Unrecognized selector sent to instance _UIAlertControllerAlertPresentationController

Question

My iOS application has a couple of errors in real-time scripts. I cannot understand this specific error in Core Foundation , which affects multiple users in my application. The thread does not break into any of my project files, and I'm not sure what causes this crash.

Attaching alarm logs. Any advice or help would be very helpful, thanks.

CoreFoundation _CF_forwarding_prep_0

Fatal exception: NSInvalidArgumentException exception - [_ UIAlertControllerAlertPresentationController adaptivePresentationController]: unrecognized selector sent to instance 0x133e29870

 Fatal Exception: NSInvalidArgumentException 0 CoreFoundation 0x18ff391b8 __exceptionPreprocess 1 libobjc.A.dylib 0x18e97055c objc_exception_throw 2 CoreFoundation 0x18ff40268 __methodDescriptionForSelector 3 CoreFoundation 0x18ff3d270 ___forwarding___ 4 CoreFoundation 0x18fe3680c _CF_forwarding_prep_0 5 UIKit 0x19689708c -[UISearchController _searchPresentationController] 6 UIKit 0x19648f8cc -[_UISearchControllerTransplantSearchBarAnimator animateTransition:] 7 UIKit 0x19613d464 __56-[UIPresentationController runTransitionForCurrentState]_block_invoke 8 UIKit 0x19607ffdc _runAfterCACommitDeferredBlocks 9 UIKit 0x196071d50 _cleanUpAfterCAFlushAndRunDeferredBlocks 10 UIKit 0x195de10b4 _afterCACommitHandler 11 CoreFoundation 0x18fee60c0 __CFRUNLOOP_IS_CALLING_OUT_TO_AN_OBSERVER_CALLBACK_FUNCTION__ 12 CoreFoundation 0x18fee3cf0 __CFRunLoopDoObservers 13 CoreFoundation 0x18fee4180 __CFRunLoopRun 14 CoreFoundation 0x18fe122b8 CFRunLoopRunSpecific 15 GraphicsServices 0x1918c6198 GSEventRunModal 16 UIKit 0x195e597fc -[UIApplication _run] 17 UIKit 0x195e54534 UIApplicationMain 18 Levo 0x1000c1c30 main (AppDelegate.swift:22) 19 libdispatch.dylib 0x18edf55b8 (Missing) 

 func showErrorView(errorType: ErrorType, retryClickDelegate: ErrorViewRetryClickDelegate?) { var message = "" switch errorType { case .INTERNET: message = "Your internet connection does not seem to be working. Kindly ensure that you are connected to the internet and try again" break case .INVALID_DATA: message = "Something went wrong. Please try again!" break case .JSON_PARSING: message = "Something went wrong. Please try again!" break case .UNAUTHORIZED: self.showInformativeAlert("Logged Out", message: "Looks like you have been logged out. Please login in again!", completion: nil) self.switchStoryboard(Storyboard.SIGNIN) return default: message = "Something went wrong. Please try again!" } let errorAlert = UIAlertController(title: "Error", message: message, preferredStyle: .Alert) if let retryClickDelegate = retryClickDelegate { errorAlert.addAction(UIAlertAction(title: "Try again", style: UIAlertActionStyle.Default, handler: { (action) in retryClickDelegate.onErrorRetryClicked(errorType) errorAlert.dismissViewControllerAnimated(true, completion: nil) })) } errorAlert.addAction(UIAlertAction(title: "Dismiss", style: UIAlertActionStyle.Default, handler: nil)) if (isTopViewController) { self.presentViewController(errorAlert, animated: true, completion: nil) } } func showInformativeAlert(title: String?, message: String?,completion : (() -> Void)?) { let informativeAlert = UIAlertController(title: title, message: message, preferredStyle: UIAlertControllerStyle.Alert) informativeAlert.addAction(UIAlertAction(title: "Got it!", style: UIAlertActionStyle.Default, handler: { (action) in informativeAlert.dismissViewControllerAnimated(true, completion: nil) completion?() })) self.presentViewController(informativeAlert, animated: true, completion: nil) } public var isTopViewController: Bool { if self.navigationController != nil { return self.navigationController?.visibleViewController === self } else if self.tabBarController != nil { return self.tabBarController?.selectedViewController == self && self.presentedViewController == nil } else { return self.presentedViewController == nil && self.isVisible } } 

Answer 1

I think the problem is that you are not using completion handlers correctly, so at the same time, one warning appears and disappears. For example, instead of:

  informativeAlert.dismissViewControllerAnimated(true, completion: nil) completion?() 

You have to use

  informativeAlert.dismissViewControllerAnimated(true, completion: completion) 

In addition, the implementation of isTopViewController may fail if the animation of the view controller is in progress.

For example, if you call showErrorView twice, isTopViewController will probably be true for both calls, and two warnings will immediately appear, your application crashes.