Handoff and restoring view controller hierarchy

Good evening,

I have been trying to implement handoff from my watchkit 1 extension to my iPhone app. The NSUserActivity creation works fine, the icon gets displayed on the iPhone's lock screen and my application delegate gets called with the proper activity/data.

What I'm struggling with is to restore the required view controller hierarchy to resume the activity on the iPhone. I was expecting this to be as straightforward as UIKit state restoration, which I have recently implemented, but I keep hitting a wall.

My app supports two activities for handoff right now: Activity A and Activity B.

My view controller hierarchy is as follows:

Root (UISplitViewController)

• 1. primary (UINavigationController)

  "index" UITableViewController

  • "subindex" UITableViewController
    • "details" UITableViewController (see below)
• 2. secondary (UINavigationController)

  "details" UITableViewController

  • "complete details" UIViewController

Here is my continueUserActivity function:

    func application(application: UIApplication, continueUserActivity userActivity: NSUserActivity, restorationHandler: (([AnyObject]!) -> Void)) -> Bool {
        let storyboard = UIStoryboard(name: "MainStoryboard", bundle: nil)
        let viewController = storyboard.instantiateInitialViewController() as! UISplitViewController
        if let rootController = viewController.viewControllers.first?.topViewController {
            rootController.restoreUserActivityState(userActivity)
            // also tried restorationHandler([rootController]) with same outcome
        }
        self.window!.rootViewController = viewController
        return true
    }

Then, in my rootController ("index" UITableViewController in the bulleted list above) I do the following:

    override func restoreUserActivityState(activity: NSUserActivity) {
        performSegueWithIdentifier("SomeExistingSegue", sender: activity)
        super.restoreUserActivityState(activity)
    }

    override func prepareForSegue(segue: UIStoryboardSegue, sender: AnyObject!) {
        switch segue.identifier! {
        case "SomeExistingSegue":
            let subindexViewController = segue.destinationViewController as! SubindexViewController
            var subindexGroup: SubindexGroup?
            if sender is NSUserActivity {
                // retrieve data from CoreData
                // subindexGroup = ...
            } else {
                subindexGroup = _fetched!.objectAtIndexPath(tableView.indexPathForSelectedRow()!) as? SubindexGroup
            }
            subindexViewController.subindexGroup = subindexGroup
            if sender is NSUserActivity {
                subindexViewController.restoreUserActivityState(sender as! NSUserActivity)
            }
       // ...
        default:
            break
        }
    }

The idea behind this was to go through the same segue sequence as a user, therefore rebuilding the hierarchy properly.

I am getting weird results, however, with the controllers not consistently being added to the stack. I believe I'm on the right track but I have a feeling I'm not doing everything in the proper sequence.

Any suggestions?

Thanks!