How to let UISplitViewController on Storyboard show master view first?

Question

I have a simple app with a storyboard with just a split view controller freshly drag-dropped from the UI objects list.

When I start the app on an iPhone simulator, the detail view appears first.

How do I make sure that the master view is shown at app startup? Is there a way to arrange that on the storyboard?

Answer 1

In order to enable the master view to collapse on iPhone by default, override some delegate methods:

class SplitViewController : UISplitViewController {
    override func viewDidLoad() {
        super.viewDidLoad()
        self.delegate = self
    }
}

extension SplitViewController : UISplitViewControllerDelegate {

    // The default for this is .secondary!!
    @available(iOS 14.0, *)
    public func splitViewController(_ svc: UISplitViewController, 
        topColumnForCollapsingToProposedTopColumn 
        proposedTopColumn: UISplitViewController.Column) -> UISplitViewController.Column {
        return .primary
    }

    // default is false!
    public func splitViewController(_ splitViewController: UISplitViewController,
                             collapseSecondary secondaryViewController:UIViewController,
                             onto primaryViewController:UIViewController) -> Bool {
        return true
    }
}

Previously you'd use preferredDisplayMode = .primaryOverlay, but this is now deprecated. The code works for iOS 14 and is backwards compatible for earlier iOS versions also.