Single Instance Windows on visionOS

You could either disable "Enable Multiple Windows" , use a State variable or check if the Window is already open programmatically.

Hi @benfromchicago ,

If I want to have a window with only one instance (say, a Menu or similar), how can I ensure that each time I call openWindow, the same window appears, and a new one is not created?

This is detailed in the WindowGroup documentation, so please take a look! I'll review the important parts below.

How openWindow works:

openWindow allows you to pass an id, value, or both to indicate which scene to open.

The id parameter always takes a string. For a WindowGroup, if you pass just an id, the system creates a new window for the group. If the WindowGroup presents data, the system provides the default value or nil to the window’s root view. Ex:

WindowGroup(id: "firstWindow"){
 ContentView()
 }

In ContentView, call openWindow(id: "firstWindow")

The value parameter takes in a variable of any type, so long as that type matches one specified in the WindowGroup. This allows you to provide a value to present to the WindowGroup. If the interface already has a window from the group that’s presenting the specified value, the system brings the window to the front. Otherwise, the system creates a new window and passes a binding to the specified value.

WindowGroup(for: String.self){ $num in
    ContentView(number: num)
}

In ContentView, call openWindow(value: "open") (or use any variable of type String)

Lastly, you can also pass both an identifier and a value. This enables you to define multiple window groups that take input values of the same type like a UUID. This has the same behavior as above, a window presenting the value will be brought to the front, otherwise a new window will be created.