How to tell the active view controller when applicationDidBecomeActive is called?

Question

I feel I am missing a trick here...

I just want to call viewDidLoad or viewDidAppear on the current active view controller when applicationDidBecomeActive gets called, s

Answer 1

your AppDelegate will have a window property, that window will have a rootViewController property. You can find your viewController here.

If you are using a TabBarController, the rootviewcontroller will be the tabbarcontroller, and you can call the tabbarcontroller's selectedViewController to get the current viewController.

UIViewController *rootViewController = [[[[UIApplication sharedApplication] delegate] window] rootViewController];
if ([rootViewController isKindOfClass:[UITabBarController Class]])
    rootViewController = ((UITabBarController *)rootViewController).selectedViewController;
else if ([rootViewController isKindOfClass:[UINavigationController Class]])
    rootViewController = ((UINavigationController *)rootViewController).topViewController;

[rootViewController viewDidAppear];

If you have a more complex view hierarchy with navigation controllers, or modal views, you can call on presentedViewController, or topViewController.