Update hello-world.c to GtkApplication, document

1 files changed, 23 insertions, 81 deletions

diff --git a/examples/hello-world.c b/examples/hello-world.c
index 204b46eb4d..843b9b2d85 100644
--- a/examples/hello-world.c
+++ b/examples/hello-world.c
@@ -1,8 +1,5 @@
 #include <gtk/gtk.h>
 
-/* This is a callback function. The data arguments are ignored
- * in this example. More on callbacks below.
- */
 static void
 print_hello (GtkWidget *widget,
              gpointer   data)
@@ -10,95 +7,40 @@ print_hello (GtkWidget *widget,
   g_print ("Hello World\n");
 }
 
-static gboolean
-on_delete_event (GtkWidget *widget,
-                 GdkEvent  *event,
-                 gpointer   data)
-{
-  /* If you return FALSE in the "delete_event" signal handler,
-   * GTK will emit the "destroy" signal. Returning TRUE means
-   * you don't want the window to be destroyed.
-   *
-   * This is useful for popping up 'are you sure you want to quit?'
-   * type dialogs.
-   */
-
-  g_print ("delete event occurred\n");
-
-  return TRUE;
-}
-
-int
-main (int   argc,
-      char *argv[])
+static void
+activate (GtkApplication *app,
+          gpointer        user_data)
 {
-  /* GtkWidget is the storage type for widgets */
   GtkWidget *window;
   GtkWidget *button;
+  GtkWidget *button_box;
 
-  /* This is called in all GTK applications. Arguments are parsed
-   * from the command line and are returned to the application.
-   */
-  gtk_init (&argc, &argv);
-
-  /* create a new window, and set its title */
-  window = gtk_window_new (GTK_WINDOW_TOPLEVEL);
-  gtk_window_set_title (GTK_WINDOW (window), "Hello");
+  window = gtk_application_window_new (app);
+  gtk_window_set_title (GTK_WINDOW (window), "Window");
+  gtk_window_set_default_size (GTK_WINDOW (window), 200, 200);
 
-  /* When the window emits the "delete-event" signal (which is emitted
-   * by GTK+ in response to an event coming from the window manager,
-   * usually as a result of clicking the "close" window control), we
-   * ask it to call the on_delete_event() function as defined above.
-   *
-   * The data passed to the callback function is NULL and is ignored
-   * in the callback function.
-   */
-  g_signal_connect (window, "delete-event", G_CALLBACK (on_delete_event), NULL);
+  button_box = gtk_button_box_new (GTK_ORIENTATION_HORIZONTAL);
+  gtk_container_add (GTK_CONTAINER (window), button_box);
 
-  /* Here we connect the "destroy" event to the gtk_main_quit() function.
-   *
-   * This signal is emitted when we call gtk_widget_destroy() on the window,
-   * or if we return FALSE in the "delete_event" callback.
-   */
-  g_signal_connect (window, "destroy", G_CALLBACK (gtk_main_quit), NULL);
-
-  /* Sets the border width of the window. */
-  gtk_container_set_border_width (GTK_CONTAINER (window), 10);
-
-  /* Creates a new button with the label "Hello World". */
   button = gtk_button_new_with_label ("Hello World");
-
-  /* When the button receives the "clicked" signal, it will call the
-   * function print_hello() passing it NULL as its argument.
-   *
-   * The print_hello() function is defined above.
-   */
   g_signal_connect (button, "clicked", G_CALLBACK (print_hello), NULL);
-
-  /* The g_signal_connect_swapped() function will connect the "clicked" signal
-   * of the button to the gtk_widget_destroy() function; instead of calling it
-   * using the button as its argument, it will swap it with the user data
-   * argument. This will cause the window to be destroyed by calling
-   * gtk_widget_destroy() on the window.
-   */
   g_signal_connect_swapped (button, "clicked", G_CALLBACK (gtk_widget_destroy), window);
+  gtk_container_add (GTK_CONTAINER (button_box), button);
 
-  /* This packs the button into the window. A GtkWindow inherits from GtkBin,
-   * which is a special container that can only have one child
-   */
-  gtk_container_add (GTK_CONTAINER (window), button);
-
-  /* The final step is to display this newly created widget... */
-  gtk_widget_show (button);
+  gtk_widget_show_all (window);
+}
 
-  /* ... and the window */
-  gtk_widget_show (window);
+int
+main (int    argc,
+      char **argv)
+{
+  GtkApplication *app;
+  int status;
 
-  /* All GTK applications must have a gtk_main(). Control ends here
-   * and waits for an event to occur (like a key press or a mouse event),
-   * until gtk_main_quit() is called.
-   */
-  gtk_main ();
+  app = gtk_application_new ("org.gtk.example", G_APPLICATION_FLAGS_NONE);
+  g_signal_connect (app, "activate", G_CALLBACK (activate), NULL);
+  status = g_application_run (G_APPLICATION (app), argc, argv);
+  g_object_unref (app);
 
-  return 0;
+  return status;
 }