收纳套装<CustomObject>到用户默认值

Question

I have a custom class which I use as Set<ListItem> . I want to store this to userDefaults. However, I'm getting Attempt to set a non-property-list object as an NSUserDefaults error when trying to. I tried to change it to Array and then save it but still same error. I also tried Saving as data after saw some posts, again this gives me below error.

NSForwarding: warning: object 0x600003bf9a00 of class 'iTunes_Search_Me.ListItem' does not implement methodSignatureForSelector: -- trouble ahead

class ListItem: Codable ,Equatable, Hashable {
    let wrapperType, kind: String?
    let artistID, collectionID, trackID: Int?
    let artistName, collectionName, trackName: String?
    let trackViewURL: String?
    let artworkUrl30, artworkUrl60, artworkUrl100: String?
    let releaseDate: String?
    let primaryGenreName: String?
    var isSelected: Bool = false
    enum CodingKeys: String, CodingKey {
        case wrapperType, kind
        case artistID
        case collectionID
        case trackID
        case artistName, collectionName, trackName
        case trackViewURL
        case artworkUrl30, artworkUrl60, artworkUrl100, releaseDate, primaryGenreName
    }

    static func ==(lhs: ListItem, rhs: ListItem) -> Bool {
        return lhs.trackID == rhs.trackID
    }

    func hash(into hasher: inout Hasher) {
        hasher.combine(trackID)
    }
}

Attempt to set a non-property-list object as an NSUserDefaults

Answer 1

You can set the model to UserDefaults like this:

• Firstly you should create an instance of your model

• And then you can save your model to UserDefaults :

   let encoder = JSONEncoder() if let encoded = try? encoder.encode(listItemInstance) { let defaults = UserDefaults.standard defaults.set(encoded, forKey: "ListItemObject") }

  You can get model from UserDefaults like this

  if let savedItem = defaults.object(forKey: "ListItemObject") as? Data { let decoder = JSONDecoder() if let loadedItem = try? decoder.decode(ListItem.self, from: savedItem) { print(loadedItem) } }

Answer 2

You could try first setting up saved data:

struct saveData{
   static let encoded = "encoded"
}

Then save it under that key:

UserDefaults.standard.set(encoded as! Data, forKey: "encoded")

or try saving it as a string instead.