I have custom class named User
witch conforms to NSCoding protocol. But when I'm trying to store it in NSUserDefaults I get this error:
Property list invalid for format: 200
(property lists cannot contain objects of type 'CFType')
And this warning:
NSForwarding: warning: object 0x7f816a681110 of class 'Shikimori.User'
does not implement methodSignatureForSelector: -- trouble ahead
Unrecognized selector -[Shikimori.User _copyDescription]
User
class:
class User: NSCoding {
private enum CoderKeys: String {
case ID = "user.id"
case Username = "user.username"
case Email = "user.email"
case Avatar = "user.avatar"
}
let id: Int
let username: String
let email: String
let avatar: String
init(id: Int, username: String, email: String, avatar: String) {
self.id = id
self.username = username
self.email = email
self.avatar = avatar
}
required init(coder aDecoder: NSCoder) {
id = aDecoder.decodeIntegerForKey(CoderKeys.ID.rawValue)
username = aDecoder.decodeObjectForKey(CoderKeys.Username.rawValue) as String
email = aDecoder.decodeObjectForKey(CoderKeys.Email.rawValue) as String
avatar = aDecoder.decodeObjectForKey(CoderKeys.Avatar.rawValue) as String
}
func encodeWithCoder(aCoder: NSCoder) {
aCoder.encodeInteger(id, forKey: CoderKeys.ID.rawValue)
aCoder.encodeObject(username as NSString, forKey: CoderKeys.Username.rawValue)
aCoder.encodeObject(email as NSString, forKey: CoderKeys.Email.rawValue)
aCoder.encodeObject(avatar as NSString, forKey: CoderKeys.Avatar.rawValue)
}
}
Update Saving code:
let userKeyForDefaults = "apimanager.user"
let defaults = NSUserDefaults.standardUserDefaults()
defaults.setObject(user, forKey: self.userKeyForDefaults)
NSUserDefaults
does not support all objects, just things like NSString
, NSDictionary
, and most importantly, NSData
. This is where the NSCoding
protocol comes in handy. It allows us to transform custom objects into chunks of NSData
. To do this, use the NSKeyedArchiver
class to turn a custom object that conforms to NSCoding
to the equivalent NSData
let obj = User()
let data = NSKeyedArchiver. archivedDataWithRootObject(obj)
/// Now you can store data
The docs can be found here and the method you are looking for is
class func archivedDataWithRootObject(_ rootObject: AnyObject) -> NSData
To get things out of NSUserDefaults
, use the "inverse" class, NSKeyedUnarchiver
. Its appropriate method is as follows
class func unarchiveObjectWithData(_ data: NSData) -> AnyObject?
Here is a sample.
let data = NSUserDefaults.standardUserDefaults().objectForKey("somekey")
let obj = NSKeyedUnarchiver. unarchiveObjectWithData(data) as User?
Note: I may have mixed up some optionals, but you get the jist. The documentation for NSKeyedUnarchiver
can be found here.
Edit: Fixing the OP's problem was as simple as correctly using NSKeyedArchiver
and subclassing NSObject
.
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