Add GTK event emission for menu and item actions

Introduces GTK signal handlers to emit events for menu item activation, menu open/close, and submenu open/close. Connects these handlers to the relevant GTK signals in Menu and MenuItem constructors and submenu assignment. Also updates menu popup logic to position menus at explicit coordinates when available.

Author: lijy91

src/platform/linux/menu_linux.cpp

@@ -10,6 +10,7 @@
 #include <vector>
 #include "../../image.h"
 #include "../../menu.h"
+#include "../../menu_event.h"
 
 namespace nativeapi {
 
@@ -21,6 +22,63 @@ static std::atomic<MenuId> g_next_menu_id{1};
 static std::unordered_map<MenuItemId, MenuItem*> g_menu_item_registry;
 static std::unordered_map<MenuId, Menu*> g_menu_registry;
 
+// GTK signal handlers → Event emission
+static void OnGtkMenuItemActivate(GtkMenuItem* /*item*/, gpointer user_data) {
+  MenuItemId item_id = static_cast<MenuItemId>(GPOINTER_TO_SIZE(user_data));
+  auto it = g_menu_item_registry.find(item_id);
+  if (it == g_menu_item_registry.end()) {
+    return;
+  }
+  MenuItem* menu_item = it->second;
+  std::string text = "";
+  if (auto label = menu_item->GetLabel(); label.has_value()) {
+    text = *label;
+  }
+  menu_item->EmitSync(MenuItemClickedEvent(item_id, text));
+}
+
+static void OnGtkMenuShow(GtkWidget* /*menu*/, gpointer user_data) {
+  MenuId menu_id = static_cast<MenuId>(GPOINTER_TO_SIZE(user_data));
+  auto it = g_menu_registry.find(menu_id);
+  if (it == g_menu_registry.end()) {
+    return;
+  }
+  Menu* menu_obj = it->second;
+  menu_obj->EmitSync(MenuOpenedEvent(menu_id));
+}
+
+static void OnGtkMenuHide(GtkWidget* /*menu*/, gpointer user_data) {
+  MenuId menu_id = static_cast<MenuId>(GPOINTER_TO_SIZE(user_data));
+  auto it = g_menu_registry.find(menu_id);
+  if (it == g_menu_registry.end()) {
+    return;
+  }
+  Menu* menu_obj = it->second;
+  menu_obj->EmitSync(MenuClosedEvent(menu_id));
+}
+
+static void OnGtkSubmenuShow(GtkWidget* /*submenu*/, gpointer user_data) {
+  MenuItemId item_id = static_cast<MenuItemId>(GPOINTER_TO_SIZE(user_data));
+  auto it = g_menu_item_registry.find(item_id);
+  if (it == g_menu_item_registry.end()) {
+    return;
+  }
+  MenuItem* menu_item = it->second;
+  // Emit submenu opened on the item
+  menu_item->EmitSync(MenuItemSubmenuOpenedEvent(item_id));
+}
+
+static void OnGtkSubmenuHide(GtkWidget* /*submenu*/, gpointer user_data) {
+  MenuItemId item_id = static_cast<MenuItemId>(GPOINTER_TO_SIZE(user_data));
+  auto it = g_menu_item_registry.find(item_id);
+  if (it == g_menu_item_registry.end()) {
+    return;
+  }
+  MenuItem* menu_item = it->second;
+  // Emit submenu closed on the item
+  menu_item->EmitSync(MenuItemSubmenuClosedEvent(item_id));
+}
+
 // Private implementation class for MenuItem
 class MenuItem::Impl {
  public:
@@ -79,6 +137,13 @@ MenuItem::MenuItem(const std::string& text, MenuItemType type)
 
   // Register the MenuItem for event emission
   g_menu_item_registry[id] = this;
+
+  // Connect activation signal for click events (except separators)
+  if (gtk_item && type != MenuItemType::Separator) {
+    g_signal_connect(G_OBJECT(gtk_item), "activate",
+                     G_CALLBACK(OnGtkMenuItemActivate),
+                     GSIZE_TO_POINTER(static_cast<gsize>(id)));
+  }
 }
 
 MenuItem::MenuItem(void* menu_item)
@@ -94,6 +159,12 @@ MenuItem::MenuItem(void* menu_item)
     }
   }
   g_menu_item_registry[id] = this;
+
+  if (pimpl_->gtk_menu_item_) {
+    g_signal_connect(G_OBJECT(pimpl_->gtk_menu_item_), "activate",
+                     G_CALLBACK(OnGtkMenuItemActivate),
+                     GSIZE_TO_POINTER(static_cast<gsize>(id)));
+  }
 }
 
 MenuItem::~MenuItem() {
@@ -209,6 +280,17 @@ void MenuItem::SetSubmenu(std::shared_ptr<Menu> submenu) {
   if (pimpl_->gtk_menu_item_ && submenu) {
     gtk_menu_item_set_submenu(GTK_MENU_ITEM(pimpl_->gtk_menu_item_),
                               (GtkWidget*)submenu->GetNativeObject());
+
+    // Emit submenu open/close events on the parent item when submenu shows/hides
+    GtkWidget* submenu_widget = (GtkWidget*)submenu->GetNativeObject();
+    if (submenu_widget) {
+      g_signal_connect(G_OBJECT(submenu_widget), "show",
+                       G_CALLBACK(OnGtkSubmenuShow),
+                       GSIZE_TO_POINTER(static_cast<gsize>(id)));
+      g_signal_connect(G_OBJECT(submenu_widget), "hide",
+                       G_CALLBACK(OnGtkSubmenuHide),
+                       GSIZE_TO_POINTER(static_cast<gsize>(id)));
+    }
   }
 }
 
@@ -252,11 +334,30 @@ Menu::Menu()
     : id(g_next_menu_id++),
       pimpl_(std::unique_ptr<Impl>(new Impl(gtk_menu_new()))) {
   g_menu_registry[id] = this;
+
+  // Connect menu show/hide to emit open/close events
+  if (pimpl_->gtk_menu_) {
+    g_signal_connect(G_OBJECT(pimpl_->gtk_menu_), "show",
+                     G_CALLBACK(OnGtkMenuShow),
+                     GSIZE_TO_POINTER(static_cast<gsize>(id)));
+    g_signal_connect(G_OBJECT(pimpl_->gtk_menu_), "hide",
+                     G_CALLBACK(OnGtkMenuHide),
+                     GSIZE_TO_POINTER(static_cast<gsize>(id)));
+  }
 }
 
 Menu::Menu(void* menu)
     : id(g_next_menu_id++), pimpl_(new Impl((GtkWidget*)menu)) {
   g_menu_registry[id] = this;
+
+  if (pimpl_->gtk_menu_) {
+    g_signal_connect(G_OBJECT(pimpl_->gtk_menu_), "show",
+                     G_CALLBACK(OnGtkMenuShow),
+                     GSIZE_TO_POINTER(static_cast<gsize>(id)));
+    g_signal_connect(G_OBJECT(pimpl_->gtk_menu_), "hide",
+                     G_CALLBACK(OnGtkMenuHide),
+                     GSIZE_TO_POINTER(static_cast<gsize>(id)));
+  }
 }
 
 Menu::~Menu() {
@@ -392,7 +493,23 @@ std::shared_ptr<MenuItem> Menu::FindItemByText(const std::string& text,
 bool Menu::Open(double x, double y) {
   if (pimpl_->gtk_menu_) {
     pimpl_->visible_ = true;
-    gtk_menu_popup_at_pointer(GTK_MENU(pimpl_->gtk_menu_), nullptr);
+    gtk_widget_show_all(pimpl_->gtk_menu_);
+
+    // Try to position at explicit coordinates if available
+    GdkWindow* root_window = gdk_get_default_root_window();
+    if (root_window) {
+      GdkRectangle rect;
+      rect.x = static_cast<int>(x);
+      rect.y = static_cast<int>(y);
+      rect.width = 1;
+      rect.height = 1;
+      gtk_menu_popup_at_rect(GTK_MENU(pimpl_->gtk_menu_), root_window, &rect,
+                             GDK_GRAVITY_NORTH_WEST, GDK_GRAVITY_NORTH_WEST,
+                             nullptr);
+    } else {
+      // Fallback to pointer if root window not available
+      gtk_menu_popup_at_pointer(GTK_MENU(pimpl_->gtk_menu_), nullptr);
+    }
     return true;
   }
   return false;