Object Hierarchy:

Object hierarchy for Expander


[ CCode ( type_id = "gtk_expander_get_type ()" ) ]
public class Expander : Widget, Accessible, Buildable, ConstraintTarget

`GtkExpander` allows the user to reveal its child by clicking on an expander triangle.

![An example GtkExpander](expander.png)

This is similar to the triangles used in a `GtkTreeView`.

Normally you use an expander as you would use a frame; you create the child widget and use [method@Gtk.Expander.set_child] to add it to the expander. When the expander is toggled, it will take care of showing and hiding the child automatically.

Special Usage

There are situations in which you may prefer to show and hide the expanded widget yourself, such as when you want to actually create the widget at expansion time. In this case, create a `GtkExpander` but do not add a child to it. The expander widget has an [property@Gtk.Expander:expanded[ property which can be used to monitor its expansion state. You should watch this property with a signal connection as follows:

```c static void expander_callback (GObject *object, GParamSpec *param_spec, gpointer user_data) { GtkExpander *expander;

expander = GTK_EXPANDER (object);

if (gtk_expander_get_expanded (expander)) { // Show or create widgets } else { // Hide or destroy widgets } }

static void create_expander (void) { GtkWidget *expander = gtk_expander_new_with_mnemonic ("_More Options"); g_signal_connect (expander, "notify:expanded", G_CALLBACK (expander_callback), NULL);

// ... } ```

GtkExpander as GtkBuildable

The `GtkExpander` implementation of the `GtkBuildable` interface supports placing a child in the label position by specifying “label” as the “type” attribute of a <child> element. A normal content child can be specified without specifying a <child> type attribute.

An example of a UI definition fragment with GtkExpander:

```xml <object class="GtkExpander"> <child type="label"> <object class="GtkLabel" id="expander-label"/> </child> <child> <object class="GtkEntry" id="expander-content"/> </child> </object> ```

CSS nodes

``` expander ╰── box ├── title │ ├── arrow │ ╰── <label widget> ╰── <child> ```

`GtkExpander` has three CSS nodes, the main node with the name expander, a subnode with name title and node below it with name arrow. The arrow of an expander that is showing its child gets the GtkExpander:checked pseudoclass added to it.


`GtkExpander` uses the gtk_accessible_role_button role.

Namespace: Gtk
Package: gtk4



Creation methods:



Inherited Members:

All known members inherited from class Gtk.Widget