Port 'Contex Menu' demo to Vala

demos/Context Menu/main.vala

@@ -0,0 +1,28 @@
+#!/usr/bin/env -S vala workbench.vala --pkg gtk4 --pkg libadwaita-1
+
+public void main() {
+  Gtk.init();
+
+  var box_menu_parent =
+      workbench.builder.get_object("box_menu_parent") as Gtk.Box;
+  var label_emoji =
+      workbench.builder.get_object("label_emoji") as Gtk.Label;
+  var gesture_click =
+      workbench.builder.get_object("gesture_click") as Gtk.GestureClick;
+  var popover_menu =
+      workbench.builder.get_object("popover_menu") as Gtk.PopoverMenu;
+
+  gesture_click.pressed.connect((_gesture, _n_press, x, y) => {
+    var position = Gdk.Rectangle() { x = (int)x, y = (int)y };
+    popover_menu.set_pointing_to(position);
+    popover_menu.popup();
+  });
+
+  var mood_group = new SimpleActionGroup();
+  box_menu_parent.insert_action_group("mood", mood_group);
+
+  var emoji_action = new SimpleAction("emoji", new GLib.VariantType("s"));
+
+  emoji_action.activate.connect((_action, parameter) => { label_emoji.label = parameter.get_string(); });
+  mood_group.add_action(emoji_action);
+}