Attempt to insert non-property list object when trying to save a custom object in Swift 3

Question

I have a simple object which conforms to the NSCoding protocol.

import Foundation  class JobCategory: NSObject, NSCoding {     var id: Int     var name: String     var URLString: String      init(id: Int, name: String, URLString: String) {         self.id = id         self.name = name         self.URLString = URLString     }      // MARK: - NSCoding     required init(coder aDecoder: NSCoder) {         id = aDecoder.decodeObject(forKey: "id") as? Int ?? aDecoder.decodeInteger(forKey: "id")         name = aDecoder.decodeObject(forKey: "name") as! String         URLString = aDecoder.decodeObject(forKey: "URLString") as! String     }      func encode(with aCoder: NSCoder) {         aCoder.encode(id, forKey: "id")         aCoder.encode(name, forKey: "name")         aCoder.encode(URLString, forKey: "URLString")     } } 

I'm trying to save an instance of it in UserDefaults but it keeps failing with the following error.

Terminating app due to uncaught exception 'NSInvalidArgumentException', reason: 'Attempt to insert non-property list object for key jobCategory'

This is the code where I'm saving in UserDefaults.

enum UserDefaultsKeys: String {     case jobCategory }  class ViewController: UIViewController {      @IBAction func didTapSaveButton(_ sender: UIButton) {         let category = JobCategory(id: 1, name: "Test Category", URLString: "http://www.example-job.com")          let userDefaults = UserDefaults.standard         userDefaults.set(category, forKey: UserDefaultsKeys.jobCategory.rawValue)         userDefaults.synchronize()     } } 

I replaced the enum value to key with a normal string but the same error still occurs. Any idea what's causing this?

Answer 1

You need to create Data instance from your JobCategory instance using archivedData(withRootObject:) and store that Data instance in UserDefaults and later unarchive using unarchiveTopLevelObjectWithData(_:), So try like this.

For Storing data in UserDefaults

let category = JobCategory(id: 1, name: "Test Category", URLString: "http://www.example-job.com") let encodedData = NSKeyedArchiver.archivedData(withRootObject: category, requiringSecureCoding: false) let userDefaults = UserDefaults.standard userDefaults.set(encodedData, forKey: UserDefaultsKeys.jobCategory.rawValue) 

For retrieving data from UserDefaults

let decoded  = UserDefaults.standard.object(forKey: UserDefaultsKeys.jobCategory.rawValue) as! Data let decodedTeams = NSKeyedUnarchiver.unarchiveTopLevelObjectWithData(decoded) as! JobCategory print(decodedTeams.name)