Struct gtk::Expander

#[repr(transparent)]
pub struct Expander { /* private fields */ }

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

Normally you use an expander as you would use any other descendant of Bin; you create the child widget and use ContainerExt::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 Expander but do not add a child to it. The expander widget has an property::Expander::expanded property which can be used to monitor its expansion state. You should watch this property with a signal connection as follows:

⚠️ The following code is in 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:

⚠️ The following code is in 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

⚠️ The following code is in 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.

Implements

ExpanderExt, BinExt, ContainerExt, WidgetExt, glib::ObjectExt, BuildableExt, ContainerExtManual, WidgetExtManual, BuildableExtManual

Implementations

impl Expander

pub const NONE: Option<&'static Expander> = None

pub fn new(label: Option<&str>) -> Expander

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

label

the text of the label

Returns

a new Expander widget.

pub fn with_mnemonic(label: &str) -> Expander

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.

label

the text of the label with an underscore in front of the mnemonic character

Returns

a new Expander widget.

pub fn builder() -> ExpanderBuilder

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

This method returns an instance of ExpanderBuilder which can be used to create Expander objects.

Trait Implementations

impl Clone for Expander

fn clone(&self) -> Self

Returns a copy of the value.

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

Performs copy-assignment from source.

impl Debug for Expander

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

Formats the value using the given formatter.

impl Default for Expander

fn default() -> Self

Returns the “default value” for a type.

impl Display for Expander

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

Formats the value using the given formatter.

impl Hash for Expander

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

Feeds this value into the given Hasher.

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

Feeds a slice of this type into the given Hasher.

impl Ord for Expander

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

This method returns an Ordering between self and other.

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

Compares and returns the maximum of two values.

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

Compares and returns the minimum of two values.

const fn clamp(self, min: Self, max: Self) -> Selfwhere
    Self: PartialOrd<Self>,

Restrict a value to a certain interval.

impl ParentClassIs for Expander

type Parent = Bin

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

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

This method tests for self and other values to be equal, and is used by ==.

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

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

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

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

This method returns an ordering between self and other values if one exists.

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

This method tests less than (for self and other) and is used by the < operator.

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

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

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

This method tests greater than (for self and other) and is used by the > operator.

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

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

impl StaticType for Expander

fn static_type() -> Type

Returns the type identifier of Self.

impl Eq for Expander

impl IsA<Bin> for Expander

impl IsA<Buildable> for Expander

impl IsA<Container> for Expander

impl IsA<Widget> for Expander