In SwiftUI, how can I access the current value of .foregroundColor and other modifiers inside my UIViewRepresentable?

Question

Given the following example code:

struct ActivityIndicatorView : UIViewRepresentable {
    var style: UIActivityIndicatorView.Style = .medium

    func makeUIView(context: UIViewRepresentableContext<ActivityIndicatorView>) -> UIActivityIndicatorView {
        return UIActivityIndicatorView(style: style)
    }

    func updateUIView(_ uiView: UIActivityIndicatorView, context: UIViewRepresentableContext<ActivityIndicatorView>) {
        uiView.color = UIColor.white // how would I set this to the current .foregroundColor value?
    }
}

How do I find out the current value of .foregroundColor(…) in order to render my UIView correctly?

I have read this question but that is from the perspective of inspecting the ModifiedContent from the outside, not the wrapped View.

Answer 1

There is no way to access the foreground colour but you can access the colour scheme and determine the colour of your activity indicator based on that:

struct ActivityIndicatorView : UIViewRepresentable {

   @Environment(\.colorScheme) var colorScheme: ColorScheme

    //...

    func updateUIView(_ uiView: UIActivityIndicatorView, context: UIViewRepresentableContext<ActivityIndicatorView>) {

        switch colorScheme {
        case .dark:
            uiView.color = .white
        case .light:
            uiView.color = .black
        }

    }
}

Answer 2

Agreed, this should be addressed. I took a stab at trying to pull this value out of the Environment and this is what I got. Looks like the EnvironmentKey exists, but is internal :(