问题描述
我想将对象数组保存到UserDefaults中,然后重新加载。
当尝试取消归档数据时,它总是返回nil ..有什么想法吗?
这是我的对象
class DbInsideLevel: NSObject,NSSecureCoding {
static var supportsSecureCoding: Bool {
return true
}
let idNum: Int!
var topicId: Int = 0
var tryCount: Int = 0
var score: Int = 0
var isOpen: Bool = false
var lastPlayedDate: Date?
init(idNum: Int,topicId: Int,tryCount: Int = 0,score: Int = 0,open: Bool,lastPlayedDate: Date?) {
self.idNum = idNum
self.topicId = topicId
self.tryCount = tryCount
self.score = score
self.isOpen = open
self.lastPlayedDate = lastPlayedDate
}
convenience required init?(coder: NSCoder) {
guard
let idNum = coder.decodeObject(forKey: "idNum") as? Int,let topicId = coder.decodeObject(forKey: "topicId") as? Int,let tryCount = coder.decodeObject(forKey: "tryCount") as? Int,let score = coder.decodeObject(forKey: "score") as? Int,let open = coder.decodeObject(forKey: "isOpen") as? Bool,let lastPlayed = coder.decodeObject(forKey: "lastPlayedDate") as? Date
else {
return nil
}
self.init(idNum: idNum,topicId: topicId,tryCount: tryCount,score: score,open: open,lastPlayedDate: lastPlayed)
}
func encode(with coder: NSCoder) {
coder.encode(idNum,forKey: "idNum")
coder.encode(topicId,forKey: "topicId")
coder.encode(tryCount,forKey: "tryCount")
coder.encode(score,forKey: "score")
coder.encode(isOpen,forKey: "isOpen")
coder.encode(lastPlayedDate,forKey: "lastPlayedDate")
}
func update(score: Int) {
// Update score if necessary
if score > self.score {
self.score = score
}
// Increment try count
self.tryCount = self.tryCount + 1
}
}
归档数据:
func archiveData(with object: Any,to key: String) -> Data? {
do {
guard
let data = try? NSKeyedArchiver.archivedData(withRootObject: object,requiringSecureCoding: true) else {
return nil
}
return data
}
}
取消存档数据:
func unarchiveData(data: Data) -> Any? {
do {
let unarchivedData = try NSKeyedUnarchiver.unarchivetopLevelObjectWithData(data) as? [DbInsideLevel]
return unarchivedData
} catch {
return nil
}
}
class func americanSaveContext(data: [DbInsideLevel]) {
if data.count != 0 {
if let archived = MainDb.sharedInstance.archiveData(with: data,to: AppConstants.Keys.UserDefaults.American) {
MainDb.sharedInstance.dataStore(data: archived)
}
}
}
从UserDefaults加载:
class func americanDataRetrive(topicId: Int) -> [DbInsideLevel]? {
if let data = MainDb.sharedInstance.dataRetrive() {
let unarchived = MainDb.sharedInstance.unarchiveData(data: data) as! [DbInsideLevel]
return unarchived
}
return nil
}
用于保存/加载的UserDefaults助手:
extension MainDb {
// MARK: - UserDefaults helpers
func dataRetrive() -> Data? {
let defaults = UserDefaults.standard
return defaults.value(forKey: AppConstants.Keys.UserDefaults.American) as? Data
}
func dataStore(data: Data) {
let defaults = UserDefaults.standard
defaults.setValue(data,forKey: AppConstants.Keys.UserDefaults.American)
}
func dataReset() {
let defaults = UserDefaults.standard
defaults.removeObject(forKey: AppConstants.Keys.UserDefaults.American)
}
}
解决方法
您的问题是,您使用错误的方法来解码整数和布尔值。我还将实现所需的解码器,而不是便捷的初始化程序。
required init(coder decoder: NSCoder) {
self.idNum = decoder.decodeInteger(forKey: "idNum")
self.topicId = decoder.decodeInteger(forKey: "topicId")
self.tryCount = decoder.decodeInteger(forKey: "tryCount")
self.score = decoder.decodeInteger(forKey: "score")
self.isOpen = decoder.decodeBool(forKey: "isOpen")
self.lastPlayedDate = decoder.decodeObject(forKey: "lastPlayedDate") as? Date
}
请注意,您还可以使用Swift 4或更高版本的Codable协议对自定义类/结构进行编码和解码,并将它们另存为UserDefaults中的数据或应用程序支持文件夹中的plist文件。最后但并非最不重要的一点是,不要使用setValue和value(forKey :)来保存和检索数据,用户默认值具有一种用于检索数据的特定方法,称为data(forKey:)
和set(_ value: Any)
以保留数据:>
extension UserDefaults {
func decode<T: Decodable>(_ type: T.Type,forKey defaultName: String) throws -> T {
try JSONDecoder().decode(T.self,from: data(forKey: defaultName) ?? .init())
}
func encode<T: Encodable>(_ value: T,forKey defaultName: String) throws {
try set(JSONEncoder().encode(value),forKey: defaultName)
}
}
class DbInsideLevel: Codable {
let idNum: Int!
var topicId: Int = 0
var tryCount: Int = 0
var score: Int = 0
var isOpen: Bool = false
var lastPlayedDate: Date?
init(idNum: Int,topicId: Int,tryCount: Int = 0,score: Int = 0,open: Bool,lastPlayedDate: Date?) {
self.idNum = idNum
self.topicId = topicId
self.tryCount = tryCount
self.score = score
self.isOpen = open
self.lastPlayedDate = lastPlayedDate
}
func update(score: Int) {
if score > self.score {
self.score = score
}
self.tryCount = self.tryCount + 1
}
}
游乐场测试
let insideLevel = DbInsideLevel(idNum: 1,topicId: 2,tryCount: 3,score: 4,open: true,lastPlayedDate: Date())
do {
try UserDefaults.standard.encode(insideLevel,forKey: "insideLevel")
let decodedLevel = try UserDefaults.standard.decode(DbInsideLevel.self,forKey: "insideLevel")
print("decodedLevel idNum",decodedLevel.idNum) // decodedLevel idNum Optional(1)
} catch {
print(error)
}
编辑/更新:
它也适用于Codable类型的数组:
let insideLevel = DbInsideLevel(idNum: 1,lastPlayedDate: Date())
do {
try UserDefaults.standard.encode([insideLevel],forKey: "insideLevels")
let decodedLevel = try UserDefaults.standard.decode([DbInsideLevel].self,forKey: "insideLevels")
print("decodedLevel idNum",decodedLevel.first?.idNum) // decodedLevel idNum Optional(1)
} catch {
print(error)
}