gtk_tut-13.html

GTK development guide

    gtk_init (&argc, &argv);

    /* create a new window */
    window = gtk_window_new (GTK_WINDOW_TOPLEVEL);
    gtk_widget_set_usize (GTK_WIDGET (window), 200, 100);
    gtk_window_set_title (GTK_WINDOW (window), "GTK Menu Test");
    gtk_signal_connect (GTK_OBJECT (window), "delete_event",
                        (GtkSignalFunc) gtk_main_quit, NULL);

    /* Init the menu-widget, and remember -- never
     * gtk_show_widget() the menu widget!! 
     * This is the menu that holds the menu items, the one that
     * will pop up when you click on the "Root Menu" in the app */
    menu = gtk_menu_new ();

    /* Next we make a little loop that makes three menu-entries for "test-menu".
     * Notice the call to gtk_menu_append.  Here we are adding a list of
     * menu items to our menu.  Normally, we'd also catch the "clicked"
     * signal on each of the menu items and setup a callback for it,
     * but it's omitted here to save space. */

    for (i = 0; i < 3; i++)
        {
            /* Copy the names to the buf. */
            sprintf (buf, "Test-undermenu - %d", i);

            /* Create a new menu-item with a name... */
            menu_items = gtk_menu_item_new_with_label (buf);

            /* ...and add it to the menu. */
            gtk_menu_append (GTK_MENU (menu), menu_items);

            /* Do something interesting when the menuitem is selected */
            gtk_signal_connect_object (GTK_OBJECT (menu_items), "activate",
                GTK_SIGNAL_FUNC (menuitem_response), (gpointer) g_strdup (buf));

            /* Show the widget */
            gtk_widget_show (menu_items);
        }

    /* This is the root menu, and will be the label
     * displayed on the menu bar.  There won't be a signal handler attached,
     * as it only pops up the rest of the menu when pressed. */
    root_menu = gtk_menu_item_new_with_label ("Root Menu");

    gtk_widget_show (root_menu);

    /* Now we specify that we want our newly created "menu" to be the menu
     * for the "root menu" */
    gtk_menu_item_set_submenu (GTK_MENU_ITEM (root_menu), menu);

    /* A vbox to put a menu and a button in: */
    vbox = gtk_vbox_new (FALSE, 0);
    gtk_container_add (GTK_CONTAINER (window), vbox);
    gtk_widget_show (vbox);

    /* Create a menu-bar to hold the menus and add it to our main window */
    menu_bar = gtk_menu_bar_new ();
    gtk_box_pack_start (GTK_BOX (vbox), menu_bar, FALSE, FALSE, 2);
    gtk_widget_show (menu_bar);

    /* Create a button to which to attach menu as a popup */
    button = gtk_button_new_with_label ("press me");
    gtk_signal_connect_object (GTK_OBJECT (button), "event",
        GTK_SIGNAL_FUNC (button_press), GTK_OBJECT (menu));
    gtk_box_pack_end (GTK_BOX (vbox), button, TRUE, TRUE, 2);
    gtk_widget_show (button);

    /* And finally we append the menu-item to the menu-bar -- this is the
     * "root" menu-item I have been raving about =) */
    gtk_menu_bar_append (GTK_MENU_BAR (menu_bar), root_menu);

    /* always display the window as the last step so it all splashes on
     * the screen at once. */
    gtk_widget_show (window);

    gtk_main ();

    return(0);
}

/* Respond to a button-press by posting a menu passed in as widget.
 *
 * Note that the "widget" argument is the menu being posted, NOT
 * the button that was pressed.
 */

static gint button_press( GtkWidget *widget,
                          GdkEvent *event )
{

    if (event->type == GDK_BUTTON_PRESS) {
        GdkEventButton *bevent = (GdkEventButton *) event; 
        gtk_menu_popup (GTK_MENU (widget), NULL, NULL, NULL, NULL,
                        bevent->button, bevent->time);
        /* Tell calling code that we have handled this event; the buck
         * stops here. */
        return TRUE;
    }

    /* Tell calling code that we have not handled this event; pass it on. */
    return FALSE;
}


/* Print a string when a menu item is selected */

static void menuitem_response( gchar *string )
{
    printf ("%s\n", string);
}
/* example-end */
</PRE>
</CODE></BLOCKQUOTE>
<P>You may also set a menu item to be insensitive and, using an accelerator
table, bind keys to menu functions.
<P>
<H2><A NAME="ss13.3">13.3 Using ItemFactory</A>
</H2>

<P>Now that we've shown you the hard way, here's how you do it using the
gtk_item_factory calls.
<P>
<H2><A NAME="ss13.4">13.4 Item Factory Example</A>
</H2>

<P>Here is an example using the GTK item factory.
<P>
<BLOCKQUOTE><CODE>
<PRE>
/* example-start menu itemfactory.c */

#include &lt;gtk/gtk.h>
#include &lt;strings.h>

/* Obligatory basic callback */
static void print_hello( GtkWidget *w,
                         gpointer   data )
{
  g_message ("Hello, World!\n");
}

/* This is the GtkItemFactoryEntry structure used to generate new menus.
   Item 1: The menu path. The letter after the underscore indicates an
           accelerator key once the menu is open.
   Item 2: The accelerator key for the entry
   Item 3: The callback function.
   Item 4: The callback action.  This changes the parameters with
           which the function is called.  The default is 0.
   Item 5: The item type, used to define what kind of an item it is.
           Here are the possible values:

           NULL               -> "&lt;Item>"
           ""                 -> "&lt;Item>"
           "&lt;Title>"          -> create a title item
           "&lt;Item>"           -> create a simple item
           "&lt;CheckItem>"      -> create a check item
           "&lt;ToggleItem>"     -> create a toggle item
           "&lt;RadioItem>"      -> create a radio item
           &lt;path>             -> path of a radio item to link against
           "&lt;Separator>"      -> create a separator
           "&lt;Branch>"         -> create an item to hold sub items (optional)
           "&lt;LastBranch>"     -> create a right justified branch 
*/

static GtkItemFactoryEntry menu_items[] = {
  { "/_File",         NULL,         NULL, 0, "&lt;Branch>" },
  { "/File/_New",     "&lt;control>N", print_hello, 0, NULL },
  { "/File/_Open",    "&lt;control>O", print_hello, 0, NULL },
  { "/File/_Save",    "&lt;control>S", print_hello, 0, NULL },
  { "/File/Save _As", NULL,         NULL, 0, NULL },
  { "/File/sep1",     NULL,         NULL, 0, "&lt;Separator>" },
  { "/File/Quit",     "&lt;control>Q", gtk_main_quit, 0, NULL },
  { "/_Options",      NULL,         NULL, 0, "&lt;Branch>" },
  { "/Options/Test",  NULL,         NULL, 0, NULL },
  { "/_Help",         NULL,         NULL, 0, "&lt;LastBranch>" },
  { "/_Help/About",   NULL,         NULL, 0, NULL },
};


void get_main_menu( GtkWidget  *window,
                    GtkWidget **menubar )
{
  GtkItemFactory *item_factory;
  GtkAccelGroup *accel_group;
  gint nmenu_items = sizeof (menu_items) / sizeof (menu_items[0]);

  accel_group = gtk_accel_group_new ();

  /* This function initializes the item factory.
     Param 1: The type of menu - can be GTK_TYPE_MENU_BAR, GTK_TYPE_MENU,
              or GTK_TYPE_OPTION_MENU.
     Param 2: The path of the menu.
     Param 3: A pointer to a gtk_accel_group.  The item factory sets up
              the accelerator table while generating menus.
  */

  item_factory = gtk_item_factory_new (GTK_TYPE_MENU_BAR, "&lt;main>", 
                                       accel_group);

  /* This function generates the menu items. Pass the item factory,
     the number of items in the array, the array itself, and any
     callback data for the the menu items. */
  gtk_item_factory_create_items (item_factory, nmenu_items, menu_items, NULL);

  /* Attach the new accelerator group to the window. */
  gtk_window_add_accel_group (GTK_WINDOW (window), accel_group);

  if (menubar)
    /* Finally, return the actual menu bar created by the item factory. */ 
    *menubar = gtk_item_factory_get_widget (item_factory, "&lt;main>");
}

int main( int argc,
          char *argv[] )
{
  GtkWidget *window;
  GtkWidget *main_vbox;
  GtkWidget *menubar;
  
  gtk_init (&amp;argc, &amp;argv);
  
  window = gtk_window_new (GTK_WINDOW_TOPLEVEL);
  gtk_signal_connect (GTK_OBJECT (window), "destroy", 
                      GTK_SIGNAL_FUNC (gtk_main_quit), 
                      "WM destroy");
  gtk_window_set_title (GTK_WINDOW(window), "Item Factory");
  gtk_widget_set_usize (GTK_WIDGET(window), 300, 200);
  
  main_vbox = gtk_vbox_new (FALSE, 1);
  gtk_container_border_width (GTK_CONTAINER (main_vbox), 1);
  gtk_container_add (GTK_CONTAINER (window), main_vbox);
  gtk_widget_show (main_vbox);
  
  get_main_menu (window, &amp;menubar);
  gtk_box_pack_start (GTK_BOX (main_vbox), menubar, FALSE, TRUE, 0);
  gtk_widget_show (menubar);
  
  gtk_widget_show (window);
  gtk_main ();
  
  return(0);
}
/* example-end */
</PRE>
</CODE></BLOCKQUOTE>
<P>
<P>For now, there's only this example. An explanation and lots 'o' comments
will follow later.
<P>
<HR>
<A HREF="gtk_tut-14.html">Next</A>
<A HREF="gtk_tut-12.html">Previous</A>
<A HREF="gtk_tut.html#toc13">Contents</A>
</BODY>
</HTML>