How to use eventcontroller in gtk4

I would like to add onclick event handling to a GtkBox widget. I see that only GtkButton has clicked signal, so I feel like the only option is to attach a GtkEventController to my widget.

As per the doc, gtk_get_current_event(GtkEventController *ctr) returns the events if there are any and NULL otherwise. How do I listen to this function? Should I implement manual while loop for the main application loop? It feels like there must be a best practice for this.

Thank you in advance

To determine events over a GtkBox, you can create a new event controller to listen to events and add a signal callback for the events you care.

For your case, you can create a new gesture event controller with gtk_gesture_click_new () and add a callback to the signal released.

Here is a minimal example:

/* button-event.c
 *
 * Compile: cc -ggdb button-event.c -o button-event $(pkg-config --cflags --libs gtk4)
 * Run: ./button-event
 *
 * Author: Mohammed Sadiq <www.sadiqpk.org>
 *
 * SPDX-License-Identifier: LGPL-2.1-or-later OR CC0-1.0
 */

#include <gtk/gtk.h>

static gboolean
gesture_released_cb (GtkWidget *widget)
{
  g_warning ("do something");

  return GDK_EVENT_STOP;
}

static void
app_activated_cb (GtkApplication *app)
{
  GtkGesture *gesture;
  GtkWindow *window;
  GtkWidget *box, *label;

  window = GTK_WINDOW (gtk_application_window_new (app));
  gtk_window_set_default_size (window, 400, 300);

  box = gtk_box_new (GTK_ORIENTATION_VERTICAL, 6);
  label = gtk_label_new ("Hello");
  gtk_box_append (GTK_BOX (box), label);
  gtk_window_set_child (window, box);

  gesture = gtk_gesture_click_new ();

  g_signal_connect_object (gesture, "released",
                           G_CALLBACK (gesture_released_cb),
                           box, G_CONNECT_SWAPPED);
  gtk_widget_add_controller (label, GTK_EVENT_CONTROLLER (gesture));

  gtk_window_present (window);
}

int
main (int   argc,
      char *argv[])
{
  g_autoptr(GtkApplication) app = gtk_application_new (NULL, 0);

  g_signal_connect (app, "activate", G_CALLBACK (app_activated_cb), NULL);

  return g_application_run (G_APPLICATION (app), argc, argv);
}