Using WCSession with more than one ViewController

Question

I found many questions and many answers but no final example for the request:

Can anyone give a final example in Objective C what is best practice t

Answer 1

Well, this is simplified version of my solution as requested by Greg Robertson. Sorry it's not in Objective-C anymore; I'm just copy-pasting from existing AppStore-approved project to make sure there will be no mistakes.

Essentially, any WatchDataProviderDelegate can hook to data provider class as that provides array holder for delegates (instead of one weak var). Incoming WCSessionData are forwarded to all delegates using the notifyDelegates() method.

// MARK: - Data Provider Class

class WatchDataProvider: WCSessionDelegate {

    // This class is singleton
    static let sharedInstance = WatchDataProvider()

    // Sub-Delegates we'll forward to
    var delegates = [AnyObject]()

    init() {
        if WCSession.isSupported() {
            WCSession.defaultSession().delegate = self
            WCSession.defaultSession().activateSession()
            WatchDataProvider.activated = true;
        }
    }

    // MARK: - WCSessionDelegate                

    public func session(session: WCSession, didReceiveUserInfo userInfo: [String : AnyObject]) {
        processIncomingMessage(userInfo)
    }

    public func session(session: WCSession, didReceiveApplicationContext applicationContext: [String: AnyObject]) {
        processIncomingMessage(applicationContext)
    }

    func processIncomingMessage(dictionary: [String:AnyObject] ) {
        // do something with incoming data<
        notifyDelegates()
    }

    // MARK: - QLWatchDataProviderDelegate     

   public func addDelegate(delegate: AnyObject) {
       if !(delegates as NSArray).containsObject(delegate) {
           delegates.append(delegate)
       }
   }

   public func removeDelegate(delegate: AnyObject) {
       if (delegates as NSArray).containsObject(delegate) {
           delegates.removeAtIndex((delegates as NSArray).indexOfObject(delegate))
       }
   }

   func notifyDelegates()
   {
       for delegate in delegates {
           if delegate.respondsToSelector("watchDataDidUpdate") {
               let validDelegate = delegate as! WatchDataProviderDelegate
               validDelegate.watchDataDidUpdate()
           }
       }
   }    
}


// MARK: - Watch Glance (or any view controller) listening for changes

class GlanceController: WKInterfaceController, WatchDataProviderDelegate {

    // A var in Swift is strong by default
    var dataProvider = WatchDataProvider.sharedInstance()
    // Obj-C would be: @property (nonatomic, string) WatchDataProvider *dataProvider

    override func awakeWithContext(context: AnyObject?) {
        super.awakeWithContext(context)
        dataProvider.addDelegate(self)
    }

    // WatchDataProviderDelegate
    func watchDataDidUpdate() {
        dispatch_async(dispatch_get_main_queue(), {
            // update UI on main thread
        })
    }}
}

class AnyOtherClass: UIViewController, WatchDataProviderDelegate {

    func viewDidLoad() {
        WatchDataProvider.sharedInstance().addDelegate(self)
    }

    // WatchDataProviderDelegate
    func watchDataDidUpdate() {
        dispatch_async(dispatch_get_main_queue(), {
            // update UI on main thread
        })
    }}
}