoundation                      0x000000010ba0cf76 -[NSObject(NSObject) __dealloc_zombie] + 150

18  WikitudeSDK                         0x0000000104bda469 -[WTARchitectManager dealloc] + 662

19  libobjc.A.dylib                     0x000000010b492afe _ZN11objc_object17sidetable_releaseEb + 232

20  WikitudeSDK                         0x0000000104c241a2 -[WTArchitectView .cxx_destruct] + 43

21  libobjc.A.dylib                     0x000000010b47d7bb _ZL27object_cxxDestructFromClassP11objc_objectP10objc_class + 127

22  libobjc.A.dylib                     0x000000010b488332 objc_destructInstance + 93

23  CoreFoundation                      0x000000010ba0cf76 -[NSObject(NSObject) __dealloc_zombie] + 150

24  UIKit                               0x0000000107ad207d -[UIResponder dealloc] + 146

25  UIKit                               0x0000000107953da8 -[UIView dealloc] + 1557

26  WikitudeSDK                         0x0000000104c22a27 -[WTArchitectView dealloc] + 105

27  libobjc.A.dylib                     0x000000010b4930b8 _ZN12_GLOBAL__N_119AutoreleasePoolPage3popEPv + 488

28  CoreFoundation                      0x000000010b8eb736 _CFAutoreleasePoolPop + 22

29  CoreFoundation                      0x000000010b91eba1 __CFRunLoopRun + 2081

30  CoreFoundation                      0x000000010b91e0f8 CFRunLoopRunSpecific + 488

31  GraphicsServices                    0x000000010d247ad2 GSEventRunModal + 161

32  UIKit                               0x00000001078bef09 UIApplicationMain + 171

33                      0x000000010310b36c main + 220

34  libdyld.dylib                       0x000000010bf4b92d start + 1

35  ???                                 0x0000000000000001 0x0 + 1


libc++abi.dylib: terminating with uncaught exception of type NSException

On dealloc we also call removeObserver method. Only difference with sample app, sample app use storyboard, we are using .xib file for uiviewcontrooler, we connect WTArchitectView to .h file, works fine but after dealloc this crash occurres.

We also try to set some variables on dealloc, result is same

self.architectView.delegate = nil;

self.architectView = nil;

You can find uiviewcontroller .h .m and .xib file in attachment.

Please help us about crash.


- (void)dealloc


    [[NSNotificationCenter defaultCenter] removeObserver:self];



    //self.architectView = nil;


- (void)viewWillDisappear:(BOOL)animated


    [super viewWillDisappear:animated];


    self.navigationController.interactivePopGestureRecognizer.delegate = nil;




- (void)viewDidDisappear:(BOOL)animated


    [super viewDidDisappear:animated];


    /* Pause architect view rendering when this view is not visible anymore */

    [self stopArchitectViewRendering];



Hi doğukan,

This seems indeed weird.

Which version of our SDK are you using and which iOS version are you running on your device?

Can you make sure that the -stop method of WTArchitectView was called before dealloc is called (Set a breakpoint in that line in Debug configuration)?

Are you using AR.VideoDrawables or AR.context.startVideoPlayer in your Architect World? If so, you could try to remove the usage temporarily to see if they have something to do with the problem.

Best regards,



I am using WikitudeSDK_iOS_7-1-0_2017-09-20_19-21-52, latest sample. Build with Xcode 9.1

iOS deployment target 9.0. 

Crash happens with iOS 9.3, not happened with 10.3 or 11.1. Just happening with iOS 9.3.

And good news, it is also happening with your sample project. You can try and debug. This one:


JAVASCRIPT API Version 7.1.0

21.09.2017 – 635.6 MB

After build, go to Html Drawable page, then press back button from navigation. It will be crash.

Can you make sure that the -stop method of WTArchitectView was called before dealloc is called (Set a breakpoint in that line in Debug configuration)?
Yes  we call stop method before dealloc. I debugged it. 
if ( [self.architectView isRunning] )


        [self.architectView stop]; 

Are you using AR.VideoDrawables or AR.context.startVideoPlayer in your Architect World? If so, you could try to remove the usage temporarily to see if they have something to do with the problem.
Not using AR.VideoDrawables, you can try with wikitude sample app. 
When press back button from "Html Drawable Page" or "Native Detail Screen Page(this one not using any AR.VideoDrawables )", crash happening. 

It likes version based sdk bug i think.
Waiting hearing from you :)


Hi doğukan,

I tried to reproduce the crash on an iPad running iOS 9.3 but wasn't successful. Could you send us a video that shows all the steps you do to crash our SDK? Maybe I didn't do the same steps as you.

Best regards,


Hi Andreas,

You can find crash video link here:

Best regards,

Hi doğukan,

Thx for the video! I would have never realised that you're using the iOS Simulator.

I'll check the simulator impl. again. Might be that there is a problem hidden somewhere.

FYI: You might have already realised that the iOS Simulator shows a black camera image and that Geo AR is not working as expected. For the camera you need to specify a video that should be used to replace the device camera. Simply add the video to your application bundle (you can remove it for the app store build) and specify the 'WTCameraReplacementVideoPath' key in your application .plist to define which video should be used (In an dictionary named 'WTSimulatorSettings').

For GeoAR you need to run your application on the device.

Best regards,


Hi Andreas,

We know why black screen seems on iOS simulator. It is expected behavior.

When we will test AR feature with demo, we are using real device, not simulator. So it is not a problem for us ;)

But we don't have any iPhone 9.3 device. So i recorded this video with simulator.

Once you've checked the simulator impl, we'll be happy to share your results with us.

Best regards.

FYI : It's just happening with iOS 9.3 simulator. (maybe with iOS 9.3 real device also, but  i did not test it with iPhone 9.3 real device yet)

Hi doğukan,

I tested it with an iOS 9.3 device and it was fine. It's a specific iOS Simulator issue related to the camera replacement video.

Just in case you didn't know: If you provide a camera replacement video, you can run image or object tracking on the simulator with augmentations rendered and callback called as on the device.

Best regards,


Hi Andreas,

Thanks for quick response.

Best regards,


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