Class

GioMenuModel

Description [src]

abstract class Gio.MenuModel : GObject.Object {
  parent_instance: GObject,
  priv: GMenuModelPrivate*
}

GMenuModel represents the contents of a menu — an ordered list of menu items. The items are associated with actions, which can be activated through them. Items can be grouped in sections, and may have submenus associated with them. Both items and sections usually have some representation data, such as labels or icons. The type of the associated action (ie whether it is stateful, and what kind of state it has) can influence the representation of the item.

The conceptual model of menus in GMenuModel is hierarchical: sections and submenus are again represented by GMenuModels. Menus themselves do not define their own roles. Rather, the role of a particular GMenuModel is defined by the item that references it (or, in the case of the ‘root’ menu, is defined by the context in which it is used).

As an example, consider the visible portions of this menu:

An example menu # {#menu-example}

There are 8 “menus” visible in the screenshot: one menubar, two submenus and 5 sections:

  • the toplevel menubar (containing 4 items)
  • the View submenu (containing 3 sections)
  • the first section of the View submenu (containing 2 items)
  • the second section of the View submenu (containing 1 item)
  • the final section of the View submenu (containing 1 item)
  • the Highlight Mode submenu (containing 2 sections)
  • the Sources section (containing 2 items)
  • the Markup section (containing 2 items)

The [example][menu-model] illustrates the conceptual connection between these 8 menus. Each large block in the figure represents a menu and the smaller blocks within the large block represent items in that menu. Some items contain references to other menus.

A menu example # {#menu-model}

Notice that the separators visible in the [example][menu-example] appear nowhere in the [menu model][menu-model]. This is because separators are not explicitly represented in the menu model. Instead, a separator is inserted between any two non-empty sections of a menu. Section items can have labels just like any other item. In that case, a display system may show a section header instead of a separator.

The motivation for this abstract model of application controls is that modern user interfaces tend to make these controls available outside the application. Examples include global menus, jumplists, dash boards, etc. To support such uses, it is necessary to ‘export’ information about actions and their representation in menus, which is exactly what the [GActionGroup exporter][gio-GActionGroup-exporter] and the [GMenuModel exporter][gio-GMenuModel-exporter] do for GActionGroup and GMenuModel. The client-side counterparts to make use of the exported information are GDBusActionGroup and GDBusMenuModel.

The API of GMenuModel is very generic, with iterators for the attributes and links of an item, see g_menu_model_iterate_item_attributes() and g_menu_model_iterate_item_links(). The ‘standard’ attributes and link types have predefined names: G_MENU_ATTRIBUTE_LABEL, G_MENU_ATTRIBUTE_ACTION, G_MENU_ATTRIBUTE_TARGET, G_MENU_LINK_SECTION and G_MENU_LINK_SUBMENU.

Items in a GMenuModel represent active controls if they refer to an action that can get activated when the user interacts with the menu item. The reference to the action is encoded by the string id in the G_MENU_ATTRIBUTE_ACTION attribute. An action id uniquely identifies an action in an action group. Which action group(s) provide actions depends on the context in which the menu model is used. E.g. when the model is exported as the application menu of a GtkApplication, actions can be application-wide or window-specific (and thus come from two different action groups). By convention, the application-wide actions have names that start with “app.”, while the names of window-specific actions start with “win.”.

While a wide variety of stateful actions is possible, the following is the minimum that is expected to be supported by all users of exported menu information: - an action with no parameter type and no state - an action with no parameter type and boolean state - an action with string parameter type and string state

Stateless

A stateless action typically corresponds to an ordinary menu item.

Selecting such a menu item will activate the action (with no parameter).

Boolean State

An action with a boolean state will most typically be used with a “toggle” or “switch” menu item. The state can be set directly, but activating the action (with no parameter) results in the state being toggled.

Selecting a toggle menu item will activate the action. The menu item should be rendered as “checked” when the state is true.

String Parameter and State

Actions with string parameters and state will most typically be used to represent an enumerated choice over the items available for a group of radio menu items. Activating the action with a string parameter is equivalent to setting that parameter as the state.

Radio menu items, in addition to being associated with the action, will have a target value. Selecting that menu item will result in activation of the action with the target value as the parameter. The menu item should be rendered as “selected” when the state of the action is equal to the target value of the menu item.

Available since:2.32

Hierarchy

hierarchy this GMenuModel ancestor_0 GObject ancestor_0--this

Ancestors

Instance methods

g_menu_model_get_item_attribute

Queries item at position item_index in model for the attribute specified by attribute.

Available since: 2.32

g_menu_model_get_item_attribute_value

Queries the item at position item_index in model for the attribute specified by attribute.

Available since: 2.32

g_menu_model_get_item_link

Queries the item at position item_index in model for the link specified by link.

Available since: 2.32

g_menu_model_get_n_items

Query the number of items in model.

Available since: 2.32

g_menu_model_is_mutable

Queries if model is mutable.

Available since: 2.32

g_menu_model_items_changed

Requests emission of the GMenuModel::items-changed signal on model.

Available since: 2.32

g_menu_model_iterate_item_attributes

Creates a GMenuAttributeIter to iterate over the attributes of the item at position item_index in model.

Available since: 2.32

g_menu_model_iterate_item_links

Creates a GMenuLinkIter to iterate over the links of the item at position item_index in model.

Available since: 2.32

Methods inherited from GObject (43)

Signals

Gio.MenuModel::items-changed

Emitted when a change has occurred to the menu.

Signals inherited from GObject (1)

Class structure

struct GioMenuModelClass {
  GObjectClass parent_class;
  gboolean (* is_mutable) (
    GMenuModel* model
  );
  gint (* get_n_items) (
    GMenuModel* model
  );
  void (* get_item_attributes) (
    GMenuModel* model,
    gint item_index,
    GHashTable** attributes
  );
  GMenuAttributeIter* (* iterate_item_attributes) (
    GMenuModel* model,
    gint item_index
  );
  GVariant* (* get_item_attribute_value) (
    GMenuModel* model,
    gint item_index,
    const gchar* attribute,
    const GVariantType* expected_type
  );
  void (* get_item_links) (
    GMenuModel* model,
    gint item_index,
    GHashTable** links
  );
  GMenuLinkIter* (* iterate_item_links) (
    GMenuModel* model,
    gint item_index
  );
  GMenuModel* (* get_item_link) (
    GMenuModel* model,
    gint item_index,
    const gchar* link
  );
  
}
Class members
parent_class
GObjectClass
  No description available.
is_mutable
gboolean (* is_mutable) (
    GMenuModel* model
  )
  No description available.
get_n_items
gint (* get_n_items) (
    GMenuModel* model
  )
  No description available.
get_item_attributes
void (* get_item_attributes) (
    GMenuModel* model,
    gint item_index,
    GHashTable** attributes
  )
  No description available.
iterate_item_attributes
GMenuAttributeIter* (* iterate_item_attributes) (
    GMenuModel* model,
    gint item_index
  )
  No description available.
get_item_attribute_value
GVariant* (* get_item_attribute_value) (
    GMenuModel* model,
    gint item_index,
    const gchar* attribute,
    const GVariantType* expected_type
  )
  No description available.
get_item_links
void (* get_item_links) (
    GMenuModel* model,
    gint item_index,
    GHashTable** links
  )
  No description available.
iterate_item_links
GMenuLinkIter* (* iterate_item_links) (
    GMenuModel* model,
    gint item_index
  )
  No description available.
get_item_link
GMenuModel* (* get_item_link) (
    GMenuModel* model,
    gint item_index,
    const gchar* link
  )
  No description available.

Virtual methods

Gio.MenuModelClass.get_item_attribute_value

Queries the item at position item_index in model for the attribute specified by attribute.

Available since: 2.32

Gio.MenuModelClass.get_item_attributes

Gets all the attributes associated with the item in the menu model.

Queries the item at position item_index in model for the link specified by link.

Available since: 2.32

Gets all the links associated with the item in the menu model.

Gio.MenuModelClass.get_n_items

Query the number of items in model.

Available since: 2.32

Gio.MenuModelClass.is_mutable

Queries if model is mutable.

Available since: 2.32

Gio.MenuModelClass.iterate_item_attributes

Creates a GMenuAttributeIter to iterate over the attributes of the item at position item_index in model.

Available since: 2.32

Creates a GMenuLinkIter to iterate over the links of the item at position item_index in model.

Available since: 2.32