swift - 使用字符串按键访问类扩展中结构中的静态变量

Question

目标是访问类扩展中结构中的静态变量:

extension UIColor {
    struct MyColors {
        static var happy: UIColor {
            return UIColor(hexString: "#FFB100")!
        }
        static var superHappy: UIColor {
            return UIColor(hexString: "#FFB101")!
        }

        static func withName(_ name: String = "") -> UIColor? {
            return UIColor.value(forKey: name) as? UIColor
        }
    }
}

// Produces error "this class is not key value coding-compliant for the key happy."
let myHappyColor = UIColor.MyColors.withName("happy")

我们可以在 PHP 中做类似的事情吗？

<?php
$prop = 'Name';
echo $obj->$prop;

Answer 1

您可以使用静态变量或枚举:

extension UIColor {

    // MARK: - Static

    static let myColor = UIColor(/* setup */)

或

enum MyColors {
case red

var color: UIColor {
switch self {
case .red:
return .red
}
}