How to save struct to NSUserDefaults in Swift 2.0

Question

I have a struct named Jarand I would like to save an array of them to NSUserDefaults. Here is the jar struct code:

struct Jar {

    let name: String
    let amount: Int

    init(name: String, amount: Int){
        self.name = name
        self.amount = amount
    }
}

I belive that I will need to convert this to an NSObject to be able to save it. (Because you can't save a struct directly to NSUserDefaults). My questions are: How do I convert an array of structs to an NSObject? and How to convert an NSObject back at an array of structs.

Firstly, storing data like that in NSUserDefaults isn't really what it is for, but if you must then look into NSKeyedArchiver. — Paulw11, Sep 20 '15 at 00:13
Not directly. You will need to use an NSManagedObject subclass. Xcode can generate all of the code for to create this object and then you can use it instead of your struct. — Paulw11, Sep 20 '15 at 00:20
For more help see this link http://stackoverflow.com/questions/38406457/how-to-save-an-array-of-custom-struct-to-nsuserdefault-with-swift/41296754#41296754 — Vijayvir Sing Pantlia, Dec 23 '16 at 07:17

score 9 · Answer 1 · answered Mar 24 '16 at 14:41

This solution is inspired by @Duncan C. I wrote it more familiar way as we do in case Custom Class encoding and decoding.

public struct IRDriver {

  public var name: String?
  public var amount: Int?

  public init() {

  }

  // Decode
  public init(dictionary: Dictionary<String, AnyObject>){
    name = dictionary["name"] as? String
    amount = dictionary["amount"] as? Int
  }

  // Encode
  public func encode() -> Dictionary<String, AnyObject> {

    var dictionary : Dictionary = Dictionary<String, AnyObject>()
    dictionary["name"] = name
    dictionary["amount"] = amount
    return dictionary
  }

}

Can you please tell me how to use this to convert struct to dictionary and dictionary to struct ? — Bhavin Ramani, Jan 12 '17 at 06:28

score 3 · Answer 2 · answered Sep 20 '15 at 01:30

For saving to user defaults you have a couple of options: Have the object conform to NSCoding, or implement methods that convert it to/from an NSDictionary, and save that.

Something like this:

func dictionaryFromJar() -> NSDictionary
{
   let dictionary: [AnyObject: AnyObject] = ["name": name, "amount": amount]
   return dictionary
}

I think the automatic bridging between Swift dictionaries and NSDictionary would work here, but I'm not positive. My swift is getting a little rusty. :(

Non-class type '' cannot conform to class protocol 'NSCoding' — farzadshbfn, Apr 27 '16 at 08:47

How to save struct to NSUserDefaults in Swift 2.0

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