Only the first time. When Activity is started and application is not loaded, then both onCreate() methods will be called. But for subsequent starts of Activity, the onCreate() of application will not be called.
I don’t think 500kb will be that big of a deal. What you described is exactly how I tackled my problem of losing data in an activity. I created a global singleton in the Application class and was able to access it from the activities I used. You can pass data around in a Global … Read more
When calling finish() on an activity, the method onDestroy() is executed. This method can do things like: Dismiss any dialogs the activity was managing. Close any cursors the activity was managing. Close any open search dialog Also, onDestroy() isn’t a destructor. It doesn’t actually destroy the object. It’s just a method that’s called based on … Read more
App delegate gets callbacks indicating state transitions. You can track it based on that. Also the applicationState property in UIApplication returns the current state. [[UIApplication sharedApplication] applicationState]