尝试在Swift 3中保存自定义对象时尝试插入非属性列表对象

Question

我有一个符合NSCoding协议的简单对象。

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")
    }
}

我正在尝试在UserDefaults中保存它的一个实例，但它仍然失败，出现以下错误。

由于未捕获的异常'NSInvalidArgumentException'而终止应用程序，原因：'尝试为关键jobCategory插入非属性列表对象'

这是我在UserDefaults中保存的代码。

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()
    }
}

我用一个普通的字符串将枚举值替换为key，但仍然会出现相同的错误。知道是什么导致了这个吗？

Answer 1

你需要使用Data从你的JobCategory实例创建NSKeyedArchiver.archivedData(withRootObject:)实例并将Data实例存储在UserDefaults中，然后使用NSKeyedUnarchiver.unarchiveObject(with:)解压缩，所以试试这样。

用于在UserDefaults中存储数据

let category = JobCategory(id: 1, name: "Test Category", URLString: "http://www.example-job.com")
let encodedData = NSKeyedArchiver.archivedData(withRootObject: category)
let userDefaults = UserDefaults.standard
userDefaults.set(encodedData, forKey: UserDefaultsKeys.jobCategory.rawValue)

用于从UserDefaults检索数据

let decoded  = UserDefaults.standard.object(forKey: UserDefaultsKeys.jobCategory.rawValue) as! Data
let decodedTeams = NSKeyedUnarchiver.unarchiveObject(with: decoded) as! JobCategory
print(decodedTeams.name)

Answer 2

更新Swift 4，Xcode 10

我已经围绕它编写了一个结构，以便于访问。

//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是一个Json编码对象。

struct Profile: Codable {
let id: Int!
let firstName: String
let dob: String!
}

用法：

//save details in user defaults...
UserProfileCache.save(profileDetails)

希望有所帮助！

谢谢

Answer 3

将字典保存到userdefault

let data = NSKeyedArchiver.archivedData(withRootObject: DictionaryData)
UserDefaults.standard.set(data, forKey: kUserData)

检索字典

let outData = UserDefaults.standard.data(forKey: kUserData)
let dict = NSKeyedUnarchiver.unarchiveObject(with: outData!)as!NSDictionary