我有个奇怪的问题。我将自定义类对象保存在NSUserDefaults
中,并且在检索对象的nil
变量的数据时得到int
。下面是自定义类
class User {
var name: String?
var user_id: Int?
var account_id: Int?
var location: String?
}
我把它保存为,
let defaults = NSUserDefaults.standardUserDefaults()
var data = NSKeyedArchiver.archivedDataWithRootObject([user]) // I can see the int values for the user objects here
defaults.setObject(data, forKey: "all_users")
检索数据为,
let defaults = NSUserDefaults.standardUserDefaults()
let data = defaults.dataForKey("all_users")
var users = [Users]()
if data != nil {
let userData = NSKeyedUnarchiver.unarchiveObjectWithData(data!) as! [Users]
for usr in userData {
print("\(usr.name!)") // Prints the name
print("\(usr.user_id!)") // Nil value here
users.append(usr)
}
}
我完全不知道这种行为的原因。
最佳答案
没有属性列表项的自定义类需要符合NSCoding才能保存在NSUserDefaults中。
以下是符合NSCoding的指南:http://nshipster.com/nscoding/
您需要这两个功能:
init(coder decoder: NSCoder) {
self.name = decoder.decodeObjectForKey("name") as String
self.user_id = decoder.decodeIntegerForKey("user_id")
self.account_id = decoder.decodeIntegerForKey("account_id")
self.location = decoder.decodeObjectForKey("self.location") as String
}
func encodeWithCoder(coder: NSCoder) {
coder.encodeObject(self.name, forKey: "name")
coder.encodeInt(self.user_id, forKey: "user_id")
coder.encodeInt(account_id, forKey: "account_id")
coder.encodeObject(self.location, forKey: "location")
}
关于ios - iOS:自定义对象的int变量在NSUserDefaults中返回nil,我们在Stack Overflow上找到一个类似的问题:https://stackoverflow.com/questions/38513791/