Transfer Data From Apple Watch To iPhone in Swift [closed]

Question

I have been trying for multiple hours to find a way to send a global variable from the Apple Watch to the iPhone.

There are a lot of questions abut transferring data from iPhone to Apple Watch but not vice versa in Swift 3.

This is not a duplicate because I want to transfer data from the Apple Watch to iPhone, not vice Versa.

How can I do this?

Answer 1

Transferring data from Apple Watch to iPhone is very similar to vice versa.

For global variable you probably should use updateApplicationContext() of WCSession:

let session = WCSession.default()
if session.activationState == .activated {
    session.updateApplicationContext(["my_global": g_myGlobal])
}

On the iPhone you should assign delegate to the default WCSession and activate it. In the WCSessionDelegate, implement the following method:

func session(_ session: WCSession, didReceiveApplicationContext applicationContext: [String : Any]) {
    let receivedGlobal = applicationContext["my_global"] as? TypeOfTheGlobal
}

---

Alternatively you can use sendMessage(_:replyHandler:errorHandler:) but this will require iPhone to be reachable.

In general I would recommend you to follow Zak Kautz advice and read about WatchConnectivity. This is the most common way to communicate between watch and phone.