将具有NSCoding的自定义SWIFT类保存到UserDefaults

Question

我目前正在尝试将自定义Swift类保存到NSUserDefaults。下面是我的游乐场代码：

import Foundation 

class Blog : NSObject, NSCoding { 

    var blogName: String? 

    override init() {} 

    required init(coder aDecoder: NSCoder) { 
     if let blogName = aDecoder.decodeObjectForKey("blogName") as? String { 
      self.blogName = blogName 
     } 
    } 

    func encodeWithCoder(aCoder: NSCoder) { 
     if let blogName = self.blogName { 
      aCoder.encodeObject(blogName, forKey: "blogName") 
     } 
    } 

} 

var blog = Blog() 
blog.blogName = "My Blog" 

let ud = NSUserDefaults.standardUserDefaults()  
ud.setObject(blog, forKey: "blog") 

当我运行代码，我得到错误“的执行被中断，原因是：信号SIGABRT”在最后一行（ud.setObject ...）

相同的代码在消息“属性列表对于格式无效：200（属性列表不能包含CFType类型的对象）时无效”

任何人都可以帮忙吗？我在Maverick上使用Xcode 6.0.1。谢谢。

Answer 1

正如@丹蟠龙建议我回答我的问题：

这是现在的工作代码：

注意：对于代码在Playgrounds中工作，不需要对类名进行Demangling。

import Foundation 

class Blog : NSObject, NSCoding { 

    var blogName: String? 

    override init() {} 

    required init(coder aDecoder: NSCoder) { 
     if let blogName = aDecoder.decodeObjectForKey("blogName") as? String { 
      self.blogName = blogName 
     } 
    } 

    func encodeWithCoder(aCoder: NSCoder) { 
     if let blogName = self.blogName { 
      aCoder.encodeObject(blogName, forKey: "blogName") 
     } 
    } 

} 

let ud = NSUserDefaults.standardUserDefaults() 

var blog = Blog() 
blog.blogName = "My Blog" 

ud.setObject(NSKeyedArchiver.archivedDataWithRootObject(blog), forKey: "blog") 

if let data = ud.objectForKey("blog") as? NSData { 
    let unarc = NSKeyedUnarchiver(forReadingWithData: data) 
    let newBlog = unarc.decodeObjectForKey("root") as Blog 
} 

Answer 2

第一个问题是，你必须确保具有非错位类名：

@objc(Blog) 
class Blog : NSObject, NSCoding { 

然后，你必须以编码对象（进入一个NSData），然后才能将其存储到用户的默认值：

ud.setObject(NSKeyedArchiver.archivedDataWithRootObject(blog), forKey: "blog") 

同样，恢复则需要解除封存对象：

if let data = ud.objectForKey("blog") as? NSData { 
    let unarc = NSKeyedUnarchiver(forReadingWithData: data) 
    unarc.setClass(Blog.self, forClassName: "Blog") 
    let blog = unarc.decodeObjectForKey("root") 
} 

无TE，如果你不是在操场上使用它是因为你不必用手注册类稍微简单：

if let data = ud.objectForKey("blog") as? NSData { 
    let blog = NSKeyedUnarchiver.unarchiveObjectWithData(data) 
} 

Answer 3

测试与雨燕2.1 &的Xcode 7.1.1

如果您不需要BLOGNAME是一个可选的（我认为你不这样做），我会建议一个稍微不同的实现：

class Blog : NSObject, NSCoding { 

    var blogName: String 

    // designated initializer 
    // 
    // ensures you'll never create a Blog object without giving it a name 
    // unless you would need that for some reason? 
    // 
    // also : I would not override the init method of NSObject 

    init(blogName: String) { 
     self.blogName = blogName 

     super.init()  // call NSObject's init method 
    } 

    func encodeWithCoder(aCoder: NSCoder) { 
     aCoder.encodeObject(blogName, forKey: "blogName") 
    } 

    required convenience init?(coder aDecoder: NSCoder) { 
     // decoding could fail, for example when no Blog was saved before calling decode 
     guard let unarchivedBlogName = aDecoder.decodeObjectForKey("blogName") as? String 
      else { 
       // option 1 : return an default Blog 
       self.init(blogName: "unnamed") 
       return 

       // option 2 : return nil, and handle the error at higher level 
     } 

     // convenience init must call the designated init 
     self.init(blogName: unarchivedBlogName) 
    } 
} 

测试代码看起来是这样的：

let blog = Blog(blogName: "My Blog") 

    // save 
    let ud = NSUserDefaults.standardUserDefaults() 
    ud.setObject(NSKeyedArchiver.archivedDataWithRootObject(blog), forKey: "blog") 
    ud.synchronize() 

    // restore 
    guard let decodedNSData = ud.objectForKey("blog") as? NSData, 
    let someBlog = NSKeyedUnarchiver.unarchiveObjectWithData(decodedNSData) as? Blog 
     else { 
      print("Failed") 
      return 
    } 

    print("loaded blog with name : \(someBlog.blogName)") 

最后，我想指出的是，使用NSKeyedArchiver并将您的自定义对象数组直接保存到文件会更容易，而不是使用NSUserDefaults。你可以在我的回答here中找到更多关于他们的区别。

Answer 4

我，我用我的结构是比较容易

struct UserDefaults { 
    private static let kUserInfo = "kUserInformation" 

    var UserInformation: DataUserInformation? { 
     get { 
      guard let user = NSUserDefaults.standardUserDefaults().objectForKey(UserDefaults.kUserInfo) as? DataUserInformation else { 
       return nil 
      } 
      return user 
     } 
     set { 

      NSUserDefaults.standardUserDefaults().setObject(newValue, forKey: UserDefaults.kUserInfo) 
      NSUserDefaults.standardUserDefaults().synchronize() 
     } 
    } 

} 



Use : let userinfo = UserDefaults.UserInformation 

Answer 5

不能存储直接在属性列表的对象;您只能存储单个字符串或其他基本类型（整数等）。），所以你需要把它存储为单个字符串，如：

override init() { 
    } 

    required public init(coder decoder: NSCoder) { 
     func decode(obj:AnyObject) -> AnyObject? { 
     return decoder.decodeObjectForKey(String(obj)) 
     } 

     self.login = decode(login) as! String 
     self.password = decode(password) as! String 
     self.firstname = decode(firstname) as! String 
     self.surname = decode(surname) as! String 
     self.icon = decode(icon) as! UIImage 
    } 

    public func encodeWithCoder(coder: NSCoder) { 
     func encode(obj:AnyObject) { 
     coder.encodeObject(obj, forKey:String(obj)) 
     } 

     encode(login) 
     encode(password) 
     encode(firstname) 
     encode(surname) 
     encode(icon) 
    } 

Answer 6

斯威夫特3版本：

class CustomClass: NSObject, NSCoding { 

var name = "" 
var isActive = false 

init(name: String, isActive: Bool) { 
    self.name = name 
    self.isActive = isActive 
} 

// MARK: NSCoding 

required convenience init?(coder decoder: NSCoder) { 
    guard let name = decoder.decodeObject(forKey: "name") as? String, 
     let isActive = decoder.decodeObject(forKey: "isActive") as? Bool 
     else { return nil } 

    self.init(name: name, isActive: isActive) 
} 

func encode(with coder: NSCoder) { 
    coder.encode(self.name, forKey: "name") 
    coder.encode(self.isActive, forKey: "isActive") 
} 

}

Answer 7

在斯威夫特4，你有一个新的协议，取代了NSCoding协议。它被称为Codable，它支持类和Swift类型！ （枚举，结构）：

struct CustomStruct: Codable { 
    let name: String 
    let isActive: Bool 
}