Swift: Safe practices regarding presentScene()

Question

In my program, some of the transitions between viewControllers are managed programmatically via the following code:

let storyBoard: UIStoryboard = UIStoryboard(name: "Main", bundle: nil)
let newViewController = storyBoard.instantiateViewController(withIdentifier: "NewViewController") as! NewViewController
self.present(newViewController, animated: true, completion: nil)

I've been wondering how safe of a practice this is. When presentScene gets called, does it do anything to "wipe" the screen under it, or does it just stack more view on top of existing ones? If not, how does it work? Also is this the best way (in terms of performance) of managing this programatic transitions?

Answer 1

First of all, you don't need to create an object of UIStoaryboard every time unless you have different name of it apart from Main . Modification to your code:

let newViewController = self.storyBoard!.instantiateViewController(withIdentifier: "NewViewController") as! NewViewController

Now coming to your question! When you are presenting any UIViewController on another UIViewController or UINavigationController , the presented controller has no stack.

In short, you are presenting a UIViewController modally over the presentee UIViewController . This can happen across any UIViewController without any relationship rules. The presenter should take care of dismissing the VC it presented.

Hope this clears your doubt.