`scene(_ scene: UIScene, continue userActivity: NSUserActivity)` doesn't get called when the app is launched after the user clicks on a universal link

Question

Method scene(_ scene: UIScene, continue userActivity: NSUserActivity) doesn't get called when the app is launched after the user clicks on a universal link.

It works fine when already launched app opens again after the user clicks on the universal link. The sample code:

func scene(_ scene: UIScene, continue userActivity: NSUserActivity) {
    guard userActivity.activityType == NSUserActivityTypeBrowsingWeb,
        let incomingURL = userActivity.webpageURL,
        let components = NSURLComponents(url: incomingURL, resolvingAgainstBaseURL: true),
        let path = components.path else {
            return
    }
    let params = components.queryItems ?? [URLQueryItem]()

    print("path = \(path)")
    print("params = \(params)")
}

I tried to use application(_ application: UIApplication, configurationForConnecting connectingSceneSession: UISceneSession, options: UIScene.ConnectionOptions) -> UISceneConfiguration, but it never gets called when the user clicks on the link:

func application(_ application: UIApplication, configurationForConnecting connectingSceneSession: UISceneSession, options: UIScene.ConnectionOptions) -> UISceneConfiguration {
    if let scene = connectingSceneSession.scene, let userActivity = scene.userActivity {
        if userActivity.activityType == NSUserActivityTypeBrowsingWeb {
            if let incomingURL = userActivity.webpageURL,
                let components = NSURLComponents(url: incomingURL, resolvingAgainstBaseURL: true),
                let path = components.path {
                let params = components.queryItems ?? [URLQueryItem]()

                print("path = \(path)")
                print("params = \(params)")
            }
        }
    }
    return UISceneConfiguration(name: "Default Configuration", sessionRole: connectingSceneSession.role)
}

I tried to use scene(_ scene: UIScene, willConnectTo session: UISceneSession, options connectionOptions: UIScene.ConnectionOptions):

func scene(_ scene: UIScene, willConnectTo session: UISceneSession, options connectionOptions: UIScene.ConnectionOptions) {
    if let userActivity = scene.userActivity {
        self.scene(scene, continue: userActivity)
    }
}

I also tried the following methods:

func sceneDidBecomeActive(_ scene: UIScene) {
    if let userActivity = scene.userActivity {
        self.scene(scene, continue: userActivity)
    }
}

func sceneWillEnterForeground(_ scene: UIScene) {
    if let userActivity = scene.userActivity {
        self.scene(scene, continue: userActivity)
    }
}

But scene.userActivity is always nil there and I can't get userActivity.webpageURL.

How can we recognize that the link was clicked and the app was launched (not just opened)?

Answer 1

You almost had it:

func scene(_ scene: UIScene, willConnectTo session: UISceneSession, options connectionOptions: UIScene.ConnectionOptions) {
    if let userActivity = scene.userActivity { // <-- not quite
        self.scene(scene, continue: userActivity)
    }
}

It's not in the scene; it's in the connectionOptions . Look in the connectionOptions.userActivities. (Though if what has happened is that the user clicked a link to launch us, I would expect to find the URL in the connectionOptions.urlContexts.)