So I had a full working solution in iOS7 that displays a LoginViewController via presentViewController in the AppDelegate's didFinishLaunching.
Basically I am doing something like this:
UIViewController *backgroundViewController = ...
self.window.rootViewController = backgroundViewController;
[self.window makeKeyAndVisible];
[self.window.rootViewController presentViewController:loginViewController
animated:NO ...]
In iOS8 I see a jump. First I see the backgroundViewController then after about 1 second or so the login appears.
So, how can I prevent this jump in iOS8?
I am seeing that are a ton of developers with this kind of problem but still didn't find a solution.
Also a hack (for now), but just one line of code
Add the view of the view controller you're presenting to the window before presentation
UIViewController *viewController = [[UIViewController alloc] init];
[viewController.view setBackgroundColor:[UIColor greenColor]];
// Temporary iOS8 fix for 'presentation lag' on launch
[self.window addSubview:viewController.view];
[self.window.rootViewController presentViewController:viewController animated:NO completion:nil];
If you are presenting a navigation controller than add the navigation controller's view instead of its top view controller.