How do I disable the Show Tab Bar menu option in SwiftUI - swift

Question

I have created a very simple app on MacOS created with SwiftUI. Default there is a menu item show tab bar. How do I remove this? I doesn't make sense to have tabs in this app.
I've found the following answering the same question, but for older versions of Swift, not for SwiftUI: How do I disable the Show Tab Bar menu option in Sierra apps?

Answer 1

The equivalent in SwiftUI is the same thing as the equivalent in Swift (which is missed in that post for some reason). To completely remove these items from any windows for your application, in your app delegate you can set the boolean value allowsAutomaticWindowTabbing to false
func applicationWillFinishLaunching(_ notification: Notification) {
NSWindow.allowsAutomaticWindowTabbing = false
}

Answer 2

Thanks to #JuJoDi
In case you are using SwiftUI life cycle (Scene), you could do the following:
#main
struct MyApp: App {
var body: some Scene {
WindowGroup {
ContentView()
.onAppear {
NSWindow.allowsAutomaticWindowTabbing = false
}
}
}
}

Answer 3

I was looking for an answer for this as well and found out the following:
by default - as you already mentioned - the Show/Hide Tab is active:
There is a property on NSWindow called tabbingMode which allows us to take control by setting it to .disallowed. My problem though was: in a SwiftUI 2-lifecycle app, how can I get hold of the windows of the app?
Well, there's NSApplication.shared.windows, so my first (non working!!) attempt was to modify all the windows in my #main-App struct (as I already prevented new windows from being created, that should be suffice):
import SwiftUI
#main
struct DQ_SyslogApp: App {
var body: some Scene {
WindowGroup {
ContentView()
.onAppear {
let _ = NSApplication.shared.windows.map { $0.tabbingMode = .disallowed }
}
}
.commands {
CommandGroup(replacing: .newItem) {} //remove "New Item"-menu entry
}
}
}
Unfortunately this did not work as NSApplication.shared.windows is empty in .onAppear.
My next step involved introducing an AppDelegate to my SwiftUI 2-lifecycle that implements applicationDidFinishLaunching(_:)...
class AppDelegate: NSObject, NSApplicationDelegate {
func applicationDidFinishLaunching(_ notification: Notification) {
print("Info from `applicationDidFinishLaunching(_:): Finished launching…")
let _ = NSApplication.shared.windows.map { $0.tabbingMode = .disallowed }
}
}
...and introducing this AppDelegate to the app:
import SwiftUI
#main
struct DQ_SyslogApp: App {
#NSApplicationDelegateAdaptor(AppDelegate.self) var appDelegate
var body: some Scene {
WindowGroup {
ContentView()
}
.commands {
CommandGroup(replacing: .newItem) {} //remove "New Item"-menu entry
}
}
}
This did the trick for me:
While I would prefer to have the menu entries removed entirely, this at least prevents the user from having tabs which is what the OP was asking for.
If anybody should happen to know a solution to hide those entries, please let us know. I couldn't find a CommandGroupPlacement that represents these menus...

Answer 4

I found how to remove the 'Edit' menu item after reading this article
https://steipete.com/posts/top-level-menu-visibility-in-swiftui/
func applicationDidFinishLaunching(_ notification: Notification) {
NSWindow.allowsAutomaticWindowTabbing = false
if let mainMenu = NSApp .mainMenu {
DispatchQueue.main.async {
if let edit = mainMenu.items.first(where: { $0.title == "Edit"}) {
mainMenu.removeItem(edit);
}
}
}
}

Answer 5

2021, swiftUI 2 and higher
Result in release build:
look at places with comments "HERE":
#main
struct MyFirstApp: App {
#NSApplicationDelegateAdaptor(AppDelegate.self) var appDelegate
init() {
// HERE
disallowTabbingMode()
}
#SceneBuilder
var body: some Scene {
WindowGroup {
AppMainView()
}
.commands {
//MenuLine_MyFirstApp_CustomAbout()
// HERE
MenuLine_File_NewWindow_Disable()
//MenuLine_Help_SupportEmail()
}
}
}
And method + bonuses for understanding menus in SwiftUI
// Set Custom About window instead of default
fileprivate func MenuLine_MyFirstApp_CustomAbout() -> CommandGroup<Button<Text>> {
CommandGroup(replacing: CommandGroupPlacement.appInfo) {
Button("About") { appDelegate.showAboutWnd() }
}
}
//Add some menu button into Help menu
fileprivate func MenuLine_Help_SupportEmail() -> CommandGroup<Button<Text>> {
CommandGroup(after: CommandGroupPlacement.help) {
Button("Support Email") { NSWorkspace.shared.open("mailto:support#myfirstapp.com") }
}
}
// Disable "File -> New window" menu item (make it absent in release build)
fileprivate func MenuLine_File_NewWindow_Disable() -> CommandGroup<EmptyView> {
CommandGroup(replacing: .newItem) { }
}
fileprivate func disallowTabbingMode() {
NSWindow.allowsAutomaticWindowTabbing = false
}