get notification on timezone change in iOS

Question

can my application get any notification when device timezone changed? I want to get a notification when my application is foreground. NSTimezone does not worked for me as i have to continuously check for timezone.

Answer 1

UIApplicationDelegate has a method called applicationSignificantTimeChange: that gets called when there is a significant change in the time.

The examples listed in the documentation are:

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

But I would assume that timezone changes count as a significant time change.

The docs also say that if the time change happens when your app is in the background you will get it when you go to the foreground

If your application is currently suspended, this message is queued until your application returns to the foreground, at which point it is delivered.

You can also listen for UIApplicationSignificantTimeChangeNotification to be posted to get the same information anywhere else in your app.

Answer 2

Just listen to NSSystemTimeZoneDidChangeNotification.

[[NSNotificationCenter defaultCenter] addObserver:self selector:@selector(timeZoneChanged) name: NSSystemTimeZoneDidChangeNotification object:nil];

And remember to unregister, for example in dealloc method.

[[NSNotificationCenter defaultCenter] removeObserver:self name:NSSystemTimeZoneDidChangeNotification object:nil];