How to call a method defined on the iPhone from the Apple Watch

Question

Is there any way to call a defined method in a class on the iPhone from the Watchkit extension?

From my understanding currently one of the ways to communicate locally between Watch kit and the iPhone is by using NSUserDefaults, but are there other ways?

A simple example would be great.

Answer 1

For WatchOS2 openParentApplication is deprecated. The replacement for it is WCSession in Watch Connectivity Framework

First, initialize WCSession in both watch(ExtensionDelegate)& iOS(AppDelegate) with following code

if WCSession.isSupported() {
  let session = WCSession.defaultSession()
  session.delegate = self
  session.activateSession()
}

Send a notification from watch to Phone using

session.sendMessage(msg, replyHandler: { (responses) -> Void in
  print(responses)
 }) { (err) -> Void in
 print(err)
}

Handle the message in AppDelegate using

func session(_ session: WCSession,
             didReceiveMessage message: [String : AnyObject],
             replyHandler replyHandler: ([String : AnyObject]) -> Void)     
{
   //do something according to the message dictionary
   responseMessage = ["key" : "value"] //values for the replyHandler
   replyHandler(responseMessage)
}