Unrecognized selector sent to instance while archiving data (NSCoding)

You need to implement NSCoding protocol inside your Furniture object:

- (void)encodeWithCoder:(NSCoder *)aCoder{  [aCoder encodeObject:self.yourpoperty forKey:@"PROPERTY_KEY"];}-(id)initWithCoder:(NSCoder *)aDecoder{  if(self = [super init]){    self.yourpoperty = [aDecoder decodeObjectForKey:@"PROPERTY_KEY"];  }  return self;}

Basically you specify what should be written (encoded) and read from a file (decoded). Usually for each property you want to store in a file, you make same as I did here in an example.

You'll need to implement NSCoding - here is an example with an object called SNStock that has two string properties, ticker and name:

import Foundationclass SNStock: NSObject, NSCoding{  let ticker: NSString  let name: NSString  init(ticker: NSString, name: NSString)  {    self.ticker = ticker    self.name = name  }  //MARK: NSCoding  required init(coder aDecoder: NSCoder) {    self.ticker = aDecoder.decodeObjectForKey("ticker") as! NSString    self.name = aDecoder.decodeObjectForKey("name") as! NSString  }  func encodeWithCoder(aCoder: NSCoder) {    aCoder.encodeObject(ticker, forKey: "ticker")    aCoder.encodeObject(name, forKey: "name")  }  //MARK: NSObjectProtocol  override func isEqual(object: AnyObject?) -> Bool {    if let object = object as? SNStock {      return self.ticker == object.ticker &&        self.name == object.name    } else {      return false    }  }  override var hash: Int {    return ticker.hashValue  }}

For Swift 4.1 (tested code)

import UIKitimport SwiftyJSONclass UserObject: NSObject, NSCoding {    var username: String? = ""    var userID: String? = ""    var user_email: String? = ""    var name: String? = ""    var age: String? = ""    var gender: String? = ""    override init() {        super.init()    }    init(dictionary: JSON) {        //User data initialize...        username = dictionary["username"].stringValue        userID = dictionary["iUserID"].stringValue        user_email = dictionary["email"].stringValue        name = dictionary["name"].stringValue        age = dictionary["age"].stringValue        gender = dictionary["gender"].stringValue    }    required public init(coder aDecoder: NSCoder) {        username = aDecoder.decodeObject(forKey: "username") as? String        userID = aDecoder.decodeObject(forKey: "iUserID") as? String        user_email = aDecoder.decodeObject(forKey: "email") as? String        name = aDecoder.decodeObject(forKey: "name") as? String        age = aDecoder.decodeObject(forKey: "age") as? String        gender = aDecoder.decodeObject(forKey: "gender") as? String    }    func encode(with aCoder: NSCoder) {        aCoder.encode(username, forKey: "username")        aCoder.encode(userID, forKey: "iUserID")        aCoder.encode(user_email, forKey: "email")        aCoder.encode(name, forKey: "name")        aCoder.encode(age, forKey: "age")        aCoder.encode(gender, forKey: "gender")    }}

Note : NSCoding protocol is important