WatchConnectivity Singleton Demo

WatchConnectivitySingletonDemo.swift

//
//  WatchSessionManager.swift
//  WatchConnectivityDemo
//
//  Created by Natasha Murashev on 9/3/15.
//  Copyright © 2015 NatashaTheRobot. All rights reserved.
//

import WatchConnectivity

class WatchSessionManager: NSObject, WCSessionDelegate {
    
    static let sharedManager = WatchSessionManager()
    private override init() {
        super.init()
    }
    
    private let session: WCSession? = WCSession.isSupported() ? WCSession.defaultSession() : nil
    
    private var validSession: WCSession? {
        
        // paired - the user has to have their device paired to the watch
        // watchAppInstalled - the user must have your watch app installed
        
        // Note: if the device is paired, but your watch app is not installed
        // consider prompting the user to install it for a better experience
        
        if let session = session where session.paired && session.watchAppInstalled {
            return session
        }
        return nil
    }
    
    func startSession() {
        session?.delegate = self
        session?.activateSession()
    }
}

// MARK: Application Context
// use when your app needs only the latest information
// if the data was not sent, it will be replaced
extension WatchSessionManager {
    
    // Sender
    func updateApplicationContext(applicationContext: [String : AnyObject]) throws {
        if let session = validSession {
            do {
                try session.updateApplicationContext(applicationContext)
            } catch let error {
                throw error
            }
        }
    }
    
    // Receiver
    func session(session: WCSession, didReceiveApplicationContext applicationContext: [String : AnyObject]) {
        // handle receiving application context
        
        dispatch_async(dispatch_get_main_queue()) {
            // make sure to put on the main queue to update UI!
        }
    }
}

// MARK: User Info
// use when your app needs all the data
// FIFO queue
extension WatchSessionManager {
    
    // Sender
    func transferUserInfo(userInfo: [String : AnyObject]) -> WCSessionUserInfoTransfer? {
        return validSession?.transferUserInfo(userInfo)
    }
    
    func session(session: WCSession, didFinishUserInfoTransfer userInfoTransfer: WCSessionUserInfoTransfer, error: NSError?) {
        // implement this on the sender if you need to confirm that
        // the user info did in fact transfer
    }
    
    // Receiver
    func session(session: WCSession, didReceiveUserInfo userInfo: [String : AnyObject]) {
        // handle receiving user info
        dispatch_async(dispatch_get_main_queue()) {
            // make sure to put on the main queue to update UI!
        }
    }
    
}

// MARK: Transfer File
extension WatchSessionManager {
    
    // Sender
    func transferFile(file: NSURL, metadata: [String : AnyObject]) -> WCSessionFileTransfer? {
        return validSession?.transferFile(file, metadata: metadata)
    }
    
    func session(session: WCSession, didFinishFileTransfer fileTransfer: WCSessionFileTransfer, error: NSError?) {
        // handle filed transfer completion
    }
    
    // Receiver
    func session(session: WCSession, didReceiveFile file: WCSessionFile) {
        // handle receiving file
        dispatch_async(dispatch_get_main_queue()) {
            // make sure to put on the main queue to update UI!
        }
    }
}


// MARK: Interactive Messaging
extension WatchSessionManager {
    
    // Live messaging! App has to be reachable
    private var validReachableSession: WCSession? {
        if let session = validSession where session.reachable {
            return session
        }
        return nil
    }
    
    // Sender
    func sendMessage(message: [String : AnyObject],
        replyHandler: (([String : AnyObject]) -> Void)? = nil,
        errorHandler: ((NSError) -> Void)? = nil)
    {
        validReachableSession?.sendMessage(message, replyHandler: replyHandler, errorHandler: errorHandler)
    }
    
    func sendMessageData(data: NSData,
        replyHandler: ((NSData) -> Void)? = nil,
        errorHandler: ((NSError) -> Void)? = nil)
    {
        validReachableSession?.sendMessageData(data, replyHandler: replyHandler, errorHandler: errorHandler)
    }
    
    // Receiver
    func session(session: WCSession, didReceiveMessage message: [String : AnyObject], replyHandler: ([String : AnyObject]) -> Void) {
        // handle receiving message
        dispatch_async(dispatch_get_main_queue()) {
            // make sure to put on the main queue to update UI!
        }
    }
    
    func session(session: WCSession, didReceiveMessageData messageData: NSData, replyHandler: (NSData) -> Void) {
        // handle receiving message data
        dispatch_async(dispatch_get_main_queue()) {
            // make sure to put on the main queue to update UI!
        }
    }
}

If you are using @kayoslab version it has some wrong method names e.g.
func session(session: WCSession, didReceiveUserInfo userInfo: [String : AnyObject])
should be
func session(_ session: WCSession, didReceiveUserInfo userInfo: [String : Any] = [:]) for example

The easiest way to find such problems is to make Watch app call these and then run iOS App in debug. WCSession on phone often prints in console if there is something wrong. You can clearly see if you miss a delegate method. WCSession on watch app does not do it.

// handle receiving message data
DispatchQueue.main.async() {
// make sure to put on the main queue to update UI!
}

if this is on the watch side, how to access UI elements from here? Thanks!

Swift 5.0+ Version:

Both for iOS and WatchOS targets

import WatchConnectivity

class WatchSessionManager: NSObject, WCSessionDelegate {

    static let sharedManager = WatchSessionManager()
    private override init() {
        super.init()
    }

    private let session: WCSession? = WCSession.isSupported() ? WCSession.default : nil

    @available(iOS 9.3, *)
    func session(_ session: WCSession, activationDidCompleteWith activationState: WCSessionActivationState, error: Error?) {
    }

    #if os(iOS)
    func sessionDidBecomeInactive(_ session: WCSession) {
    }

    func sessionDidDeactivate(_ session: WCSession) {
    }
    #endif

    var validSession: WCSession? {

        // paired - the user has to have their device paired to the watch
        // watchAppInstalled - the user must have your watch app installed

        // Note: if the device is paired, but your watch app is not installed
        // consider prompting the user to install it for a better experience

        #if os(iOS)
            if let session = session, session.isPaired && session.isWatchAppInstalled {
                return session
            }
        #elseif os(watchOS)
            return session
        #endif
        
        return nil
    }

    func startSession() {
        session?.delegate = self
        session?.activate()
    }
}

// MARK: Application Context
// use when your app needs only the latest information
// if the data was not sent, it will be replaced
extension WatchSessionManager {

    // Sender
    func updateApplicationContext(applicationContext: [String : AnyObject]) throws {
        if let session = validSession {
            do {
                try session.updateApplicationContext(applicationContext)
            } catch let error {
                throw error
            }
        }
    }

    // Receiver
    func session(_ session: WCSession, didReceiveApplicationContext applicationContext: [String : Any]) {
        // handle receiving application context

        DispatchQueue.main.async {
            // make sure to put on the main queue to update UI!
        }
    }
}

// MARK: User Info
// use when your app needs all the data
// FIFO queue
extension WatchSessionManager {

    // Sender
    func transferUserInfo(userInfo: [String : AnyObject]) -> WCSessionUserInfoTransfer? {
        return validSession?.transferUserInfo(userInfo)
    }

    func session(_ session: WCSession, didFinish userInfoTransfer: WCSessionUserInfoTransfer, error: Error?) {
        // implement this on the sender if you need to confirm that
        // the user info did in fact transfer
    }

    // Receiver
    func session(_ session: WCSession, didReceiveUserInfo userInfo: [String : Any] = [:]) {
        // handle receiving user info
        DispatchQueue.main.async {
            // make sure to put on the main queue to update UI!
        }
    }

}

// MARK: Transfer File
extension WatchSessionManager {

    // Sender
    func transferFile(file: NSURL, metadata: [String : AnyObject]) -> WCSessionFileTransfer? {
        return validSession?.transferFile(file as URL, metadata: metadata)
    }

    func session(_ session: WCSession, didFinish fileTransfer: WCSessionFileTransfer, error: Error?) {
        // handle filed transfer completion
    }

    // Receiver
    func session(_ session: WCSession, didReceive file: WCSessionFile) {
        // handle receiving file
        DispatchQueue.main.async {
            // make sure to put on the main queue to update UI!
        }
    }
}


// MARK: Interactive Messaging
extension WatchSessionManager {

    // Live messaging! App has to be reachable
    private var validReachableSession: WCSession? {
        if let session = validSession , session.isReachable {
            return session
        }
        return nil
    }

    // Sender
    func sendMessage(message: [String : AnyObject],
                     replyHandler: (([String : Any]) -> Void)? = nil,
                     errorHandler: ((Error) -> Void)? = nil)
    {
        validReachableSession?.sendMessage(message, replyHandler: replyHandler, errorHandler: errorHandler)
    }

    func sendMessageData(data: Data,
                         replyHandler: ((Data) -> Void)? = nil,
                         errorHandler: ((Error) -> Void)? = nil)
    {
        validReachableSession?.sendMessageData(data, replyHandler: replyHandler, errorHandler: errorHandler)
    }

    // Receiver
    func session(_ session: WCSession, didReceiveMessage message: [String : Any], replyHandler: @escaping ([String : Any]) -> Void) {
        // handle receiving message
        DispatchQueue.main.async {
            // make sure to put on the main queue to update UI!
        }
    }

    func session(_ session: WCSession, didReceiveMessageData messageData: Data) {
        // handle receiving message data
        DispatchQueue.main.async {
            // make sure to put on the main queue to update UI!
        }
    }
}

also can be found in the gist

didReceiveApplicationContext not called

i have used startSession() in appdelegate
after i sent params on updateApplicationContext
and am not getting called didReceiveApplicationContext func

@Manikarthi-vaiha in the past didReceiveApplicationContext did not work properly on simulator (If your problem occured on simulator), please see the documentation for details.