如何在NSUserDefaults

Question

我尝试了几种不同的方法，我可以在NSUserDefaults中保存这个类。我不知道如何使用覆盖功能保存类。我该怎么做？

class CountryEntity: AnyObject {
private(set) var id: UInt = 0
private(set) var name = ""

override func cityData(data: Dictionary<String, AnyObject>!) {
    id = data.uint(key: "id")
    name = data.string(key: "name")
}

}

我试过这样但但它并没有帮助我

  private static var _selectedCountryEntity: AnyObject? = NSUserDefaults.standardUserDefaults().objectForKey(countryNameKey) {
    didSet {
        let savedData = NSKeyedArchiver.archivedDataWithRootObject(selectedCountryEntity as! NSData)

        NSUserDefaults.standardUserDefaults().setObject(savedData, forKey: countryNameKey)
        NSUserDefaults.standardUserDefaults().synchronize()
    }
}

static var selectedCountryEntity: AnyObject? {
    get {
        return _selectedCountryEntity
    }


      set {
//            if newValue != _selectedCountryTuple {
                _selectedCountryEntity = newValue
//            }
        }
    }

Answer 1

要在NSUserDefaults中存储自定义类，数据类型必须是NSObject的子类，并且应遵循NSCoding协议。

1）为您的数据创建自定义类

class CustomData: NSObject, NSCoding {
let name : String
let url : String
let desc : String

init(tuple : (String,String,String)){
    self.name = tuple.0
    self.url = tuple.1
    self.desc = tuple.2
}
func getName() -> String {
    return name
}
func getURL() -> String{
    return url
}
func getDescription() -> String {
    return desc
}
func getTuple() -> (String,String,String) {
    return (self.name,self.url,self.desc)
}

required init(coder aDecoder: NSCoder) {
    self.name = aDecoder.decodeObjectForKey("name") as! String
    self.url = aDecoder.decodeObjectForKey("url") as! String
    self.desc = aDecoder.decodeObjectForKey("desc") as! String
}

func encodeWithCoder(aCoder: NSCoder) {
    aCoder.encodeObject(self.name, forKey: "name")
    aCoder.encodeObject(self.url, forKey: "url")
    aCoder.encodeObject(self.desc, forKey: "desc")
} 
}

2）要保存数据，请使用以下功能：

func saveData()
    {
        let data  = NSKeyedArchiver.archivedDataWithRootObject(custom)
        let defaults = NSUserDefaults.standardUserDefaults()
        defaults.setObject(data, forKey:"customArray" )
    }

3）要检索：

if let data = NSUserDefaults().dataForKey("customArray"),
custom = NSKeyedUnarchiver.unarchiveObjectWithData(data) as? [CustomData] {
// Do something with retrieved data
    for item in custom {
    print(item)
    }
}

注意：这里我保存并检索自定义类对象的数组。