Although many things in SwiftUI are idiomatic and straightforward, showing your view in a new window needs a bit of coding to do. Hence, this short post.
First, let’s create a Window Controller that will hold your window/view:
import AppKit
import SwiftUI
class WindowController<RootView: View>: NSWindowController {
convenience init(rootView: RootView) {
let hostingController = NSHostingController(rootView: rootView.frame(width: 400, height: 400))
let window = NSWindow(contentViewController: hostingController)
window.setContentSize(NSSize(width: 400, height: 400))
self.init(window: window)
}
}
What we’re doing here is creating a Hosting Controller (which is a subclass of View Controller) that takes your supplied View, does its magic, and then gives it to NSWindow.
Now, let’s create two Views in SwiftUI, Parent and Child, like below:
import SwiftUI
struct NewWindowParentView: View {
@State private var windowCount = 1
var body: some View {
Button("Show new window") {
let windowController = WindowController(rootView: NewWindowChildView())
windowController.window?.title = "Child Window \(windowCount)"
windowCount += 1
windowController.showWindow(nil)
}
}
}
import SwiftUI
struct NewWindowChildView: View {
var body: some View {
Text("Child view")
}
}
Parent View resemble whatever your main View in your app is and the Child View is the View that you want to show in a new Window.
That’s it. So, when you open the Parent View, you will see a Button and every time you press this button, a new Window will be created showing your Child View.
Lastly, the entire example code can be found on GitHub.
Note: Apple has now added better ways to open windows programmatically in SwiftUI.
