Share datas between two apps with iOS 8 App Groups (using NSUserDefaults)

Question

I wonder if we can share datas between apps with the new iOS 8 feature : App groups (using NSUserDefaults) - Or if App Groups only share datas between the main app and its e

Answer 1

App Groups no longer work in WatchOS2. You must use the watch connectivity Framework.

in your iOS App:

import UIKit
import WatchConnectivity

class ViewController: UIViewController, WCSessionDelegate {

override func viewDidLoad() {
    super.viewDidLoad()

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

    do {
        let applicationDict = ["key" : "value"]
        try WCSession.defaultSession().updateApplicationContext(applicationDict)
    } catch {
        // Handle errors here
    }
}

}

In your Watch OS2 App:

import WatchKit
import WatchConnectivity
import Foundation

class InterfaceController: WKInterfaceController, WCSessionDelegate {

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

Answer 2

Check out this thread on the Apple Developer Forums: https://devforums.apple.com/message/977151#977151

I believe that both instances need to use the group ID (initializing with initWithSuiteName:) or else they are reading/writing to different user defaults sets.

So your Swift code would change to:

var userDefaults = NSUserDefaults(suiteName: "group.com.company.myApp")
userDefaults.setBool(true, forKey: "Bool")
userDefaults.synchronize()