Get 'NSInvalidArgumentException' 'Attempt to insert non-property list object when saving class type array to UserDefaults [duplicate] - swift

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 model using JSONEncoder and store that Data instance in UserDefaults and later decode using JSONDecoder.
struct JobCategory: Codable {
let id: Int
let name: String
}
// To store in UserDefaults
if let encoded = try? JSONEncoder().encode(category) {
UserDefaults.standard.set(encoded, forKey: UserDefaultsKeys.jobCategory.rawValue)
}
// Retrieve from UserDefaults
if let data = UserDefaults.standard.object(forKey: UserDefaultsKeys.jobCategory.rawValue) as? Data,
let category = try? JSONDecoder().decode(JobCategory.self, from: data) {
print(category.name)
}
Old Answer
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)

Answer 2

Update Swift 4, Xcode 10
I have written a struct around it for easy access.
//set, get & remove User own profile in cache
struct UserProfileCache {
static let key = "userProfileCache"
static func save(_ value: Profile!) {
UserDefaults.standard.set(try? PropertyListEncoder().encode(value), forKey: key)
}
static func get() -> Profile! {
var userData: Profile!
if let data = UserDefaults.standard.value(forKey: key) as? Data {
userData = try? PropertyListDecoder().decode(Profile.self, from: data)
return userData!
} else {
return userData
}
}
static func remove() {
UserDefaults.standard.removeObject(forKey: key)
}
}
Profile is a Json encoded object.
struct Profile: Codable {
let id: Int!
let firstName: String
let dob: String!
}
Usage:
//save details in user defaults...
UserProfileCache.save(profileDetails)
Hope that helps!!!
Thanks

Answer 3

Swift save Codable object to UserDefault with #propertyWrapper
#propertyWrapper
struct UserDefault<T: Codable> {
let key: String
let defaultValue: T
init(_ key: String, defaultValue: T) {
self.key = key
self.defaultValue = defaultValue
}
var wrappedValue: T {
get {
if let data = UserDefaults.standard.object(forKey: key) as? Data,
let user = try? JSONDecoder().decode(T.self, from: data) {
return user
}
return defaultValue
}
set {
if let encoded = try? JSONEncoder().encode(newValue) {
UserDefaults.standard.set(encoded, forKey: key)
}
}
}
}
enum GlobalSettings {
#UserDefault("user", defaultValue: User(name:"",pass:"")) static var user: User
}
Example User model confirm Codable
struct User:Codable {
let name:String
let pass:String
}
How to use it
//Set value
GlobalSettings.user = User(name: "Ahmed", pass: "Ahmed")
//GetValue
print(GlobalSettings.user)

Answer 4

Save dictionary Into userdefault
let data = NSKeyedArchiver.archivedData(withRootObject: DictionaryData)
UserDefaults.standard.set(data, forKey: kUserData)
Retrieving the dictionary
let outData = UserDefaults.standard.data(forKey: kUserData)
let dict = NSKeyedUnarchiver.unarchiveObject(with: outData!) as! NSDictionary

Answer 5

Based on Harjot Singh answer. I've used like this:
struct AppData {
static var myObject: MyObject? {
get {
if UserDefaults.standard.object(forKey: "UserLocationKey") != nil {
if let data = UserDefaults.standard.value(forKey: "UserLocationKey") as? Data {
let myObject = try? PropertyListDecoder().decode(MyObject.self, from: data)
return myObject!
}
}
return nil
}
set {
UserDefaults.standard.set(try? PropertyListEncoder().encode(newValue), forKey: "UserLocationKey")
}
}
}

Answer 6

Here's a UserDefaults extension to set and get a Codable object, and keep it human-readable in the plist (User Defaults) if you open it as a plain text file:
extension Encodable {
var asDictionary: [String: Any]? {
guard let data = try? JSONEncoder().encode(self) else { return nil }
return try? JSONSerialization.jsonObject(with: data) as? [String : Any]
}
}
extension Decodable {
init?(dictionary: [String: Any]) {
guard let data = try? JSONSerialization.data(withJSONObject: dictionary) else { return nil }
guard let object = try? JSONDecoder().decode(Self.self, from: data) else { return nil }
self = object
}
}
extension UserDefaults {
func setEncodableAsDictionary<T: Encodable>(_ encodable: T, for key: String) {
self.set(encodable.asDictionary, forKey: key)
}
func getDecodableFromDictionary<T: Decodable>(for key: String) -> T? {
guard let dictionary = self.dictionary(forKey: key) else {
return nil
}
return T(dictionary: dictionary)
}
}
If you want to also support array (of codables) to and from plist array, add the following to the extension:
extension UserDefaults {
func setEncodablesAsArrayOfDictionaries<T: Encodable>(_ encodables: Array<T>, for key: String) {
let arrayOfDictionaries = encodables.map({ $0.asDictionary })
self.set(arrayOfDictionaries, forKey: key)
}
func getDecodablesFromArrayOfDictionaries<T: Decodable>(for key: String) -> [T]? {
guard let arrayOfDictionaries = self.array(forKey: key) as? [[String: Any]] else {
return nil
}
return arrayOfDictionaries.compactMap({ T(dictionary: $0) })
}
}
If you don't care about plist being human-readable, it can be simply saved as Data (will look like random string if opened as plain text):
extension UserDefaults {
func setEncodable<T: Encodable>(_ encodable: T, for key: String) throws {
let data = try PropertyListEncoder().encode(encodable)
self.set(data, forKey: key)
}
func getDecodable<T: Decodable>(for key: String) -> T? {
guard
self.object(forKey: key) != nil,
let data = self.value(forKey: key) as? Data
else {
return nil
}
let obj = try? PropertyListDecoder().decode(T.self, from: data)
return obj
}
}
(With this second approach, you don't need the Encodable and Decodable extensions from the top)