GtkUIManager
Constructing menus and toolbars from an XML description
A #GtkUIManager constructs a user interface (menus and toolbars) from
one or more UI definitions, which reference actions from one or more
action groups.
UI Definitions
The UI definitions are specified in an XML format which can be
roughly described by the following DTD.
Do not confuse the GtkUIManager UI Definitions described here with
the similarly named GtkBuilder UI
Definitions.
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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.
A UI definition
<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:
menubara #GtkMenuBartoolbara #GtkToolbarpopupa toplevel #GtkMenumenua #GtkMenu attached to a menuitemmenuitema #GtkMenuItem subclass, the exact type depends on the
actiontoolitema #GtkToolItem subclass, the exact type depends on the
action. Note that toolitem elements may contain a menu element, but only
if their associated action specifies a #GtkMenuToolButton as proxy.separatora #GtkSeparatorMenuItem or
#GtkSeparatorToolItemacceleratora keyboard accelerator
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.
For separators in toolbars, you can set expand="true" to
turn them from a small, visible separator to an expanding, invisible one.
Toolitems following an expanding separator are effectively right-aligned.
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:
make them disappear by hiding the menu item they're attached to
add an insensitive "Empty" item
The behaviour is chosen based on the "hide_if_empty" property of the action
to which the submenu is associated.
GtkUIManager as GtkBuildable
The GtkUIManager implementation of the GtkBuildable interface accepts
GtkActionGroup objects as <child> elements in UI definitions.
A GtkUIManager UI definition as described above can be embedded in
an GtkUIManager <object> element in a GtkBuilder UI definition.
The widgets that are constructed by a GtkUIManager can be embedded in
other parts of the constructed user interface with the help of the
"constructor" attribute. See the example below.
An embedded GtkUIManager UI definition
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#GtkBuilder
The GtkUIManager struct contains only private
members and should not be accessed directly.
@uimanager: the object which received the signal.
@uimanager: the object which received the signal.
@widget:
@uimanager: the object which received the signal.
@arg1:
@widget:
@uimanager: the object which received the signal.
@arg1:
@widget:
@uimanager: the object which received the signal.
@arg1:
@uimanager: the object which received the signal.
@arg1:
@void:
@Returns:
@self:
@add_tearoffs:
@self:
@Returns:
@self:
@action_group:
@pos:
@self:
@action_group:
@self:
@Returns:
@self:
@Returns:
@self:
@path:
@Returns:
@self:
@types:
@Returns:
@self:
@path:
@Returns:
@self:
@buffer:
@length:
@error:
@Returns:
@Returns:
@self:
@Returns:
These enumeration values are used by gtk_ui_manager_add_ui() to determine
what UI element to create.
@GTK_UI_MANAGER_AUTO: Pick the type of the UI element according to context.
@GTK_UI_MANAGER_MENUBAR: Create a menubar.
@GTK_UI_MANAGER_MENU: Create a menu.
@GTK_UI_MANAGER_TOOLBAR: Create a toolbar.
@GTK_UI_MANAGER_PLACEHOLDER: Insert a placeholder.
@GTK_UI_MANAGER_POPUP: Create a popup menu.
@GTK_UI_MANAGER_MENUITEM: Create a menuitem.
@GTK_UI_MANAGER_TOOLITEM: Create a toolitem.
@GTK_UI_MANAGER_SEPARATOR: Create a separator.
@GTK_UI_MANAGER_ACCELERATOR: Install an accelerator.
@GTK_UI_MANAGER_POPUP_WITH_ACCELS: Same as %GTK_UI_MANAGER_POPUP, but the actions' accelerators are shown.
@self:
@merge_id:
@path:
@name:
@action:
@type:
@top:
@self:
@merge_id:
@self:
@Returns:
@self: