How to preview your layout in light and dark mode

Paul Hudson @twostraws September 3rd 2021

Updated for Xcode 13.0

Most of Apple’s operating systems support both light and dark mode user interfaces, so it’s no surprise that SwiftUI has support for this functionality built right in.

Even better, once you’ve designed your interface Xcode allows you to preview your layouts in either appearance by setting the ‌preferredColorScheme() modifier value in your preview.

For example, this shows a preview using dark mode:

struct ContentView_Previews: PreviewProvider {
    static var previews: some View {
        ContentView().preferredColorScheme(.dark)
    }
}

An Xcode Preview in Dark Mode.

If you want to see both light and dark mode side by side, place multiple previews in a group, like this:

struct ContentView_Previews: PreviewProvider {
    static var previews: some View {
        ForEach(ColorScheme.allCases, id: \.self) { 
             ContentView().preferredColorScheme($0)
        }
    }
}

Xcode showing Previews in Light and Dark Mode.

For a little extra conciseness, you can boil that down even further:

struct ContentView_Previews: PreviewProvider {
    static var previews: some View {
        ForEach(ColorScheme.allCases, id: \.self, content: ContentView().preferredColorScheme)
    }
}

Tip: If your preview is zoomed right in, you should either scroll around or zoom out to the other previews.