NSKeyedUnarchiver.unarchiveTopLevelObjectWithData return 无

Question

我想将一组对象保存到 UserDefaults 中并加载回来。

尝试取消归档数据时，它总是 returns 没有..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
    }
}

正在解档数据：

func unarchiveData(data: Data) -> Any? {
    
    do {
        let unarchivedData = try NSKeyedUnarchiver.unarchiveTopLevelObjectWithData(data) as? [DbInsideLevel]
        return unarchivedData
    } catch {
        return nil
    }
}

保存到用户默认值：

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)
    }
}

Answer 1

你的问题是你使用了错误的方法来解码你的整数和布尔值。我还将实现所需的解码器而不是便利的初始化程序。

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 协议对您的自定义 classes/structures 进行编码和解码，并将它们保存为 UserDefaults 中的数据或保存为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，用户默认值有一个特定的方法来检索数据，称为 data(forKey:) 和 set(_ value: Any) 来保存你的数据：

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)
}

edit/update:

它也适用于 Codable 类型的数组：

let insideLevel = DbInsideLevel(idNum: 1, topicId: 2, tryCount: 3, score: 4, open: true, 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)
}

NSKeyedUnarchiver.unarchiveTopLevelObjectWithData return 无

NSKeyedUnarchiver.unarchiveTopLevelObjectWithData return nil

swift

nscoding

nskeyedarchiver

nskeyedunarchiver

nssecurecoding