Struct qt_gui::QGuiApplication

#[repr(C)]
pub struct QGuiApplication { /* fields omitted */ }

The QGuiApplication class manages the GUI application's control flow and main settings.

C++ class: QGuiApplication.

C++ documentation:

The QGuiApplication class manages the GUI application's control flow and main settings.

QGuiApplication contains the main event loop, where all events from the window system and other sources are processed and dispatched. It also handles the application's initialization and finalization, and provides session management. In addition, QGuiApplication handles most of the system-wide and application-wide settings.

For any GUI application using Qt, there is precisely one QGuiApplication object no matter whether the application has 0, 1, 2 or more windows at any given time. For non-GUI Qt applications, use QCoreApplication instead, as it does not depend on the Qt GUI module. For QWidget based Qt applications, use QApplication instead, as it provides some functionality needed for creating QWidget instances.

The QGuiApplication object is accessible through the instance() function, which returns a pointer equivalent to the global qApp pointer.

QGuiApplication's main areas of responsibility are:

• It initializes the application with the user's desktop settings, such as palette(), font() and styleHints(). It keeps track of these properties in case the user changes the desktop globally, for example, through some kind of control panel.
• It performs event handling, meaning that it receives events from the underlying window system and dispatches them to the relevant widgets. You can send your own events to windows by using sendEvent() and postEvent().
• It parses common command line arguments and sets its internal state accordingly. See the constructor documentation below for more details.
• It provides localization of strings that are visible to the user via translate().
• It provides some magical objects like the clipboard().
• It knows about the application's windows. You can ask which window is at a certain position using topLevelAt(), get a list of topLevelWindows(), etc.
• It manages the application's mouse cursor handling, see setOverrideCursor()
• It provides support for sophisticated session management. This makes it possible for applications to terminate gracefully when the user logs out, to cancel a shutdown process if termination isn't possible and even to preserve the entire application's state for a future session. See isSessionRestored(), sessionId() and commitDataRequest() and saveStateRequest() for details.

Since the QGuiApplication object does so much initialization, it must be created before any other objects related to the user interface are created. QGuiApplication also deals with common command line arguments. Hence, it is usually a good idea to create it before any interpretation or modification of argv is done in the application itself.

Groups of functions
System settings	desktopSettingsAware(), setDesktopSettingsAware(), styleHints(), palette(), setPalette(), font(), setFont().
Event handling	exec(), processEvents(), exit(), quit(). sendEvent(), postEvent(), sendPostedEvents(), removePostedEvents(), hasPendingEvents(), notify().
Windows	allWindows(), topLevelWindows(), focusWindow(), clipboard(), topLevelAt().
Advanced cursor handling	overrideCursor(), setOverrideCursor(), restoreOverrideCursor().
Session management	isSessionRestored(), sessionId(), commitDataRequest(), saveStateRequest().
Miscellaneous	startingUp(), closingDown().

Methods

impl QGuiApplication

pub fn init<F: FnOnce(MutPtr<QGuiApplication>) -> i32>(f: F) -> !

A convenience function for performing proper initialization and de-initialization of a Qt application.

This function creates CoreApplication with valid argc and argv, calls the passed closure f(app) with the application object and exist the process with the exit code returned by the closure. The closure should perform the initialization of the application and either return immediately or call CoreApplication::exec() and return its return value:

use qt_gui::QGuiApplication;

fn main() {
    QGuiApplication::init(|app| {
        unsafe {
            // initialization goes here
            QGuiApplication::exec()
        }
    })
}

impl QGuiApplication

pub fn font_database_changed(&self) -> Signal<()>

This signal is emitted when application fonts are loaded or removed.

Returns a built-in Qt signal QGuiApplication::fontDatabaseChanged that can be passed to qt_core::Signal::connect.

C++ documentation:

This signal is emitted when application fonts are loaded or removed.

See also QFontDatabase::addApplicationFont(), QFontDatabase::addApplicationFontFromData(), QFontDatabase::removeAllApplicationFonts(), and QFontDatabase::removeApplicationFont().

pub fn screen_added(&self) -> Signal<(*mut QScreen,)>

This signal is emitted whenever a new screen screen has been added to the system.

Returns a built-in Qt signal QGuiApplication::screenAdded that can be passed to qt_core::Signal::connect.

C++ documentation:

This signal is emitted whenever a new screen screen has been added to the system.

See also screens(), primaryScreen, and screenRemoved().

pub fn screen_removed(&self) -> Signal<(*mut QScreen,)>

This signal is emitted whenever a screen is removed from the system. It provides an opportunity to manage the windows on the screen before Qt falls back to moving them to the primary screen.

Returns a built-in Qt signal QGuiApplication::screenRemoved that can be passed to qt_core::Signal::connect.

C++ documentation:

This signal is emitted whenever a screen is removed from the system. It provides an opportunity to manage the windows on the screen before Qt falls back to moving them to the primary screen.

This function was introduced in Qt 5.4.

See also screens(), screenAdded(), QObject::destroyed(), and QWindow::setScreen().

pub fn primary_screen_changed(&self) -> Signal<(*mut QScreen,)>

This property holds the primary (or default) screen of the application.

Returns a built-in Qt signal QGuiApplication::primaryScreenChanged that can be passed to qt_core::Signal::connect.

C++ documentation:

This property holds the primary (or default) screen of the application.

This will be the screen where QWindows are initially shown, unless otherwise specified.

The primaryScreenChanged signal was introduced in Qt 5.6.

Access functions:

QScreen *

primaryScreen()

Notifier signal:

void	primaryScreenChanged(QScreen *screen)

See also screens().

pub fn last_window_closed(&self) -> Signal<()>

This signal is emitted from exec() when the last visible primary window (i.e. window with no parent) is closed.

Returns a built-in Qt signal QGuiApplication::lastWindowClosed that can be passed to qt_core::Signal::connect.

C++ documentation:

This signal is emitted from exec() when the last visible primary window (i.e. window with no parent) is closed.

By default, QGuiApplication quits after this signal is emitted. This feature can be turned off by setting quitOnLastWindowClosed to false.

See also QWindow::close() and QWindow::isTopLevel().

pub fn focus_object_changed(&self) -> Signal<(*mut QObject,)>

This signal is emitted when final receiver of events tied to focus is changed. focusObject is the new receiver.

Returns a built-in Qt signal QGuiApplication::focusObjectChanged that can be passed to qt_core::Signal::connect.

C++ documentation:

This signal is emitted when final receiver of events tied to focus is changed. focusObject is the new receiver.

See also focusObject().

pub fn focus_window_changed(&self) -> Signal<(*mut QWindow,)>

This signal is emitted when the focused window changes. focusWindow is the new focused window.

Returns a built-in Qt signal QGuiApplication::focusWindowChanged that can be passed to qt_core::Signal::connect.

C++ documentation:

This signal is emitted when the focused window changes. focusWindow is the new focused window.

See also focusWindow().

pub fn application_state_changed(&self) -> Signal<(ApplicationState,)>

This signal is emitted when the state of the application changes.

Returns a built-in Qt signal QGuiApplication::applicationStateChanged that can be passed to qt_core::Signal::connect.

C++ documentation:

This signal is emitted when the state of the application changes.

This function was introduced in Qt 5.2.

See also applicationState().

pub fn layout_direction_changed(&self) -> Signal<(LayoutDirection,)>

This property holds the default layout direction for this application

Returns a built-in Qt signal QGuiApplication::layoutDirectionChanged that can be passed to qt_core::Signal::connect.

C++ documentation:

This property holds the default layout direction for this application

On system start-up, the default layout direction depends on the application's language.

The notifier signal was introduced in Qt 5.4.

Access functions:

Qt::LayoutDirection	layoutDirection()
void	setLayoutDirection(Qt::LayoutDirection direction)

Notifier signal:

void	layoutDirectionChanged(Qt::LayoutDirection direction)

See also QWidget::layoutDirection, isLeftToRight(), and isRightToLeft().

pub fn commit_data_request(&self) -> Signal<(*mut QSessionManager,)>

This signal deals with session management. It is emitted when the QSessionManager wants the application to commit all its data.

Returns a built-in Qt signal QGuiApplication::commitDataRequest that can be passed to qt_core::Signal::connect.

C++ documentation:

This signal deals with session management. It is emitted when the QSessionManager wants the application to commit all its data.

Usually this means saving all open files, after getting permission from the user. Furthermore you may want to provide a means by which the user can cancel the shutdown.

You should not exit the application within this signal. Instead, the session manager may or may not do this afterwards, depending on the context.

Warning: Within this signal, no user interaction is possible, unless you ask the manager for explicit permission. See QSessionManager::allowsInteraction() and QSessionManager::allowsErrorInteraction() for details and example usage.

Note: You should use Qt::DirectConnection when connecting to this signal.

This function was introduced in Qt 4.2.

See also setFallbackSessionManagementEnabled(), isSessionRestored(), sessionId(), saveStateRequest(), and Session Management.

pub fn save_state_request(&self) -> Signal<(*mut QSessionManager,)>

This signal deals with session management. It is invoked when the session manager wants the application to preserve its state for a future session.

Returns a built-in Qt signal QGuiApplication::saveStateRequest that can be passed to qt_core::Signal::connect.

C++ documentation:

This signal deals with session management. It is invoked when the session manager wants the application to preserve its state for a future session.

For example, a text editor would create a temporary file that includes the current contents of its edit buffers, the location of the cursor and other aspects of the current editing session.

You should never exit the application within this signal. Instead, the session manager may or may not do this afterwards, depending on the context. Futhermore, most session managers will very likely request a saved state immediately after the application has been started. This permits the session manager to learn about the application's restart policy.

Warning: Within this signal, no user interaction is possible, unless you ask the manager for explicit permission. See QSessionManager::allowsInteraction() and QSessionManager::allowsErrorInteraction() for details.

Note: You should use Qt::DirectConnection when connecting to this signal.

This function was introduced in Qt 4.2.

See also isSessionRestored(), sessionId(), commitDataRequest(), and Session Management.

pub fn palette_changed(&self) -> Signal<(*const QPalette,)>

This signal is emitted when the palette of the application changes.

Returns a built-in Qt signal QGuiApplication::paletteChanged that can be passed to qt_core::Signal::connect.

C++ documentation:

This signal is emitted when the palette of the application changes.

This function was introduced in Qt 5.4.

See also palette().

pub fn application_display_name_changed(&self) -> Signal<()>

This property holds the user-visible name of this application

Returns a built-in Qt signal QGuiApplication::applicationDisplayNameChanged that can be passed to qt_core::Signal::connect.

C++ documentation:

This property holds the user-visible name of this application

This name is shown to the user, for instance in window titles. It can be translated, if necessary.

If not set, the application display name defaults to the application name.

This property was introduced in Qt 5.0.

Access functions:

QString	applicationDisplayName()
void	setApplicationDisplayName(const QString &name)

Notifier signal:

void	applicationDisplayNameChanged()

See also applicationName.

pub unsafe fn all_windows() -> CppBox<QListOfQWindow>

Returns a list of all the windows in the application.

Calls C++ function: static QList<QWindow*> QGuiApplication::allWindows().

C++ documentation:

Returns a list of all the windows in the application.

The list is empty if there are no windows.

See also topLevelWindows().

pub unsafe fn application_display_name() -> CppBox<QString>

This property holds the user-visible name of this application

Calls C++ function: static QString QGuiApplication::applicationDisplayName().

C++ documentation:

This property holds the user-visible name of this application

This name is shown to the user, for instance in window titles. It can be translated, if necessary.

If not set, the application display name defaults to the application name.

This property was introduced in Qt 5.0.

Access functions:

QString	applicationDisplayName()
void	setApplicationDisplayName(const QString &name)

Notifier signal:

void	applicationDisplayNameChanged()

See also applicationName.

pub unsafe fn application_state() -> ApplicationState

Returns the current state of the application.

Calls C++ function: static Qt::ApplicationState QGuiApplication::applicationState().

C++ documentation:

Returns the current state of the application.

You can react to application state changes to perform actions such as stopping/resuming CPU-intensive tasks, freeing/loading resources or saving/restoring application data.

This function was introduced in Qt 5.2.

pub unsafe fn change_override_cursor(arg1: impl CastInto<Ref<QCursor>>)

Changes the currently active application override cursor to cursor.

Calls C++ function: static void QGuiApplication::changeOverrideCursor(const QCursor& arg1).

C++ documentation:

Changes the currently active application override cursor to cursor.

This function has no effect if setOverrideCursor() was not called.

See also setOverrideCursor(), overrideCursor(), restoreOverrideCursor(), and QWidget::setCursor().

pub unsafe fn clipboard() -> MutPtr<QClipboard>

Returns the object for interacting with the clipboard.

Calls C++ function: static QClipboard* QGuiApplication::clipboard().

C++ documentation:

Returns the object for interacting with the clipboard.

pub unsafe fn desktop_file_name() -> CppBox<QString>

This property holds the base name of the desktop entry for this application

Calls C++ function: static QString QGuiApplication::desktopFileName().

C++ documentation:

This property holds the base name of the desktop entry for this application

This is the file name, without the full path, of the desktop entry that represents this application according to the freedesktop desktop entry specification.

This property gives a precise indication of what desktop entry represents the application and it is needed by the windowing system to retrieve such information without resorting to imprecise heuristics.

The latest version of the freedesktop desktop entry specification can be obtained here.

This property was introduced in Qt 5.7.

Access functions:

QString	desktopFileName()
void	setDesktopFileName(const QString &name)

pub unsafe fn desktop_settings_aware() -> bool

Returns true if Qt is set to use the system's standard colors, fonts, etc.; otherwise returns false. The default is true.

Calls C++ function: static bool QGuiApplication::desktopSettingsAware().

C++ documentation:

Returns true if Qt is set to use the system's standard colors, fonts, etc.; otherwise returns false. The default is true.

See also setDesktopSettingsAware().

pub unsafe fn device_pixel_ratio(&self) -> c_double

Returns the highest screen device pixel ratio found on the system. This is the ratio between physical pixels and device-independent pixels.

Calls C++ function: double QGuiApplication::devicePixelRatio() const.

C++ documentation:

Returns the highest screen device pixel ratio found on the system. This is the ratio between physical pixels and device-independent pixels.

Use this function only when you don't know which window you are targeting. If you do know the target window, use QWindow::devicePixelRatio() instead.

See also QWindow::devicePixelRatio().

pub unsafe fn exec() -> c_int

Enters the main event loop and waits until exit() is called, and then returns the value that was set to exit() (which is 0 if exit() is called via quit()).

Calls C++ function: static int QGuiApplication::exec().

C++ documentation:

Enters the main event loop and waits until exit() is called, and then returns the value that was set to exit() (which is 0 if exit() is called via quit()).

It is necessary to call this function to start event handling. The main event loop receives events from the window system and dispatches these to the application widgets.

Generally, no user interaction can take place before calling exec().

To make your application perform idle processing, e.g., executing a special function whenever there are no pending events, use a QTimer with 0 timeout. More advanced idle processing schemes can be achieved using processEvents().

We recommend that you connect clean-up code to the aboutToQuit() signal, instead of putting it in your application's main() function. This is because, on some platforms, the QApplication::exec() call may not return.

See also quitOnLastWindowClosed, quit(), exit(), processEvents(), and QCoreApplication::exec().

pub unsafe fn focus_object() -> MutPtr<QObject>

Returns the QObject in currently active window that will be final receiver of events tied to focus, such as key events.

Calls C++ function: static QObject* QGuiApplication::focusObject().

C++ documentation:

Returns the QObject in currently active window that will be final receiver of events tied to focus, such as key events.

pub unsafe fn focus_window() -> MutPtr<QWindow>

Returns the QWindow that receives events tied to focus, such as key events.

Calls C++ function: static QWindow* QGuiApplication::focusWindow().

C++ documentation:

Returns the QWindow that receives events tied to focus, such as key events.

pub unsafe fn font() -> CppBox<QFont>

Returns the default application font.

Calls C++ function: static QFont QGuiApplication::font().

C++ documentation:

Returns the default application font.

See also setFont().

pub unsafe fn font_changed(&mut self, font: impl CastInto<Ref<QFont>>)

This signal is emitted when the font of the application changes.

Calls C++ function: void QGuiApplication::fontChanged(const QFont& font).

C++ documentation:

This signal is emitted when the font of the application changes.

This function was introduced in Qt 5.11.

See also font().

This item is available if any(cpp_lib_version="5.11.3", cpp_lib_version="5.12.2", cpp_lib_version="5.13.0").

pub unsafe fn input_method() -> MutPtr<QInputMethod>

returns the input method.

Calls C++ function: static QInputMethod* QGuiApplication::inputMethod().

C++ documentation:

returns the input method.

The input method returns properties about the state and position of the virtual keyboard. It also provides information about the position of the current focused input element.

See also QInputMethod.

pub unsafe fn is_fallback_session_management_enabled() -> bool

Returns whether QGuiApplication will use fallback session management.

Calls C++ function: static bool QGuiApplication::isFallbackSessionManagementEnabled().

C++ documentation:

Returns whether QGuiApplication will use fallback session management.

The default is true.

If this is true and the session manager allows user interaction, QGuiApplication will try to close toplevel windows after commitDataRequest() has been emitted. If a window cannot be closed, session shutdown will be canceled and the application will keep running.

Fallback session management only benefits applications that have an "are you sure you want to close this window?" feature or other logic that prevents closing a toplevel window depending on certain conditions, and that do nothing to explicitly implement session management. In applications that do implement session management using the proper session management API, fallback session management interferes and may break session management logic.

Warning: If all windows are closed due to fallback session management and quitOnLastWindowClosed() is true, the application will quit before it is explicitly instructed to quit through the platform's session management protocol. That violation of protocol may prevent the platform session manager from saving application state.

This function was introduced in Qt 5.6.

See also setFallbackSessionManagementEnabled(), QSessionManager::allowsInteraction(), saveStateRequest(), commitDataRequest(), and Session Management.

pub unsafe fn is_left_to_right() -> bool

Returns true if the application's layout direction is Qt::LeftToRight; otherwise returns false.

Calls C++ function: static bool QGuiApplication::isLeftToRight().

C++ documentation:

Returns true if the application's layout direction is Qt::LeftToRight; otherwise returns false.

See also layoutDirection() and isRightToLeft().

pub unsafe fn is_right_to_left() -> bool

Returns true if the application's layout direction is Qt::RightToLeft; otherwise returns false.

Calls C++ function: static bool QGuiApplication::isRightToLeft().

C++ documentation:

Returns true if the application's layout direction is Qt::RightToLeft; otherwise returns false.

See also layoutDirection() and isLeftToRight().

pub unsafe fn is_saving_session(&self) -> bool

Returns true if the application is currently saving the session; otherwise returns false.

Calls C++ function: bool QGuiApplication::isSavingSession() const.

C++ documentation:

Returns true if the application is currently saving the session; otherwise returns false.

This is true when commitDataRequest() and saveStateRequest() are emitted, but also when the windows are closed afterwards by session management.

This function was introduced in Qt 5.0.

See also sessionId(), commitDataRequest(), and saveStateRequest().

pub unsafe fn is_session_restored(&self) -> bool

Returns true if the application has been restored from an earlier session; otherwise returns false.

Calls C++ function: bool QGuiApplication::isSessionRestored() const.

C++ documentation:

Returns true if the application has been restored from an earlier session; otherwise returns false.

See also sessionId(), commitDataRequest(), and saveStateRequest().

pub unsafe fn keyboard_modifiers() -> QFlags<KeyboardModifier>

Returns the current state of the modifier keys on the keyboard. The current state is updated sychronously as the event queue is emptied of events that will spontaneously change the keyboard state (QEvent::KeyPress and QEvent::KeyRelease events).

Calls C++ function: static QFlags<Qt::KeyboardModifier> QGuiApplication::keyboardModifiers().

C++ documentation:

Returns the current state of the modifier keys on the keyboard. The current state is updated sychronously as the event queue is emptied of events that will spontaneously change the keyboard state (QEvent::KeyPress and QEvent::KeyRelease events).

It should be noted this may not reflect the actual keys held on the input device at the time of calling but rather the modifiers as last reported in one of the above events. If no keys are being held Qt::NoModifier is returned.

See also mouseButtons() and queryKeyboardModifiers().

pub unsafe fn layout_direction() -> LayoutDirection

This property holds the default layout direction for this application

Calls C++ function: static Qt::LayoutDirection QGuiApplication::layoutDirection().

C++ documentation:

This property holds the default layout direction for this application

On system start-up, the default layout direction depends on the application's language.

The notifier signal was introduced in Qt 5.4.

Access functions:

Qt::LayoutDirection	layoutDirection()
void	setLayoutDirection(Qt::LayoutDirection direction)

Notifier signal:

void	layoutDirectionChanged(Qt::LayoutDirection direction)

See also QWidget::layoutDirection, isLeftToRight(), and isRightToLeft().

pub unsafe fn meta_object(&self) -> Ptr<QMetaObject>

Calls C++ function: virtual const QMetaObject* QGuiApplication::metaObject() const.

pub unsafe fn modal_window() -> MutPtr<QWindow>

Returns the most recently shown modal window. If no modal windows are visible, this function returns zero.

Calls C++ function: static QWindow* QGuiApplication::modalWindow().

C++ documentation:

Returns the most recently shown modal window. If no modal windows are visible, this function returns zero.

A modal window is a window which has its modality property set to Qt::WindowModal or Qt::ApplicationModal. A modal window must be closed before the user can continue with other parts of the program.

Modal window are organized in a stack. This function returns the modal window at the top of the stack.

See also Qt::WindowModality and QWindow::setModality().

pub unsafe fn mouse_buttons() -> QFlags<MouseButton>

Returns the current state of the buttons on the mouse. The current state is updated syncronously as the event queue is emptied of events that will spontaneously change the mouse state (QEvent::MouseButtonPress and QEvent::MouseButtonRelease events).

Calls C++ function: static QFlags<Qt::MouseButton> QGuiApplication::mouseButtons().

C++ documentation:

Returns the current state of the buttons on the mouse. The current state is updated syncronously as the event queue is emptied of events that will spontaneously change the mouse state (QEvent::MouseButtonPress and QEvent::MouseButtonRelease events).

It should be noted this may not reflect the actual buttons held on the input device at the time of calling but rather the mouse buttons as last reported in one of the above events. If no mouse buttons are being held Qt::NoButton is returned.

See also keyboardModifiers().

pub unsafe fn new_3a(
    argc: impl CastInto<MutRef<c_int>>,
    argv: impl CastInto<MutPtr<*mut c_char>>,
    arg3: c_int
) -> CppBox<QGuiApplication>

Initializes the window system and constructs an application object with argc command line arguments in argv.

Calls C++ function: [constructor] void QGuiApplication::QGuiApplication(int& argc, char** argv, int arg3 = …).

Warning: no exact match found in C++ documentation. Below is the C++ documentation for QGuiApplication::QGuiApplication(int &argc, char **argv):

Initializes the window system and constructs an application object with argc command line arguments in argv.

Warning: The data referred to by argc and argv must stay valid for the entire lifetime of the QGuiApplication object. In addition, argc must be greater than zero and argv must contain at least one valid character string.

The global qApp pointer refers to this application object. Only one application object should be created.

This application object must be constructed before any paint devices (including pixmaps, bitmaps etc.).

Note: argc and argv might be changed as Qt removes command line arguments that it recognizes.

Supported Command Line Options

All Qt programs automatically support a set of command-line options that allow modifying the way Qt will interact with the windowing system. Some of the options are also accessible via environment variables, which are the preferred form if the application can launch GUI sub-processes or other applications (environment variables will be inherited by child processes). When in doubt, use the environment variables.

The options currently supported are the following:

• -platform platformName[:options], specifies the Qt Platform Abstraction (QPA) plugin.

  Overridden by the QT_QPA_PLATFORM environment variable.

• -platformpluginpath path, specifies the path to platform plugins.

  Overridden by the QT_QPA_PLATFORM_PLUGIN_PATH environment variable.

• -platformtheme platformTheme, specifies the platform theme.

  Overridden by the QT_QPA_PLATFORMTHEME environment variable.

• -plugin plugin, specifies additional plugins to load. The argument may appear multiple times.

  Overridden by the QT_QPA_GENERIC_PLUGINS environment variable.

• -qmljsdebugger=, activates the QML/JS debugger with a specified port. The value must be of format port:1234[,block], where block is optional and will make the application wait until a debugger connects to it.
• -qwindowgeometry geometry, specifies window geometry for the main window using the X11-syntax. For example: -qwindowgeometry 100x100+50+50
• -qwindowicon, sets the default window icon
• -qwindowtitle, sets the title of the first window
• -reverse, sets the application's layout direction to Qt::RightToLeft. This option is intended to aid debugging and should not be used in production. The default value is automatically detected from the user's locale (see also QLocale::textDirection()).
• -session session, restores the application from an earlier session.

The following standard command line options are available for X11:

• -display hostname:screen_number, switches displays on X11.

  Overrides the DISPLAY environment variable.

• -geometry geometry, same as -qwindowgeometry.

Platform-Specific Arguments

You can specify platform-specific arguments for the -platform option. Place them after the platform plugin name following a colon as a comma-separated list. For example, -platform windows:dialogs=xp,fontengine=freetype.

The following parameters are available for -platform windows:

• dialogs=[xp|none], xp uses XP-style native dialogs and none disables them.
• fontengine=freetype, uses the FreeType font engine.

For more information about the platform-specific arguments available for embedded Linux platforms, see Qt for Embedded Linux.

See also arguments() and QGuiApplication::platformName.

pub unsafe fn new_2a(
    argc: impl CastInto<MutRef<c_int>>,
    argv: impl CastInto<MutPtr<*mut c_char>>
) -> CppBox<QGuiApplication>

Initializes the window system and constructs an application object with argc command line arguments in argv.

Calls C++ function: [constructor] void QGuiApplication::QGuiApplication(int& argc, char** argv).

Warning: no exact match found in C++ documentation. Below is the C++ documentation for QGuiApplication::QGuiApplication(int &argc, char **argv):

Initializes the window system and constructs an application object with argc command line arguments in argv.

Warning: The data referred to by argc and argv must stay valid for the entire lifetime of the QGuiApplication object. In addition, argc must be greater than zero and argv must contain at least one valid character string.

The global qApp pointer refers to this application object. Only one application object should be created.

This application object must be constructed before any paint devices (including pixmaps, bitmaps etc.).

Note: argc and argv might be changed as Qt removes command line arguments that it recognizes.

Supported Command Line Options

All Qt programs automatically support a set of command-line options that allow modifying the way Qt will interact with the windowing system. Some of the options are also accessible via environment variables, which are the preferred form if the application can launch GUI sub-processes or other applications (environment variables will be inherited by child processes). When in doubt, use the environment variables.

The options currently supported are the following:

• -platform platformName[:options], specifies the Qt Platform Abstraction (QPA) plugin.

  Overridden by the QT_QPA_PLATFORM environment variable.

• -platformpluginpath path, specifies the path to platform plugins.

  Overridden by the QT_QPA_PLATFORM_PLUGIN_PATH environment variable.

• -platformtheme platformTheme, specifies the platform theme.

  Overridden by the QT_QPA_PLATFORMTHEME environment variable.

• -plugin plugin, specifies additional plugins to load. The argument may appear multiple times.

  Overridden by the QT_QPA_GENERIC_PLUGINS environment variable.

• -qmljsdebugger=, activates the QML/JS debugger with a specified port. The value must be of format port:1234[,block], where block is optional and will make the application wait until a debugger connects to it.
• -qwindowgeometry geometry, specifies window geometry for the main window using the X11-syntax. For example: -qwindowgeometry 100x100+50+50
• -qwindowicon, sets the default window icon
• -qwindowtitle, sets the title of the first window
• -reverse, sets the application's layout direction to Qt::RightToLeft. This option is intended to aid debugging and should not be used in production. The default value is automatically detected from the user's locale (see also QLocale::textDirection()).
• -session session, restores the application from an earlier session.

The following standard command line options are available for X11:

• -display hostname:screen_number, switches displays on X11.

  Overrides the DISPLAY environment variable.

• -geometry geometry, same as -qwindowgeometry.

Platform-Specific Arguments

You can specify platform-specific arguments for the -platform option. Place them after the platform plugin name following a colon as a comma-separated list. For example, -platform windows:dialogs=xp,fontengine=freetype.

The following parameters are available for -platform windows:

• dialogs=[xp|none], xp uses XP-style native dialogs and none disables them.
• fontengine=freetype, uses the FreeType font engine.

For more information about the platform-specific arguments available for embedded Linux platforms, see Qt for Embedded Linux.

See also arguments() and QGuiApplication::platformName.

pub unsafe fn notify(
    &mut self,
    arg1: impl CastInto<MutPtr<QObject>>,
    arg2: impl CastInto<MutPtr<QEvent>>
) -> bool

Reimplemented from QCoreApplication::notify().

Calls C++ function: virtual bool QGuiApplication::notify(QObject* arg1, QEvent* arg2).

C++ documentation:

Reimplemented from QCoreApplication::notify().

pub unsafe fn override_cursor() -> MutPtr<QCursor>

Returns the active application override cursor.

Calls C++ function: static QCursor* QGuiApplication::overrideCursor().

C++ documentation:

Returns the active application override cursor.

This function returns 0 if no application cursor has been defined (i.e. the internal cursor stack is empty).

See also setOverrideCursor() and restoreOverrideCursor().

pub unsafe fn palette() -> CppBox<QPalette>

Returns the default application palette.

Calls C++ function: static QPalette QGuiApplication::palette().

C++ documentation:

Returns the default application palette.

See also setPalette().

pub unsafe fn platform_function(
    function: impl CastInto<Ref<QByteArray>>
) -> Option<extern "C" fn()>

Returns a function pointer from the platformplugin matching function

Calls C++ function: static void (*FN_PTR)() QGuiApplication::platformFunction(const QByteArray& function).

C++ documentation:

Returns a function pointer from the platformplugin matching function

pub unsafe fn platform_name() -> CppBox<QString>

This property holds the name of the underlying platform plugin.

Calls C++ function: static QString QGuiApplication::platformName().

C++ documentation:

This property holds the name of the underlying platform plugin.

The QPA platform plugins are located in qtbase\src\plugins\platforms. At the time of writing, the following platform plugin names are supported:

• android
• cocoa is a platform plugin for macOS.
• directfb
• eglfs is a platform plugin for running Qt5 applications on top of EGL and OpenGL ES 2.0 without an actual windowing system (like X11 or Wayland). For more information, see EGLFS.
• ios (also used for tvOS)
• kms is an experimental platform plugin using kernel modesetting and DRM (Direct Rendering Manager).
• linuxfb writes directly to the framebuffer. For more information, see LinuxFB.
• minimal is provided as an examples for developers who want to write their own platform plugins. However, you can use the plugin to run GUI applications in environments without a GUI, such as servers.
• minimalegl is an example plugin.
• offscreen
• openwfd
• qnx
• windows
• xcb is the X11 plugin used on regular desktop Linux platforms.

For more information about the platform plugins for embedded Linux devices, see Qt for Embedded Linux.

Access functions:

QString

platformName()

pub unsafe fn primary_screen() -> MutPtr<QScreen>

This property holds the primary (or default) screen of the application.

Calls C++ function: static QScreen* QGuiApplication::primaryScreen().

C++ documentation:

This property holds the primary (or default) screen of the application.

This will be the screen where QWindows are initially shown, unless otherwise specified.

The primaryScreenChanged signal was introduced in Qt 5.6.

Access functions:

QScreen *

primaryScreen()

Notifier signal:

void	primaryScreenChanged(QScreen *screen)

See also screens().

pub unsafe fn qt_metacall(
    &mut self,
    arg1: Call,
    arg2: c_int,
    arg3: impl CastInto<MutPtr<*mut c_void>>
) -> c_int

Calls C++ function: virtual int QGuiApplication::qt_metacall(QMetaObject::Call arg1, int arg2, void** arg3).

pub unsafe fn qt_metacast(
    &mut self,
    arg1: impl CastInto<Ptr<c_char>>
) -> MutPtr<c_void>

Calls C++ function: virtual void* QGuiApplication::qt_metacast(const char* arg1).

pub unsafe fn query_keyboard_modifiers() -> QFlags<KeyboardModifier>

Queries and returns the state of the modifier keys on the keyboard. Unlike keyboardModifiers, this method returns the actual keys held on the input device at the time of calling the method.

Calls C++ function: static QFlags<Qt::KeyboardModifier> QGuiApplication::queryKeyboardModifiers().

C++ documentation:

Queries and returns the state of the modifier keys on the keyboard. Unlike keyboardModifiers, this method returns the actual keys held on the input device at the time of calling the method.

It does not rely on the keypress events having been received by this process, which makes it possible to check the modifiers while moving a window, for instance. Note that in most cases, you should use keyboardModifiers(), which is faster and more accurate since it contains the state of the modifiers as they were when the currently processed event was received.

See also keyboardModifiers().

pub unsafe fn quit_on_last_window_closed() -> bool

This property holds whether the application implicitly quits when the last window is closed.

Calls C++ function: static bool QGuiApplication::quitOnLastWindowClosed().

C++ documentation:

This property holds whether the application implicitly quits when the last window is closed.

The default is true.

If this property is true, the applications quits when the last visible primary window (i.e. window with no parent) is closed.

Access functions:

bool	quitOnLastWindowClosed()
void	setQuitOnLastWindowClosed(bool quit)

See also quit() and QWindow::close().

pub unsafe fn restore_override_cursor()

Undoes the last setOverrideCursor().

Calls C++ function: static void QGuiApplication::restoreOverrideCursor().

C++ documentation:

Undoes the last setOverrideCursor().

If setOverrideCursor() has been called twice, calling restoreOverrideCursor() will activate the first cursor set. Calling this function a second time restores the original widgets' cursors.

See also setOverrideCursor() and overrideCursor().

pub unsafe fn screen_at(point: impl CastInto<Ref<QPoint>>) -> MutPtr<QScreen>

Returns the screen at point, or nullptr if outside of any screen.

Calls C++ function: static QScreen* QGuiApplication::screenAt(const QPoint& point).

C++ documentation:

Returns the screen at point, or nullptr if outside of any screen.

The point is in relation to the virtualGeometry() of each set of virtual siblings. If the point maps to more than one set of virtual siblings the first match is returned.

This function was introduced in Qt 5.10.

This item is available if any(cpp_lib_version="5.11.3", cpp_lib_version="5.12.2", cpp_lib_version="5.13.0").

pub unsafe fn screens() -> CppBox<QListOfQScreen>

Returns a list of all the screens associated with the windowing system the application is connected to.

Calls C++ function: static QList<QScreen*> QGuiApplication::screens().

C++ documentation:

Returns a list of all the screens associated with the windowing system the application is connected to.

pub unsafe fn session_id(&self) -> CppBox<QString>

Returns the current session's identifier.

Calls C++ function: QString QGuiApplication::sessionId() const.

C++ documentation:

Returns the current session's identifier.

If the application has been restored from an earlier session, this identifier is the same as it was in that previous session. The session identifier is guaranteed to be unique both for different applications and for different instances of the same application.

See also isSessionRestored(), sessionKey(), commitDataRequest(), and saveStateRequest().

pub unsafe fn session_key(&self) -> CppBox<QString>

Returns the session key in the current session.

Calls C++ function: QString QGuiApplication::sessionKey() const.

C++ documentation:

Returns the session key in the current session.

If the application has been restored from an earlier session, this key is the same as it was when the previous session ended.

The session key changes every time the session is saved. If the shutdown process is cancelled, another session key will be used when shutting down again.

See also isSessionRestored(), sessionId(), commitDataRequest(), and saveStateRequest().

pub unsafe fn set_application_display_name(name: impl CastInto<Ref<QString>>)

This property holds the user-visible name of this application

Calls C++ function: static void QGuiApplication::setApplicationDisplayName(const QString& name).

C++ documentation:

This property holds the user-visible name of this application

This name is shown to the user, for instance in window titles. It can be translated, if necessary.

If not set, the application display name defaults to the application name.

This property was introduced in Qt 5.0.

Access functions:

QString	applicationDisplayName()
void	setApplicationDisplayName(const QString &name)

Notifier signal:

void	applicationDisplayNameChanged()

See also applicationName.

pub unsafe fn set_desktop_file_name(name: impl CastInto<Ref<QString>>)

This property holds the base name of the desktop entry for this application

Calls C++ function: static void QGuiApplication::setDesktopFileName(const QString& name).

C++ documentation:

This property holds the base name of the desktop entry for this application

This is the file name, without the full path, of the desktop entry that represents this application according to the freedesktop desktop entry specification.

This property gives a precise indication of what desktop entry represents the application and it is needed by the windowing system to retrieve such information without resorting to imprecise heuristics.

The latest version of the freedesktop desktop entry specification can be obtained here.

This property was introduced in Qt 5.7.

Access functions:

QString	desktopFileName()
void	setDesktopFileName(const QString &name)

pub unsafe fn set_desktop_settings_aware(on: bool)

Sets whether Qt should use the system's standard colors, fonts, etc., to on. By default, this is true.

Calls C++ function: static void QGuiApplication::setDesktopSettingsAware(bool on).

C++ documentation:

Sets whether Qt should use the system's standard colors, fonts, etc., to on. By default, this is true.

This function must be called before creating the QGuiApplication object, like this:

int main(int argc, char *argv[])
{
      QApplication::setDesktopSettingsAware(false);
      QApplication app(argc, argv);
      ...
      return app.exec();
}

See also desktopSettingsAware().

pub unsafe fn set_fallback_session_management_enabled(arg1: bool)

Sets whether QGuiApplication will use fallback session management to enabled.

Calls C++ function: static void QGuiApplication::setFallbackSessionManagementEnabled(bool arg1).

C++ documentation:

Sets whether QGuiApplication will use fallback session management to enabled.

This function was introduced in Qt 5.6.

See also isFallbackSessionManagementEnabled().

pub unsafe fn set_font(arg1: impl CastInto<Ref<QFont>>)

Changes the default application font to font.

Calls C++ function: static void QGuiApplication::setFont(const QFont& arg1).

C++ documentation:

Changes the default application font to font.

See also font().

pub unsafe fn set_layout_direction(direction: LayoutDirection)

This property holds the default layout direction for this application

Calls C++ function: static void QGuiApplication::setLayoutDirection(Qt::LayoutDirection direction).

C++ documentation:

This property holds the default layout direction for this application

On system start-up, the default layout direction depends on the application's language.

The notifier signal was introduced in Qt 5.4.

Access functions:

Qt::LayoutDirection	layoutDirection()
void	setLayoutDirection(Qt::LayoutDirection direction)

Notifier signal:

void	layoutDirectionChanged(Qt::LayoutDirection direction)

See also QWidget::layoutDirection, isLeftToRight(), and isRightToLeft().

pub unsafe fn set_override_cursor(arg1: impl CastInto<Ref<QCursor>>)

Sets the application override cursor to cursor.

Calls C++ function: static void QGuiApplication::setOverrideCursor(const QCursor& arg1).

C++ documentation:

Sets the application override cursor to cursor.

Application override cursors are intended for showing the user that the application is in a special state, for example during an operation that might take some time.

This cursor will be displayed in all the application's widgets until restoreOverrideCursor() or another setOverrideCursor() is called.

Application cursors are stored on an internal stack. setOverrideCursor() pushes the cursor onto the stack, and restoreOverrideCursor() pops the active cursor off the stack. changeOverrideCursor() changes the curently active application override cursor.

Every setOverrideCursor() must eventually be followed by a corresponding restoreOverrideCursor(), otherwise the stack will never be emptied.

Example:

QApplication::setOverrideCursor(QCursor(Qt::WaitCursor));
calculateHugeMandelbrot();              // lunch time...
QApplication::restoreOverrideCursor();

See also overrideCursor(), restoreOverrideCursor(), changeOverrideCursor(), and QWidget::setCursor().

pub unsafe fn set_palette(pal: impl CastInto<Ref<QPalette>>)

Changes the default application palette to pal.

Calls C++ function: static void QGuiApplication::setPalette(const QPalette& pal).

C++ documentation:

Changes the default application palette to pal.

See also palette().

pub unsafe fn set_quit_on_last_window_closed(quit: bool)

This property holds whether the application implicitly quits when the last window is closed.

Calls C++ function: static void QGuiApplication::setQuitOnLastWindowClosed(bool quit).

C++ documentation:

This property holds whether the application implicitly quits when the last window is closed.

The default is true.

If this property is true, the applications quits when the last visible primary window (i.e. window with no parent) is closed.

Access functions:

bool	quitOnLastWindowClosed()
void	setQuitOnLastWindowClosed(bool quit)

See also quit() and QWindow::close().

pub unsafe fn set_window_icon(icon: impl CastInto<Ref<QIcon>>)

This property holds the default window icon

Calls C++ function: static void QGuiApplication::setWindowIcon(const QIcon& icon).

C++ documentation:

This property holds the default window icon

Access functions:

QIcon	windowIcon()
void	setWindowIcon(const QIcon &icon)

See also QWindow::setIcon() and Setting the Application Icon.

pub unsafe fn static_meta_object() -> Ref<QMetaObject>

Returns a reference to the staticMetaObject field.

pub unsafe fn style_hints() -> MutPtr<QStyleHints>

Returns the application's style hints.

Calls C++ function: static QStyleHints* QGuiApplication::styleHints().

C++ documentation:

Returns the application's style hints.

The style hints encapsulate a set of platform dependent properties such as double click intervals, full width selection and others.

The hints can be used to integrate tighter with the underlying platform.

See also QStyleHints.

pub unsafe fn sync()

Function that can be used to sync Qt state with the Window Systems state.

Calls C++ function: static void QGuiApplication::sync().

C++ documentation:

Function that can be used to sync Qt state with the Window Systems state.

This function will first empty Qts events by calling QCoreApplication::processEvents(), then the platform plugin will sync up with the windowsystem, and finally Qts events will be delived by another call to QCoreApplication::processEvents();

This function is timeconsuming and its use is discouraged.

This function was introduced in Qt 5.2.

pub unsafe fn top_level_at(pos: impl CastInto<Ref<QPoint>>) -> MutPtr<QWindow>

Returns the top level window at the given position pos, if any.

Calls C++ function: static QWindow* QGuiApplication::topLevelAt(const QPoint& pos).

C++ documentation:

Returns the top level window at the given position pos, if any.

pub unsafe fn top_level_windows() -> CppBox<QListOfQWindow>

Returns a list of the top-level windows in the application.

Calls C++ function: static QList<QWindow*> QGuiApplication::topLevelWindows().

C++ documentation:

Returns a list of the top-level windows in the application.

See also allWindows().

pub unsafe fn tr(
    s: impl CastInto<Ptr<c_char>>,
    c: impl CastInto<Ptr<c_char>>,
    n: c_int
) -> CppBox<QString>

Calls C++ function: static QString QGuiApplication::tr(const char* s, const char* c, int n).

pub unsafe fn tr_utf8(
    s: impl CastInto<Ptr<c_char>>,
    c: impl CastInto<Ptr<c_char>>,
    n: c_int
) -> CppBox<QString>

Calls C++ function: static QString QGuiApplication::trUtf8(const char* s, const char* c, int n).

pub unsafe fn window_icon() -> CppBox<QIcon>

This property holds the default window icon

Calls C++ function: static QIcon QGuiApplication::windowIcon().

C++ documentation:

This property holds the default window icon

Access functions:

QIcon	windowIcon()
void	setWindowIcon(const QIcon &icon)

See also QWindow::setIcon() and Setting the Application Icon.

Methods from Deref<Target = QCoreApplication>

pub fn slot_quit(&self) -> Receiver<()>

Tells the application to exit with return code 0 (success). Equivalent to calling QCoreApplication::exit(0).

Returns a built-in Qt slot QCoreApplication::quit that can be passed to qt_core::Signal::connect.

C++ documentation:

Tells the application to exit with return code 0 (success). Equivalent to calling QCoreApplication::exit(0).

It's common to connect the QGuiApplication::lastWindowClosed() signal to quit(), and you also often connect e.g. QAbstractButton::clicked() or signals in QAction, QMenu, or QMenuBar to it.

Example:

QPushButton *quitButton = new QPushButton("Quit");
connect(quitButton, SIGNAL(clicked()), &app, SLOT(quit()));

See also exit(), aboutToQuit(), and QGuiApplication::lastWindowClosed().

pub fn about_to_quit(&self) -> Signal<()>

This signal is emitted when the application is about to quit the main event loop, e.g. when the event loop level drops to zero. This may happen either after a call to quit() from inside the application or when the user shuts down the entire desktop session.

Returns a built-in Qt signal QCoreApplication::aboutToQuit that can be passed to qt_core::Signal::connect.

C++ documentation:

This signal is emitted when the application is about to quit the main event loop, e.g. when the event loop level drops to zero. This may happen either after a call to quit() from inside the application or when the user shuts down the entire desktop session.

The signal is particularly useful if your application has to do some last-second cleanup. Note that no user interaction is possible in this state.

Note: This is a private signal. It can be used in signal connections but cannot be emitted by the user.

See also quit().

pub fn organization_name_changed(&self) -> Signal<()>

This property holds the name of the organization that wrote this application

Returns a built-in Qt signal QCoreApplication::organizationNameChanged that can be passed to qt_core::Signal::connect.

C++ documentation:

This property holds the name of the organization that wrote this application

The value is used by the QSettings class when it is constructed using the empty constructor. This saves having to repeat this information each time a QSettings object is created.

On Mac, QSettings uses organizationDomain() as the organization if it's not an empty string; otherwise it uses organizationName(). On all other platforms, QSettings uses organizationName() as the organization.

Access functions:

QString	organizationName()
void	setOrganizationName(const QString &orgName)

Notifier signal:

void	organizationNameChanged()

See also organizationDomain and applicationName.

pub fn organization_domain_changed(&self) -> Signal<()>

This property holds the Internet domain of the organization that wrote this application

Returns a built-in Qt signal QCoreApplication::organizationDomainChanged that can be passed to qt_core::Signal::connect.

C++ documentation:

This property holds the Internet domain of the organization that wrote this application

The value is used by the QSettings class when it is constructed using the empty constructor. This saves having to repeat this information each time a QSettings object is created.

On Mac, QSettings uses organizationDomain() as the organization if it's not an empty string; otherwise it uses organizationName(). On all other platforms, QSettings uses organizationName() as the organization.

Access functions:

QString	organizationDomain()
void	setOrganizationDomain(const QString &orgDomain)

Notifier signal:

void	organizationDomainChanged()

See also organizationName, applicationName, and applicationVersion.

pub fn application_name_changed(&self) -> Signal<()>

This property holds the name of this application

Returns a built-in Qt signal QCoreApplication::applicationNameChanged that can be passed to qt_core::Signal::connect.

C++ documentation:

This property holds the name of this application

The value is used by the QSettings class when it is constructed using the empty constructor. This saves having to repeat this information each time a QSettings object is created.

If not set, the application name defaults to the executable name (since 5.0).

Access functions:

QString	applicationName()
void	setApplicationName(const QString &application)

Notifier signal:

void	applicationNameChanged()

See also organizationName, organizationDomain, applicationVersion, and applicationFilePath().

pub fn application_version_changed(&self) -> Signal<()>

This property holds the version of this application

Returns a built-in Qt signal QCoreApplication::applicationVersionChanged that can be passed to qt_core::Signal::connect.

C++ documentation:

This property holds the version of this application

If not set, the application version defaults to a platform-specific value determined from the main application executable or package (since Qt 5.9):

Platform	Source
Windows (classic desktop)	PRODUCTVERSION parameter of the VERSIONINFO resource
Universal Windows Platform	version attribute of the application package manifest
macOS, iOS, tvOS, watchOS	CFBundleVersion property of the information property list
Android	android:versionName property of the AndroidManifest.xml manifest element

On other platforms, the default is the empty string.

This property was introduced in Qt 4.4.

Access functions:

QString	applicationVersion()
void	setApplicationVersion(const QString &version)

Notifier signal:

void	applicationVersionChanged()

See also applicationName, organizationName, and organizationDomain.

pub unsafe fn install_native_event_filter(
    &mut self,
    filter_obj: impl CastInto<MutPtr<QAbstractNativeEventFilter>>
)

Installs an event filter filterObj for all native events received by the application in the main thread.

Calls C++ function: void QCoreApplication::installNativeEventFilter(QAbstractNativeEventFilter* filterObj).

C++ documentation:

Installs an event filter filterObj for all native events received by the application in the main thread.

The event filter filterObj receives events via its nativeEventFilter() function, which is called for all native events received in the main thread.

The QAbstractNativeEventFilter::nativeEventFilter() function should return true if the event should be filtered, i.e. stopped. It should return false to allow normal Qt processing to continue: the native event can then be translated into a QEvent and handled by the standard Qt event filtering, e.g. QObject::installEventFilter().

If multiple event filters are installed, the filter that was installed last is activated first.

Note: The filter function set here receives native messages, i.e. MSG or XCB event structs.

Note: Native event filters will be disabled in the application when the Qt::AA_PluginApplication attribute is set.

For maximum portability, you should always try to use QEvent and QObject::installEventFilter() whenever possible.

This function was introduced in Qt 5.0.

See also QObject::installEventFilter().

pub unsafe fn meta_object(&self) -> Ptr<QMetaObject>

Calls C++ function: virtual const QMetaObject* QCoreApplication::metaObject() const.

pub unsafe fn notify(
    &mut self,
    arg1: impl CastInto<MutPtr<QObject>>,
    arg2: impl CastInto<MutPtr<QEvent>>
) -> bool

Sends event to receiver: receiver->event(event). Returns the value that is returned from the receiver's event handler. Note that this function is called for all events sent to any object in any thread.

Calls C++ function: virtual bool QCoreApplication::notify(QObject* arg1, QEvent* arg2).

C++ documentation:

Sends event to receiver: receiver->event(event). Returns the value that is returned from the receiver's event handler. Note that this function is called for all events sent to any object in any thread.

For certain types of events (e.g. mouse and key events), the event will be propagated to the receiver's parent and so on up to the top-level object if the receiver is not interested in the event (i.e., it returns false).

There are five different ways that events can be processed; reimplementing this virtual function is just one of them. All five approaches are listed below:

1. Reimplementing paintEvent(), mousePressEvent() and so on. This is the most common, easiest, and least powerful way.
2. Reimplementing this function. This is very powerful, providing complete control; but only one subclass can be active at a time.
3. Installing an event filter on QCoreApplication::instance(). Such an event filter is able to process all events for all widgets, so it's just as powerful as reimplementing notify(); furthermore, it's possible to have more than one application-global event filter. Global event filters even see mouse events for disabled widgets. Note that application event filters are only called for objects that live in the main thread.
4. Reimplementing QObject::event() (as QWidget does). If you do this you get Tab key presses, and you get to see the events before any widget-specific event filters.
5. Installing an event filter on the object. Such an event filter gets all the events, including Tab and Shift+Tab key press events, as long as they do not change the focus widget.

Future direction: This function will not be called for objects that live outside the main thread in Qt 6. Applications that need that functionality should find other solutions for their event inspection needs in the meantime. The change may be extended to the main thread, causing this function to be deprecated.

Warning: If you override this function, you must ensure all threads that process events stop doing so before your application object begins destruction. This includes threads started by other libraries that you may be using, but does not apply to Qt's own threads.

See also QObject::event() and installNativeEventFilter().

pub unsafe fn qt_metacall(
    &mut self,
    arg1: Call,
    arg2: i32,
    arg3: impl CastInto<MutPtr<*mut c_void>>
) -> i32

Calls C++ function: virtual int QCoreApplication::qt_metacall(QMetaObject::Call arg1, int arg2, void** arg3).

pub unsafe fn qt_metacast(
    &mut self,
    arg1: impl CastInto<Ptr<i8>>
) -> MutPtr<c_void>

Calls C++ function: virtual void* QCoreApplication::qt_metacast(const char* arg1).

pub unsafe fn remove_native_event_filter(
    &mut self,
    filter_obj: impl CastInto<MutPtr<QAbstractNativeEventFilter>>
)

Removes an event filterObject from this object. The request is ignored if such an event filter has not been installed.

Calls C++ function: void QCoreApplication::removeNativeEventFilter(QAbstractNativeEventFilter* filterObj).

C++ documentation:

Removes an event filterObject from this object. The request is ignored if such an event filter has not been installed.

All event filters for this object are automatically removed when this object is destroyed.

It is always safe to remove an event filter, even during event filter activation (i.e. from the nativeEventFilter() function).

This function was introduced in Qt 5.0.

See also installNativeEventFilter().

Trait Implementations

impl CppDeletable for QGuiApplication

unsafe fn delete(&mut self)

Destructs the application.

Calls C++ function: virtual [destructor] void QGuiApplication::~QGuiApplication().

C++ documentation:

Destructs the application.

impl Deref for QGuiApplication

type Target = QCoreApplication

The resulting type after dereferencing.

fn deref(&self) -> &QCoreApplication

Calls C++ function: QCoreApplication* static_cast<QCoreApplication*>(QGuiApplication* ptr).

impl DerefMut for QGuiApplication

fn deref_mut(&mut self) -> &mut QCoreApplication

Calls C++ function: QCoreApplication* static_cast<QCoreApplication*>(QGuiApplication* ptr).

impl DynamicCast<QGuiApplication> for QCoreApplication

unsafe fn dynamic_cast(ptr: Ptr<QCoreApplication>) -> Ptr<QGuiApplication>

Calls C++ function: QGuiApplication* dynamic_cast<QGuiApplication*>(QCoreApplication* ptr).

unsafe fn dynamic_cast_mut(
    ptr: MutPtr<QCoreApplication>
) -> MutPtr<QGuiApplication>

Calls C++ function: QGuiApplication* dynamic_cast<QGuiApplication*>(QCoreApplication* ptr).

impl DynamicCast<QGuiApplication> for QObject

unsafe fn dynamic_cast(ptr: Ptr<QObject>) -> Ptr<QGuiApplication>

Calls C++ function: QGuiApplication* dynamic_cast<QGuiApplication*>(QObject* ptr).

unsafe fn dynamic_cast_mut(ptr: MutPtr<QObject>) -> MutPtr<QGuiApplication>

Calls C++ function: QGuiApplication* dynamic_cast<QGuiApplication*>(QObject* ptr).

impl StaticDowncast<QGuiApplication> for QCoreApplication

unsafe fn static_downcast(ptr: Ptr<QCoreApplication>) -> Ptr<QGuiApplication>

Calls C++ function: QGuiApplication* static_cast<QGuiApplication*>(QCoreApplication* ptr).

unsafe fn static_downcast_mut(
    ptr: MutPtr<QCoreApplication>
) -> MutPtr<QGuiApplication>

Calls C++ function: QGuiApplication* static_cast<QGuiApplication*>(QCoreApplication* ptr).

impl StaticDowncast<QGuiApplication> for QObject

unsafe fn static_downcast(ptr: Ptr<QObject>) -> Ptr<QGuiApplication>

Calls C++ function: QGuiApplication* static_cast<QGuiApplication*>(QObject* ptr).

unsafe fn static_downcast_mut(ptr: MutPtr<QObject>) -> MutPtr<QGuiApplication>

Calls C++ function: QGuiApplication* static_cast<QGuiApplication*>(QObject* ptr).

impl StaticUpcast<QCoreApplication> for QGuiApplication

unsafe fn static_upcast(ptr: Ptr<QGuiApplication>) -> Ptr<QCoreApplication>

Calls C++ function: QCoreApplication* static_cast<QCoreApplication*>(QGuiApplication* ptr).

unsafe fn static_upcast_mut(
    ptr: MutPtr<QGuiApplication>
) -> MutPtr<QCoreApplication>

Calls C++ function: QCoreApplication* static_cast<QCoreApplication*>(QGuiApplication* ptr).

impl StaticUpcast<QObject> for QGuiApplication

unsafe fn static_upcast(ptr: Ptr<QGuiApplication>) -> Ptr<QObject>

Calls C++ function: QObject* static_cast<QObject*>(QGuiApplication* ptr).

unsafe fn static_upcast_mut(ptr: MutPtr<QGuiApplication>) -> MutPtr<QObject>

Calls C++ function: QObject* static_cast<QObject*>(QGuiApplication* ptr).