Instance Method


Tells the delegate when there is a significant change in the time.


optional func applicationSignificantTimeChange(_ application: UIApplication)



Your singleton app object.


Examples of significant time changes include the arrival of midnight, an update of the time by a carrier, and the change to daylight savings time. The delegate can implement this method to adjust any object of the app that displays time or is sensitive to time changes.

Prior to calling this method, the app also posts a significantTimeChangeNotification notification to give interested objects a chance to respond to the change.

If your app is currently suspended, this message is queued until your app returns to the foreground, at which point it is delivered. If multiple time changes occur, only the most recent one is delivered.

See Also

Responding to Environment Changes

func applicationProtectedDataDidBecomeAvailable(UIApplication)

Tells the delegate that protected files are available now.

func applicationProtectedDataWillBecomeUnavailable(UIApplication)

Tells the delegate that the protected files are about to become unavailable.

func applicationDidReceiveMemoryWarning(UIApplication)

Tells the delegate when the app receives a memory warning from the system.

class let protectedDataDidBecomeAvailableNotification: NSNotification.Name

Posted when the protected files become available for your code to access.

class let protectedDataWillBecomeUnavailableNotification: NSNotification.Name

Posted shortly before protected files are locked down and become inaccessible.

class let didReceiveMemoryWarningNotification: NSNotification.Name

Posted when the app receives a warning from the operating system about low memory availability.

class let significantTimeChangeNotification: NSNotification.Name

Posted when there is a significant change in time, for example, change to a new day (midnight), carrier time update, and change to or from daylight savings time.