What is the call back method for killing the application instance?

Question

In my application I want to get notified when the instance of the application is deleted.

Even though I can easily get what I am asking simply by googling, I can't find anything useful to me. May be the synonym i'm using deleting the app instance (deleting the app from the list shown at the bottom of the screen when double-clicking the home button in IPad and I'm looking for the UIAppdelegate method called in response to that action).

Is there a way of knowing this?

Answer 1

This is when your app gets killed, either by the user (removing from the task bar) or by the system, to reclaim memory. There's no callback for it. You never get informed that it's going to happen or has happened.

Answer 2

Yes. The - (void)applicationWillTerminate:(UIApplication *)application will be called.

It'll call when user quits the application from the taskbar if and only if your application supports background tasks else it'll be called when user presses the home button to hide your app.

applicationWillTerminate:

Tells the delegate when the application is about to terminate. - (void)applicationWillTerminate:(UIApplication *)application

Parameters

application

The delegating application object.

Discussion

This method lets your application know that it is about to be terminated and purged from memory entirely. You should use this method to perform any final clean-up tasks for your application, such as freeing shared resources, saving user data, and invalidating timers. Your implementation of this method has approximately five seconds to perform any tasks and return. If the method does not return before time expires, the system may kill the process altogether.

For applications that do not support background execution or are linked against iOS 3.x or earlier, this method is always called when the user quits the application. For applications that support background execution, this method is generally not called when the user quits the application because the application simply moves to the background in that case. However, this method may be called in situations where the application is running in the background (not suspended) and the system needs to terminate it for some reason.

After calling this method, the application also posts a UIApplicationWillTerminateNotification notification to give interested objects a chance to respond to the transition. Availability

Available in iOS 2.0 and later.

Reference : UIApplicationDelegate