iOS 13 UISplitView Problems

I had the same issue.

After a bit of investigation it seems like viewDidLoad is too late to set it to all visible.

I subclassed the UISplitViewController and changed the setting in awakeFromNib method. Now it is working as expected.

Alxlives's answer helped me. By using the debugger, I notice that in the master view controller, viewDidLoad is not called. So the delegate is never set, thus the collapse method is never called.

I fixed this by setting the delegate in awakeFromNib():

override func awakeFromNib() {
    self.splitViewController?.delegate = self
}

Now the splitViewController(_ splitViewController: UISplitViewController, collapseSecondary secondaryViewController: UIViewController, onto primaryViewController: UIViewController) -> Bool is called, and if you return true, the master will be displayed.

Warren Milward's answer helped me to guide me in the right direction, but actually I got it working with viewDidLoad().

I ended up using a subclass for the UISplitViewController and set the required values in viewDidLoad() as well as the delegate calls here.

class CustomSplitViewController: UISplitViewController, UISplitViewControllerDelegate {

    override func viewDidLoad() {
        super.viewDidLoad()

        self.delegate = self
        self.preferredDisplayMode = .allVisible
    }

    func splitViewController(_ splitViewController: UISplitViewController, collapseSecondary secondaryViewController: UIViewController, onto primaryViewController: UIViewController) -> Bool {
        return true
    }
}