Instance Method


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


optional func applicationProtectedDataWillBecomeUnavailable(_ application: UIApplication)



Your singleton app object.


On a device that uses content protection, protected files are stored in an encrypted form and made available only at certain times, usually when the device is unlocked. This notification lets your app know that the device is about to be locked and that any protected files it is currently accessing might become unavailable shortly.

If your app is currently accessing a protected file, you can use this method to release any references to that file. Although it is not an error to access the file while the device is locked, any attempts to do so will fail. Therefore, if your app depends on the file, you might want to take steps to avoid using that file while the device is locked.

See Also

Responding to Environment Changes

func applicationProtectedDataDidBecomeAvailable(UIApplication)

Tells the delegate that protected files are available now.

func applicationDidReceiveMemoryWarning(UIApplication)

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

func applicationSignificantTimeChange(UIApplication)

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

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.