How can I change a SwiftUI Color to UIColor?

I'm trying to change a SwiftUI Color to an instance of UIColor.

I can easily get the RGBA from the UIColor, but I don't know how to get the "Color" instance to return the corresponding RGB and opacity values.

@EnvironmentObject var colorStore: ColorStore

init() {
    let red =     //get red value from colorStore.primaryThemeColor
    let green = //get green value from colorStore.primaryThemeColor
    let blue =   //get blue value from colorStore.primaryThemeColor
    let alpha = //get alpha value from colorStore.primaryThemeColor
    
    let color = UIColor(red: red, green: green, blue: blue, alpha: alpha)
    UINavigationBar.appearance().tintColor = color
}

...or maybe there is a better way to accomplish what I am looking for?

SwiftUI 2.0

There is a new initializer that takes a Color and returns a UIColor for iOS or NSColor for macOS now. So:

iOS

UIColor(Color.red)

macOS

NSColor(Color.red)

Core Graphics

UIColor(Color.red).cgColor /* For iOS */
NSColor(Color.red).cgColor /* For macOS */

If you are looking for color components, you can find a helpful extensions here in this answer

Also, check out How to convert UIColor to SwiftUI‘s Color

How about this solution?

extension Color {
 
    func uiColor() -> UIColor {

        if #available(iOS 14.0, *) {
            return UIColor(self)
        }

        let components = self.components()
        return UIColor(red: components.r, green: components.g, blue: components.b, alpha: components.a)
    }

    private func components() -> (r: CGFloat, g: CGFloat, b: CGFloat, a: CGFloat) {

        let scanner = Scanner(string: self.description.trimmingCharacters(in: CharacterSet.alphanumerics.inverted))
        var hexNumber: UInt64 = 0
        var r: CGFloat = 0.0, g: CGFloat = 0.0, b: CGFloat = 0.0, a: CGFloat = 0.0

        let result = scanner.scanHexInt64(&hexNumber)
        if result {
            r = CGFloat((hexNumber & 0xff000000) >> 24) / 255
            g = CGFloat((hexNumber & 0x00ff0000) >> 16) / 255
            b = CGFloat((hexNumber & 0x0000ff00) >> 8) / 255
            a = CGFloat(hexNumber & 0x000000ff) / 255
        }
        return (r, g, b, a)
    }
}

Usage:

let uiColor = myColor.uiColor()

It's a bit of a hack, but it's at least something until we get a valid method for this. The key here is self.description which gives a hexadecimal description of the color (if it's not dynamic I should add). And the rest is just calculations to get the color components, and create a UIColor.