Correct way of removing (deleting) a view/viewController from the stack after segue in Swift

Question

I am running into a problem here. I am presenting views with performSegueWithIdentifier. Everything goes smoothly. The problem is that as a test, I only have 2 viewControllers with some data in them and I have two buttons that call a segue back to the other VC. If I keep performingSegues, you can clearly see that the memory usage goes up every two segues by around 0.4Mb. This tells me that the Views are not being deleted/removed from the view stack and are just using memory. I would like to know the correct way of getting rid of the view that presents the other view by using performSegueWithIdentifier (of course, after it finished presenting the view, else it will not work I guess).

Could you point me in the right direction? I found some objective-c code that tried to do this but it was very extensive and I don't know much about objective-C, so it was a little hard for me to understand.

Thank you in advance for your help!

Cheers!

Edit:

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I am doing a "manual segue". By this I mean I have two view controllers standing on their own. They are not embedded in any navigationVCs or something like that. I am using an "Adaptive Segue" of type "Show".

Answer 1

When you do normal segues, you are piling up new view controllers on top of the existing ones without dismissing them. That's why your memory usage keeps going up.

You need to provide more information before we can give you specific guidance. Are you doing modal segues or pushing onto a navigation stack?

If you're pushing, you want to pop to the view controller you came from. Think in terms of a stack of plates. When you push, you add plates to the stack. When you pop, you take plates off and reveal the plates (view controllers) underneath. Do a search in the Xcode help system on "PopTo" to find the methods that let you either pop back to a specific view controller or back to the root view controller of your navigation controller.

Modal view controllers stack on top of each other in a similar fashion, but without the origination of a navigation controller. If you've pushed a series of one or more modals and you send the dismissViewControllerAnimated:completion: method to the view controller you want get back to it will dismiss the modals that are on top of it.

You can also look at using unwind segues. Unwind segues let you go back where you came. Do a search in the Xcode help system on "Using unwind segues" for more information. Most of the tutorials on unwind segues are written in Objective-C but you should be able to find some in Swift if you look. Explaining unwind segues in enough detail to be useful is more than I can cover in this answer.

Answer 2

If your goal is to always keep one VC, and since you already have a manual segue, what you can do is, after presenting the next VC you can pop the existing VC from the root and assign the destination VC as your root VC like so

class ManualSegue: UIStoryboardSegue {

  override func perform() {
    sourceViewController.presentViewController(destinationViewController, animated: true) {
      self.sourceViewController.navigationController?.popToRootViewControllerAnimated(false)
      UIApplication.sharedApplication().delegate?.window??.rootViewController = self.destinationViewController
    }
  }
}