is there any exit or close event in mobile application for iOS app?

Add a listener for EXITING event. AIR dispatches EXITING event on iOS when application is about to be exited. Your application can execute for around 5 seconds after receiving this event.

NativeApplication.nativeApplication.addEventListener(Event.EXITING, onExit);

function onExit(e:Event):void

{
// code to be executed upon exit.
}

Please note that EXITING event is not dispatch if application is in suspended in background.

-Neha