Re: Problems with GtkComboBoxEntry

[Martyn Russell <martyn russell bt com>]

On Tue, 2004-10-05 at 18:04, Carlo Agrusti wrote:
> Martyn Russell ha scritto lo scorso 05/10/2004 17:45:
> > If you use the following code:
> >
> >         gtk_cell_layout_clear (GTK_CELL_LAYOUT (combo_box));
> >
> >         renderer = gtk_cell_renderer_text_new ();
> >         gtk_cell_layout_pack_start (GTK_CELL_LAYOUT (combo_box), renderer, TRUE);
> >         gtk_cell_layout_set_attributes (GTK_CELL_LAYOUT (combo_box), renderer,
> >                                         "text", 0,
> >                                         NULL);
> >         
> > or
> >
> >         renderer = gtk_cell_renderer_text_new ();
> >         gtk_cell_layout_pack_start (GTK_CELL_LAYOUT (combo_box), renderer, TRUE);
> >         gtk_cell_layout_set_attributes (GTK_CELL_LAYOUT (combo_box), renderer,
> >                                         "text", 0,
> >                                         NULL);
> >         
> >         gtk_cell_layout_reorder (GTK_CELL_LAYOUT (combo_box), renderer, 0);
> >         
> > does it make any difference? 
>
> With this code added after the call to gtk_combo_box_entry_set_model the 
> combo box (created with gtk_combo_box_entry_new) displays correctly all 
> entries described by the model (both with and without a 
> gtk_cell_layout_reorder call). 

Yea, I found that you can either call the gtk_cell_layout_clear ()
function or use gtk_cell_layout_reorder () .  However, without looking
at the source, I would guess the reorder function merely pushes other
renderers to the back of the queue so to speak so long as the renderer
passed is in the right position.

> Is the use of the cell renderer mandatory 
> for this kind of combo box manipulation?

No I don't think so, but I found this problem while implementing
multiple cell renderers being packed into a layout for a combo box (i.e.
an image and text together).  

I think the problem is that if you use glade and have some predetermined
text entries, glade uses the following code to set up the combo box:

        combo_box = gtk_combo_box_new_text ();
        gtk_widget_show (combo_box);
        gtk_box_pack_start (GTK_BOX (hbox), combo_box, TRUE, TRUE, 0);
        gtk_combo_box_append_text (GTK_COMBO_BOX (combo_box), "text");
        gtk_combo_box_append_text (GTK_COMBO_BOX (combo_box), "etc");
        
When using this code, GTK must internally create a renderer for the text
entries and expects you to use the gtk_combo_box_append_text () and
associated functions.

When you set a new model to the combo box, it must still have a resident
cell renderer attributes and layouts.

Matthias, have I got that about right? any comments to add?

If you use my test case you can play with adding/removing the above code
and see how things differ.

-- 
Regards,
Martyn