Make SwiftyUserDefaults array accessible to iOS and watchOS app

Question

I am using the excellent SwiftyUserDefaults, a wrapper for NSUserDefaults with Swift to allow my app to persist a certain array of data, like so (lots of code removed to show just the important parts:

Working Code

 import SwiftyUserDefaults //The following is to show implementation in the parent iOS app. It works fine.
    class ViewController: UICollectionViewController { 

    var arrayToStore = DefaultsKey<NSArray>("arrayToStore")

    override func viewDidLoad() {
         Defaults[arrayToStore] = ["Element 1", "Element 2", "Element 3"]
        }
     func aFunctionThatNeedsToReadTheArray() {
         print([Defaults[arrayToStore]])
         }
    }

Research

The above works fine, but I also want the watchKit watchOS 2 app of this parent app to be able to read arrayToStore.

I did a bit of research and learned that Apple offers a solution for this, App Groups, which enables things in NSUserDefaults and other data storage means to be available across apps - in this case, between a parent iOS app and its companion watchOS watchKit app. EDIT: I LEARNED THANKS TO @PETAHCHRISTIAN THAT APP GROUPS DOES NOT WORK FOR WATCHOS 2. SO, WHAT OTHER MEANS ARE THERE?

Edit 2: Knowing that App Groups is not the solution, I did a bit more research and have determined that a possible solution is theWatchConnectivity framework. Is this correct, and if so, how can I use it to allow the watch app to have access to arrayToStore?

Question

However, my question is: How do I do this with SwiftyUserDefaults? I want to be able to have arrayToStore, an array in the parent app, readable by the watchOS 2 app via app groups (or another means, if there is a better way NOTE: Thanks to @PetahChristian I have learned that App Groups is not the way to do this. As such, how can I obtain the desired result of the watch app reading an array from the parent app via other means?).

What I am trying:

Enable app groups by, in "Capabilities" of the iOS app and watchKit app, turning on app groups and selecting the app group as shown in the answer here
In the app extension for the watchKit app, using print([Defaults[arrayToStore]]), resulting in "Use of unresolved identifier arrayToStore". The expected result is printing "Element 1", "Element 2", "Element 3"

@PetahChristian Thanks! If you post an answer of how to do this without app groups, I would be happy to accept it! — rocket101

user2529173 user2529173 · Accepted Answer · 2016-02-17T14:46:43

Use WatchConnectivity

You can send a request from the watch to the phone and then send something back to the watch. I would store the array in a Singleton, and then use the sendMessage function of WatchConnectivity. This function works even if the iPhone App is in Background.

Make SwiftyUserDefaults array accessible to iOS and watchOS app

1 Answers