Xcode 11 - SwiftUI Preview Dark Mode

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You should have something like this at the bottom of the file that's being previewed. This is what Xcode uses to generate the preview:

#if DEBUG
struct ContentView_Previews : PreviewProvider {
    static var previews: some View {
        ContentView()
    }
}
#endif

To change the preview to dark mode, you just need to specify a colorScheme:

static var previews: some View {
    ContentView().colorScheme(.dark)
}

Or, you can even chose to preview light and dark mode at the same time:

static var previews: some View {
    Group {
        ContentView().colorScheme(.light)
        ContentView().colorScheme(.dark)
    }
}

I recommend watching the Introducing SwiftUI session for more examples of SwiftUI and how powerful the previews can be.

Xcode 11: How to Preview Your App in Dark Mode Using SwiftUI, Xcode 11's Interface Builder also comes with a new feature for you to preview the screen in dark mode. Open any of your storyboards file, you� In Xcode 11, we can enable dark mode when the app is running by toggling the Environment Overrides at the bottom of the debug area like so. SwiftUI has the Canvas editor which generates live previews of the app as you are building your interface. Is there a way where we can toggle to dark mode in these previews? swiftui xcode11


TLDR:

Just add the .background(Color(UIColor.systemBackground)) and .environment(\.colorScheme, .dark) modifiers to the preview. For an explanation, examples, some modifications and a few tips to make it prettier and even simpler, please read the whole answer.

Explanation

I know this question is fairly old, but I've found a way that isn't too painful to implement and doesn't require any wrapping in a NavigationView. Furthermore, it also retains the correct behaviour of .previewLayout(.sizeThatFits).

Essentially, when you define a struct that conforms to PreviewProvider, you are only defining the content, but the background of the preview is managed for you by Xcode. Therefore, applying .environment(\.colorScheme, .dark) only changes the actual View to dark mode, but not the background. The reason NavigationView solves this issue is fairly simple - it adds a background to the view covering all of the preview's white background.

The fix itself is also fairly simple - all that you need to do is to add a background to your view in the preview. So for a simple view like this:

struct ExampleView: View {
    var body: some View {
        Text("Hello, World!")
    }
}

And a set of previews like this:

struct ExampleView_Previews: PreviewProvider {
    static var previews: some View {
        Group {
            ExampleView()
            ExampleView()
                .environment(\.colorScheme, .dark)
        }.previewLayout(.sizeThatFits)
    }
}

You get an output that looks like this:

In order to make the second preview appear on a dark background, add it by calling .background(Color(UIColor.systemBackground)) on the View:

struct ExampleView_Previews: PreviewProvider {
    static var previews: some View {
        Group {
            ExampleView()
            ExampleView()
                .background(Color(UIColor.systemBackground))
                .environment(\.colorScheme, .dark)
        }.previewLayout(.sizeThatFits)
    }
}

And you get two previews that look like this:

Extra options

There are several modifications you could make. Firstly, depending on the layer the cell will be on you can replace UIColor.systemBackground with UIColor.secondarySystemBackground or UIColor.tertiarySystemBackground. Read more about dynamic system colours in the human interface guidelines or the UI Element Colors portion of the UIColor developer documentation.

Lastly, if you're going to be using this often and don't want to write out the whole call to UIColor every time, it might be a good idea to create an extension on Color and define them as static variables there:

extension Color {
    static let systemBackground = Color(UIColor.systemBackground)
    static let secondarySystemBackground = Color(UIColor.secondarySystemBackground)
    static let tertiarySystemBackground = Color(UIColor.tertiarySystemBackground)
}

Then you can replace your calls to Color(UIColor.systemBackground) with a much nicer Color.systemBackground.

Xcode 11 - SwiftUI Preview Dark Mode, You should have something like this at the bottom of the file that's being previewed. This is what Xcode uses to generate the preview: The previews are by default in light mode in SwiftUI. This can be changed to dark mode using an environment setting. In this tutorial the preview will be altered to dark mode and dark mode will also be enabled in the iOS simulator. SwiftUI requires Xcode 11 and MacOS Catalina, which can be downloaded at the Apple developer portal.


Note: At the time of writing, you need a NavigationView as your top-level view for .environment(.colorScheme, .dark) to work. But then the (large) navigation bar covers the color blocks, so the two navigationBar modifiers make the bar smaller and hide it ... sort of. This might be a bug in Xcode.

Source - paid content

I tested this on Xcode 11.2.1 and the issue with the NavigationView still exists. The environment doesn't seem to change unless your entire view is wrapped in a NavigationView. You can try to hide the NavigationView using .navigationBarTitle("") & .navigationBarHidden(true).

Example:

struct ContentView: View {
    var body: some View {
        NavigationView {
            Text("Light vs Dark Mode")

            // Uncomment these lines if you don't want the navigation bar
            // .navigationBarTitle("")
            // .navigationBarHidden(true)

            // You can also apply a colorScheme here
            // which will impact how the view looks when the app
            // is launched on device. Regardless of the users theme settings
        }// .environment(\.colorScheme, .dark)
    }
}

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

        // If you want you can display both schemes in a group
        Group {
            ContentView()
            .environment(\.colorScheme, .light)

           ContentView()
           .environment(\.colorScheme, .dark)
       }
    }
}

Sample preview in dark mode:

SwiftUI Dark Mode Preview Tutorial, In this tutorial the preview will be altered to dark mode and dark mode will also be enabled in the iOS simulator . SwiftUI requires Xcode 11 and� Previewing Dark Mode. With Dark Mode in iOS 13, it’s always a good idea to double-check that your custom views are configured with dynamic colors or accommodate both light and dark appearance in some other way. An easy way to do this would be to use a For Each element to render a preview for each case in the Color Scheme enumeration:


SwiftUI Previews on macOS Catalina and Xcode 11, Previewing Dark Mode. With Dark Mode in iOS 13, it's always a good idea to double-check that your custom views are configured with dynamic� SwiftUI lets us detect whether dark mode or light mode is currently enabled using the colorScheme environment key. If you declare this using @Environment, you can refer to it in your views and they will automatically be reloaded when the color scheme changes.


Supporting Dark Mode in Your Interface, In macOS and iOS, users can choose to adopt a system-wide light or dark appearance. The dark appearance, known as Dark Mode, implements an interface style that many You configure custom color assets using Xcode's asset editor. Showing a group of views at once in Xcode Showing Dark Mode in a SwiftUI Preview. Now that we know how to display multiple previews at once it’s time to add a different state to the stage. The first state we’re adding is a preview that is using a Dark Mode environment so we can easily see both view states side by side.


Really Basic Dark Mode implementat…, Let's say I create a "SwiftUI View" file called "Test" #if DEBUG struct Test_Previews : PreviewProvider { static var previews: some View So the text on the Dark Mode Version will not show up since it is white on white. Booker, it will help you emulate dark mode simply until it is fixed in XCode Posted 11 months ago by. Xcode 11 - SwiftUI Preview Dark Mode. 12. Previewing ContentView with CoreData. 0. How to modify UIView properties for SwiftUI preview? Hot Network Questions