TreeExpander
Superclasses: Widget
, InitiallyUnowned
, Object
Implemented Interfaces: Accessible
, Buildable
, ConstraintTarget
GtkTreeExpander
is a widget that provides an expander for a list.
It is typically placed as a bottommost child into a GtkListView
to allow users to expand and collapse children in a list with a
TreeListModel
. GtkTreeExpander
provides the common UI
elements, gestures and keybindings for this purpose.
On top of this, the “listitem.expand”, “listitem.collapse” and “listitem.toggle-expand” actions are provided to allow adding custom UI for managing expanded state.
It is important to mention that you want to set the
focusable
property to FALSE when using this
widget, as you want the keyboard focus to be in the treexpander, and not
inside the list to make use of the keybindings.
The GtkTreeListModel
must be set to not be passthrough. Then it
will provide TreeListRow
items which can be set via
set_list_row
on the expander.
The expander will then watch that row item automatically.
set_child
sets the widget that displays
the actual row contents.
GtkTreeExpander
can be modified with properties such as
indent_for_icon
,
indent_for_depth
, and
hide_expander
to achieve a different appearance.
This can even be done to influence individual rows, for example by binding
the hide_expander
property to the item count of
the model of the treelistrow, to hide the expander for rows without children,
even if the row is expandable.
CSS nodes
treeexpander
├── [indent]*
├── [expander]
╰── <child>
GtkTreeExpander
has zero or one CSS nodes with the name “expander” that
should display the expander icon. The node will be :checked
when it
is expanded. If the node is not expandable, an “indent” node will be
displayed instead.
For every level of depth, another “indent” node is prepended.
Accessibility
Until GTK 4.10, GtkTreeExpander
used the GTK_ACCESSIBLE_ROLE_GROUP
role.
Since GTK 4.12, GtkTreeExpander
uses the GTK_ACCESSIBLE_ROLE_BUTTON
role.
Toggling it will change the GTK_ACCESSIBLE_STATE_EXPANDED
state.
Constructors
Methods
- class TreeExpander
-
- get_hide_expander() bool
Gets whether the TreeExpander should be hidden in a GtkTreeListRow.
Added in version 4.10.
- get_indent_for_depth() bool
TreeExpander indents each level of depth with an additional indent.
Added in version 4.10.
- get_indent_for_icon() bool
TreeExpander indents the child by the width of an expander-icon if it is not expandable.
Added in version 4.6.
- get_item() Object | None
Forwards the item set on the
GtkTreeListRow
thatself
is managing.This call is essentially equivalent to calling:
gtk_tree_list_row_get_item (gtk_tree_expander_get_list_row (``self``));
- get_list_row() TreeListRow | None
Gets the list row managed by
self
.
- set_child(child: Widget | None = None) None
Sets the content widget to display.
- Parameters:
child – a
GtkWidget
- set_hide_expander(hide_expander: bool) None
Sets whether the expander icon should be visible in a GtkTreeListRow.
Added in version 4.10.
- Parameters:
hide_expander – TRUE if the expander should be hidden. Otherwise FALSE.
- set_indent_for_depth(indent_for_depth: bool) None
Sets if the TreeExpander should indent the child according to its depth.
Added in version 4.10.
- Parameters:
indent_for_depth – TRUE if the child should be indented. Otherwise FALSE.
- set_indent_for_icon(indent_for_icon: bool) None
Sets if the TreeExpander should indent the child by the width of an expander-icon when it is not expandable.
Added in version 4.6.
- Parameters:
indent_for_icon – TRUE if the child should be indented without expander. Otherwise FALSE.
- set_list_row(list_row: TreeListRow | None = None) None
Sets the tree list row that this expander should manage.
- Parameters:
list_row – a
GtkTreeListRow
Properties
- class TreeExpander
-
- props.hide_expander: bool
Whether the expander icon should be hidden in a GtkTreeListRow. Note that this property simply hides the icon. The actions and keybinding (i.e. collapse and expand) are not affected by this property.
A common use for this property would be to bind to the number of children in a GtkTreeListRow’s model in order to hide the expander when a row has no children.
Added in version 4.10.
- props.indent_for_depth: bool
TreeExpander indents the child according to its depth.
Added in version 4.10.
- props.indent_for_icon: bool
TreeExpander indents the child by the width of an expander-icon if it is not expandable.
Added in version 4.6.
- props.list_row: TreeListRow
The list row to track for expander state.