将 UIColor 保存到 NSUserDefaults 并从 NSUserDefaults 加载 [英] Saving UIColor to and loading from NSUserDefaults

问题描述

将 UIColor 保存到 NSUserDefaults 中，然后将其取回的最简单方法是什么?

What's the easiest way to save a UIColor into NSUserDefaults and then get it back out?

推荐答案

有了接受的答案，你会很快最终得到了很多 NSKeyed 档案 &取消归档您的所有代码.更简洁的解决方案是扩展 UserDefaults.这正是扩展的用途；UserDefaults 可能不了解 UIColor，因为 UIKit 和 Foundation 是不同的框架.

With the accepted answer, you'll quickly end up with a lot of NSKeyed archives & unarchives all over your code. A cleaner solution is to extend UserDefaults. This is exactly what extensions are for; UserDefaults probably doesn't know about UIColor as it is because UIKit and Foundation are different frameworks.

extension UserDefaults {

    func color(forKey key: String) -> UIColor? {
        var color: UIColor?
        if let colorData = data(forKey: key) {
            color = NSKeyedUnarchiver.unarchiveObject(with: colorData) as? UIColor
        }
        return color
    }

    func set(_ value: UIColor?, forKey key: String) {
        var colorData: Data?
        if let color = value {
            colorData = NSKeyedArchiver.archivedData(withRootObject: color)
        }
        set(colorData, forKey: key)
    }

}

斯威夫特 4.2

extension UserDefaults {

    func color(forKey key: String) -> UIColor? {

        guard let colorData = data(forKey: key) else { return nil }

        do {
            return try NSKeyedUnarchiver.unarchivedObject(ofClass: UIColor.self, from: colorData)
        } catch let error {
            print("color error (error.localizedDescription)")
            return nil
        }

    }

    func set(_ value: UIColor?, forKey key: String) {

        guard let color = value else { return }
        do {
            let data = try NSKeyedArchiver.archivedData(withRootObject: color, requiringSecureCoding: false)
            set(data, forKey: key)
        } catch let error {
            print("error color key data not saved (error.localizedDescription)")
        }

    }

}

用法

UserDefaults.standard.set(UIColor.white, forKey: "white")
let whiteColor = UserDefaults.standard.color(forKey: "white")

这也可以在带有类别的 Objective-C 中完成.

This can also be done in Objective-C with a category.

我在此处添加了 Swift 文件作为要点.

I've added the Swift file as a gist here.

这篇关于将 UIColor 保存到 NSUserDefaults 并从 NSUserDefaults 加载的文章就介绍到这了，希望我们推荐的答案对大家有所帮助，也希望大家多多支持IT屋！