问题描述
我正在尝试使用 NSUserDefaults 将数组保存到我的应用程序的核心数据中.我认为使用 NSUserDefaults 会很好,但问题是,无论我将创建默认值的代码放在何处,都会引发 SIGABRT 错误.
I am trying to use NSUserDefaults to save an array in to my app's core data. I thought it would be good to use NSUserDefaults but the problem is that wherever I put the code that creates the default it throws up the SIGABRT error.
这是创建默认值的代码:
Here is the code that creates the default:
let levelArrayDefault = NSUserDefaults.standardUserDefaults()
levelArrayDefault.setValue(levelsArray, forKey: "levelsArray")
levelArrayDefault.synchronize()
levelsArray 是一个 List 对象数组:
levelsArray is an array of List objects:
class List: NSObject, NSCoding {
// MARK: Properties
var name: String
var AnswersArray = [Answer]()
init?(name: String) {
// Initialize stored properties.
self.name = name
if name.isEmpty {
return nil
}
}
required init(coder decoder: NSCoder){
self.AnswersArray = (decoder.decodeObjectForKey("AA") as? [Answer])!
self.name = (decoder.decodeObjectForKey("name") as? String)!
}
func encodeWithCoder(coder: NSCoder) {
if let AnswersArray = AnswersArray { coder.encodeObject(AnswersArray, forKey: "AA") }
if let name = name { coder.encodeObject(name, forKey: "name") }
}
}
class Answer: NSObject, NSCoding {
var EnglishAnswer: String = ""
var ChineseAnswer: String = ""
init(newEng: String, newChi: String){
self.EnglishAnswer = newEng
self.ChineseAnswer = newChi
}
required init(coder decoder: NSCoder){
self.EnglishAnswer = (decoder.decodeObjectForKey("EnglishAnswer") as? String)!
self.ChineseAnswer = (decoder.decodeObjectForKey("ChineseAnswer") as? String)!
}
func encodeWithCoder(coder: NSCoder) {
if let EnglishAnswer = EnglishAnswer { coder.encodeObject(EnglishAnswer, forKey: "EnglishAnswer") }
if let ChineseAnswer = ChineseAnswer { coder.encodeObject(ChineseAnswer, forKey: "ChineseAnswer") }
}
}
如何阻止 SIGABRT 弹出并获取要存储的数组.非常感谢您的帮助.
How can I stop SIGABRT from popping up and get the array to be stored.Help would be much appreciated.
推荐答案
在存储到 NSUserDefaults 之前,您需要使用 NSKeyedArchiver 将其转换为 NSData,尝试如下:
You need to convert it to NSData using NSKeyedArchiver before storing it to NSUserDefaults, try like this:
更新:Xcode 11.4 • Swift 5.2 或更高版本
import UIKit
class ViewController: UIViewController {
override func viewDidLoad() {
super.viewDidLoad()
let list = List(name: "Student")
list.answers = [Answer(english: "english answer", chinese: "中文回答")]
let data = (try? NSKeyedArchiver.archivedData(withRootObject: [list], requiringSecureCoding: false)) ?? Data()
UserDefaults.standard.set(data, forKey: "listData")
guard
let loadedData = UserDefaults.standard.data(forKey: "listData"),
let loadedArray = try? NSKeyedUnarchiver.unarchiveTopLevelObjectWithData(loadedData) as? [List]
else { return }
print(loadedData.count)
print(loadedArray.first ?? "none")
print(loadedArray.first?.name ?? "no name")
print(loadedArray.first?.answers.first?.english ?? "no english")
print(loadedArray.first?.answers.first?.chinese ?? "no chinese")
}
}
class Answer: NSObject, NSCoding {
let english: String
let chinese: String
init(english: String, chinese: String) {
self.english = english
self.chinese = chinese
}
required init(coder decoder: NSCoder) {
self.english = decoder.decodeString(forKey: "english")
self.chinese = decoder.decodeString(forKey: "chinese")
}
func encode(with coder: NSCoder) {
coder.encode(english, forKey: "english")
coder.encode(chinese, forKey: "chinese")
}
}
class List: NSObject, NSCoding {
let name: String
fileprivate var data = Data()
var answers: [Answer] {
get {
(try? NSKeyedUnarchiver.unarchiveTopLevelObjectWithData(data)) as? [Answer] ?? []
}
set {
data = (try? NSKeyedArchiver.archivedData(withRootObject: newValue, requiringSecureCoding: false)) ?? Data()
}
}
init(name: String) {
self.name = name
}
required init(coder decoder: NSCoder) {
self.data = decoder.decodeData(forKey: "answersData")
self.name = decoder.decodeString(forKey: "name")
}
func encode(with coder: NSCoder) {
coder.encode(data, forKey: "answersData")
coder.encode(name, forKey: "name")
}
}
extension NSCoder {
func decodeString(forKey key: String) -> String {
return decodeObject(forKey: key) as? String ?? ""
}
func decodeData(forKey key: String) -> Data {
return decodeObject(forKey: key) as? Data ?? Data()
}
}
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