[英]Using Codable to archiving with Swift
我正在尝试使用可编码的方式迅速地从iOS应用程序中的textFields中保存一些数据,但是当我定义用于归档xcode的函数时,它告诉我“无法推断出通用参数'Value'”。
我正在学习有关归档的信息,如果有人可以帮助我,我将非常感激。
这是我正在使用的代码
class ProfileViewController: UITableViewController {
var currentProfile: Profile?
@IBOutlet weak var name: UITextField!
@IBOutlet weak var surname: UITextField!
@IBAction func saveProfileButton(_ sender: Any) {
addCurrentProfile()
saveProfile()
}
func addCurrentProfile(){
currentProfile?.name = name.text ?? ""
currentProfile?.surname = surname.text ?? ""
}
struct Profile {
var name: String
var surname: String
enum CodingKeys: String, CodingKey {
case name
case surname
}
init(name:String, surname:String) {
self.name = name
self.surname = surname
}
func encode(to encoder: Encoder) throws {
var container = encoder.container(keyedBy: CodingKeys.self)
try container.encode(name, forKey: .name)
try container.encode(surname, forKey: .surname)
}
init(from decoder: Decoder) throws {
let container = try decoder.container(keyedBy: CodingKeys.self)
name = try container.decode(String.self, forKey: .name)
surname = try container.decode(String.self, forKey: .surname)
}
}
func saveProfile() {
do {
let data = try PropertyListEncoder().encode(currentProfile)
let success = NSKeyedArchiver.archiveRootObject(data, toFile: profile_data.path)
print(success ? "Successful save" : "Save Failed")
} catch {
print("Save Failed")
}
}
}
首先是使您的结构对Codable
协议进行确认,例如:
struct Profile:Codable {
var name: String
var surname: String
enum CodingKeys: String, CodingKey {
case name
case surname
}
init(name:String, surname:String) {
self.name = name
self.surname = surname
}
func encode(to encoder: Encoder) throws {
var container = encoder.container(keyedBy: CodingKeys.self)
try container.encode(name, forKey: .name)
try container.encode(surname, forKey: .surname)
}
init(from decoder: Decoder) throws {
let container = try decoder.container(keyedBy: CodingKeys.self)
name = try container.decode(String.self, forKey: .name)
surname = try container.decode(String.self, forKey: .surname)
}
}
然后,您可以使用PropertyListEncoder
来实现该对象,如下所示:
func saveProfile() {
do {
let data = try PropertyListEncoder().encode(currentProfile)
let success = NSKeyedArchiver.archiveRootObject(data, toFile: profile_data.path)
print(success ? "Successful save" : "Save Failed")
} catch {
print("Save Failed")
}
}
似乎这里有几个问题。 您的问题的直接答案:“无法推断出通用参数'值'”。 是:您忘记添加协议:
struct Profile: Codable {
...}
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