Get the root ViewController - Objective-C

Question

Here's my problem: I've actually created a custom segue to manage in a different way the transitions between my UIViewControllers (I'm working on a Storyboard based project). I added some animations using CATransform3D to move the views...so...when I do that, the only thing I can see in the background is a black view.

I would love to know how to change that color and if is possible to replace it with a UIImageView . Do you have any trick/idea to do that?

Thanks! :)

Answer 1

You can try following if you are sure the black view is a root controller's view:

UIImageView *imageView = [[UIImageView alloc] initWithImage:[UIImage imageNamed:@"my_image"]];
UIView *rootView = [[UIApplication sharedApplication].keyWindow.rootViewController.view];
[rootView insertSubview:imageView atIndex:0];

Answer 2

Actually，this is a grave, but I would leave the answer for later-comers.

We know that iOS is migrated from OS X, so all viewControllers are in UIWindow , the black color is the backgroundColor of the window . so that you should not find any root viewController , what you find is the top window .

if you want to change the black backgroundColor to other color , like white, do:

  UIWindow *window = [[UIApplication sharedApplication].windows lastObject];
  window.backgroundColor = [UIColor whiteColor];