iOS Get id of top most view controller in app delegate - ios

Question

When my app resumes I find the top most view controller (whatever was last presented when the app was active) in one of my app delegate methods. I know it works because calling viewDidLoad runs the one from the right view controller.
However I only want to call viewDidLoad if the top most controller is one of a particular few view controllers. How do I do this? I've attempted returning the restoration id, title and navigationitem.title of the view controller to find which one it is but all return (null). I set the restoration id programmatically before I call any view controller so it should be ok, but somehow is not when accessed in the app delegate.
Edit:
Process is as follows:
The first time the app starts the app delegate method didFinishLaunchingWithOptions checks if some data is stored. If it is, the following code is run:
AACMainViewController *firstController = [storyBoard instantiateViewControllerWithIdentifier:#"aacmainViewController"];
firstController.restorationIdentifier = #"AACMainViewController";
UINavigationController *navController = [[UINavigationController alloc] initWithRootViewController:firstController];
self.window.rootViewController = navController;
The user is now in the main menu. If at this point the user shrinks the app and then resumes it, the app delegate method applicationDidBecomeActive is eventually called. When it is, it runs another method. The code we're interested in is this:
UIViewController * top = [self topViewController];
//[top viewDidAppear:YES];
NSString * toptitle = top.title;
NSString * resid = top.restorationIdentifier;
NSLog(#"App top res ID is %#",resid);
NSLog(#"App top title is %#",top title);
The method topViewController and the method it calls are:
- (UIViewController *)topViewController
{
return [self topViewController:[UIApplication sharedApplication].keyWindow.rootViewController];
}
- (UIViewController *)topViewController:(UIViewController *)rootViewController
{
NSLog(#"%#",#"topViewController: ---");
if (rootViewController.presentedViewController == nil)
{
NSLog(#"%#",#"presentedViewController == nil");
return rootViewController;
}
//isMemberOfClass: //isKindOfClass:
if ([rootViewController.presentedViewController isMemberOfClass:[UINavigationController class]])
{
NSLog(#"%#",#"isMemberOfClass");
UINavigationController *navigationController = (UINavigationController *)rootViewController.presentedViewController;
UIViewController *lastViewController = [[navigationController viewControllers] lastObject];
return [self topViewController:lastViewController];
}
NSLog(#"%#",#"End");
UIViewController *presentedViewController = (UIViewController *)rootViewController.presentedViewController;
return [self topViewController:presentedViewController];
}
As it stands, although a title is shown in the Main view when you are running the app, the NSLog in the app delegate will think it is null!
Edit 2:
I found that if you manually set the title in viewDidLoad or viewDidAppear BEFORE you shrink it, then it knows about the title on resume. Which doesn't make sense since the title is already shown on the device. It also presents a problem. Once you set the title in code this way (let's say title is "Test1"), it doesn't matter which view you shrink and resume from, unless you set the title in code for that new view controller (say "Test2"), it'll still think the title is the last one ("Test1"). I've a lot of view controllers so manually setting it is too tedious to contemplate.