如何使用 UserDefaults 保存 UIColor? [英] How do I save a UIColor with UserDefaults?

问题描述

我正在尝试对我的代码进行编程，以便如果用户按下夜间按钮，背景将变为黑色，如果用户关闭应用程序则保持黑色.(白天模式也是如此.)

I'm trying to program my code so that if the user presses the Night Button the background will turn black and stay black if the user closes the app. (Same goes for day mode.)

请注意:我已经对按钮进行了编码，当他们按下它时，所有场景都会更改为该模式.

Please note: I already coded buttons and when they press it, all of the scenes change to that mode.

这是我需要保存背景颜色的代码:(我在两个 if 语句中都需要它)

Here's my code where I'm going going to need the background color to be saved: (I need it in both if statements)

if GlobalData.dayBool == true && GlobalData.night == false {
    backgroundColor = GlobalData.dayColor 
}

if GlobalData.nightBool == true && GlobalData.dayBool == false {
    backgroundColor = GlobalData.nightColor 
}

我的昼夜颜色:

struct GlobalData {
    static var score = 0
    static var dayColor = UIColor(red:0.93, green:0.93, blue:0.93, alpha:1.0)
    static var nightColor = UIColor(red:0.10, green:0.10, blue:0.10, alpha:1.0)  
    static var dayBool = true
    static var nightBool = true
}

推荐答案

Swift 5.2 或更高版本

请注意，这只会将 RGBA CGFloat 值保存为属性列表中的数据.这将使用 32 字节(原始数据)而不是在使用标准方法和 NSKeyedUnarchiver (NSCoding) 时所需的 424 字节:

Note that this will save only the RGBA CGFloat values as Data inside the property list. This will use 32 bytes (raw data) instead of 424 bytes needed when using the standard approach with NSKeyedUnarchiver (NSCoding):

extension Numeric {
    var data: Data {
        var bytes = self
        return Data(bytes: &bytes, count: MemoryLayout<Self>.size)
    }
}

---

extension Data {
    func object<T>() -> T { withUnsafeBytes{$0.load(as: T.self)} }
    var color: UIColor { .init(data: self) }
}

---

extension UIColor {
    convenience init(data: Data) {
        let size = MemoryLayout<CGFloat>.size
        self.init(red:   data.subdata(in: size*0..<size*1).object(),
                  green: data.subdata(in: size*1..<size*2).object(),
                  blue:  data.subdata(in: size*2..<size*3).object(),
                  alpha: data.subdata(in: size*3..<size*4).object())
    }
    var rgba: (red: CGFloat, green: CGFloat, blue: CGFloat, alpha: CGFloat)? {
        var (red, green, blue, alpha): (CGFloat, CGFloat, CGFloat, CGFloat) = (0, 0, 0, 0)
        return getRed(&red, green: &green, blue: &blue, alpha: &alpha) ?
        (red, green, blue, alpha) : nil
    }
    var data: Data? {
        guard let rgba = rgba else { return nil }
        return rgba.red.data + rgba.green.data + rgba.blue.data + rgba.alpha.data
    }
}

---

extension UserDefaults {
    func set(_ color: UIColor?, forKey defaultName: String) {
        guard let data = color?.data else {
            removeObject(forKey: defaultName)
            return
        }
        set(data, forKey: defaultName)
    }
    func color(forKey defaultName: String) -> UIColor? {
        data(forKey: defaultName)?.color
    }
}

---

extension UserDefaults {
    var backgroundColor: UIColor? {
        get { color(forKey: "backgroundColor") }
        set { set(newValue, forKey: "backgroundColor") }
    }
}

---

UserDefaults.standard.backgroundColor = .red
UserDefaults.standard.backgroundColor  // r 1.0 g 0.0 b 0.0 a 1.0

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