how to find a child

bil · **Joined:** Tue Mar 27, 2007 8:56 am **Posts:** 26

I'm new to gtk+ and want to ask a newbie question, apologise if it has been asked before.

Suppose I create a toplevel gtkwindow, and add a gtkvbox to it. Then I add a menu, a toolbar, a gtkfixed, and a statusbar to the gtkvbox.

Code:

  window=. 0{:: gtk_window_new <GTK_WINDOW_TOPLEVEL
  gtk_window_set_title window ;< id
  vbox1=. 0{:: gtk_vbox_new 0 ;< 0
  gtk_widget_show <vbox1
  gtk_container_add window ;< vbox1
NB. menubar
  menubar1=. 0{:: gtk_menu_bar_new ''
  gtk_box_pack_start vbox1 ; menubar1 ; 0 ; 0 ;< 0
NB. toolbar
  toolbar1=. 0{:: gtk_toolbar_new ''
  gtk_box_pack_start vbox1 ; toolbar1 ; 0 ; 0 ;< 0
NB. fixed
  fixed1=. 0{:: gtk_fixed_new ''
  gtk_widget_show <fixed1
  gtk_box_pack_start vbox1 ; fixed1 ; 0 ; 0 ;< 0
NB. statusbar
  statusbar1=. 0{:: gtk_statusbar_new ''
  gtk_widget_show <statusbar1
  gtk_statusbar_set_has_resize_grip statusbar1 ;< 0
  gtk_box_pack_start vbox1 ; statusbar1 ; 0 ; 0 ;< 0

Then I want to get the pointer of each child using code

Code:

NB. get handle of child gtkfixed
  g1=. 0{:: gtk_container_get_children <window
  vbox1=. 0{:: g_list_nth_data g1 ;< 0
  g2=. 0{:: gtk_container_get_children <vbox1
  fixed1=. 0{:: g_list_nth_data g2 ;< 2  NB. menu toolbar fxied  statusbar
  g_list_free <g2
  g_list_free <g1

Here fixed1 for g_list_nth_data is the 2 (index-0) child, but I might not create menu or toolbar so that the index method does not always work. What is the better way of finding fixed1?

PS. the programming language I used is not c/c++ but it directly call gtk+ api. Please interpret it as pseudo code for discussion.

openldev · **Posted:** Tue Apr 03, 2007 11:11 am

Well, what you _should_ do is create a structure that holds all of the children and pass that to your function. If you want to use gtk_container_get_children(), use:

Code:

GList *list;
for (list = g1; list != NULL; list = list->next)
  if (GTK_IS_FIXED (list->data))
    /* Use the fixed widget. */

This is in C, but can easily be converted to any other language. By looping like this, you avoid traversing the list on every call to g_list_nth_data().

bil · **Joined:** Tue Mar 27, 2007 8:56 am **Posts:** 26

openldev wrote:

Well, what you _should_ do is create a structure that holds all of the children and pass that to your function. If you want to use gtk_container_get_children(), use:

Thank you for suggestion. I use a scripting language that creates gui dynamically so it is more convinient to discover children using gtk_container_get_children.
Another question, does structures in gtk+ always use 4-bytes alignment in 32-bit os? And will it be 8-bytes on 64-bit os?

openldev · **Posted:** Wed Apr 04, 2007 11:51 am

Structures in GTK+ are pure C, so if you look into the implementation of C structures, you can find out.

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