Activatable widgets can be connected to a Action and reflects the state of its action. A Activatable can also provide feedback through its action, as they are responsible for activating their related actions.

Implementing GtkActivatable

When extending a class that is already Activatable; it is only necessary to implement the Activatable->sync_action_properties() and Activatable->update() methods and chain up to the parent implementation, however when introducing a new Activatable class; the Activatable:related-action and Activatable:use-action-appearance properties need to be handled by the implementor. Handling these properties is mostly a matter of installing the action pointer and boolean flag on your instance, and calling activatableDoSetRelatedAction and activatableSyncActionProperties at the appropriate times.

## A class fragment implementing Activatable

C code

enum {
...

PROP_ACTIVATABLE_RELATED_ACTION,
PROP_ACTIVATABLE_USE_ACTION_APPEARANCE
}

struct _FooBarPrivate
{

  ...

  GtkAction      *action;
  gboolean        use_action_appearance;
};

...

static void foo_bar_activatable_interface_init         (GtkActivatableIface  *iface);
static void foo_bar_activatable_update                 (GtkActivatable       *activatable,
						           GtkAction            *action,
						           const gchar          *property_name);
static void foo_bar_activatable_sync_action_properties (GtkActivatable       *activatable,
						           GtkAction            *action);
...


static void
foo_bar_class_init (FooBarClass *klass)
{

  ...

  g_object_class_override_property (gobject_class, PROP_ACTIVATABLE_RELATED_ACTION, "related-action");
  g_object_class_override_property (gobject_class, PROP_ACTIVATABLE_USE_ACTION_APPEARANCE, "use-action-appearance");

  ...
}


static void
foo_bar_activatable_interface_init (GtkActivatableIface  *iface)
{
  iface->update = foo_bar_activatable_update;
  iface->sync_action_properties = foo_bar_activatable_sync_action_properties;
}

... Break the reference using gtk_activatable_do_set_related_action()...

static void
foo_bar_dispose (GObject *object)
{
  FooBar *bar = FOO_BAR (object);
  FooBarPrivate *priv = FOO_BAR_GET_PRIVATE (bar);

  ...

  if (priv->action)
    {
      gtk_activatable_do_set_related_action (GTK_ACTIVATABLE (bar), NULL);
      priv->action = NULL;
    }
  G_OBJECT_CLASS (foo_bar_parent_class)->dispose (object);
}

... Handle the “related-action” and “use-action-appearance” properties ...

static void
foo_bar_set_property (GObject         *object,
                      guint            prop_id,
                      const GValue    *value,
                      GParamSpec      *pspec)
{
  FooBar *bar = FOO_BAR (object);
  FooBarPrivate *priv = FOO_BAR_GET_PRIVATE (bar);

  switch (prop_id)
    {

      ...

    case PROP_ACTIVATABLE_RELATED_ACTION:
      foo_bar_set_related_action (bar, g_value_get_object (value));
      break;
    case PROP_ACTIVATABLE_USE_ACTION_APPEARANCE:
      foo_bar_set_use_action_appearance (bar, g_value_get_boolean (value));
      break;
    default:
      G_OBJECT_WARN_INVALID_PROPERTY_ID (object, prop_id, pspec);
      break;
    }
}

static void
foo_bar_get_property (GObject         *object,
                         guint            prop_id,
                         GValue          *value,
                         GParamSpec      *pspec)
{
  FooBar *bar = FOO_BAR (object);
  FooBarPrivate *priv = FOO_BAR_GET_PRIVATE (bar);

  switch (prop_id)
    {

      ...

    case PROP_ACTIVATABLE_RELATED_ACTION:
      g_value_set_object (value, priv->action);
      break;
    case PROP_ACTIVATABLE_USE_ACTION_APPEARANCE:
      g_value_set_boolean (value, priv->use_action_appearance);
      break;
    default:
      G_OBJECT_WARN_INVALID_PROPERTY_ID (object, prop_id, pspec);
      break;
    }
}


static void
foo_bar_set_use_action_appearance (FooBar   *bar,
				   gboolean  use_appearance)
{
  FooBarPrivate *priv = FOO_BAR_GET_PRIVATE (bar);

  if (priv->use_action_appearance != use_appearance)
    {
      priv->use_action_appearance = use_appearance;
      
      gtk_activatable_sync_action_properties (GTK_ACTIVATABLE (bar), priv->action);
    }
}

... call gtk_activatable_do_set_related_action() and then assign the action pointer,
no need to reference the action here since gtk_activatable_do_set_related_action() already
holds a reference here for you...
static void
foo_bar_set_related_action (FooBar    *bar,
			    GtkAction *action)
{
  FooBarPrivate *priv = FOO_BAR_GET_PRIVATE (bar);

  if (priv->action == action)
    return;

  gtk_activatable_do_set_related_action (GTK_ACTIVATABLE (bar), action);

  priv->action = action;
}

... Selectively reset and update activatable depending on the use-action-appearance property ...
static void
gtk_button_activatable_sync_action_properties (GtkActivatable       *activatable,
		                                  GtkAction            *action)
{
  GtkButtonPrivate *priv = GTK_BUTTON_GET_PRIVATE (activatable);

  if (!action)
    return;

  if (gtk_action_is_visible (action))
    gtk_widget_show (GTK_WIDGET (activatable));
  else
    gtk_widget_hide (GTK_WIDGET (activatable));
  
  gtk_widget_set_sensitive (GTK_WIDGET (activatable), gtk_action_is_sensitive (action));

  ...
  
  if (priv->use_action_appearance)
    {
      if (gtk_action_get_stock_id (action))
	foo_bar_set_stock (button, gtk_action_get_stock_id (action));
      else if (gtk_action_get_label (action))
	foo_bar_set_label (button, gtk_action_get_label (action));

      ...

    }
}

static void
foo_bar_activatable_update (GtkActivatable       *activatable,
			       GtkAction            *action,
			       const gchar          *property_name)
{
  FooBarPrivate *priv = FOO_BAR_GET_PRIVATE (activatable);

  if (strcmp (property_name, "visible") == 0)
    {
      if (gtk_action_is_visible (action))
	gtk_widget_show (GTK_WIDGET (activatable));
      else
	gtk_widget_hide (GTK_WIDGET (activatable));
    }
  else if (strcmp (property_name, "sensitive") == 0)
    gtk_widget_set_sensitive (GTK_WIDGET (activatable), gtk_action_is_sensitive (action));

  ...

  if (!priv->use_action_appearance)
    return;

  if (strcmp (property_name, "stock-id") == 0)
    foo_bar_set_stock (button, gtk_action_get_stock_id (action));
  else if (strcmp (property_name, "label") == 0)
    foo_bar_set_label (button, gtk_action_get_label (action));

  ...
}

The action that this activatable will activate and receive updates from for various states and possibly appearance.

'GI.Gtk.Interfaces.Activatable.Activatable' implementors need to handle the this property and
call 'GI.Gtk.Interfaces.Activatable.activatableDoSetRelatedAction' when it changes.

Since: 2.16

Whether this activatable should reset its layout and appearance when setting the related action or when the action changes appearance.

See the Action documentation directly to find which properties should be ignored by the Activatable when this property is False.

'GI.Gtk.Interfaces.Activatable.Activatable' implementors need to handle this property
and call 'GI.Gtk.Interfaces.Activatable.activatableSyncActionProperties' on the activatable
widget when it changes.

Since: 2.16