CODEWITHSUNDEEP
iosswiftuiviewcontroller
Muindor
Muindor

Reputation: 357

How to correctly dismiss previous view controller

Apologies as I know there are some similar questions, but I've been looking for two weeks through every one I can find, and cannot figure it out (I'm a bit of a novice).

I have a few different View Controllers, not using a Navigation Controller. I can segue between them no problem. The issue is, I need each view to be dismissed when I segue to a new one. Here is some of what I've tried so far.

Option 1 (in new View Controller)

override func viewDidAppear(_ animated: Bool) {
    presentingViewController?.dismiss(animated: false, completion: nil)
}

Option 2 (in old View Controller)

override func viewDidDisappear(_ animated: Bool) {
    self.dismiss(animated: false, completion: nil)
}

In both of these cases, the new view gets dismissed and I'm taken back to the old view. I've tried about 20 versions of similar code.

Should I be using the first VC in my program as my "main" view controller, and presenting/dismissing all others on top of it? I didn't think this approach seemed memory efficient, when the "main" VC is not often used after initially loading the app.

It seems like I'm missing or not understanding something. Any help would be greatly appreciated.

Upvotes: 8

Views: 7950

Answers (2)

Sourabh Jain
Sourabh Jain

Reputation: 49

if you want to present VC B from VC A and want to dismiss VC A while Presenting you can use this Code 

let parentVC = presentingViewController
dismiss(animated: true) {
    let vc = self.storyboard!.instantiateViewController(withIdentifier...)
    parentVC.present(vc, animated: true)`enter code here`
}  `enter code here`

Upvotes: 2

LulzCow
LulzCow

Reputation: 1229

Think of it this way: A view controller can't exist on an island. It has to be presented on top of something.

That means when you present one VC on top of another, the presenting view controller is the "foundation" for the new one you just presented.

If you don't want to present VCs on top of each other, you have a couple of options:

1) Use a navigation controller. This is probably the best approach. You can present or push any view controller. If you decide to push, you can remove the old one from the navigation stack, or you can keep it there so the user can go back. There are lots of ways to use a navigation controller, and it's easily the most flexible way to navigate between controllers.

2) Use a tab bar controller. This works best if you have just a few different view controllers in your app, but it's good for certain use cases.

3) Do exactly what you said in your post (use the root view controller to present/dismiss all other VCs). As I said, you can't present a view controller out of thin air-- there always has to be something behind it. Unless there's a ton of stuff going on in your root VC, this shouldn't cause any memory issues. This approach should be fine unless you're very particular about the animations between your view controllers.

In general, I wouldn't worry too much about memory usage until it becomes a problem. It should be fine to present view controllers on top of each other for 99% of normal use cases.

Upvotes: 9

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