Xcode 11 — SwiftUI's dark mode setup

Question

Okay. I know this shouldn\'t be rocket science. I can\'t seem to get dark mode working and I\'ve read the documentation a few times. Hoping someone can pick out what I\'m

Answer 1

This is probably a bug in this beta release of Xcode 11. I tried the dark mode feature in a UIKit application and it is working perfectly using UIColor but the same color wouldn’t work using Color in SwiftUI. Hopefully this will be fixed in the next releases.

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Update: This issue was fixed with Xcode 11 beta 3.

Answer 2

You can change color scheme in your preview

struct ContentView_Previews : PreviewProvider {
    static var previews: some View {
        ContentView().environment(\.colorScheme, .dark)
    }
}

upd: and you can create any previews for light and dark modes

struct ContentView_Previews : PreviewProvider {
    static var previews: some View {
        Group {
            ContentView()
            ContentView().environment(\.colorScheme, .dark)
        }
    }
}

Answer 3

A working (but quite verbose) solution we can use to overcome this current limitation is to extend Color with methods parameterised with the current color scheme as follows:

import SwiftUI

extension Color {

    static let lightBackgroundColor = Color(white: 1.0)

    static let darkBackgroundColor = Color(white: 0.0)

    static func backgroundColor(for colorScheme: ColorScheme) -> Color {
        if colorScheme == .dark {
            return darkBackgroundColor
        } else {
            return lightBackgroundColor
        }
    }
}

And in the views where you need to access these colors you would add an environment property for the color scheme and use it to retrieve the dynamic color:

import SwiftUI

struct ColoredView : View {

    @Environment(\.colorScheme) var colorScheme: ColorScheme

    var body: some View {
        Rectangle().fill(Color.backgroundColor(for: self.colorScheme))
    }
}

These colours defined in code work for Xcode previews as well as the simulator.