Calling UIViewController method from app delegate [duplicate]

1. Notification. But you don't want this.
2. You can get the reference to your that viewController in the AppDelegate. Than call that (void)goToBeginning method in the (void)applicationDidEnterBackground

For example: In your ViewController

- (void)viewDidLoad
{
    [super viewDidLoad];

    AppDelegate *appDelegate = (AppDelegate *)[[UIApplication sharedApplication] delegate];
    appDelegate.myViewController = self;
}

And in your AppDelegate:

@class MyViewController;

@interface AppDelegate : UIResponder <UIApplicationDelegate>

@property (weak, nonatomic) MyViewController *myViewController;

@end

And in the AppDelegate's implementation:

- (void)applicationDidEnterBackground:(UIApplication *)application
{
    [self.myViewController goToBeginning];
}