Struct TreeExpander

pub struct TreeExpander { /* private fields */ }

TreeExpander is a widget that provides an expander for a list.

It is typically placed as a bottommost child into a ListView to allow users to expand and collapse children in a list with a TreeListModel. TreeExpander 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 TreeListModel 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.

TreeExpander 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.

Shortcuts and Gestures

TreeExpander supports the following keyboard shortcuts:

• + or * expands the expander.
• - or / collapses the expander.
• Left and right arrow keys, when combined with Shift or Ctrl+Shift, will expand or collapse, depending on the locale’s text direction.
• Ctrl+␣ toggles the expander state.

The row can also expand on drag gestures.

Actions

TreeExpander defines a set of built-in actions:

• listitem.expand expands the expander if it can be expanded.
• listitem.collapse collapses the expander.
• listitem.toggle-expand tries to expand the expander if it was collapsed or collapses it if it was expanded.

CSS nodes

treeexpander
├── [indent]*
├── [expander]
╰── <child>

TreeExpander 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, TreeExpander used the GTK_ACCESSIBLE_ROLE_GROUP role.

Since GTK 4.12, TreeExpander uses the GTK_ACCESSIBLE_ROLE_BUTTON role. Toggling it will change the GTK_ACCESSIBLE_STATE_EXPANDED state.

Properties

child

The child widget with the actual contents.

Readable | Writeable

hide-expander

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.

Readable | Writeable

indent-for-depth

TreeExpander indents the child according to its depth.

Readable | Writeable

indent-for-icon

TreeExpander indents the child by the width of an expander-icon if it is not expandable.

Readable | Writeable

item

The item held by this expander’s row.

Readable

list-row

The list row to track for expander state.

Readable | Writeable

Widget

can-focus

Whether the widget or any of its descendents can accept the input focus.

This property is meant to be set by widget implementations, typically in their instance init function.

Readable | Writeable

can-target

Whether the widget can receive pointer events.

Readable | Writeable

css-classes

A list of css classes applied to this widget.

Readable | Writeable

css-name

The name of this widget in the CSS tree.

This property is meant to be set by widget implementations, typically in their instance init function.

Readable | Writeable | Construct Only

cursor

The cursor used by @widget.

Readable | Writeable

focus-on-click

Whether the widget should grab focus when it is clicked with the mouse.

This property is only relevant for widgets that can take focus.

Readable | Writeable

focusable

Whether this widget itself will accept the input focus.

Readable | Writeable

halign

How to distribute horizontal space if widget gets extra space.

Readable | Writeable

has-default

Whether the widget is the default widget.

Readable

has-focus

Whether the widget has the input focus.

Readable

has-tooltip

Enables or disables the emission of the query-tooltip signal on @widget.

A true value indicates that @widget can have a tooltip, in this case the widget will be queried using query-tooltip to determine whether it will provide a tooltip or not.

Readable | Writeable

height-request

Overrides for height request of the widget.

If this is -1, the natural request will be used.

Readable | Writeable

hexpand

Whether to expand horizontally.

Readable | Writeable

hexpand-set

Whether to use the hexpand property.

Readable | Writeable

layout-manager

The LayoutManager instance to use to compute the preferred size of the widget, and allocate its children.

This property is meant to be set by widget implementations, typically in their instance init function.

Readable | Writeable

margin-bottom

Margin on bottom side of widget.

This property adds margin outside of the widget’s normal size request, the margin will be added in addition to the size from WidgetExt::set_size_request() for example.

Readable | Writeable

margin-end

Margin on end of widget, horizontally.

This property supports left-to-right and right-to-left text directions.

This property adds margin outside of the widget’s normal size request, the margin will be added in addition to the size from WidgetExt::set_size_request() for example.

Readable | Writeable

margin-start

Margin on start of widget, horizontally.

This property supports left-to-right and right-to-left text directions.

This property adds margin outside of the widget’s normal size request, the margin will be added in addition to the size from WidgetExt::set_size_request() for example.

Readable | Writeable

margin-top

Margin on top side of widget.

This property adds margin outside of the widget’s normal size request, the margin will be added in addition to the size from WidgetExt::set_size_request() for example.

Readable | Writeable

name

The name of the widget.

Readable | Writeable

opacity

The requested opacity of the widget.

Readable | Writeable

overflow

How content outside the widget’s content area is treated.

This property is meant to be set by widget implementations, typically in their instance init function.

Readable | Writeable

parent

The parent widget of this widget.

Readable

receives-default

Whether the widget will receive the default action when it is focused.

Readable | Writeable

root

The Root widget of the widget tree containing this widget.

This will be NULL if the widget is not contained in a root widget.

Readable

scale-factor

The scale factor of the widget.

Readable

sensitive

Whether the widget responds to input.

Readable | Writeable

tooltip-markup

Sets the text of tooltip to be the given string, which is marked up with Pango markup.

Also see Tooltip::set_markup().

This is a convenience property which will take care of getting the tooltip shown if the given string is not NULL: has-tooltip will automatically be set to true and there will be taken care of query-tooltip in the default signal handler.

Note that if both tooltip-text and tooltip-markup are set, the last one wins.

Readable | Writeable

tooltip-text

Sets the text of tooltip to be the given string.

Also see Tooltip::set_text().

This is a convenience property which will take care of getting the tooltip shown if the given string is not NULL: has-tooltip will automatically be set to true and there will be taken care of query-tooltip in the default signal handler.

Note that if both tooltip-text and tooltip-markup are set, the last one wins.

Readable | Writeable

valign

How to distribute vertical space if widget gets extra space.

Readable | Writeable

vexpand

Whether to expand vertically.

Readable | Writeable

vexpand-set

Whether to use the vexpand property.

Readable | Writeable

visible

Whether the widget is visible.

Readable | Writeable

width-request

Overrides for width request of the widget.

If this is -1, the natural request will be used.

Readable | Writeable

Accessible

accessible-role

The accessible role of the given Accessible implementation.

The accessible role cannot be changed once set.

Readable | Writeable

Implements

WidgetExt, [trait@glib::ObjectExt], AccessibleExt, BuildableExt, ConstraintTargetExt, WidgetExtManual, AccessibleExtManual

GLib type: GObject with reference counted clone semantics.

Implementations

impl TreeExpander

pub fn new() -> TreeExpander

Creates a new TreeExpander

Returns

a new TreeExpander

pub fn builder() -> TreeExpanderBuilder

Creates a new builder-pattern struct instance to construct TreeExpander objects.

This method returns an instance of TreeExpanderBuilder which can be used to create TreeExpander objects.

pub fn child(&self) -> Option<Widget>

Gets the child widget displayed by @self.

Returns

The child displayed by @self

pub fn hides_expander(&self) -> bool

Available on crate feature v4_10 only.

Gets whether the TreeExpander should be hidden in a GtkTreeListRow.

Returns

TRUE if the expander icon should be hidden. Otherwise FALSE.

pub fn is_indent_for_depth(&self) -> bool

Available on crate feature v4_10 only.

TreeExpander indents each level of depth with an additional indent.

Returns

TRUE if the child should be indented . Otherwise FALSE.

pub fn is_indent_for_icon(&self) -> bool

Available on crate feature v4_6 only.

TreeExpander indents the child by the width of an expander-icon if it is not expandable.

Returns

TRUE if the child should be indented when not expandable. Otherwise FALSE.

pub fn item(&self) -> Option<Object>

Forwards the item set on the TreeListRow that @self is managing.

This call is essentially equivalent to calling:

⚠️ The following code is in c ⚠️

gtk_tree_list_row_get_item (gtk_tree_expander_get_list_row (@self));

Returns

The item of the row

pub fn list_row(&self) -> Option<TreeListRow>

Gets the list row managed by @self.

Returns

The list row displayed by @self

pub fn set_child(&self, child: Option<&impl IsA<Widget>>)

Sets the content widget to display.

child

a Widget

pub fn set_hide_expander(&self, hide_expander: bool)

Available on crate feature v4_10 only.

Sets whether the expander icon should be visible in a GtkTreeListRow.

hide_expander

TRUE if the expander should be hidden. Otherwise FALSE.

pub fn set_indent_for_depth(&self, indent_for_depth: bool)

Available on crate feature v4_10 only.

Sets if the TreeExpander should indent the child according to its depth.

indent_for_depth

TRUE if the child should be indented. Otherwise FALSE.

pub fn set_indent_for_icon(&self, indent_for_icon: bool)

Available on crate feature v4_6 only.

Sets if the TreeExpander should indent the child by the width of an expander-icon when it is not expandable.

indent_for_icon

TRUE if the child should be indented without expander. Otherwise FALSE.

pub fn set_list_row(&self, list_row: Option<&TreeListRow>)

Sets the tree list row that this expander should manage.

list_row

a TreeListRow

pub fn connect_child_notify<F: Fn(&Self) + 'static>( &self, f: F, ) -> SignalHandlerId

pub fn connect_hide_expander_notify<F: Fn(&Self) + 'static>( &self, f: F, ) -> SignalHandlerId

Available on crate feature v4_10 only.

pub fn connect_indent_for_depth_notify<F: Fn(&Self) + 'static>( &self, f: F, ) -> SignalHandlerId

Available on crate feature v4_10 only.

pub fn connect_indent_for_icon_notify<F: Fn(&Self) + 'static>( &self, f: F, ) -> SignalHandlerId

Available on crate feature v4_6 only.

pub fn connect_item_notify<F: Fn(&Self) + 'static>( &self, f: F, ) -> SignalHandlerId

pub fn connect_list_row_notify<F: Fn(&Self) + 'static>( &self, f: F, ) -> SignalHandlerId

Trait Implementations

impl Clone for TreeExpander

fn clone(&self) -> Self

Makes a clone of this shared reference.

This increments the strong reference count of the object. Dropping the object will decrement it again.

fn clone_from(&mut self, source: &Self)

Performs copy-assignment from source.

impl Debug for TreeExpander

fn fmt(&self, f: &mut Formatter<'_>) -> Result

Formats the value using the given formatter.

impl Default for TreeExpander

fn default() -> Self

Returns the “default value” for a type.

impl HasParamSpec for TreeExpander

type ParamSpec = ParamSpecObject

type SetValue = TreeExpander

Preferred value to be used as setter for the associated ParamSpec.

type BuilderFn = fn(_: &str) -> ParamSpecObjectBuilder<'_, TreeExpander>

fn param_spec_builder() -> Self::BuilderFn

impl Hash for TreeExpander

fn hash<H>(&self, state: &mut H)

where H: Hasher,

Hashes the memory address of this object.

fn hash_slice<H>(data: &[Self], state: &mut H)

where H: Hasher, Self: Sized,

Feeds a slice of this type into the given Hasher.

impl Ord for TreeExpander

fn cmp(&self, other: &Self) -> Ordering

Comparison for two GObjects.

Compares the memory addresses of the provided objects.

fn max(self, other: Self) -> Self

where Self: Sized,

Compares and returns the maximum of two values.

fn min(self, other: Self) -> Self

where Self: Sized,

Compares and returns the minimum of two values.

fn clamp(self, min: Self, max: Self) -> Self

where Self: Sized,

Restrict a value to a certain interval.

impl ParentClassIs for TreeExpander

type Parent = Widget

impl<OT: ObjectType> PartialEq<OT> for TreeExpander

fn eq(&self, other: &OT) -> bool

Equality for two GObjects.

Two GObjects are equal if their memory addresses are equal.

fn ne(&self, other: &Rhs) -> bool

Tests for !=. The default implementation is almost always sufficient, and should not be overridden without very good reason.

impl<OT: ObjectType> PartialOrd<OT> for TreeExpander

fn partial_cmp(&self, other: &OT) -> Option<Ordering>

Partial comparison for two GObjects.

Compares the memory addresses of the provided objects.

fn lt(&self, other: &Rhs) -> bool

Tests less than (for self and other) and is used by the < operator.

fn le(&self, other: &Rhs) -> bool

Tests less than or equal to (for self and other) and is used by the <= operator.

fn gt(&self, other: &Rhs) -> bool

Tests greater than (for self and other) and is used by the > operator.

fn ge(&self, other: &Rhs) -> bool

Tests greater than or equal to (for self and other) and is used by the >= operator.

impl StaticType for TreeExpander

fn static_type() -> Type

Returns the type identifier of Self.

impl Eq for TreeExpander

impl IsA<Accessible> for TreeExpander

impl IsA<Buildable> for TreeExpander

impl IsA<ConstraintTarget> for TreeExpander

impl IsA<Widget> for TreeExpander