NSUserDefaults not saving in setter of class variable

Question

When I try to save to NSUserDefaults by adding a setter to my class variable (in this case the id and authToken variables, the values don't seem to be saved. When I run with a breakpoint on, the getter of id and authToken always return nil even after setting them with a value.

class CurrentUser {

    static let defaultInstance = CurrentUser()

    func updateUser(id id: String, authToken: String) {
        self.id = id
        self.authToken = authToken
    }

    var authToken: String? {
        get {
            if let authToken = NSUserDefaults.standardUserDefaults().objectForKey("userAuthToken") {
                return (authToken as! String)
            } else {
                return nil
            }
        }
        set {
            NSUserDefaults.standardUserDefaults().setObject(authToken, forKey: "userAuthToken")
            NSUserDefaults.standardUserDefaults().synchronize()
        }
    }

    var id: String? {
        get {
            if let id = NSUserDefaults.standardUserDefaults().objectForKey("userId") {
                return (id as! String)
            } else {
                return nil
            }
        }
        set {
            NSUserDefaults.standardUserDefaults().setObject(id, forKey: "userId")
            NSUserDefaults.standardUserDefaults().synchronize()
        }
    }
}

However, when I pull the lines out to the updateUser function (one level higher), all works as expected.

class CurrentUser {

    static let defaultInstance = CurrentUser()

    func updateUser(id id: String, authToken: String) {
        NSUserDefaults.standardUserDefaults().setObject(id, forKey: "userId")
        NSUserDefaults.standardUserDefaults().synchronize()

        NSUserDefaults.standardUserDefaults().setObject(authToken, forKey: "userAuthToken")
        NSUserDefaults.standardUserDefaults().synchronize()
    }

    var authToken: String? {
        get {
            if let authToken = NSUserDefaults.standardUserDefaults().objectForKey("userAuthToken") {
                return (authToken as! String)
            } else {
                return nil
            }
        }
    }

    var id: String? {
        get {
            if let id = NSUserDefaults.standardUserDefaults().objectForKey("userId") {
                return (id as! String)
            } else {
                return nil
            }
        }
    }
}

Why would this be? What am I missing? Does the { set } run on a different thread / mode where NSUserDefaults isn't accessible?

Why not load/save during object lifetime and keep them as simple instance variables? It's over-engineered. — Droppy, Jun 15 '16 at 14:51
Load the values during init and save during dealloc (or whatever its called in swift) and just keep the values as normal instance variables. Alternatively have explicit load/save methods. I doubt there is a need to sync to user-defaults every time they change. — Droppy, Jun 15 '16 at 14:57
You are using the variables as computed variables, so they don't actually have a value storage location. So when you do `NSUserDefaults.standardUserDefaults().setObject(id, forKey: "userId")`, `id` doesn't really exist... Change that to `NSUserDefaults.standardUserDefaults().setObject(newVal, forKey: "userId")` — Putz1103, Jun 15 '16 at 15:16

score 1 · Answer 1 · answered Jun 15 '16 at 15:11

1

You must use newValue inside set method, value is still nil, or use didSet and then you can use variable.

answered Jun 15 '16 at 15:11

tbilopavlovic

1,096
7
13

score 0 · Answer 2 · edited May 23 '17 at 11:58

0

As Alex said, you must use newValue in set method. Moreover, you can refer to this link for more detail: Store [String] in NSUserDefaults (Swift)

edited May 23 '17 at 11:58

Community

1
1

answered Jun 15 '16 at 15:36

Thanh Pham

75
2

NSUserDefaults not saving in setter of class variable

2 Answers2