Current controller

gistfile1.m

- (UIViewController *)currentController {
    UIResponder *currentController = [[[[[UIApplication sharedApplication] keyWindow] subviews] objectAtIndex:0] nextResponder];
    if ([currentController isMemberOfClass:[UINavigationController class]]) {
        NSArray *navStack = ((UINavigationController *)currentController).viewControllers;
        currentController = [navStack objectAtIndex:[navStack count] - 1];
    }

    if ([currentController isKindOfClass:[UIViewController class]])
        return (UIViewController *)currentController;
    return nil;
}