Question

Looking at the example in Beginning iOS 5 for persisting your application state, in the first viewController that is shown for the app, they register for applicationWillResignActive in viewDidLoad:. So that makes sense to me in that you register for that notification when your first view is shown.

I’m confused on whether you always do this, or where you typically register for this notification. Q1) Like do they register for this notification in this viewController so they can recreate this view? Q2) If so, do I do this for each viewController?

Q3) I’m using UIStoryboard and my first viewController is a UITabBarController. So do I register for the notification in the first tab’s viewController?

I also have a singleton DataManager object that holds the data for the app if that helps anyone guide me in the right direction of where I should save my data. Thanks!

Answer 1

These methods are in the AppDelegate.m

- (void)applicationWillResignActive:(UIApplication *)application
{
    /*
     Sent when the application is about to move from active to inactive state. This can occur for certain types of temporary interruptions (such as an incoming phone call or SMS message) or when the user quits the application and it begins the transition to the background state.
     Use this method to pause ongoing tasks, disable timers, and throttle down OpenGL ES frame rates. Games should use this method to pause the game.
     */
}

You can perform your actions here. You can however register to “listen” to that event in another view controller (like your example) but that is just to make it easier to send that event notification into that viewcontroller.

1) no, only to ensure that whenver this VC is loaded it will be able to listen to this event.

2) no, only for the ones you want to pass the even easily like this. However using the appdelegate.m and each’s vc view did appear is better.

3) depends on the kind of data you want to save, but typically you create your own file and just save it to disk like in any other OS. ios gives you access to the “documents” folder of your app and each folder is used for something specific, read the documentation.