Qualities of a great Mac Catalyst app

6:50 - System button

let button = UIButton(type: .system)
button.setTitle("Button", for: .normal)

7:06 - Pull-down button

button.menu = UIMenu(...)
button.showsMenuAsPrimaryAction = true

7:44 - Pop-up button

button.menu = UIMenu(...)
button.showsMenuAsPrimaryAction = true
button.changesSelectionAsPrimaryAction = true

8:24 - Checkbox

let checkbox = UISwitch()
if checkbox.style == .checkbox {
    checkbox.title = "Checkbox"
}

13:20 - Delegating actions

final class MyView: UIView {
    override func target(forAction action: Selector, withSender sender: Any?) -> Any? {
        if action == #selector(Model.setAsFavorite(_:)) {
            return myModel
        } else {
            return super.target(forAction: action, withSender: sender)
        }
    }
}

14:43 - Requesting a new scene

let viewDetailActivityType = "viewDetail"
let itemIDKey = "itemID"

final class MyView: UIView {
    @objc func viewDoubleClicked(_ sender: Any?) {
        let userActivity = NSUserActivity(activityType: viewDetailActivityType)
        userActivity.userInfo = [itemIDKey: selectedItem.itemID]
        UIApplication.shared.requestSceneSessionActivation(nil,
            userActivity: userActivity,
            options: nil,
            errorHandler: { error in //...
        })
    }
    //...
}

15:57 - Responding to a new scene request

let viewDetailActivityType = "viewDetail"

final class AppDelegate: UIApplicationDelegate {
    func application(_ application: UIApplication, 
        configurationForConnecting session: UISceneSession, 
        options: UIScene.ConnectionOptions) -> UISceneConfiguration {
        if let activity = options.userActivities.first {
            if activity.activityType == viewDetailActivityType {
                return UISceneConfiguration(name: "DetailViewer", sessionRole:session.role)
            }
        }
        return UISceneConfiguration(name: "Default Configuration",
            sessionRole: session.role)
    }
    //...
}

17:13 - Setting item ID on new scene's root view controller

let itemIDKey = "itemID"

final class SceneDelegate: UIWindowSceneDelegate {
    func scene(_ scene: UIScene, willConnectTo session: UISceneSession,
        options: UIScene.ConnectionOptions) {
        if let userActivity = connectionOptions.userActivities.first {
            if let itemId = userActivity.userInfo?[itemIDKey] as? ItemIDType {
               // Set item ID on new view controller
            }
        }
        //...
    }
    //...

17:47 - Saving state for later restoration

final class SceneDelegate: UIWindowSceneDelegate {
    func stateRestorationActivity(for scene: UIScene) -> NSUserActivity? {
        //...
    }
}

17:57 - State restoration

final class AppDelegate: UIApplicationDelegate {
    func application(_ application: UIApplication, 
        configurationForConnecting session: UISceneSession, 
        options: UIScene.ConnectionOptions) -> UISceneConfiguration {
        //...
    }
}

18:42 - Handle both new scene requests and state restoration

let itemIDKey = "itemID"

final class SceneDelegate: UIWindowSceneDelegate {
    func scene(_ scene: UIScene, willConnectTo session: UISceneSession,
        options connectionOptions: UIScene.ConnectionOptions) {
        if let userActivity = connectionOptions.userActivities.first ??
            session.stateRestorationActivity {
            if let itemId = userActivity.userInfo?[itemIDKey] as? ItemIDType {
               // Set item ID on new view controller
            }
        }
    }
}

20:20 - Provide sharing configuration for the scene

final class RootViewController: UIViewController {
    override var activityItemsConfiguration: UIActivityItemsConfigurationReading? {
      get { UIActivityItemsConfiguration(objects: [image]) }
      //...
    }
}

20:56 - Support sharing through context menu

final class MyView: UIView {
    override var activityItemsConfiguration: UIActivityItemsConfigurationReading? {
      get { UIActivityItemsConfiguration(objects: images) }
      //...
    }

    func viewDidLoad() {
      let contextMenuInteraction = UIContextMenuInteraction(delegate: self)
      addInteraction(contextMenuInteraction)
    }
}

22:08 - Supporting continuity camera

final class MyView: UIView {
    override var pasteConfiguration: UIPasteConfiguration? {
      get { UIPasteConfiguration(forAcceptingClass: UIImage.self) }
      //...
    }

    func willMove(toWindow: UIWindow) {
       addInteraction(contextMenuInteraction)
    }

    override func paste(itemProviders: [NSItemProvider]) {
       for itemProvider in itemProviders {
            if itemProvider.canLoadObject(ofClass: UIImage.self) {
                if let image = try? await itemProvider.loadObject(ofClass:UIImage.self) {
                    insertImage(image)
                }          
                //...