Expander

A gtk.Expander allows the user to hide or show its child by clicking on an expander triangle similar to the triangles used in a gtk.TreeView

Normally you use an expander as you would use any other descendant of gtk.Bin; you create the child widget and use Container.add 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 gtk.Expander 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:

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

# CSS nodes

|[<!-- language="plain" -->
expander
├── 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.

Constructors

this this(GtkExpander* gtkExpander, bool ownedRef): Sets our main struct and passes it to the parent class.
this this(string label, bool mnemonic): Creates a new expander using label as the text of the label. Since 2.4

Members

Functions

addOnActivate gulong addOnActivate(void delegate(Expander) dlg, ConnectFlags connectFlags)
getExpanded bool getExpanded(): Queries a gtk.Expander and returns its current state. Returns TRUE if the child widget is revealed.
getExpanderStruct GtkExpander* getExpanderStruct(bool transferOwnership): Get the main Gtk struct
getLabel string getLabel(): Fetches the text from a label widget including any embedded underlines indicating mnemonics and Pango markup, as set by Expander.setLabel. 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 Button.new to use as a container.
getLabelFill bool getLabelFill(): Returns whether the label widget will fill all available horizontal space allocated to expander.
getLabelWidget Widget getLabelWidget(): Retrieves the label widget for the frame. See Expander.setLabelWidget.
getResizeToplevel bool getResizeToplevel(): Returns whether the expander will resize the toplevel widget containing the expander upon resizing and collpasing.
getSpacing int getSpacing(): Gets the value set by Expander.setSpacing.
getStruct void* getStruct(): the main Gtk struct as a void*
getUseMarkup bool getUseMarkup(): Returns whether the label’s text is interpreted as marked up with the [Pango text markup language]PangoMarkupFormat. See Expander.setUseMarkup.
getUseUnderline bool getUseUnderline(): Returns whether an embedded underline in the expander label indicates a mnemonic. See Expander.setUseUnderline.
setExpanded void setExpanded(bool 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.
setLabel void setLabel(string label): Sets the text of the label of the expander to label.
setLabelFill void setLabelFill(bool labelFill): Sets whether the label widget should fill all available horizontal space allocated to expander.
setLabelWidget void setLabelWidget(Widget labelWidget): Set the label widget for the expander. This is the widget that will appear embedded alongside the expander arrow.
setResizeToplevel void setResizeToplevel(bool resizeToplevel): Sets whether the expander will resize the toplevel widget containing the expander upon resizing and collpasing.
setSpacing void setSpacing(int spacing): Sets the spacing field of expander, which is the number of pixels to place between expander and the child.
setUseMarkup void setUseMarkup(bool useMarkup): Sets whether the text of the label contains markup in [Pango’s text markup language]PangoMarkupFormat. See Label.setMarkup.
setUseUnderline void setUseUnderline(bool useUnderline): If true, an underline in the text of the expander label indicates the next character should be used for the mnemonic accelerator key.

Static functions

getType GType getType()

Variables

gtkExpander GtkExpander* gtkExpander;: the main Gtk struct

Inherited Members

From Bin

gtkBin GtkBin* gtkBin;: the main Gtk struct
getBinStruct GtkBin* getBinStruct(bool transferOwnership): Get the main Gtk struct
getStruct void* getStruct(): the main Gtk struct as a void*
getType GType getType()
getChild Widget getChild(): Gets the child of the gtk.Bin, or NULL if the bin contains no child widget. The returned widget does not have a reference added, so you do not need to unref it.

gtk Expander classes

Expander