- (void)applicationDidEnterBackground:(UIApplication *)application

Question

Can i use below method somewhere other than AppDelegate ?if yes how?

- (void)applicationDidEnterBackground:(UIApplication *)application

Answer 1

This is a method of the UIApplicationDelegate protocol, and can only be implemented by classes that conform to it.

You can set up a notification to other objects in your app from your app delegate by using the NSNotificationCenter object:

- (void)applicationDidEnterBackground:(UIApplication *)application {
   [[NSNotificationCenter defaultCenter] postNotificationName:@"didEnterBackground" object:self];
}

There is also the UIApplicationDidEnterBackgroundNotification notification that you can listen for instead of doing the above.

Register the objects that you want to listen for the notification like this:

[[NSNotificationCenter defaultCenter] addObserver:someObject selector:@selector(someMethod:) name:@"UIApplicationDidEnterBackgroundNotification" object:nil];

Answer 2

No, But you can have other objects register for the UIApplicationDidEnterBackgroundNotification notification. These objects will then be notified at the same time applicationDidEnterBackground: is called.