Struct gtk::Expander

pub struct Expander(_, _);

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 Expander: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);

  // ...
}

Expander as Buildable

The Expander implementation of the Buildable 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 Expander:

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

Expander 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::object::ObjectExt, BuildableExt, WidgetExtManual, BuildableExtManual

Implementations

impl Expander

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

Trait Implementations

impl Clone for Expander

fn clone(&self) -> Expander

Returns a copy of the value.

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 Display for Expander

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

Formats the value using the given formatter.

impl Eq for Expander

impl Hash for Expander

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

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 IsA<Bin> for Expander

impl IsA<Buildable> for Expander

impl IsA<Container> for Expander

impl IsA<Widget> for Expander

impl Ord for Expander

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

This method returns an [Ordering] between self and other.

#[must_use]fn max(self, other: Self) -> Self

Compares and returns the maximum of two values.

#[must_use]fn min(self, other: Self) -> Self

Compares and returns the minimum of two values.

#[must_use]fn clamp(self, min: Self, max: Self) -> Self

🔬 This is a nightly-only experimental API. (clamp)

Restrict a value to a certain interval.

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

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

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

#[must_use]fn ne(&self, other: &Rhs) -> bool

This method tests for !=.

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

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

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

#[must_use]fn lt(&self, other: &Rhs) -> bool

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

#[must_use]fn le(&self, other: &Rhs) -> bool

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

#[must_use]fn gt(&self, other: &Rhs) -> bool

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

#[must_use]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.