Sets our main struct and passes it to the parent class
Get the main Gtk struct
Gets the name of the attribute at the current iterator position, as a string. The iterator is not advanced. Since 2.32
This function combines g_menu_attribute_iter_next() with g_menu_attribute_iter_get_name() and g_menu_attribute_iter_get_value(). First the iterator is advanced to the next (possibly first) attribute. If that fails, then FALSE is returned and there are no other effects. If successful, name and value are set to the name and value of the attribute that has just been advanced to. At this point, g_menu_attribute_iter_get_name() and g_menu_attribute_iter_get_value() will return the same values again. The value returned in name remains valid for as long as the iterator remains at the current position. The value returned in value must be unreffed using g_variant_unref() when it is no longer in use. Since 2.32
the main Gtk struct as a void*
Gets the value of the attribute at the current iterator position. The iterator is not advanced. Since 2.32
Attempts to advance the iterator to the next (possibly first) attribute. TRUE is returned on success, or FALSE if there are no more attributes. You must call this function when you first acquire the iterator to advance it to the first attribute (and determine if the first attribute exists at all). Since 2.32
the main Gtk struct
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 the menu in Figure 2, “An example menu”.
Figure 2. An example menu
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)
Figure 3, “A 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.
Figure 3. A menu model
Notice that the separators visible in Figure 2, “An example menu” appear nowhere in Figure 3, “A 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 and the 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.