Description
GtkApplication is a class that handles many important aspects
of a GTK+ application in a convenient fashion, without enforcing
a one-size-fits-all application model.
Currently, GtkApplication handles GTK+ initialization, application
uniqueness, session management, provides some basic scriptability and
desktop shell integration by exporting actions and menus and manages a
list of toplevel windows whose life-cycle is automatically tied to the
life-cycle of your application.
While GtkApplication works fine with plain GtkWindows, it is recommended
to use it together with GtkApplicationWindow.
When GDK threads are enabled, GtkApplication will acquire the GDK
lock when invoking actions that arrive from other processes. The GDK
lock is not touched for local action invocations. In order to have
actions invoked in a predictable context it is therefore recommended
that the GDK lock be held while invoking actions locally with
g_action_group_activate_action(). The same applies to actions
associated with GtkApplicationWindow and to the “activate” and
“open” GApplication methods.
Automatic resources
GtkApplication will automatically load menus from the GtkBuilder
resource located at "gtk/menus.ui", relative to the application's
resource base path (see g_application_set_resource_base_path()). The
menu with the ID "app-menu" is taken as the application's app menu
and the menu with the ID "menubar" is taken as the application's
menubar. Additional menus (most interesting submenus) can be named
and accessed via gtk_application_get_menu_by_id() which allows for
dynamic population of a part of the menu structure.
If the resources "gtk/menus-appmenu.ui" or "gtk/menus-traditional.ui" are
present then these files will be used in preference, depending on the value
of gtk_application_prefers_app_menu(). If the resource "gtk/menus-common.ui"
is present it will be loaded as well. This is useful for storing items that
are referenced from both "gtk/menus-appmenu.ui" and
"gtk/menus-traditional.ui".
It is also possible to provide the menus manually using
gtk_application_set_app_menu() and gtk_application_set_menubar().
GtkApplication will also automatically setup an icon search path for
the default icon theme by appending "icons" to the resource base
path. This allows your application to easily store its icons as
resources. See gtk_icon_theme_add_resource_path() for more
information.
If there is a resource located at "gtk/help-overlay.ui" which
defines a GtkShortcutsWindow with ID "help_overlay" then GtkApplication
associates an instance of this shortcuts window with each
GtkApplicationWindow and sets up keyboard accelerators (Control-F1
and Control-?) to open it. To create a menu item that displays the
shortcuts window, associate the item with the action win.show-help-overlay.
A simple application
A simple example
GtkApplication optionally registers with a session manager
of the users session (if you set the “register-session”
property) and offers various functionality related to the session
life-cycle.
An application can block various ways to end the session with
the gtk_application_inhibit() function. Typical use cases for
this kind of inhibiting are long-running, uninterruptible operations,
such as burning a CD or performing a disk backup. The session
manager may not honor the inhibitor, but it can be expected to
inform the user about the negative consequences of ending the
session while inhibitors are present.
Functions
gtk_application_new ()
GtkApplication *
gtk_application_new (const gchar *application_id,
GApplicationFlags flags);
Creates a new GtkApplication instance.
When using GtkApplication, it is not necessary to call gtk_init()
manually. It is called as soon as the application gets registered as
the primary instance.
Concretely, gtk_init() is called in the default handler for the
“startup” signal. Therefore, GtkApplication subclasses should
chain up in their “startup” handler before using any GTK+ API.
Note that commandline arguments are not passed to gtk_init().
All GTK+ functionality that is available via commandline arguments
can also be achieved by setting suitable environment variables
such as G_DEBUG, so this should not be a big
problem. If you absolutely must support GTK+ commandline arguments,
you can explicitly call gtk_init() before creating the application
instance.
If non-NULL, the application ID must be valid. See
g_application_id_is_valid().
If no application ID is given then some features (most notably application
uniqueness) will be disabled. A null application ID is only allowed with
GTK+ 3.6 or later.
Since: 3.0
gtk_application_add_window ()
void
gtk_application_add_window (GtkApplication *application,
GtkWindow *window);
Adds a window to application
.
This call can only happen after the application
has started;
typically, you should add new application windows in response
to the emission of the “activate” signal.
This call is equivalent to setting the “application”
property of window
to application
.
Normally, the connection between the application and the window
will remain until the window is destroyed, but you can explicitly
remove it with gtk_application_remove_window().
GTK+ will keep the application
running as long as it has
any windows.
Since: 3.0
gtk_application_remove_window ()
void
gtk_application_remove_window (GtkApplication *application,
GtkWindow *window);
Remove a window from application
.
If window
belongs to application
then this call is equivalent to
setting the “application” property of window
to
NULL.
The application may stop running as a result of a call to this
function.
Since: 3.0
gtk_application_get_windows ()
GList *
gtk_application_get_windows (GtkApplication *application);
Gets a list of the GtkWindows associated with application
.
The list is sorted by most recently focused window, such that the first
element is the currently focused window. (Useful for choosing a parent
for a transient window.)
The list that is returned should not be modified in any way. It will
only remain valid until the next focus change or window creation or
deletion.
Since: 3.0
gtk_application_get_active_window ()
GtkWindow *
gtk_application_get_active_window (GtkApplication *application);
Gets the “active” window for the application.
The active window is the one that was most recently focused (within
the application). This window may not have the focus at the moment
if another application has it — this is just the most
recently-focused window within this application.
Returns
the active window, or NULL if
there isn't one.
[transfer none][nullable]
Since: 3.6
gtk_application_inhibit ()
guint
gtk_application_inhibit (GtkApplication *application,
GtkWindow *window,
GtkApplicationInhibitFlags flags,
const gchar *reason);
Inform the session manager that certain types of actions should be
inhibited. This is not guaranteed to work on all platforms and for
all types of actions.
Applications should invoke this method when they begin an operation
that should not be interrupted, such as creating a CD or DVD. The
types of actions that may be blocked are specified by the flags
parameter. When the application completes the operation it should
call gtk_application_uninhibit() to remove the inhibitor. Note that
an application can have multiple inhibitors, and all of them must
be individually removed. Inhibitors are also cleared when the
application exits.
Applications should not expect that they will always be able to block
the action. In most cases, users will be given the option to force
the action to take place.
Reasons should be short and to the point.
If window
is given, the session manager may point the user to
this window to find out more about why the action is inhibited.
Returns
A non-zero cookie that is used to uniquely identify this
request. It should be used as an argument to gtk_application_uninhibit()
in order to remove the request. If the platform does not support
inhibiting or the request failed for some reason, 0 is returned.
Since: 3.4
gtk_application_uninhibit ()
void
gtk_application_uninhibit (GtkApplication *application,
guint cookie);
Removes an inhibitor that has been established with gtk_application_inhibit().
Inhibitors are also cleared when the application exits.
Since: 3.4
gtk_application_is_inhibited ()
gboolean
gtk_application_is_inhibited (GtkApplication *application,
GtkApplicationInhibitFlags flags);
Determines if any of the actions specified in flags
are
currently inhibited (possibly by another application).
Note that this information may not be available (for example
when the application is running in a sandbox).
Returns
TRUE if any of the actions specified in flags
are inhibited
Since: 3.4
gtk_application_prefers_app_menu ()
gboolean
gtk_application_prefers_app_menu (GtkApplication *application);
Determines if the desktop environment in which the application is
running would prefer an application menu be shown.
If this function returns TRUE then the application should call
gtk_application_set_app_menu() with the contents of an application
menu, which will be shown by the desktop environment. If it returns
FALSE then you should consider using an alternate approach, such as
a menubar.
The value returned by this function is purely advisory and you are
free to ignore it. If you call gtk_application_set_app_menu() even
if the desktop environment doesn't support app menus, then a fallback
will be provided.
Applications are similarly free not to set an app menu even if the
desktop environment wants to show one. In that case, a fallback will
also be created by the desktop environment (GNOME, for example, uses
a menu with only a "Quit" item in it).
The value returned by this function never changes. Once it returns a
particular value, it is guaranteed to always return the same value.
You may only call this function after the application has been
registered and after the base startup handler has run. You're most
likely to want to use this from your own startup handler. It may
also make sense to consult this function while constructing UI (in
activate, open or an action activation handler) in order to determine
if you should show a gear menu or not.
This function will return FALSE on Mac OS and a default app menu
will be created automatically with the "usual" contents of that menu
typical to most Mac OS applications. If you call
gtk_application_set_app_menu() anyway, then this menu will be
replaced with your own.
Returns
TRUE if you should set an app menu
Since: 3.14
gtk_application_get_app_menu ()
GMenuModel *
gtk_application_get_app_menu (GtkApplication *application);
Returns the menu model that has been set with
gtk_application_set_app_menu().
Returns
the application menu of application
or NULL if no application menu has been set.
[transfer none][nullable]
Since: 3.4
gtk_application_set_app_menu ()
void
gtk_application_set_app_menu (GtkApplication *application,
GMenuModel *app_menu);
Sets or unsets the application menu for application
.
This can only be done in the primary instance of the application,
after it has been registered. “startup” is a good place
to call this.
The application menu is a single menu containing items that typically
impact the application as a whole, rather than acting on a specific
window or document. For example, you would expect to see
“Preferences” or “Quit” in an application menu, but not “Save” or
“Print”.
If supported, the application menu will be rendered by the desktop
environment.
Use the base GActionMap interface to add actions, to respond to the user
selecting these menu items.
Since: 3.4
gtk_application_set_menubar ()
void
gtk_application_set_menubar (GtkApplication *application,
GMenuModel *menubar);
Sets or unsets the menubar for windows of application
.
This is a menubar in the traditional sense.
This can only be done in the primary instance of the application,
after it has been registered. “startup” is a good place
to call this.
Depending on the desktop environment, this may appear at the top of
each window, or at the top of the screen. In some environments, if
both the application menu and the menubar are set, the application
menu will be presented as if it were the first item of the menubar.
Other environments treat the two as completely separate — for example,
the application menu may be rendered by the desktop shell while the
menubar (if set) remains in each individual window.
Use the base GActionMap interface to add actions, to respond to the
user selecting these menu items.
Since: 3.4
gtk_application_get_menu_by_id ()
GMenu *
gtk_application_get_menu_by_id (GtkApplication *application,
const gchar *id);
Gets a menu from automatically loaded resources.
See Automatic resources
for more information.
Returns
Gets the menu with the
given id from the automatically loaded resources.
[transfer none]
Since: 3.14
gtk_application_add_accelerator ()
void
gtk_application_add_accelerator (GtkApplication *application,
const gchar *accelerator,
const gchar *action_name,
GVariant *parameter);
Installs an accelerator that will cause the named action
to be activated when the key combination specificed by accelerator
is pressed.
accelerator
must be a string that can be parsed by gtk_accelerator_parse(),
e.g. "<Primary>q" or “<Control><Alt>p”.
action_name
must be the name of an action as it would be used
in the app menu, i.e. actions that have been added to the application
are referred to with an “app.” prefix, and window-specific actions
with a “win.” prefix.
GtkApplication also extracts accelerators out of “accel” attributes
in the GMenuModels passed to gtk_application_set_app_menu() and
gtk_application_set_menubar(), which is usually more convenient
than calling this function for each accelerator.
Since: 3.4
gtk_application_get_accels_for_action ()
gchar **
gtk_application_get_accels_for_action (GtkApplication *application,
const gchar *detailed_action_name);
Gets the accelerators that are currently associated with
the given action.
Returns
accelerators for detailed_action_name
, as
a NULL-terminated array. Free with g_strfreev() when no longer needed.
[transfer full]
Since: 3.12
gtk_application_set_accels_for_action ()
void
gtk_application_set_accels_for_action (GtkApplication *application,
const gchar *detailed_action_name,
const gchar * const *accels);
Sets zero or more keyboard accelerators that will trigger the
given action. The first item in accels
will be the primary
accelerator, which may be displayed in the UI.
To remove all accelerators for an action, use an empty, zero-terminated
array for accels
.
For the detailed_action_name
, see g_action_parse_detailed_name() and
g_action_print_detailed_name().
Since: 3.12
gtk_application_get_actions_for_accel ()
gchar **
gtk_application_get_actions_for_accel (GtkApplication *application,
const gchar *accel);
Returns the list of actions (possibly empty) that accel
maps to.
Each item in the list is a detailed action name in the usual form.
This might be useful to discover if an accel already exists in
order to prevent installation of a conflicting accelerator (from
an accelerator editor or a plugin system, for example). Note that
having more than one action per accelerator may not be a bad thing
and might make sense in cases where the actions never appear in the
same context.
In case there are no actions for a given accelerator, an empty array
is returned. NULL is never returned.
It is a programmer error to pass an invalid accelerator string.
If you are unsure, check it with gtk_accelerator_parse() first.
Returns
a NULL-terminated array of actions for accel
.
[transfer full]
Since: 3.14