【发布时间】:2019-10-05 09:29:56
【问题描述】:
我将对象归档为数据并通过 NSKeyedArchiver 成功将其保存到磁盘,但是当我从 NSKeyedUnarchiver 获取数据时,我无法将其强制转换为 Object 类型。我尝试以多种方式做到这一点,但都没有成功。我希望你能帮我解决这个问题。这是我的代码:
类人:
class Person: NSObject, NSCoding {
func encode(with coder: NSCoder) {
coder.encode(firstName, forKey: "fisrtName")
coder.encode(lastName, forKey: "lastName")
coder.encode(age, forKey: "age")
}
required convenience init?(coder: NSCoder) {
guard let firstName = coder.decodeObject(forKey: "firstName") as? String,
let lastName = coder.decodeObject(forKey: "lastName") as? String else {
return nil
}
let age = coder.decodeInteger(forKey: "age")
self.init(firstname: firstName, lastName: lastName, age: age)
}
let firstName: String
let lastName: String
let age: Int
init(firstname: String, lastName: String, age: Int) {
self.firstName = firstname
self.lastName = lastName
self.age = age
}
}
将数据保存到磁盘:
let tuan = Person(firstname: "Tuan", lastName: "Hoang", age: 21)
let directoryPath = FileManager.default.urls(for: .documentDirectory, in: .userDomainMask)
let path = directoryPath.first!.appendingPathComponent("PersonData")
let savePath = path.appendingPathComponent("data.plist")
do {
try FileManager.default.createDirectory(at: path, withIntermediateDirectories: true, attributes: nil)
let data = try! NSKeyedArchiver.archivedData(withRootObject: tuan, requiringSecureCoding: false)
do {
try data.write(to: savePath)
print("Save data success")
} catch {
print("Cant save data to path + \(error.localizedDescription)")
}
} catch {
print("Cant not create directory + \(error.localizedDescription)")
}
加载数据:
do {
let savedData = try Data.init(contentsOf: savePath)
print("Get data success")
guard let data = try? NSKeyedUnarchiver.unarchivedObject(ofClass: Person.self, from: savedData) else {
print("Cant cast data")
return
}
print(data?.firstName)
} catch {
print("Cant get saved data ")
}
【问题讨论】:
-
不要
try?,抓住错误。 -
你需要抓住错误,看看问题出在哪里
-
@vadian 它说:无法读取数据,因为当我尝试 unarchiverObject 时它的格式不正确..
-
requiringSecureCoding: false这不是您问题的答案,但这是错误的。你应该采用 NSSecureCoding。 -
感谢@matt。我意识到必须将类 Person 扩展到 NSSecureCoding。我有一个错字..
标签: swift nscoding nskeyedarchiver nskeyedunarchiver