保存和检索UIColors到Core Data的最佳方法

Question

我可以想到几种方法,例如将每个颜色组件保存为浮点数,将数组保存为可转换的.保存图案图像的颜色可能会稍微复杂一点,但我想你可以将图像的名称保存为字符串并将其插入到创建代码中.

我是在正确的轨道上,否则一般来说最好和最有效率的是什么？

Answer 1

您可以转换UIColor为NSData然后存储它:

NSData *theData = [NSKeyedArchiver archivedDataWithRootObject:[UIColor blackColor]];

然后你可以将它转换回你的UIColor对象:

UIColor *theColor = (UIColor *)[NSKeyedUnarchiver unarchiveObjectWithData:theData];

UPD:

在关于存储数据的评论中回答您的问题,最简单的方法是将其存储在NSUserDefaults:

NSData *theData = [NSKeyedArchiver archivedDataWithRootObject:[UIColor blackColor]];
[[NSUserDefaults standardUserDefaults] setObject:theData forKey:@"myColor"];

然后检索它:

NSData *theData = [[NSUserDefaults standardUserDefaults] objectForKey:@"myColor"];
UIColor *theColor = (UIColor *)[NSKeyedUnarchiver unarchiveObjectWithData:theData];

Answer 2

我对Oleg的答案做了Swift 3版本，并对代码做了一些修改。

extension UIColor {
    class func color(withData data:Data) -> UIColor {
         return NSKeyedUnarchiver.unarchiveObject(with: data) as! UIColor
    }

    func encode() -> Data {
         return NSKeyedArchiver.archivedData(withRootObject: self)
    }
}

Swift 5版本的扩展

extension UIColor {

     class func color(data:Data) -> UIColor? {
          return try? NSKeyedUnarchiver.unarchiveTopLevelObjectWithData(data) as? UIColor
     }

     func encode() -> Data? {
          return try? NSKeyedArchiver.archivedData(withRootObject: self, requiringSecureCoding: false)
     }
}

用法

var myColor = UIColor.green
// Encoding the color to data
let myColorData = myColor.encode() // This can be saved into coredata/UserDefaulrs
let newColor = UIColor.color(withData: myColorData) // Converting back to UIColor from Data