iOS: Restoring the previously visible view when the app returns to the foreground?

Question

I'm developing an iPhone (iOS 5+) app using storyboards. The first screen of the app is a splash/login screen that checks for Facebook credentials and enables you to read and accept Terms And Conditions. In case there are valid stored credentials and the TOC has been previously accepted, this view automatically makes a modal segue (using a cross dissolve effect) to the first "real" application view, a tab bar controller with three tabs.

I'm currently implementing backgrounding and foregrounding logic. The problem is that when pressing the home button and then coming back, the login screen is briefly shown before the correct pre-backgrounding view is restored. (The Default.png of the app is of the login screen background, so it might be either that or a backgrounding-time screenshot of the actual login screen; I haven't tested replacing Default.png yet to tell the difference.)

Why is this? As far as I can tell, backgrounding the app should just take a screenshot of the view that is visible on the screen when, say, hitting the home button, and restore that prior to restoring the actual view functionality when coming back to the foreground. In this case that would be one of the tabs of the tab bar controller. Is the modal segue between the login screen and the tab bar controller the culprit here, or something else?

(I've always felt that the cross dissolve modal segue from the login screen to the first "useful" screen is a bit dirty, since IMHO a modal segue seems to imply that what your segueing to is something you'll later dismiss to get back to the "from" screen. What I'm doing now is just leaving the target of the modal segue visible indefinitely. If that is the problem here, I'd love it if someone would suggest a better method of displaying, transitioning away from and "jettisoning" the login screen.)

Answer 1

OK, turns out this was just a simulator/device discrepancy regarding Default.png. This comment on another question made me think to check. Time to file a bug report.

Answer 2

If I recall correctly, Apple has some old demo code which "remembers" which view a navigation controller was showing before it went into the background.

By way of disclaimer, I haven't worked with storyboards, so I don't know the specifics of doing what you're trying to do.

If it were me, I'd create the view controller or controllers at launch, and then only add the login screen if deemed necessary by the app delegate's logic. Only then, after setting up the view hierarchy, do I present everything.

This accomplishes two things. My login screen only exists and is visible if necessary. Additionally, the login screen won't flash unessecarily. Oh, and as a third benefit, you can present any view you like.

I'd suggest, assuming the aforementioned demo code doesn't work for you, that you'll want to save some sort of reference, tag, or ID of the currently visible view in NSUserDefaults and read that out when setting up your view hierarchy on launch.