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>Development with GTK+: widget specific questions</H1
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><A
NAME="AEN700"
>How do I find out about the selection of a GtkList?</A
></H1
><P
>Get the selection something like this:</P
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><PRE
CLASS="PROGRAMLISTING"
>GList *sel;
sel = GTK_LIST(list)->selection;</PRE
></TD
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><P
>This is how GList is defined (quoting glist.h):</P
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><PRE
CLASS="PROGRAMLISTING"
>typedef struct _GList GList;
struct _GList
{
gpointer data;
GList *next;
GList *prev;
};</PRE
></TD
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></TABLE
><P
>A GList structure is just a simple structure for doubly
linked lists. There exist several g_list_*() functions to
modify a linked list in glib.h. However the
GTK_LIST(MyGtkList)->selection is maintained by the
gtk_list_*() functions and should not be modified.</P
><P
>The selection_mode of the GtkList determines the
selection facilities of a GtkList and therefore the contents
of GTK_LIST(AnyGtkList)->selection:</P
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><TH
><TT
CLASS="LITERAL"
>selection_mode</TT
></TH
><TH
><TT
CLASS="LITERAL"
> GTK_LIST()->selection</TT
>
contents</TH
></TR
></THEAD
><TBODY
><TR
><TD
><TT
CLASS="LITERAL"
>GTK_SELECTION_SINGLE</TT
></TD
><TD
>selection is either NULL or contains a GList*
pointer for a single selected item.</TD
></TR
><TR
><TD
><TT
CLASS="LITERAL"
>GTK_SELECTION_BROWSE</TT
></TD
><TD
>selection is NULL if the list contains no
widgets, otherwise it contains a GList*
pointer for one GList structure.</TD
></TR
><TR
><TD
><TT
CLASS="LITERAL"
>GTK_SELECTION_MULTIPLE</TT
></TD
><TD
>selection is NULL if no listitems are selected
or a a GList* pointer for the first selected
item. that in turn points to a GList structure
for the second selected item and so
on.</TD
></TR
><TR
><TD
><TT
CLASS="LITERAL"
>GTK_SELECTION_EXTENDED</TT
></TD
><TD
>selection is NULL.</TD
></TR
></TBODY
></TABLE
><P
></P
></DIV
><P
>The data field of the GList structure
GTK_LIST(MyGtkList)->selection points to the first
GtkListItem that is selected. So if you would like to
determine which listitems are selected you should go like
this:</P
><TABLE
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WIDTH="100%"
><TR
><TD
><PRE
CLASS="PROGRAMLISTING"
>{
gchar *list_items[]={
"Item0",
"Item1",
"foo",
"last Item",
};
guint nlist_items=sizeof(list_items)/sizeof(list_items[0]);
GtkWidget *list_item;
guint i;
list=gtk_list_new();
gtk_list_set_selection_mode(GTK_LIST(list), GTK_SELECTION_MULTIPLE);
gtk_container_add(GTK_CONTAINER(AnyGtkContainer), list);
gtk_widget_show (list);
for (i = 0; i < nlist_items; i++)
{
list_item=gtk_list_item_new_with_label(list_items[i]);
gtk_object_set_user_data(GTK_OBJECT(list_item), (gpointer)i);
gtk_container_add(GTK_CONTAINER(list), list_item);
gtk_widget_show(list_item);
}
}</PRE
></TD
></TR
></TABLE
><P
>To get known about the selection:</P
><TABLE
BORDER="0"
BGCOLOR="#E0E0E0"
WIDTH="100%"
><TR
><TD
><PRE
CLASS="PROGRAMLISTING"
>{
GList *items;
items=GTK_LIST(list)->selection;
printf("Selected Items: ");
while (items) {
if (GTK_IS_LIST_ITEM(items->data))
printf("%d ", (guint)
gtk_object_get_user_data(items->data));
items=items->next;
}
printf("\n");
}</PRE
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