在导航栏中转到新视图 controller，memory 不断上升

Question

I am learning and working on an ios app. I have a nav bar with buttons that are programmed to present other view controllers in the app. Heres a sample of the code:

let vc = storyboard?.instantiateViewController(identifier: “ViewController”) as! ViewController
        
vc.modalPresentationStyle = .fullScreen
self.present(vc, animated: true, completion: nil)

As I navigate around the app while running the simulation the Memory keeps rising. Should I be clearing previous pages viewed so that the memory doesn't rise?

Answer 1

Every time when presenting a new scene in your app, you as a developer are responsible for presenting and dismissing the scene properly.

There are many ways of presenting a scene.

For example,The push -style navigation automatically contains/adds controls for backward navigation because it adds all ViewControllers to its navigation stack ; all ViewControllers will be embedded in the same NavigationController ; thus, when dismissing it, you have to write:

navigationController.popViewController(animated: true)

The VC will be popped (removing an element from the top of the stack, newest element in the stack) and not just dismissed.

In case of presenting scenes modally , these ViewControllers have to have their own NavigationController . thus, when dismissing it, you have to write:

dismiss(animated: true, completion: nil)

Do you see the difference? If dismissing is handled properly, then there should be no memory leak. Presenting and dismissing is related to Navigation in your app, and every scene has this navigation "section" where you handle dismissing which prevents from memory leak.

Hope it can help you a little bit.