Conversion d'un objet de classe personnalisé en NSData

Voici un exemple simple pour vous:

//Custom class.
class Person: NSObject, NSCoding {
var name: String!
var age: Int!
required convenience init(coder decoder: NSCoder) {
self.init()
self.name = decoder.decodeObjectForKey("name") as! String
self.age = decoder.decodeObjectForKey("age") as! Int
}
convenience init(name: String, age: Int) {
self.init()
self.name = name
self.age = age
}
func encodeWithCoder(coder: NSCoder) {
if let name = name { coder.encodeObject(name, forKey: "name") }
if let age = age { coder.encodeObject(age, forKey: "age") }
}
}
//create an instance of your custom class.
var newPerson = [Person]()
//add some values into custom class.
newPerson.append(Person(name: "Leo", age: 45))
newPerson.append(Person(name: "Dharmesh", age: 25))
//store you class object into NSUserDefaults.
let personData = NSKeyedArchiver.archivedDataWithRootObject(newPerson)
NSUserDefaults().setObject(personData, forKey: "personData")
//get your object from NSUserDefaults.
if let loadedData = NSUserDefaults().dataForKey("personData") {
if let loadedPerson = NSKeyedUnarchiver.unarchiveObjectWithData(loadedData) as? [Person] {
loadedPerson[0].name   //"Leo"
        loadedPerson[0].age    //45
    }
}

Testé avec aire de jeux.

Espère que cette aide.

Cet exemple de code suivant est basé sur Richie Rich réponse (voir ci-dessus) et passe des tests dans cet environnement:

• Xcode version 9.1 (9B55)
• Swift version 4.0.2 (swiftlang-900.0.69.2 clang-900.0.38, Target: x86_64-apple-macosx10.9)
• MacBook Air (11-inch, Mid 2012) with macOS High Sierra (version 10.13.1)

//Foundation is required to NSObject and NSCoding
import Foundation
//A custom class called Person with two properties (a string name and an
//integer age), that is a subclass of NSObject and adopts NSCoding protocol.
class Person: NSObject, NSCoding {
var name: String!
var age: Int!
//The convenience initializer for class Person
  //Reference
  //https://developer.apple.com/library/content/documentation/Swift/Conceptual/Swift_Programming_Language/Initialization.html#//apple_ref/doc/uid/TP40014097-CH18-ID217
  convenience init(name: String, age: Int) {
//self.init() is the designated initializer for class Person.
    //Reference
    //https://developer.apple.com/library/content/documentation/Swift/Conceptual/Swift_Programming_Language/Initialization.html#//apple_ref/doc/uid/TP40014097-CH18-ID219
    self.init()
self.name = name
self.age = age
}
//The initializer init(coder:) is required by NSCoding protocol
  //Reference
  //https://developer.apple.com/documentation/foundation/nscoding
  //https://developer.apple.com/documentation/foundation/nscoding/1416145-init
  required convenience init(coder aDecoder: NSCoder) {
self.init()
//as! is a type casting operator
    //Reference
    //https://developer.apple.com/library/content/documentation/Swift/Conceptual/Swift_Programming_Language/Expressions.html#//apple_ref/doc/uid/TP40014097-CH32-ID388
    self.name = aDecoder.decodeObject(forKey: "name") as! String
self.age = aDecoder.decodeInteger(forKey: "age")
}
//The instance method encode(with:) is required by NSCoding protocol
  //Reference
  //https://developer.apple.com/documentation/foundation/nscoding
  //https://developer.apple.com/documentation/foundation/nscoding/1413933-encode
  func encode(with anEncoder: NSCoder) {
if let name = name {
anEncoder.encode(name, forKey: "name")
}
if let age = age {
anEncoder.encode(age, forKey: "age")
}
}
}
//Create an array (or, generally speaking, a collection) as a container to
//hold instances of our custom class type Person.
//Reference
//https://developer.apple.com/library/content/documentation/Swift/Conceptual/Swift_Programming_Language/CollectionTypes.html
var anArrayOfPersons = [Person]()
print(anArrayOfPersons.count) //0

//Add two instances into anArrayOfPersons.
//Reference
//https://developer.apple.com/documentation/swift/array
//https://developer.apple.com/documentation/swift/array/1538872-append
anArrayOfPersons.append(Person(name: "Cong", age: 33))
anArrayOfPersons.append(Person(name: "Sunny", age: 2))
//Archive anArrayOfPersons into NSData using NSKeyedArchiver.
//Reference
//https://developer.apple.com/documentation/foundation/nskeyedarchiver
//https://developer.apple.com/documentation/foundation/nskeyedarchiver/1413189-archiveddata
let dataToSave = NSKeyedArchiver.archivedData(withRootObject: anArrayOfPersons)
//Persist data. Storing anArrayOfPersons into UserDefaults as data.
//Reference
//https://developer.apple.com/documentation/foundation/userdefaults
//https://developer.apple.com/documentation/foundation/userdefaults/1414067-set
UserDefaults().set(dataToSave, forKey: "tagOfData")
//Take our stored data (in previous step) from UserDefaults using the key
//"personData". Optional binding is used to make sure the retrieved data is
//not nil.
//Reference
//https://developer.apple.com/documentation/foundation/userdefaults
//https://developer.apple.com/documentation/foundation/userdefaults/1409590-data
//https://developer.apple.com/library/content/documentation/Swift/Conceptual/Swift_Programming_Language/TheBasics.html#//apple_ref/doc/uid/TP40014097-CH5-ID333
if let dataRetrieved = UserDefaults().data(forKey: "tagOfData"),
//Decode our instance objects from the retrieved data
  //Reference
  //https://developer.apple.com/documentation/foundation/nskeyedunarchiver
  //https://developer.apple.com/documentation/foundation/nskeyedunarchiver/1413894-unarchiveobject
  let anArrayOfPersonsRetrieved = NSKeyedUnarchiver.unarchiveObject(with: dataRetrieved) as? [Person] {
//See how many bytes the data we retrieved has.
    print(dataRetrieved) //393 bytes

//See if the name and age properties are the same as what we stored.
    print(anArrayOfPersonsRetrieved[0].name) //"Cong"
    print(anArrayOfPersonsRetrieved[0].age)  //45
    print(anArrayOfPersonsRetrieved[1].name) //"Sunny"
    print(anArrayOfPersonsRetrieved[1].age)  //2
  }