IOS app crashes when starting AR : Wikitude

L

Lorenzo

started a topic almost 4 years ago

IOS app crashes when starting AR

L

Lorenzo

said almost 4 years ago

I've implemented the Wikitude SDK in my app in order to display my Wikitude Studio content inside my app. Everything works fine except for a thing, if I start the AR class then I go back to the home screen and finally I restart the AR the app crashes.
The crash occurs when calling: self.architectView = ;

Does anyone know why does it happen and how to fix it?

Thanks

N

Nicola Radacher

said almost 4 years ago

Hi Lorenzo,

Can you please over further details on the crash (crash log, stack trace) so we know the reason for the crash.

Thx and greetings

Nicola

L

Lorenzo

said almost 4 years ago

This is the error log:

F1020 14:23:49.317847 2670616576 utilities.cc:320> Check failed: !IsGoogleLoggingInitialized() You called InitGoogleLogging() twice!

*** Check failure stack trace: ***

@ 0x1002444b8 google::LogMessage::Flush()

@ 0x1002452d8 google::LogMessageFatal::~LogMessageFatal()

@ 0x100244804 google::LogMessageFatal::~LogMessageFatal()

@ 0x100248954 google::glog_internal_namespace_::InitGoogleLoggingUtilities()

@ 0x100377714 wikitude::common_library::impl::iOSConsoleWriter::iOSConsoleWriter()

@ 0x10019eca8 -

@ 0x10019c0b4 -

@ 0x10019bfac -

@ 0x100149a38 -

@ 0x188993610 <redacted>

@ 0x1889ab6ec <redacted>

@ 0x188b3fd68 <redacted>

@ 0x188a4f430 <redacted>

@ 0x188a4f10c <redacted>

@ 0x188a4f074 <redacted>

@ 0x18898eff0 <redacted>

@ 0x188195f14 <redacted>

@ 0x188190b20 <redacted>

@ 0x1881909e0 <redacted>

@ 0x18819007c <redacted>

@ 0x18818fdd0 <redacted>

@ 0x1881894bc <redacted>

@ 0x1833f3c30 <redacted>

@ 0x1833f19d4 <redacted>

@ 0x1833f1e04 <redacted>

@ 0x183320dc0 CFRunLoopRunSpecific

@ 0x18e474088 GSEventRunModal

@ 0x1889faf44 UIApplicationMain

@ 0x100142000 main

@ 0x19885e8b8 <redacted>

L

Lorenzo

said almost 4 years ago

Ok I got it working, the dealloc wasn't being called because I was referring to 'self' inside a block with a strong reference. What I did was create a weak self with __unsafe_unretained AugmentedRealityViewController *weakSelf = self;

and then inside the various blocks I used weakSelf instead of self, like this:

;

;

Now it works fine

You should update the docs because I took the code from there and with the sdk 5.0 I got this error that is the same error these guys are facing

P

Pedro Antonio Seco de Herrera

said almost 4 years ago

Hi Lorenzo,

I Have the same problem using the Xamarin plugin. Do you have any solution for this?

Regards

L

Lorenzo

said almost 4 years ago

I'm sorry but I never used Xamarin and I have no idea how the code works.. sorry

A

Andreas Schacherbauer

said almost 4 years ago

Hi Pedro,
Lorenzo gave the correct answer to the problem. When using the +addObserverForName method from the NSNotificationCenter, you need to make sure to not retain self inside the block. The solution is to create a weak representation of self which you can make with __unsafe_unretained or __weak. This breaks the dependency cycle and the Wikitude SDK can get deallocated.

Best regards

Andreas

P

Pedro Antonio Seco de Herrera

said almost 4 years ago

Hello Andreas,

I tried this code on Xamarin, but it doesnt work:

Only work the first time, and the Controller is a Weak Reference like you say

This code works good with xamarin plugin 4.2.1, but fails on 5.0.0, dont know why ...

UIStoryboard story = UIStoryboard.FromName ("MainStoryboard", null);
                var view = story.InstantiateViewController ("ViewController") as WikitudeViewController;
                var weakThis = new WeakReference<WikitudeViewController> (view);
                weakThis.TryGetTarget (out view);
                var nav = new UINavigationController (view);
                UIApplication.SharedApplication.Windows .RootViewController = nav;
                UIApplication.SharedApplication.Windows .MakeKeyAndVisible ();

P

Pedro Antonio Seco de Herrera

said almost 4 years ago

One more thing ... on xamarin there is no way for do

;

you can only do:

architectView.Start or architectView.Stop

F

Frank Ortner

said almost 4 years ago

In Xamarin i have tryed everything with WeakReferences but without success.

Finaly i set architectView.RemoveFromSuperview(); in the ViewWillDisappear (bool animated) and the Error:

Check failed: !IsGoogleLoggingInitialized() You called InitGoogleLogging() twice! is gone because all references are probably unset.

N

Nicola Radacher

said almost 4 years ago

Hi,

Does this info help:

Please note that the Wikitude iOS SDKs are now more strict when it comes to memory handling. In case an application creates multiple instances of the SDK, the hosting application needs to make sure that the previously created instance is destroyed properly before the new one is created. Otherwise the application will crash with an stack trace like this mentioning InitGoogleLogging() twice:

Check failed: !IsGoogleLoggingInitialized() You called InitGoogleLogging() twice!
*** Check failure stack trace: ***
   @        0x1002444b8 google::LogMessage::Flush()
   @        0x1002452d8 google::LogMessageFatal::~LogMessageFatal()
   @        0x100244804 google::LogMessageFatal::~LogMessageFatal()
   @        0x100248954 google::glog_internal_namespace_::InitGoogleLoggingUtilities()
   @        0x100377714 wikitude::common_library::impl::iOSConsoleWriter::iOSConsoleWriter()
   @        0x10019eca8 -
   @        0x10019c0b4 -
   @        0x10019bfac -
   @        0x100149a38 -
   @        0x188993610 <redacted>
   @        0x1889ab6ec <redacted>
   @        0x188b3fd68 <redacted>
   @        0x188a4f430 <redacted>
   @        0x188a4f10c <redacted>
   @        0x188a4f074 <redacted>
   @        0x18898eff0 <redacted>
   @        0x188195f14 <redacted>
   @        0x188190b20 <redacted>
   @        0x1881909e0 <redacted>
   @        0x18819007c <redacted>
   @        0x18818fdd0 <redacted>
   @        0x1881894bc <redacted>
   @        0x1833f3c30 <redacted>
   @        0x1833f19d4 <redacted>
   @        0x1833f1e04 <redacted>
   @        0x183320dc0 CFRunLoopRunSpecific
   @        0x18e474088 GSEventRunModal
   @        0x1889faf44 UIApplicationMain
   @        0x100142000 main
   @        0x19885e8b8 <redacted>

The reason oftentimes is a retain cycle because the WTArchitectView or WTWikitudeNativeSDK object is strongly referenced in a block. Simply create a weak pointer to your Wikitude SDK object and use this weak pointer inside the block.

Greetings

Nicola

F

Frank Ortner

said almost 4 years ago

As i wrote before, the Error ist gone by explicitly calling architectView.RemoveFromSuperview() but i have wasted much time with building around the error/bug with a weak reference (seen before in the hint from Andreas Schacherbauer in the technical note).

P

Pedro Antonio Seco de Herrera

said almost 4 years ago

Hi Frank.

Your solution does not work for me. When i get back and re-open the ViewController then get the error ... it's frustrating

Regards

F

Frank Ortner

said almost 4 years ago

Hi Pedro,

i checked my solution again and noticed that there is another important step to do.

Here is my working code from the ViewController:

public override void ViewWillDisappear (bool animated) {


base.ViewWillDisappear (animated);

    if (_architectView != null) {
  _architectView.Stop ();
  _architectView.RemoveFromSuperview ();
    }
    this.Dispose (true);

}

protected override void Dispose(bool disposing) {

base.Dispose(disposing);

     if (_architectView != null) {
  _architectView.Dispose();
  _architectView = null;
     }
}

So not only the RemoveFromSuperview is important, also the overridden Dispose method is important too.

I hope it will work for you.

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