Enable muda macOS menubar on macOS

internal/backends/winit/event_loop.rs

@@ -346,17 +346,7 @@ impl winit::application::ApplicationHandler<SlintUserEvent> for EventLoopState {
                     .err();
             }
             WindowEvent::Focused(have_focus) => {
-                let have_focus = have_focus || window.input_method_focused();
-                // We don't render popups as separate windows yet, so treat
-                // focus to be the same as being active.
-                if have_focus != runtime_window.active() {
-                    self.loop_error = window
-                        .window()
-                        .try_dispatch_event(corelib::platform::WindowEvent::WindowActiveChanged(
-                            have_focus,
-                        ))
-                        .err();
-                }
+                self.loop_error = window.activation_changed(have_focus).err();
             }
 
             WindowEvent::KeyboardInput { event, is_synthetic, .. } => {

internal/backends/winit/lib.rs

@@ -235,8 +235,16 @@ impl BackendBuilder {
     /// slint::platform::set_platform(Box::new(backend));
     /// ```
     pub fn build(self) -> Result<Backend, PlatformError> {
-        let event_loop_builder =
-            self.event_loop_builder.unwrap_or_else(winit::event_loop::EventLoop::with_user_event);
+        let event_loop_builder = self.event_loop_builder.unwrap_or_else(|| {
+            #[allow(unused_mut)]
+            let mut default_builder = winit::event_loop::EventLoop::with_user_event();
+            #[cfg(all(feature = "muda", target_os = "macos"))]
+            winit::platform::macos::EventLoopBuilderExtMacOS::with_default_menu(
+                &mut default_builder,
+                false,
+            );
+            default_builder
+        });
 
         // Initialize the winit event loop and propagate errors if for example `DISPLAY` or `WAYLAND_DISPLAY` isn't set.
 

internal/backends/winit/muda.rs

@@ -8,7 +8,7 @@ use winit::window::Window;
 
 pub struct MudaAdapter {
     entries: Vec<i_slint_core::items::MenuEntry>,
-    menubar: vtable::VBox<MenuVTable>,
+    menubar: Option<vtable::VBox<MenuVTable>>,
     // We need to keep menu alive, otherwise muda segfaults
     _menu: muda::Menu,
 }
@@ -89,11 +89,49 @@ impl MudaAdapter {
             menu.init_for_nsapp();
         }
 
-        Self { entries: map, menubar, _menu: menu }
+        Self { entries: map, menubar: Some(menubar), _menu: menu }
     }
 
     pub fn invoke(&self, entry_id: usize) {
         let Some(entry) = &self.entries.get(entry_id) else { return };
-        self.menubar.activate(entry);
+        let Some(menubar) = self.menubar.as_ref() else { return };
+        menubar.activate(entry);
+    }
+
+    #[cfg(target_os = "macos")]
+    pub fn setup_default_menu() -> Result<Self, i_slint_core::api::PlatformError> {
+        let menu = muda::Menu::new();
+
+        let app_menu = muda::Submenu::new("App", true);
+        menu.append(&app_menu)
+            .and_then(|_| {
+                app_menu.append_items(&[
+                    &muda::PredefinedMenuItem::about(None, None),
+                    &muda::PredefinedMenuItem::separator(),
+                    &muda::PredefinedMenuItem::services(None),
+                    &muda::PredefinedMenuItem::separator(),
+                    &muda::PredefinedMenuItem::hide(None),
+                    &muda::PredefinedMenuItem::hide_others(None),
+                    &muda::PredefinedMenuItem::show_all(None),
+                    &muda::PredefinedMenuItem::separator(),
+                    &muda::PredefinedMenuItem::quit(None),
+                ])
+            })
+            .map_err(|menu_bar_err| {
+                i_slint_core::api::PlatformError::Other(menu_bar_err.to_string())
+            })?;
+
+        menu.init_for_nsapp();
+
+        Ok(Self { entries: vec![], menubar: None, _menu: menu })
+    }
+
+    #[cfg(target_os = "macos")]
+    pub fn window_activation_changed(&self, is_active: bool) {
+        if is_active {
+            self._menu.init_for_nsapp();
+        } else {
+            self._menu.remove_for_nsapp();
+        }
     }
 }

internal/backends/winit/winitwindowadapter.rs

@@ -685,6 +685,31 @@ impl WinitWindowAdapter {
             })
             .ok()
     }
+
+    pub fn activation_changed(&self, is_active: bool) -> Result<(), PlatformError> {
+        let have_focus = is_active || self.input_method_focused();
+        let slint_window = self.window();
+        let runtime_window = WindowInner::from_pub(slint_window);
+        // We don't render popups as separate windows yet, so treat
+        // focus to be the same as being active.
+        if have_focus != runtime_window.active() {
+            slint_window.try_dispatch_event(
+                corelib::platform::WindowEvent::WindowActiveChanged(have_focus),
+            )?;
+        }
+
+        #[cfg(all(feature = "muda", target_os = "macos"))]
+        {
+            if self.muda_adapter.borrow().is_none() {
+                *self.muda_adapter.borrow_mut() =
+                    Some(crate::muda::MudaAdapter::setup_default_menu()?);
+            }
+
+            self.muda_adapter.borrow().as_ref().unwrap().window_activation_changed(is_active);
+        }
+
+        Ok(())
+    }
 }
 
 impl WindowAdapter for WinitWindowAdapter {