How to use NSUserDefaults to store an array of custom classes in Swift?

Question

I have a custom class called Person that stores various attributes about someone when they enter information.

class Person {

    // Person dictionary variable
    var name: String?
    var age: String?
    var html_url: String?

    init(json: NSDictionary) { // Dictionary object
        self.name = json["name"] as? String
        self.age = json["age"] as? String
        self.html_url = json["html_url"] as? String // Location of the JSON file
    }
}

Once the dictionary is created, it is then placed into an array. I am having problems saving the array into NSUserDefaults when a button is tapped.

personArray.append(newPerson) // newPerson = dictionary of attributes


NSUserDefaults.standardUserDefaults().setObject(personArray, forKey: "personArray")
        NSUserDefaults.standardUserDefaults().synchronize()

I have had a look at How to store custom objects in NSUserDefaults and Saving custom SWIFT class with NSCoding to UserDefaults but I have had no luck and am finding it hard to understand.

I when I simply try to save into NSUserDefaults, I am told the following:

Attempt to set a non-property-list object (
    "PersonApp.Person"
) as an NSUserDefaults/CFPreferences value for key personArray

Would anyone be able to help me actually save an array of custom objects (custom dictionaries) via NSUserDefaults?

Swift 3 but it is exactly what you are trying to do http://stackoverflow.com/a/37983027/2303865 — Leo Dabus, Jul 27 '16 at 08:55

score 19 · Accepted Answer · edited Feb 03 '18 at 16:53

Your Person class should look like this:

Swift 3:

class Person : NSObject, NSCoding{

    // Person dictionary variable
    var name: String?
    var age: String?
    var html_url: String?

    init(json: NSDictionary) { // Dictionary object
        self.name = json["name"] as? String
        self.age = json["age"] as? String
        self.html_url = json["html_url"] as? String // Location of the JSON file
    }

    required init?(coder aDecoder: NSCoder) {

        self.name = aDecoder.decodeObjectForKey("name") as? String;
        self.age = aDecoder.decodeObjectForKey("age") as? String;
        self.html_url = aDecoder.decodeObjectForKey("html") as? String;
    }

    func encodeWithCoder(aCoder: NSCoder) {
        aCoder.encodeObject(self.name, forKey: "name");
        aCoder.encodeObject(self.age, forKey: "age");
        aCoder.encodeObject(self.html_url, forKey: "html");
    }
}

And here you have an example of saving and retrieving the array from NSUserDefaults:

let p = Person()
p.name = "person1"
p.age = "12"
p.html_url = "www.google.ro"

let p2 = Person()
p2.name = "person2"
p2.age = "11"
p2.html_url = "www.google.ro"

let array = [p, p2]

let userDefaults = NSUserDefaults.standardUserDefaults()
userDefaults.setValue(NSKeyedArchiver.archivedDataWithRootObject(array), forKey: "persons")
userDefaults.synchronize()

let array : [Person]
array = NSKeyedUnarchiver.unarchiveObjectWithData(userDefaults.objectForKey("persons") as! NSData) as! [Person]
print("\(array[0].name)\(array[1].name)")

Swift 4:

class Person : NSObject, NSCoding{

    // Person dictionary variable
    var name: String?
    var age: String?
    var html_url: String?

    init(json: NSDictionary) { // Dictionary object
        self.name = json["name"] as? String
        self.age = json["age"] as? String
        self.html_url = json["html_url"] as? String // Location of the JSON file
    }

    required init?(coder aDecoder: NSCoder) {
        self.name = aDecoder.decodeObject(forKey: "name") as? String;
        self.age = aDecoder.decodeObject(forKey: "age") as? String;
        self.html_url = aDecoder.decodeObject(forKey: "html") as? String;
    }

    func encode(with aCoder: NSCoder) {
        aCoder.encode(self.name, forKey: "name");
        aCoder.encode(self.age, forKey: "age");
        aCoder.encode(self.html_url, forKey: "html");
    }
}

score 5 · Answer 2 · answered Jul 27 '16 at 08:46

5

You need to implement NSCoding protocol to store custom object into NSUserDefaults. Check out this example http://nshipster.com/nscoding/

answered Jul 27 '16 at 08:46

Muzahid

5,072
2
24
42

score 2 · Answer 3 · answered Jan 25 '18 at 09:28

2

Swift 4

Confirm codable protocol to your class
Serialize(Data) your object using JsonEncoder class
Now save your data to userDefaults

See this answer to get clear idea Save Array of Custom Swift object to userDefaults

answered Jan 25 '18 at 09:28

Kazi Abdullah Al Mamun

1,441
17
24

How to use NSUserDefaults to store an array of custom classes in Swift?

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