preferredTransition not working when using setViewControllers(_:animated:)

Question

chou_ios OP

Created 1w

Replies 2

Boosts 0

Participants 2

I’m using the new preferredTransition = .zoom(...) API introduced in iOS 18.

Here’s a simplified version of what I do on app startup:

let listVC = CollectionViewController(collectionViewLayout: layout)
let detailVC = DetailViewController()
detailVC.preferredTransition = .zoom(sourceViewProvider: { context in
    let indexPath = IndexPath(row: 0, section: 0)
    let cell = listVC.collectionView.cellForItem(at: indexPath)
    return cell
})
let nav = UINavigationController()
nav.setViewControllers([listVC, detailVC], animated: false)
window?.rootViewController = nav
window?.makeKeyAndVisible()

This is meant to restore the UI state from a previous session — the app should launch directly into the DetailViewController.

The Problem

When I launch the app with setViewControllers([listVC, detailVC], animated: false), the transition from listVC to detailVC appears correctly (i.e., no animation, as intended), but the drag-to-dismiss gesture does not work. The back button appears, and tapping it correctly triggers the zoom-out transition back to the cell, so the preferredTransition = .zoom(...) itself is properly configured.

Interestingly, if I delay the push with a DispatchQueue.main.async and instead do:

nav.setViewControllers([listVC], animated: false)
DispatchQueue.main.async {
    nav.pushViewController(detailVC, animated: true)
}

…then everything works perfectly — including the interactive swipe-to-dismiss gesture — but that introduces an unwanted visual artifact: the user briefly sees the listVC, and then it pushes to detailVC, which I’m trying to avoid.

My Question

Is there a way to enable the swipe-to-dismiss gesture when using setViewControllers([listVC, detailVC], animated: false)

It can be very confusing for users if swipe-to-dismiss only works in certain cases inconsistently.

Thanks

Boost

Answer 1

DTS Engineer OP

Apple

6d

@chou_ios are you trying to implement a Split View with a sidebar and detail view?

0

Answer 2

chou_ios OP

4d

@DTS Engineer

I'm not building split view, nor am I using UISplitViewController — my view hierarchy is quite simple.

I have a standard UICollectionView, and tapping a cell is supposed to show a detail view. This is conceptually similar to the Apple sample code, where a detail view controller is pushed using navigationController.pushViewController.

However, due to the existing product behavior, I need to present the detail screen using: navigationController.setViewControllers([listViewController, detailViewController])

The issue is: I would still like to implement the fluid zoom transition effect as demonstrated in the Apple documentation, but it seems the transition isn't applied when using setViewControllers API

0