## GtkActivatable GtkActivatable — An interface for activatable widgets |

## Synopsis

    #include <gtk/gtk.h>

                        GtkActivatable;
                        GtkActivatableIface;
    void                gtk_activatable_do_set_related_action
                                                            (GtkActivatable *activatable,
                                                             GtkAction *action);
    GtkAction *         gtk_activatable_get_related_action  (GtkActivatable *activatable);
    gboolean            gtk_activatable_get_use_action_appearance
                                                            (GtkActivatable *activatable);
    void                gtk_activatable_sync_action_properties
                                                            (GtkActivatable *activatable,
                                                             GtkAction *action);
    void                gtk_activatable_set_related_action  (GtkActivatable *activatable,
                                                             GtkAction *action);
    void                gtk_activatable_set_use_action_appearance
                                                            (GtkActivatable *activatable,
                                                             gboolean use_appearance);

## Object Hierarchy

      GInterface
       +----GtkActivatable

## Prerequisites

GtkActivatable requires GObject.

## Known Implementations

GtkActivatable is implemented by GtkTearoffMenuItem, GtkOptionMenu, GtkLinkButton, GtkRadioButton, GtkRadioToolButton, GtkToggleButton, GtkSeparatorMenuItem, GtkImageMenuItem, GtkCheckButton, GtkRadioMenuItem, GtkButton, GtkMenuToolButton, GtkMenuItem, GtkRecentChooserMenu, GtkToolItem, GtkSeparatorToolItem, GtkCheckMenuItem, GtkToolButton, GtkFontButton, GtkScaleButton, GtkToggleToolButton, GtkVolumeButton and GtkColorButton.

## Properties

      "related-action"           GtkAction*            : Read / Write
      "use-action-appearance"    gboolean              : Read / Write

## Description

Activatable widgets can be connected to a GtkAction and reflects the state of its action. A GtkActivatable 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 GtkActivatable; it is only necessary to implement the GtkActivatable->`sync_action_properties()` and GtkActivatable->`update()` methods and chain up to the parent implementation, however when introducing a new GtkActivatable class; the "related-action" and "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 `gtk_activatable_do_set_related_action()` and `gtk_activatable_sync_action_properties()` at the appropriate times.

Example 36. A class fragment implementing GtkActivatable

    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));

      ...
    }

## Details

### GtkActivatable

    typedef struct _GtkActivatable GtkActivatable;

### GtkActivatableIface

    typedef struct {
      GTypeInterface g_iface;

      /* virtual table */
      void   (* update)                   (GtkActivatable *activatable,
    		                       GtkAction      *action,
    		                       const gchar    *property_name);
      void   (* sync_action_properties)   (GtkActivatable *activatable,
    		                       GtkAction      *action);
    } GtkActivatableIface;

GTypeInterface `g_iface`; |
`update` () | Called to update the activatable when its related action's properties change. You must check the "use-action-appearance" property only apply action properties that are meant to effect the appearance accordingly.
`sync_action_properties` () | Called to update the activatable completely, this is called internally when "related-action" property is set or unset and by the implementor when "use-action-appearance" changes. ### Note This method can be called with a `NULL` action at times

Since 2.16

### gtk_activatable_do_set_related_action ()

    void                gtk_activatable_do_set_related_action
                                                            (GtkActivatable *activatable,
                                                             GtkAction *action);

This is a utility function for GtkActivatable implementors.

When implementing GtkActivatable you must call this when handling changes of the "related-action", and you must also use this to break references in GObject->`dispose()`.

This function adds a reference to the currently set related action for you, it also makes sure the GtkActivatable->`update()` method is called when the related GtkAction properties change and registers to the action's proxy list.

### Note

Be careful to call this before setting the local copy of the GtkAction property, since this function uses `gtk_activatable_get_action()` to retrieve the previous action

`activatable` : | a GtkActivatable
`action` : | the GtkAction to set

Since 2.16

### gtk_activatable_get_related_action ()

    GtkAction *         gtk_activatable_get_related_action  (GtkActivatable *activatable);

Gets the related GtkAction for `activatable`.

`activatable` : | a GtkActivatable
Returns : | the related GtkAction if one is set.

Since 2.16

### gtk_activatable_get_use_action_appearance ()

    gboolean            gtk_activatable_get_use_action_appearance
                                                            (GtkActivatable *activatable);

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

`activatable` : | a GtkActivatable
Returns : | whether `activatable` uses its actions appearance.

Since 2.16

### gtk_activatable_sync_action_properties ()

    void                gtk_activatable_sync_action_properties
                                                            (GtkActivatable *activatable,
                                                             GtkAction *action);

This is called to update the activatable completely, this is called internally when the "related-action" property is set or unset and by the implementing class when "use-action-appearance" changes.

`activatable` : | a GtkActivatable
`action` : | the related GtkAction or `NULL`. allow-none.

Since 2.16

### gtk_activatable_set_related_action ()

    void                gtk_activatable_set_related_action  (GtkActivatable *activatable,
                                                             GtkAction *action);

Sets the related action on the `activatable` object.

### Note

GtkActivatable implementors need to handle the "related-action" property and call `gtk_activatable_do_set_related_action()` when it changes.

`activatable` : | a GtkActivatable
`action` : | the GtkAction to set

Since 2.16

### gtk_activatable_set_use_action_appearance ()

    void                gtk_activatable_set_use_action_appearance
                                                            (GtkActivatable *activatable,
                                                             gboolean use_appearance);

Sets whether this activatable should reset its layout and appearance when setting the related action or when the action changes appearance

### Note

GtkActivatable implementors need to handle the "use-action-appearance" property and call `gtk_activatable_sync_action_properties()` to update `activatable` if needed.

`activatable` : | a GtkActivatable
`use_appearance` : | whether to use the actions appearance

Since 2.16

## Property Details

### The `"related-action"` property

      "related-action"           GtkAction*            : Read / Write

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

### Note

GtkActivatable implementors need to handle the this property and call `gtk_activatable_do_set_related_action()` when it changes.

Since 2.16

### The `"use-action-appearance"` property

      "use-action-appearance"    gboolean              : Read / Write

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

See the GtkAction documentation directly to find which properties should be ignored by the GtkActivatable when this property is `FALSE`.

### Note

GtkActivatable implementors need to handle this property and call `gtk_activatable_sync_action_properties()` on the activatable widget when it changes.

Default value: TRUE

Since 2.16