尝试在 Swift 3中保存自定义对象时插入非属性列表对象

我有一个简单的对象，符合 NSCoding协议。

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")
}
}

我试图在 UserDefaults中保存它的一个实例，但是它总是出现以下错误。

终止应用程序由于未捕获异常“ NSInvalidArgumentException”，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()
}
}

我用一个普通字符串替换了键的枚举值，但是仍然会出现同样的错误。知道是什么引起的吗？

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最佳答案

You need to create Data instance from your JobCategory model using JSONEncoder and store that Data instance in UserDefaults and later decode using JSONDecoder.

struct JobCategory: Codable {
let id: Int
let name: String
}


// To store in UserDefaults
if let encoded = try? JSONEncoder().encode(category) {
UserDefaults.standard.set(encoded, forKey: UserDefaultsKeys.jobCategory.rawValue)
}


// Retrieve from UserDefaults
if let data = UserDefaults.standard.object(forKey: UserDefaultsKeys.jobCategory.rawValue) as? Data,
let category = try? JSONDecoder().decode(JobCategory.self, from: data) {
print(category.name)
}

Old Answer

You need to create Data instance from your JobCategory instance using archivedData(withRootObject:) and store that Data instance in UserDefaults and later unarchive using unarchiveTopLevelObjectWithData(_:), So try like this.

For Storing data in UserDefaults

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

For retrieving data from UserDefaults

let decoded  = UserDefaults.standard.object(forKey: UserDefaultsKeys.jobCategory.rawValue) as! Data
let decodedTeams = NSKeyedUnarchiver.unarchiveTopLevelObjectWithData(decoded) as! JobCategory
print(decodedTeams.name)
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Save dictionary Into userdefault

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

Retrieving the dictionary

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

Update Swift 4, Xcode 10

I have written a struct around it for easy access.

//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 is a Json encoded object.

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

Usage:

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

Hope that helps!!!

Thanks

小开

Based on Harjot Singh answer. I've used like this:

struct AppData {


static var myObject: MyObject? {


get {
if UserDefaults.standard.object(forKey: "UserLocationKey") != nil {
if let data = UserDefaults.standard.value(forKey: "UserLocationKey") as? Data {
let myObject = try? PropertyListDecoder().decode(MyObject.self, from: data)
return myObject!
}
}
return nil
}


set {
UserDefaults.standard.set(try? PropertyListEncoder().encode(newValue), forKey: "UserLocationKey")
}


}
}
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Swift save Codable object to UserDefault with @propertyWrapper

@propertyWrapper
struct UserDefault<T: Codable> {
let key: String
let defaultValue: T


init(_ key: String, defaultValue: T) {
self.key = key
self.defaultValue = defaultValue
}


var wrappedValue: T {
get {


if let data = UserDefaults.standard.object(forKey: key) as? Data,
let user = try? JSONDecoder().decode(T.self, from: data) {
return user


}


return  defaultValue
}
set {
if let encoded = try? JSONEncoder().encode(newValue) {
UserDefaults.standard.set(encoded, forKey: key)
}
}
}
}








enum GlobalSettings {


@UserDefault("user", defaultValue: User(name:"",pass:"")) static var user: User
}

Example User model confirm Codable

struct User:Codable {
let name:String
let pass:String
}

How to use it

//Set value
GlobalSettings.user = User(name: "Ahmed", pass: "Ahmed")


//GetValue
print(GlobalSettings.user)
小开

Here's a UserDefaults extension to set and get a Codable object, and keep it human-readable in the plist (User Defaults) if you open it as a plain text file:

extension Encodable {
var asDictionary: [String: Any]? {
guard let data = try? JSONEncoder().encode(self) else { return nil }
return try? JSONSerialization.jsonObject(with: data) as? [String : Any]
}
}


extension Decodable {
init?(dictionary: [String: Any]) {
guard let data = try? JSONSerialization.data(withJSONObject: dictionary) else { return nil }
guard let object = try? JSONDecoder().decode(Self.self, from: data) else { return nil }
self = object
}
}


extension UserDefaults {
func setEncodableAsDictionary<T: Encodable>(_ encodable: T, for key: String) {
self.set(encodable.asDictionary, forKey: key)
}


func getDecodableFromDictionary<T: Decodable>(for key: String) -> T? {
guard let dictionary = self.dictionary(forKey: key) else {
return nil
}
return T(dictionary: dictionary)
}
}

If you want to also support array (of codables) to and from plist array, add the following to the extension:

extension UserDefaults {
func setEncodablesAsArrayOfDictionaries<T: Encodable>(_ encodables: Array<T>, for key: String) {
let arrayOfDictionaries = encodables.map({ $0.asDictionary })
self.set(arrayOfDictionaries, forKey: key)
}


func getDecodablesFromArrayOfDictionaries<T: Decodable>(for key: String) -> [T]? {
guard let arrayOfDictionaries = self.array(forKey: key) as? [[String: Any]] else {
return nil
}
return arrayOfDictionaries.compactMap({ T(dictionary: $0) })
}
}

If you don't care about plist being human-readable, it can be simply saved as Data (will look like random string if opened as plain text):

extension UserDefaults {
func setEncodable<T: Encodable>(_ encodable: T, for key: String) throws {
let data = try PropertyListEncoder().encode(encodable)
self.set(data, forKey: key)
}


func getDecodable<T: Decodable>(for key: String) -> T? {
guard
self.object(forKey: key) != nil,
let data = self.value(forKey: key) as? Data
else {
return nil
}


let obj = try? PropertyListDecoder().decode(T.self, from: data)
return obj
}
}

(With this second approach, you don't need the Encodable and Decodable extensions from the top)


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