UIApplication.applicationDidBecomeActive(_:) and UIApplication.applicationWillResignActive(_:) are not called system-wide

Number:rdar://FB7647760 Date Originated:Apr 1, 2020 at 5:22 PM
Status:Open Resolved:No
Product:UIKit Product Version:iOS 13
Classification:Security Reproducible:100%
Configuration: iPhone Xs Max, iOS 13.4
Reproducibility: 100%

After using notification centre all applications stop receiving such lifecycle events as UIApplication.applicationDidBecomeActive(_:) and UIApplication.applicationWillResignActive(_:).

1 Launch any app with push notifications
2 while application is in foreground state receive a new push notification and expand it by swipe gesture
3 tap «More»
4 tap on «Settings»
5 navigate back to the application

applicationDidBecomeActive would be called

The only applicationWillEnterForeground is called

Killing an app and opening again changes nothing. System-wide these lifecycle methods are not delivered to any application anymore.
Only applicationWillEnterForeground and applicationDidEnterBackground work.

To fix this required either to restart the device or to receive new push a tap «view»
After that, all lifecycle methods are fixed and delivered.

These lifecycle events are crucial to add/remove blur on switching between apps and protect users from exposing their private info


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