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supportsMultipleWindows

A Boolean value that indicates whether the current platform supports opening multiple windows.

Declaration

var supportsMultipleWindows: Bool { get }

Discussion

Read this property from the environment to determine if your app can use the openWindow action to open new windows:

struct NewMailViewerButton: View {
    @Environment(\.supportsMultipleWindows) private var supportsMultipleWindows
    @Environment(\.openWindow) private var openWindow

    var body: some View {
        Button("Open New Window") {
            openWindow(id: "mail-viewer")
        }
        .disabled(!supportsMultipleWindows)
    }
}

The reported value depends on both the platform and how you configure your app:

In macOS, this property returns true for any app that uses the SwiftUI app lifecycle.
In iPadOS, this property returns true for any app that uses the SwiftUI app lifecycle and has the Information Property List key UIApplicationSupportsMultipleScenes set to true.
For all other platforms and configurations, the value returns false.

If the value is false and you try to open a window, SwiftUI ignores the action and logs a runtime error.

See Also

Opening windows