Question

How can I change the RootViewController in my UIWindow and have it cross dissolve to the new root?

Answer 1

I would recommend to use the transitionFromView method on UIView. You could use the following code for example to handle your transition then:

- (void)transitionToViewController:(UIViewController *)viewController
                    withTransition:(UIViewAnimationOptions)transition
{
    [UIView transitionFromView:self.window.rootViewController.view
                        toView:viewController.view
                      duration:0.65f
                       options: UIViewAnimationOptionTransitionCrossDissolve
                    completion:^(BOOL finished){
                        self.window.rootViewController = viewController;
                    }];
}

You can find the ref doc of this method here.