Optimizing Your iPad App for Mac

The Mac version of your iPad app supports many system features found in macOS without requiring any effort from you, including:

• A default menu bar for your app

• Support for trackpad, mouse, and keyboard input

• Support for window resizing and full-screen display

• Mac-style scroll bars

• Copy-and-paste support

• Drag-and-drop support

• Support for system Touch Bar controls

You can, however, extend your app to take advantage of even more system features.

The Mac version of your app comes with a standard menu bar. Customize it by adding and removing menu items using UIMenuBuilder. To learn more, see Adding Menus and Shortcuts to the Menu Bar and User Interface.

Mac apps typically let users manage app-specific settings by displaying a preferences window. Users see this window by selecting the app menu followed by the Preferences menu item in the menu bar. If your app has a Settings bundle, the system automatically provides your app with a preferences window. To learn more, see Displaying a Preferences Window.

iPad apps using a split view controller get a Mac-style vertical split view when running in macOS. But to make your iPad app look more at home on Mac, apply a translucent effect that blurs the desktop into the primary view controller's background. To do this, set your split view controller’s primaryBackgroundStyle to UISplitViewController.BackgroundStyle.sidebar, as shown in Listing 1.

func application(_ application: UIApplication, didFinishLaunchingWithOptions launchOptions: [UIApplication.LaunchOptionsKey: Any]?) -> Bool {

    let splitViewController = window!.rootViewController as! UISplitViewController
    let navigationController = splitViewController.viewControllers[splitViewController.viewControllers.count-1] as! UINavigationController
    navigationController.topViewController!.navigationItem.leftBarButtonItem = splitViewController.displayModeButtonItem
    
    // Add a translucent background to the primary view controller.
    splitViewController.primaryBackgroundStyle = .sidebar
    
    splitViewController.delegate = self
    
    return true
}

Mac users rely on a pointer to interact with apps, whether selecting a text field or moving a window. As the user moves the pointer over UI elements, some elements should change their appearance. For example, a web browser highlights a link as the pointer moves over it.

To detect when the user moves the pointer over a view in your app, add a UIHoverGestureRecognizer to that view. This tells your app when the pointer enters or leaves the view, or moves while over it.

class ViewController: UIViewController {

    @IBOutlet var button: UIButton!

    override func viewDidLoad() {
        super.viewDidLoad()

        let hover = UIHoverGestureRecognizer(target: self, action: #selector(hovering(_:)))
        button.addGestureRecognizer(hover)
    }

    @objc
    func hovering(_ recognizer: UIHoverGestureRecognizer) {
        switch recognizer.state {
        case .began, .changed:
            button.titleLabel?.textColor = #colorLiteral(red: 1, green: 0, blue: 0, alpha: 1)
        case .ended:
            button.titleLabel?.textColor = UIColor.link
        default:
            break
        }
    }
}