I want some advice on how to properly take on implementing state preservation and restoration for an app that has been build already, having lot of view controllers and complex hierarchy.
What are the things to be kept in mind when trying to preserve state for an app that is running for a while already?
EDIT:
I want to get clarified or possibly get a solution to a problem that I am facing in terms of restoring state goes. I successfully restore app' state on launch. I restore a view controller and other view controllers in hierarchy. Now when I push another view controller and sequence of other view controllers to nav. stack, at a particular view controller, for some reason the app crashes due to an exception. So when I open the app back, it still restores the first view controller's state that was preserved when pressing home button.
Specifically I want to know if there is any way to discard app state info. when app terminates due to uncaught exception? I know that the state will be discarded if user manually force kills app, or state restoration fails, or the app terminates at launch. Is there a way to catch a termination and configure app state accordingly? Suggestions would be great. Thanks.
No, I don't think that's right at all. The whole beauty of the built-in state saving-and-restoration mechanism is that it can be patched right onto the working app, one view controller at a time. You don't even have to complete it for the whole app before testing; on the contrary, another beauty of the mechanism is that it works for just the subset of the view controller hierarchy for which it is in fact implemented, with no harm done to the rest of the app. So just start at the top of the view controller hierarchy and start implementing it.