Is there any callback methods to be called When the user closes the app from the Task Manager when app is going in the background state already?

Question

Is there any callback methods to be called When the user closes the app from the Task Manager? Because i have to maintain the status i.e Online or Offline while killing the app from the task manger user should become offline.

Answer 1

No, there is no such method or function or method to handle this scenario.

func applicationWillTerminate(application: UIApplication){}

// This method will be called when system kills your app after suspending it for whatever reason.

There is no method to detect killing application by multitasking and swipe the app Up to kill(from task manager).

Though you can handle this scenario in

func applicationDidEnterBackground(application: UIApplication) {}

Answer 2

Previous answers contain needed information. The application has delegate @protocol methods that handle application appearance, focus, entereing background state or termination.

If your question is how to handle this events in the context of data transfer and sending some status outside - register NSNotification observer and postNotification from the delegate protocol handler. Notifications are being sent before any other actions and allow the app to inform remote resource that it will be closed or loses focus.

Answer 3

In Ruby

at_exit do
  # Do whatever you want before exit
end

Or if you want to do something before a specific signal that causes your program to exit, then

trap :INT do
  # Will be triggered when `SIGINT` is trapped
end

You can replace :INT with other signals you want to trap.