GtkApplication

GtkApplication — Application class

Properties

GtkWindow * active-window Read
GMenuModel * menubar Read / Write
gboolean register-session Read / Write
gboolean screensaver-active Read

Signals

void query-end Run First
void window-added Run First
void window-removed Run First

Types and Values

Object Hierarchy

    GObject
    ╰── GApplication
        ╰── GtkApplication

Implemented Interfaces

GtkApplication implements GActionGroup and GActionMap.

Includes

#include <gtk/gtk.h>

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 "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.

It is also possible to provide the menubar manually using 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 the keyboard accelerator 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 char *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.

Parameters

application_id

The application ID.

[allow-none]

flags

the application flags

Returns

a new GtkApplication instance

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.

Parameters

application

a GtkApplication

window

a GtkWindow

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.

Parameters

application

a GtkApplication

window

a GtkWindow

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.

Parameters

application

a GtkApplication

Returns

a GList of GtkWindow.

[element-type GtkWindow][transfer none]

gtk_application_get_window_by_id ()

GtkWindow *
gtk_application_get_window_by_id (GtkApplication *application,
                                  guint id);

Returns the GtkApplicationWindow with the given ID.

The ID of a GtkApplicationWindow can be retrieved with gtk_application_window_get_id().

Parameters

application

a GtkApplication

id

an identifier number

Returns

the window with ID id , or NULL if there is no window with this ID.

[nullable][transfer none]

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.

Parameters

application

a GtkApplication

Returns

the active window, or NULL if there isn't one.

[transfer none][nullable]

gtk_application_inhibit ()

guint
gtk_application_inhibit (GtkApplication *application,
                         GtkWindow *window,
                         GtkApplicationInhibitFlags flags,
                         const char *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.

Parameters

application

the GtkApplication

window

a GtkWindow, or NULL.

[allow-none]

flags

what types of actions should be inhibited

reason

a short, human-readable string that explains why these operations are inhibited.

[allow-none]

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.

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.

Parameters

application

the GtkApplication

cookie

a cookie that was returned by gtk_application_inhibit()

gtk_application_get_menubar ()

GMenuModel *
gtk_application_get_menubar (GtkApplication *application);

Returns the menu model that has been set with gtk_application_set_menubar().

Parameters

application

a GtkApplication

Returns

the menubar for windows of application .

[nullable][transfer none]

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.

Parameters

application

a GtkApplication

menubar

a GMenuModel, or NULL.

[allow-none]

gtk_application_get_menu_by_id ()

GMenu *
gtk_application_get_menu_by_id (GtkApplication *application,
                                const char *id);

Gets a menu from automatically loaded resources. See Automatic resources for more information.

Parameters

application

a GtkApplication

id

the id of the menu to look up

Returns

Gets the menu with the given id from the automatically loaded resources.

[nullable][transfer none]

gtk_application_list_action_descriptions ()

char **
gtk_application_list_action_descriptions
                               (GtkApplication *application);

Lists the detailed action names which have associated accelerators. See gtk_application_set_accels_for_action().

Parameters

application

a GtkApplication

Returns

a NULL-terminated array of strings, free with g_strfreev() when done.

[transfer full]

gtk_application_get_accels_for_action ()

char **
gtk_application_get_accels_for_action (GtkApplication *application,
                                       const char *detailed_action_name);

Gets the accelerators that are currently associated with the given action.

Parameters

application

a GtkApplication

detailed_action_name

a detailed action name, specifying an action and target to obtain accelerators for

Returns

accelerators for detailed_action_name , as a NULL-terminated array. Free with g_strfreev() when no longer needed.

[transfer full]

gtk_application_set_accels_for_action ()

void
gtk_application_set_accels_for_action (GtkApplication *application,
                                       const char *detailed_action_name,
                                       const char * 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().

Parameters

application

a GtkApplication

detailed_action_name

a detailed action name, specifying an action and target to associate accelerators with

accels

a list of accelerators in the format understood by gtk_accelerator_parse().

[array zero-terminated=1]

gtk_application_get_actions_for_accel ()

char **
gtk_application_get_actions_for_accel (GtkApplication *application,
                                       const char *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.

Parameters

application

a GtkApplication

accel

an accelerator that can be parsed by gtk_accelerator_parse()

Returns

a NULL-terminated array of actions for accel .

[transfer full]

Types and Values

struct GtkApplication

struct GtkApplication;

struct GtkApplicationClass

struct GtkApplicationClass {
  GApplicationClass parent_class;

  void (*window_added)   (GtkApplication *application,
                          GtkWindow      *window);
  void (*window_removed) (GtkApplication *application,
                          GtkWindow      *window);
};

Members

window_added ()

Signal emitted when a GtkWindow is added to application through gtk_application_add_window().

window_removed ()

Signal emitted when a GtkWindow is removed from application, either as a side-effect of being destroyed or explicitly through gtk_application_remove_window().

enum GtkApplicationInhibitFlags

Types of user actions that may be blocked by gtk_application_inhibit().

Members

GTK_APPLICATION_INHIBIT_LOGOUT

Inhibit ending the user session by logging out or by shutting down the computer

GTK_APPLICATION_INHIBIT_SWITCH

Inhibit user switching

GTK_APPLICATION_INHIBIT_SUSPEND

Inhibit suspending the session or computer

GTK_APPLICATION_INHIBIT_IDLE

Inhibit the session being marked as idle (and possibly locked)

Property Details

The “active-window” property

  “active-window”            GtkWindow *

The window which most recently had focus.

Owner: GtkApplication

Flags: Read

The “menubar” property

  “menubar”                  GMenuModel *

The GMenuModel for the menubar.

Owner: GtkApplication

Flags: Read / Write

The “register-session” property

  “register-session”         gboolean

Set this property to TRUE to register with the session manager. This will make GTK+ track the session state (such as the “screensaver-active” property).

Owner: GtkApplication

Flags: Read / Write

Default value: FALSE

The “screensaver-active” property

  “screensaver-active”       gboolean

This property is TRUE if GTK+ believes that the screensaver is currently active. GTK+ only tracks session state (including this) when “register-session” is set to TRUE.

Tracking the screensaver state is supported on Linux.

Owner: GtkApplication

Flags: Read

Default value: FALSE

Signal Details

The “query-end” signal

void
user_function (GtkApplication *application,
               gpointer        user_data)

Emitted when the session manager is about to end the session, only if “register-session” is TRUE. Applications can connect to this signal and call gtk_application_inhibit() with GTK_APPLICATION_INHIBIT_LOGOUT to delay the end of the session until state has been saved.

Parameters

application

the GtkApplication which emitted the signal

user_data

user data set when the signal handler was connected.

Flags: Run First

The “window-added” signal

void
user_function (GtkApplication *application,
               GtkWindow      *window,
               gpointer        user_data)

Emitted when a GtkWindow is added to application through gtk_application_add_window().

Parameters

application

the GtkApplication which emitted the signal

window

the newly-added GtkWindow

user_data

user data set when the signal handler was connected.

Flags: Run First

The “window-removed” signal

void
user_function (GtkApplication *application,
               GtkWindow      *window,
               gpointer        user_data)

Emitted when a GtkWindow is removed from application , either as a side-effect of being destroyed or explicitly through gtk_application_remove_window().

Parameters

application

the GtkApplication which emitted the signal

window

the GtkWindow that is being removed

user_data

user data set when the signal handler was connected.

Flags: Run First

© 2005–2020 The GNOME Project
Licensed under the GNU Lesser General Public License version 2.1 or later.
https://developer.gnome.org/gtk4/4.0/GtkApplication.html