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 “expanded” property which can be used to monitor its expansion state. You should watch this property with a signal connection as follows:

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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:

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

CSS nodes

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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 :checked pseudoclass added to it.

Accessibility

GtkExpander uses the GTK_ACCESSIBLE_ROLE_BUTTON role.

gtk_expander_new ()

GtkWidget *
gtk_expander_new (const char *label);

Creates a new expander using label as the text of the label.

gtk_expander_new_with_mnemonic ()

GtkWidget *
gtk_expander_new_with_mnemonic (const char *label);

Creates a new expander using label as the text of the label. If characters in label are preceded by an underscore, they are underlined. If you need a literal underscore character in a label, use “__” (two underscores). The first underlined character represents a keyboard accelerator called a mnemonic. Pressing Alt and that key activates the button.

gtk_expander_set_expanded ()

void
gtk_expander_set_expanded (GtkExpander *expander,
                           gboolean expanded);

Sets the state of the expander. Set to TRUE, if you want the child widget to be revealed, and FALSE if you want the child widget to be hidden.

gtk_expander_get_expanded ()

gboolean
gtk_expander_get_expanded (GtkExpander *expander);

Queries a GtkExpander and returns its current state. Returns TRUE if the child widget is revealed.

See gtk_expander_set_expanded().

gtk_expander_set_label ()

void
gtk_expander_set_label (GtkExpander *expander,
                        const char *label);

Sets the text of the label of the expander to label .

This will also clear any previously set labels.

gtk_expander_get_label ()

const char *
gtk_expander_get_label (GtkExpander *expander);

Fetches the text from a label widget including any embedded underlines indicating mnemonics and Pango markup, as set by gtk_expander_set_label(). If the label text has not been set the return value will be NULL. This will be the case if you create an empty button with gtk_button_new() to use as a container.

Note that this function behaved differently in versions prior to 2.14 and used to return the label text stripped of embedded underlines indicating mnemonics and Pango markup. This problem can be avoided by fetching the label text directly from the label widget.

gtk_expander_set_use_underline ()

void
gtk_expander_set_use_underline (GtkExpander *expander,
                                gboolean use_underline);

If true, an underline in the text of the expander label indicates the next character should be used for the mnemonic accelerator key.

gtk_expander_get_use_underline ()

gboolean
gtk_expander_get_use_underline (GtkExpander *expander);

Returns whether an embedded underline in the expander label indicates a mnemonic. See gtk_expander_set_use_underline().

gtk_expander_set_use_markup ()

void
gtk_expander_set_use_markup (GtkExpander *expander,
                             gboolean use_markup);

Sets whether the text of the label contains markup in Pango’s text markup language. See gtk_label_set_markup().

gtk_expander_get_use_markup ()

gboolean
gtk_expander_get_use_markup (GtkExpander *expander);

Returns whether the label’s text is interpreted as marked up with the Pango text markup language. See gtk_expander_set_use_markup().

gtk_expander_set_label_widget ()

void
gtk_expander_set_label_widget (GtkExpander *expander,
                               GtkWidget *label_widget);

Set the label widget for the expander. This is the widget that will appear embedded alongside the expander arrow.

gtk_expander_get_label_widget ()

GtkWidget *
gtk_expander_get_label_widget (GtkExpander *expander);

Retrieves the label widget for the frame. See gtk_expander_set_label_widget().

gtk_expander_set_resize_toplevel ()

void
gtk_expander_set_resize_toplevel (GtkExpander *expander,
                                  gboolean resize_toplevel);

Sets whether the expander will resize the toplevel widget containing the expander upon resizing and collpasing.

gtk_expander_get_resize_toplevel ()

gboolean
gtk_expander_get_resize_toplevel (GtkExpander *expander);

Returns whether the expander will resize the toplevel widget containing the expander upon resizing and collpasing.

gtk_expander_set_child ()

void
gtk_expander_set_child (GtkExpander *expander,
                        GtkWidget *child);

Sets the child widget of expander .

gtk_expander_get_child ()

GtkWidget *
gtk_expander_get_child (GtkExpander *expander);

Gets the child widget of expander .

GtkExpander

typedef struct _GtkExpander GtkExpander;

The “child” property

  “child”                    GtkWidget *

The child widget.

Owner: GtkExpander

Flags: Read / Write

The “expanded” property

  “expanded”                 gboolean

Whether the expander has been opened to reveal the child widget.

Owner: GtkExpander

Flags: Read / Write / Construct

Default value: FALSE

The “label” property

  “label”                    char *

Text of the expander’s label.

Owner: GtkExpander

Flags: Read / Write / Construct

Default value: NULL

The “label-widget” property

  “label-widget”             GtkWidget *

A widget to display in place of the usual expander label.

Owner: GtkExpander

Flags: Read / Write

The “resize-toplevel” property

  “resize-toplevel”          gboolean

When this property is TRUE, the expander will resize the toplevel widget containing the expander upon expanding and collapsing.

Owner: GtkExpander

Flags: Read / Write

Default value: FALSE

The “use-markup” property

  “use-markup”               gboolean

The text of the label includes XML markup. See pango_parse_markup().

Owner: GtkExpander

Flags: Read / Write / Construct

Default value: FALSE

The “use-underline” property

  “use-underline”            gboolean

If set, an underline in the text indicates the next character should be used for the mnemonic accelerator key.

Owner: GtkExpander

Flags: Read / Write / Construct

Default value: FALSE

The “activate” signal

void
user_function (GtkExpander *expander,
               gpointer     user_data)

Activates the GtkExpander.

Flags: Action