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

Instead of sending a notification from your app delegate, the OS sends a notification automatically that you can observe:

[[NSNotificationCenter defaultCenter] addObserver:self
                                         selector:@selector(initSongInfo)
                                             name:UIApplicationDidBecomeActiveNotification
                                           object:nil];

and of course make sure to stop observing sometime before or inside your dealloc method, by calling:

[[NSNotificationCenter defaultCenter] removeObserver:self 
                                                name:UIApplicationDidBecomeActiveNotification 
                                              object:nil];