UI Definitions

The UI definitions are specified in an XML format which can be roughly described by the following DTD.

<!ELEMENT ui          (menubar|toolbar|popup|accelerator)* >
<!ELEMENT menubar     (menuitem|separator|placeholder|menu)* >
<!ELEMENT menu        (menuitem|separator|placeholder|menu)* >
<!ELEMENT popup       (menuitem|separator|placeholder|menu)* >
<!ELEMENT toolbar     (toolitem|separator|placeholder)* >
<!ELEMENT placeholder (menuitem|toolitem|separator|placeholder|menu)* >
<!ELEMENT menuitem     EMPTY >
<!ELEMENT toolitem     EMPTY >
<!ELEMENT separator    EMPTY >
<!ELEMENT accelerator  EMPTY >
<!ATTLIST menubar      name               #IMPLIED 
                       action             #IMPLIED >
<!ATTLIST toolbar      name               #IMPLIED 
                       action             #IMPLIED >
<!ATTLIST popup        name               #IMPLIED 
                       action             #IMPLIED >
<!ATTLIST placeholder  name               #IMPLIED
                       action             #IMPLIED >
<!ATTLIST separator    name               #IMPLIED
                       action             #IMPLIED >
<!ATTLIST menu         name               #IMPLIED
                       action             #REQUIRED
                       position (top|bot) #IMPLIED >
<!ATTLIST menuitem     name               #IMPLIED
                       action             #REQUIRED
                       position (top|bot) #IMPLIED >
<!ATTLIST toolitem     name               #IMPLIED
                       action             #REQUIRED
                       position (top|bot) #IMPLIED >
<!ATTLIST accelerator  name               #IMPLIED
                       action             #REQUIRED >

There are some additional restrictions beyond those specified in the DTD, e.g. every toolitem must have a toolbar in its anchestry and every menuitem must have a menubar or popup in its anchestry. Since a GMarkup parser is used to parse the UI description, it must not only be valid XML, but valid GMarkup.

If a name is not specified, it defaults to the action. If an action is not specified either, the element name is used. The name and action attributes must not contain '/' characters after parsing (since that would mess up path lookup) and must be usable as XML attributes when enclosed in doublequotes, thus they must not '"' characters or references to the " entity.

<ui>
  <menubar>
    <menu name="FileMenu" action="FileMenuAction">
      <menuitem name="New" action="New2Action" />
      <placeholder name="FileMenuAdditions" />
    </menu>
    <menu name="JustifyMenu" action="JustifyMenuAction">
      <menuitem name="Left" action="justify-left"/>
      <menuitem name="Centre" action="justify-center"/>
      <menuitem name="Right" action="justify-right"/>
      <menuitem name="Fill" action="justify-fill"/>
    </menu>
  </menubar>
  <toolbar action="toolbar1">
    <placeholder name="JustifyToolItems">
      <separator/>
      <toolitem name="Left" action="justify-left"/>
      <toolitem name="Centre" action="justify-center"/>
      <toolitem name="Right" action="justify-right"/>
      <toolitem name="Fill" action="justify-fill"/>
      <separator/>
    </placeholder>
  </toolbar>
</ui>

The constructed widget hierarchy is very similar to the element tree of the XML, with the exception that placeholders are merged into their parents. The correspondence of XML elements to widgets should be almost obvious:

The "position" attribute determines where a constructed widget is positioned wrt. to its siblings in the partially constructed tree. If it is "top", the widget is prepended, otherwise it is appended.

UI Merging

The most remarkable feature of GtkUIManager is that it can overlay a set of menuitems and toolitems over another one, and demerge them later.

Merging is done based on the names of the XML elements. Each element is identified by a path which consists of the names of its anchestors, separated by slashes. For example, the menuitem named "Left" in the example above has the path /ui/menubar/JustifyMenu/Left and the toolitem with the same name has path /ui/toolbar1/JustifyToolItems/Left.

Accelerators

Every action has an accelerator path. Accelerators are installed together with menuitem proxies, but they can also be explicitly added with <accelerator> elements in the UI definition. This makes it possible to have accelerators for actions even if they have no visible proxies.

Smart Separators

The separators created by GtkUIManager are "smart", i.e. they do not show up in the UI unless they end up between two visible menu or tool items. Separators which are located at the very beginning or end of the menu or toolbar containing them, or multiple separators next to each other, are hidden. This is a useful feature, since the merging of UI elements from multiple sources can make it hard or impossible to determine in advance whether a separator will end up in such an unfortunate position.

Empty Menus

Submenus pose similar problems to separators inconnection with merging. It is impossible to know in advance whether they will end up empty after merging. GtkUIManager offers two ways to treat empty submenus:

The behaviour is chosen based on the "hide_if_empty" property of the action to which the submenu is associated.

GtkUIManager

typedef struct _GtkUIManager GtkUIManager;

The GtkUIManager struct contains only private members and should not be accessed directly.

gtk_ui_manager_new ()

GtkUIManager* gtk_ui_manager_new            (void);

Creates a new ui manager object.

Since 2.4

gtk_ui_manager_set_add_tearoffs ()

void        gtk_ui_manager_set_add_tearoffs (GtkUIManager *self,
                                             gboolean add_tearoffs);

Sets the "add_tearoffs" property, which controls whether menus generated by this GtkUIManager will have tearoff menu items.

Note that this only affects regular menus. Generated popup menus never have tearoff menu items.

Since 2.4

gtk_ui_manager_get_add_tearoffs ()

gboolean    gtk_ui_manager_get_add_tearoffs (GtkUIManager *self);

Returns whether menus generated by this GtkUIManager will have tearoff menu items.

Since 2.4

gtk_ui_manager_insert_action_group ()

void        gtk_ui_manager_insert_action_group
                                            (GtkUIManager *self,
                                             GtkActionGroup *action_group,
                                             gint pos);

Inserts an action group into the list of action groups associated with self. Actions in earlier groups hide actions with the same name in later groups.

Since 2.4

gtk_ui_manager_remove_action_group ()

void        gtk_ui_manager_remove_action_group
                                            (GtkUIManager *self,
                                             GtkActionGroup *action_group);

Removes an action group from the list of action groups associated with self.

Since 2.4

gtk_ui_manager_get_action_groups ()

GList*      gtk_ui_manager_get_action_groups
                                            (GtkUIManager *self);

Returns the list of action groups associated with self.

Since 2.4

gtk_ui_manager_get_accel_group ()

GtkAccelGroup* gtk_ui_manager_get_accel_group
                                            (GtkUIManager *self);

Returns the GtkAccelGroup associated with self.

Since 2.4

gtk_ui_manager_get_widget ()

GtkWidget*  gtk_ui_manager_get_widget       (GtkUIManager *self,
                                             const gchar *path);

Looks up a widget by following a path. The path consists of the names specified in the XML description of the UI. separated by '/'. Elements which don't have a name or action attribute in the XML (e.g. <popup>) can be addressed by their XML element name (e.g. "popup"). The root element ("/ui") can be omitted in the path.

Note that the widget found by following a path that ends in a <menu> element is the menuitem to which the menu is attached, not the menu itself.

Since 2.4

gtk_ui_manager_get_toplevels ()

GSList*     gtk_ui_manager_get_toplevels    (GtkUIManager *self,
                                             GtkUIManagerItemType types);

Obtains a list of all toplevel widgets of the requested types.

Since 2.4

gtk_ui_manager_get_action ()

GtkAction*  gtk_ui_manager_get_action       (GtkUIManager *self,
                                             const gchar *path);

Looks up an action by following a path. See gtk_ui_manager_get_widget() for more information about paths.

Since 2.4

gtk_ui_manager_add_ui_from_string ()

guint       gtk_ui_manager_add_ui_from_string
                                            (GtkUIManager *self,
                                             const gchar *buffer,
                                             gssize length,
                                             GError **error);

Parses a string containing a UI definition and merges it with the current contents of self. An enclosing <ui> element is added if it is missing.

Since 2.4

gtk_ui_manager_add_ui_from_file ()

guint       gtk_ui_manager_add_ui_from_file (GtkUIManager *self,
                                             const gchar *filename,
                                             GError **error);

Parses a file containing a UI definition and merges it with the current contents of self.

Since 2.4

gtk_ui_manager_new_merge_id ()

guint       gtk_ui_manager_new_merge_id     (GtkUIManager *self);

Returns an unused merge id, suitable for use with gtk_ui_manager_add_ui().

Since 2.4

enum GtkUIManagerItemType

typedef enum {
  GTK_UI_MANAGER_AUTO         = 0,
  GTK_UI_MANAGER_MENUBAR      = 1 << 0,
  GTK_UI_MANAGER_MENU         = 1 << 1,
  GTK_UI_MANAGER_TOOLBAR      = 1 << 2,
  GTK_UI_MANAGER_PLACEHOLDER  = 1 << 3,
  GTK_UI_MANAGER_POPUP        = 1 << 4,
  GTK_UI_MANAGER_MENUITEM     = 1 << 5,
  GTK_UI_MANAGER_TOOLITEM     = 1 << 6,
  GTK_UI_MANAGER_SEPARATOR    = 1 << 7,
  GTK_UI_MANAGER_ACCELERATOR  = 1 << 8
} GtkUIManagerItemType;

These enumeration values are used by gtk_ui_manager_add_ui() to determine what UI element to create.

gtk_ui_manager_add_ui ()

void        gtk_ui_manager_add_ui           (GtkUIManager *self,
                                             guint merge_id,
                                             const gchar *path,
                                             const gchar *name,
                                             const gchar *action,
                                             GtkUIManagerItemType type,
                                             gboolean top);

Adds a UI element to the current contents of self.

If type is GTK_UI_MANAGER_AUTO, GTK+ inserts a menuitem, toolitem or separator if such an element can be inserted at the place determined by path. Otherwise type must indicate an element that can be inserted at the place determined by path.

Since 2.4

gtk_ui_manager_remove_ui ()

void        gtk_ui_manager_remove_ui        (GtkUIManager *self,
                                             guint merge_id);

Unmerges the part of selfs content identified by merge_id.

Since 2.4

gtk_ui_manager_get_ui ()

gchar*      gtk_ui_manager_get_ui           (GtkUIManager *self);

Creates a UI definition of the merged UI.

Since 2.4

gtk_ui_manager_ensure_update ()

void        gtk_ui_manager_ensure_update    (GtkUIManager *self);

Makes sure that all pending updates to the UI have been completed.

This may occasionally be necessary, since GtkUIManager updates the UI in an idle function. A typical example where this function is useful is to enforce that the menubar and toolbar have been added to the main window before showing it:

gtk_container_add (GTK_CONTAINER (window), vbox); 
g_signal_connect (merge, "add_widget", 
                  G_CALLBACK (add_widget), vbox);
gtk_ui_manager_add_ui_from_file (merge, "my-menus");
gtk_ui_manager_add_ui_from_file (merge, "my-toolbars");
gtk_ui_manager_ensure_update (merge);  
gtk_widget_show (window);

Since 2.4

The "add-tearoffs" property

  "add-tearoffs"         gboolean              : Read / Write

The "add-tearoffs" property controls whether generated menus have tearoff menu items.

Note that this only affects regular menus. Generated popup menus never have tearoff menu items.

Default value: FALSE

Since 2.4

The "ui" property

  "ui"                   gchararray            : Read

An XML string describing the merged UI.

Default value: NULL

The "actions-changed" signal

void        user_function                  (GtkUIManager *merge,
                                            gpointer user_data);

The "actions-changed" signal is emitted whenever the set of actions changes.

Since 2.4

The "add-widget" signal

void        user_function                  (GtkUIManager *merge,
                                            GtkWidget *widget,
                                            gpointer user_data);

The add_widget signal is emitted for each generated menubar and toolbar. It is not emitted for generated popup menus, which can be obtained by gtk_ui_manager_get_widget().

Since 2.4

The "connect-proxy" signal

void        user_function                  (GtkUIManager *uimanager,
                                            GtkAction *action,
                                            GtkWidget *proxy,
                                            gpointer user_data);

The connect_proxy signal is emitted after connecting a proxy to an action in the group.

This is intended for simple customizations for which a custom action class would be too clumsy, e.g. showing tooltips for menuitems in the statusbar.

Since 2.4

The "disconnect-proxy" signal

void        user_function                  (GtkUIManager *uimanager,
                                            GtkAction *action,
                                            GtkWidget *proxy,
                                            gpointer user_data);

The disconnect_proxy signal is emitted after disconnecting a proxy from an action in the group.

Since 2.4

The "post-activate" signal

void        user_function                  (GtkUIManager *uimanager,
                                            GtkAction *action,
                                            gpointer user_data);

The post_activate signal is emitted just after the action is activated.

This is intended for applications to get notification just after any action is activated.

Since 2.4

The "pre-activate" signal

void        user_function                  (GtkUIManager *uimanager,
                                            GtkAction *action,
                                            gpointer user_data);

The pre_activate signal is emitted just before the action is activated.

This is intended for applications to get notification just before any action is activated.

Since 2.4