How to handle custom colors for Dark Mode in Swift

Question

Here is how I'm currently handling UI Element Colors for Dark Mode with a fallback for older operating systems.

extension UIColor {
    class var mySystemBackground: UIColor {
        if #available(iOS 13, *) {
            return .systemBackground
        } else {
            return .white
        }
    }
}

On this casesystemBackground knows when it's in Dark Mode and when it's in Light Mode and it changes accordingly. I would like to do something similar using custom colors.

For instance I have a custom Yellow color that I'm currently using throughout my app and I would like to provide a different color for when in Dark Mode.

Here is the code I'm thinking...

extension UIColor{
    class var mySystemYellowColor: UIColor {
        // default light-color 
        var myYellow = UIColor(red: 254/255, green: 219/255, blue: 2/255, alpha: 1.0) /* #fedb02 */

        if #available(iOS 13.0, *) {  

            if traitCollection.userInterfaceStyle == .light {
                return myYellow
            } else {
                // color for dark mode in iOS 13.0
                myYellow = UIColor(red: 242/255, green: 125/255, blue: 0/255, alpha: 1.0) /* #f27d00 */
            }
            return myYellow

        } else {
            return myYellow
        }
    }
}

Is this an approachable way to handle custom colors for Dark Mode in iOS13 with a fallback for other operating systems?

Answer 1

Create the colors in the asset catalog.

Colors in the asset catalog can be created for different Appearances and can be accessed with the UIColor(named:) API

Please see Supporting Dark Mode in Your Interface