The purpose of tree widgets is to display hierarchically-organized
data. The Tree widget itself is a vertical container for widgets of
type TreeItem. Tree itself is not terribly different from
CList - both are derived directly from Container, and the
Container methods work in the same way on Tree widgets as on
CList widgets. The difference is that Tree widgets can be nested
within other Tree widgets. We'll see how to do this shortly.
The Tree widget has its own window, and defaults to a white
background, as does CList. Also, most of the Tree methods work in
the same way as the corresponding CList ones. However, Tree is
not derived from CList, so you cannot use them interchangeably.
A Tree is created in the usual way, using:
GtkWidget *gtk_tree_new( void ); |
Like the CList widget, a Tree will simply keep growing as more
items are added to it, as well as when subtrees are expanded. For
this reason, they are almost always packed into a
ScrolledWindow. You might want to use gtk_widget_set_usize() on the
scrolled window to ensure that it is big enough to see the tree's
items, as the default size for ScrolledWindow is quite small.
Now that you have a tree, you'll probably want to add some items to
it. The Tree Item Widget below
explains the gory details of TreeItem. For now, it'll suffice to
create one, using:
GtkWidget *gtk_tree_item_new_with_label( gchar *label ); |
You can then add it to the tree using one of the following (see
Functions and Macros
below for more options):
void gtk_tree_append( GtkTree *tree,
GtkWidget *tree_item );
void gtk_tree_prepend( GtkTree *tree,
GtkWidget *tree_item ); |
Note that you must add items to a Tree one at a time - there is no
equivalent to gtk_list_*_items().
