Adding object to enum gives me error - ios

Question

I have an enum, and a variable that points to a certain object in the enum.
enum Collection {
case First, Second, Third, Fourth
}
var myCollection = Collection.Second
I want to pass myCollection to the NSUserDefaults. Here's what I did: (I hope viewDidLoad is the right place to put it.)
override func viewDidLoad() {
super.viewDidLoad()
// Save the sort by NSUserDefualt
let defaults = NSUserDefaults.standardUserDefaults()
defaults.setObject(self.myCollection, forKey: "myKey")
}
At the last line, I get the following error:
Cannot invoke 'setObject' with an argument list of type '(myViewController.Collection, forKey: String)'
What am I doing wrong, and how can I fix it?
Update
Does this make sense?
let defaults = NSUserDefaults.standardUserDefaults()
let defaultRawValue = defaults.integerForKey("myKey")
if defaultRawValue != nil {
defaults.setInteger(myCollection.rawValue, forKey: "myKey")
} else {
defaults.setInteger(1, forKey: "myKey")
}
myCollection = Collection(rawValue: defaultRawValue)!

Answer 1

NSUserDefaults can only take PropertyList: https://developer.apple.com/library/mac/documentation/Cocoa/Conceptual/PropertyLists/AboutPropertyLists/AboutPropertyLists.html
Try
enum Collection:Int{
case First=1, Second, Third, Fourth
}
var myCollection = Collection.Second
override func viewDidLoad() {
super.viewDidLoad()
let defaults = NSUserDefaults.standardUserDefaults()
let defaultRawValue = defaults.integerForKey("myKey")
if defaultRawValue > 0{
myCollection = Collection(rawValue: defaultRawValue)!
}
else
{
defaults.setInteger(1, forKey: "myKey")
myCollection = Collection(rawValue: 1)
}
}

Answer 2

The NSUserDefaults class provides convenience methods for accessing common types such as floats, doubles, integers, Booleans, and URLs. A default object must be a property list, that is, an instance of (or for collections a combination of instances of): NSData, NSString, NSNumber, NSDate, NSArray, or NSDictionary.
So, if you want to store your enum in NSUserDefaults, you use rawValue for your enum. Here I use String, like this:
enum Collection: String {
case First = "First"
case Second = "Second"
case Third = "Third"
case Fourth = "Fourth"
}
//create myCollection
var myCollection = Collection(rawValue: "Second")
And store it:
override func viewDidLoad() {
super.viewDidLoad()
// Save the sort by NSUserDefualt
let defaults = NSUserDefaults.standardUserDefaults()
defaults.setObject(self.myCollection.rawValue, forKey: "myKey")
}