Black screen when using ARGeoTrackingConfiguration on iOS 15.4?

Question

I am trying to run this sample project from Apple that uses ARGeoTrackingConfiguration: https://developer.apple.com/documentation/arkit/content_anchors/tracking_geographic_locations_in_ar

This sample app is supposed to show an AR camera feed in the top part of the screen, and a map view in the lower part. However, I am not seeing the camera feed, it's just black. I suspect this is something that changed in iOS 15.4, since my colleague was able to run the app successfully on a phone with iOS 15.3.1.

Some other details:

• I am seeing this issue on an iPhone 12 Pro Max and an iPhone 13 mini.
• Both these devices can support geotracking and are connected to the internet.
• I am in a location that has geotracking support, according to these docs: https://developer.apple.com/documentation/arkit/argeotrackingconfiguration
• I updated to iOS 15.4.1 but the issue is still occurring.
• I tried updating to the iOS 15.5 beta 1 and the issue is still occurring.

Has anyone else noticed this issue? Am I doing something wrong? Is there a workaround?

I filed a radar ticket as well, just in case.

EDIT: I filed a TSI request for this issue, and I got back a response saying that there is no workaround for the issue. However, it looks like the bug has been fixed in iOS 15.5 beta 2.

Answer 1

//  Class originalClass = NSClassFromString(@"NSXPCDecoder");
//  Class swizzledClass = NSClassFromString(@"SwizzledDecoder");

//  SEL originalSelector = @selector(_validateAllowedClass:forKey:allowingInvocations:);
//  SEL swizzledSelector = @selector(__validateAllowedClass:forKey:allowingInvocations:);

@interface SwizzledDecoder : NSObject

- (void)__validateAllowedClass:(Class)arg1 forKey:(id)arg2 allowingInvocations:(bool)arg3;

@end

@implementation SwizzledDecoder

- (void)__validateAllowedClass:(Class)arg1 forKey:(id)arg2 allowingInvocations:(bool)arg3 {
  if ([arg2 isEqualToString: @"collaborationData"]) {
    return;
  }
  return [self __validateAllowedClass: arg1 forKey: arg2 allowingInvocations: arg3];
}

@end

https://developer.apple.com/forums/thread/703735?answerId=711909022#711909022

I could think of a few options to "fix" this using Private (Apple) APIs. This approach is not super terrible and at least would unblock you from testing on a 15.4.x device (I confirmed this works on Xcode 13.3.1 and iOS 15.4.1).

As far as whether or not Apple would approve #YOLO #FIDLAR code like this in an App Store review? I can't help you there.

The real fix (we can hope for) is the next version of Xcode ships with an SDK that builds and compiles with a retroactive fix for 15.4.x.

Answer 2

This issue has been fixed in iOS 15.5