Gtk.Application¶

class — extends Gio.Application, Gio.ActionGroup, Gio.ActionMap

A high-level API for writing applications.

GtkApplication supports many aspects of writing a GTK application in a convenient fashion, without enforcing a one-size-fits-all model.

Currently, it 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 Windows, it is recommended to use it together with ApplicationWindow.

Initialization¶

A typical GtkApplication will create a window in its GIO.Application.activate, GIO.Application.open or GIO.Application.command-line handlers. Note that all of these signals may be emitted multiple times, so handlers must be careful to take existing windows into account.

A typical ::activate handler should look like this:

static void
activate (GApplication *gapp)
{
  GtkApplication *app = GTK_APPLICATION (gapp);
  GtkWindow *window;

  window = gtk_application_get_active_window (app);
  if (!window)
    window = create_window (app);

  gtk_window_present (window);
}

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 Gio.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 Application.get_menu_by_id which allows for dynamic population of a part of the menu structure.

Note that automatic resource loading uses the resource base path that is set at construction time and will not work if the resource base path is changed at a later time.

It is also possible to provide the menubar manually using 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 IconTheme.add_resource_path for more information.

If there is a resource located at gtk/help-overlay.ui which defines a ShortcutsWindow with ID help_overlay then GtkApplication associates an instance of this shortcuts window with each ApplicationWindow and sets up the keyboard accelerator <kbd>Control</kbd>+<kbd>?</kbd> to open it. To create a menu item that displays the shortcuts window, associate the item with the action win.show-help-overlay.

GtkApplication will also automatically set the application id as the default window icon. Use Window.set_default_icon_name or Window.icon-name to override that behavior.

Inhibiting¶

An application can block various ways to end the session with the 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.

A simple application¶

A simple example is available in the GTK source code repository

Constructors¶

new¶

@classmethod
def new(cls, application_id: str | None, flags: Gio.ApplicationFlags | int) -> Application

Creates a new application instance.

When using GtkApplication, it is not necessary to call init manually. It is called as soon as the application gets registered as the primary instance.

Concretely, init is called in the default handler for the GApplication::startup signal. Therefore, GtkApplication subclasses should always chain up in their GIO.Application.startup handler before using any GTK API.

Note that commandline arguments are not passed to init.

If application_id is not NULL, then it must be valid. See Gio.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
flags — the application flags

Methods¶

add_window¶

def add_window(self, window: Window) -> None

Adds a window to the 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 GIO.Application.activate signal.

This call is equivalent to setting the Window.application property of the 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 Application.remove_window.

GTK will keep the application running as long as it has any windows.

Parameters:

window — a window

get_accels_for_action¶

def get_accels_for_action(self, detailed_action_name: str) -> list[str]

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

Parameters:

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

get_actions_for_accel¶

def get_actions_for_accel(self, accel: str) -> list[str]

Returns the list of actions (possibly empty) that the accelerator 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 accelerator_parse first.

Parameters:

accel — an accelerator that can be parsed by accelerator_parse

get_active_window¶

def get_active_window(self) -> Window | None

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.

get_menu_by_id¶

def get_menu_by_id(self, id: str) -> Gio.Menu | None

Gets a menu from automatically loaded resources.

See the section on Automatic resources for more information.

Parameters:

id — the ID of the menu to look up

get_menubar¶

def get_menubar(self) -> Gio.MenuModel | None

Returns the menu model for the menu bar of the application.

get_window_by_id¶

def get_window_by_id(self, id: int) -> Window | None

Returns the window with the given ID.

The ID of a GtkApplicationWindow can be retrieved with ApplicationWindow.get_id.

Parameters:

id — an identifier number

get_windows¶

def get_windows(self) -> list[Window]

Gets a list of the window associated with the 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.

inhibit¶

def inhibit(self, window: Window | None, flags: ApplicationInhibitFlags | int, reason: str | None = ...) -> int

Informs 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 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.

The reason message should be short and to the point.

If a window is given, the session manager may point the user to this window to find out more about why the action is inhibited.

The cookie that is returned by this function should be used as an argument to Application.uninhibit in order to remove the request.

Parameters:

window — a window
flags — what types of actions should be inhibited
reason — a short, human-readable string that explains why these operations are inhibited

list_action_descriptions¶

def list_action_descriptions(self) -> list[str]

Lists the detailed action names which have associated accelerators.

See Application.set_accels_for_action.

remove_window¶

def remove_window(self, window: Window) -> None

Remove a window from the application.

If the window belongs to the application then this call is equivalent to setting the Window.application property of the window to NULL.

The application may stop running as a result of a call to this function, if the window was the last window of the application.

Parameters:

window — a window

set_accels_for_action¶

def set_accels_for_action(self, detailed_action_name: str, accels: list[str]) -> None

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 Gio.Action.parse_detailed_name and [Gio.Action.print_detailed_name].

Parameters:

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 accelerator_parse

set_menubar¶

def set_menubar(self, menubar: Gio.MenuModel | None = ...) -> None

Sets or unsets the menubar for windows of the 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. GIO.Application.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:

menubar — a menu model

uninhibit¶

def uninhibit(self, cookie: int) -> None

Removes an inhibitor that has been previously established.

See Application.inhibit.

Inhibitors are also cleared when the application exits.

Parameters:

cookie — a cookie that was returned by Application.inhibit

Virtual methods¶

do_window_added¶

def do_window_added(self, window: Window) -> None

Signal emitted when a GtkWindow is added to application through Application.add_window.

do_window_removed¶

def do_window_removed(self, window: Window) -> None

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

Properties¶

active_window¶

active_window: Window  # read-only

The currently focused window of the application.

menubar¶

menubar: Gio.MenuModel  # read/write

The menu model to be used for the application's menu bar.

register_session¶

register_session: bool  # read/write

:::warning Deprecated since 4.22 This API is deprecated. :::

Set this property to true to register with the session manager.

This will make GTK track the session state (such as the Application.screensaver-active property).

screensaver_active¶

screensaver_active: bool  # read-only

This property is true if GTK believes that the screensaver is currently active.

Tracking the screensaver state is currently only supported on Linux.

Signals¶

query-end¶

def on_query_end(self) -> None: ...

Emitted when the session manager is about to end the session.

Applications can connect to this signal and call Application.inhibit with ApplicationInhibitFlags.logout to delay the end of the session until state has been saved.

window-added¶

def on_window_added(self, window: Window) -> None: ...

Emitted when a window is added to an application.

See Application.add_window.

window-removed¶

def on_window_removed(self, window: Window) -> None: ...

Emitted when a window is removed from an application.

This can happen as a side-effect of the window being destroyed or explicitly through Application.remove_window.

Gtk.Application¶

Initialization¶

Automatic resources¶

Inhibiting¶

A simple application¶

See Also¶

Constructors¶

new¶

Methods¶

add_window¶

get_accels_for_action¶

get_actions_for_accel¶

get_active_window¶

get_menu_by_id¶

get_menubar¶

get_window_by_id¶

get_windows¶

inhibit¶

list_action_descriptions¶

remove_window¶

set_accels_for_action¶

set_menubar¶

uninhibit¶

Virtual methods¶

do_window_added¶

do_window_removed¶

Properties¶

active_window¶

menubar¶

register_session¶

screensaver_active¶

Signals¶

query-end¶

window-added¶

window-removed¶