Swift使用@propertyWrapper

将可编码对象保存为UserDefault

@propertyWrapper
    struct UserDefault<T: Codable> {
        let key: String
        let defaultValue: T

        init(_ key: String, defaultValue: T) {
            self.key = key
            self.defaultValue = defaultValue
        }

        var wrappedValue: T {
            get {

                if let data = UserDefaults.standard.object(forKey: key) as? Data,
                    let user = try? JSONDecoder().decode(T.self, from: data) {
                    return user

                }

                return  defaultValue
            }
            set {
                if let encoded = try? JSONEncoder().encode(newValue) {
                    UserDefaults.standard.set(encoded, forKey: key)
                }
            }
        }
    }




enum GlobalSettings {

    @UserDefault("user", defaultValue: User(name:"",pass:"")) static var user: User
}

用户模型确认可编码

struct User:Codable {
    let name:String
    let pass:String
}

如何使用

//Set value 
 GlobalSettings.user = User(name: "Ahmed", pass: "Ahmed")

//GetValue
print(GlobalSettings.user)

保存:

NSUserDefaults *currentDefaults = [NSUserDefaults standardUserDefaults];
NSData *data = [NSKeyedArchiver archivedDataWithRootObject:yourObject];
[currentDefaults setObject:data forKey:@"yourKeyName"];

得到:

NSData *data = [currentDefaults objectForKey:@"yourKeyName"];
yourObjectType * token = [NSKeyedUnarchiver unarchiveObjectWithData:data];

为消除

[currentDefaults removeObjectForKey:@"yourKeyName"];

https://developer.apple.com/reference/foundation/userdefaults 默认对象必须是一个属性列表——也就是说，一个实例(对于集合来说，是实例的组合):NSData、NSString、NSNumber、NSDate、NSArray或NSDictionary。 如果你想存储任何其他类型的对象，你通常应该存档它来创建一个NSData的实例。有关详细信息，请参阅首选项和设置编程指南。

Swift 5: Codable协议可以用来代替NSKeyedArchiever。

struct User: Codable {
    let id: String
    let mail: String
    let fullName: String
}

Pref结构体是UserDefaults标准对象的自定义包装。

struct Pref {
    static let keyUser = "Pref.User"
    static var user: User? {
        get {
            if let data = UserDefaults.standard.object(forKey: keyUser) as? Data {
                do {
                    return try JSONDecoder().decode(User.self, from: data)
                } catch {
                    print("Error while decoding user data")
                }
            }
            return nil
        }
        set {
            if let newValue = newValue {
                do {
                    let data = try JSONEncoder().encode(newValue)
                    UserDefaults.standard.set(data, forKey: keyUser)
                } catch {
                    print("Error while encoding user data")
                }
            } else {
                UserDefaults.standard.removeObject(forKey: keyUser)
            }
        }
    }
}

所以你可以这样用:

Pref.user?.name = "John"

if let user = Pref.user {...

首先，rmaddy的答案(上面)是正确的:实现NSCoding没有帮助。然而，你需要实现NSCoding来使用NSKeyedArchiver和所有这些，所以这只是一个多步骤…通过NSData转换。

例子的方法

- (NSUserDefaults *) defaults {
    return [NSUserDefaults standardUserDefaults];
}

- (void) persistObj:(id)value forKey:(NSString *)key {
    [self.defaults setObject:value  forKey:key];
    [self.defaults synchronize];
}

- (void) persistObjAsData:(id)encodableObject forKey:(NSString *)key {
    NSData *data = [NSKeyedArchiver archivedDataWithRootObject:encodableObject];
    [self persistObj:data forKey:key];
}    

- (id) objectFromDataWithKey:(NSString*)key {
    NSData *data = [self.defaults objectForKey:key];
    return [NSKeyedUnarchiver unarchiveObjectWithData:data];
}

所以你可以把你的NSCoding对象包装在NSArray或NSDictionary中。

非常简单的方法

//MARK:- First you need to encoded your arr or what ever object you want to save in UserDefaults
//in my case i want to save Picture (NMutableArray) in the User Defaults in
//in this array some objects are UIImage & Strings

//first i have to encoded the NMutableArray 
let encodedData = NSKeyedArchiver.archivedData(withRootObject: yourArrayName)
//MARK:- Array save in UserDefaults
defaults.set(encodedData, forKey: "YourKeyName")

//MARK:- When you want to retreive data from UserDefaults
let decoded  = defaults.object(forKey: "YourKeyName") as! Data
yourArrayName = NSKeyedUnarchiver.unarchiveObject(with: decoded) as! NSMutableArray

//MARK: Enjoy this arrry "yourArrayName"