Struct qt_gui::QGuiApplication

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

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().

Implementations

impl QGuiApplication

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

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

This function creates a QGuiApplication object with valid argc and argv, calls the passed closure f(app) with the application object and exits 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 QGuiApplication::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() -> QPtr<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() -> QPtr<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() -> QPtr<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(&self, font: impl CastInto<Ref<QFont>>)

Available on cpp_lib_version="5.11.3" or cpp_lib_version="5.12.2" or cpp_lib_version="5.13.0" or cpp_lib_version="5.14.0" only.

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().

pub unsafe fn high_dpi_scale_factor_rounding_policy( ) -> HighDpiScaleFactorRoundingPolicy

Available on cpp_lib_version="5.14.0" only.

Returns the high-DPI scale factor rounding policy.

Calls C++ function: static Qt::HighDpiScaleFactorRoundingPolicy QGuiApplication::highDpiScaleFactorRoundingPolicy().

C++ documentation:

Returns the high-DPI scale factor rounding policy.

This function was introduced in Qt 5.14.

See also setHighDpiScaleFactorRoundingPolicy().

pub unsafe fn input_method() -> QPtr<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() -> QPtr<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: *mut c_int, argv: *mut *mut c_char, arg3: c_int ) -> QBox<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: *mut c_int, argv: *mut *mut c_char ) -> QBox<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( &self, arg1: impl CastInto<Ptr<QObject>>, arg2: impl CastInto<Ptr<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() -> Ptr<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() -> QPtr<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( &self, arg1: Call, arg2: c_int, arg3: *mut *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(&self, arg1: *const c_char) -> *mut 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>>) -> QPtr<QScreen>

Available on cpp_lib_version="5.11.3" or cpp_lib_version="5.12.2" or cpp_lib_version="5.13.0" or cpp_lib_version="5.14.0" only.

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.

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_high_dpi_scale_factor_rounding_policy( policy: HighDpiScaleFactorRoundingPolicy )

Available on cpp_lib_version="5.14.0" only.

Sets the high-DPI scale factor rounding policy for the application. The policy decides how non-integer scale factors (such as Windows 150%) are handled, for applications that have AA_EnableHighDpiScaling enabled.

Calls C++ function: static void QGuiApplication::setHighDpiScaleFactorRoundingPolicy(Qt::HighDpiScaleFactorRoundingPolicy policy).

C++ documentation:

Sets the high-DPI scale factor rounding policy for the application. The policy decides how non-integer scale factors (such as Windows 150%) are handled, for applications that have AA_EnableHighDpiScaling enabled.

The two principal options are whether fractional scale factors should be rounded to an integer or not. Keeping the scale factor as-is will make the user interface size match the OS setting exactly, but may cause painting errors, for example with the Windows style.

If rounding is wanted, then which type of rounding should be decided next. Mathematically correct rounding is supported but may not give the best visual results: Consider if you want to render 1.5x as 1x ("small UI") or as 2x ("large UI"). See the Qt::HighDpiScaleFactorRoundingPolicy enum for a complete list of all options.

This function must be called before creating the application object, and can be overridden by setting the QT_SCALE_FACTOR_ROUNDING_POLICY environment variable. The QGuiApplication::highDpiScaleFactorRoundingPolicy() accessor will reflect the environment, if set.

The default value is Qt::HighDpiScaleFactorRoundingPolicy::RoundPreferFloor.

This function was introduced in Qt 5.14.

See also highDpiScaleFactorRoundingPolicy().

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() -> QPtr<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>>) -> QPtr<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: *const c_char, c: *const 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: *const c_char, c: *const 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( &self, filter_obj: impl CastInto<Ptr<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( &self, arg1: impl CastInto<Ptr<QObject>>, arg2: impl CastInto<Ptr<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( &self, arg1: Call, arg2: i32, arg3: *mut *mut c_void ) -> i32

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

pub unsafe fn qt_metacast(&self, arg1: *const i8) -> *mut c_void

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

pub unsafe fn remove_native_event_filter( &self, filter_obj: impl CastInto<Ptr<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().

Methods from Deref<Target = QObject>

pub unsafe fn find_child<T>( &self, name: &str ) -> Result<QPtr<T>, FindChildError>

where QObject: DynamicCast<T>, T: StaticUpcast<QObject>,

Finds a child of self with the specified object name and casts it to type T.

The search is performed recursively. If there is more than one child matching the search, the most direct ancestor is returned. If there are several direct ancestors, it is undefined which one will be returned.

Returns an error if there is no child object with object name name or the found object cannot be cast to T.

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

This signal is emitted immediately before the object obj is destroyed, and can not be blocked.

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

C++ documentation:

This signal is emitted immediately before the object obj is destroyed, and can not be blocked.

All the objects's children are destroyed immediately after this signal is emitted.

See also deleteLater() and QPointer.

pub fn object_name_changed(&self) -> Signal<(*const QString,)>

This signal is emitted after the object's name has been changed. The new object name is passed as objectName.

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

C++ documentation:

This signal is emitted after the object’s name has been changed. The new object name is passed as objectName.

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

Note: Notifier signal for property objectName.

See also QObject::objectName.

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

Schedules this object for deletion.

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

C++ documentation:

Schedules this object for deletion.

The object will be deleted when control returns to the event loop. If the event loop is not running when this function is called (e.g. deleteLater() is called on an object before QCoreApplication::exec()), the object will be deleted once the event loop is started. If deleteLater() is called after the main event loop has stopped, the object will not be deleted. Since Qt 4.8, if deleteLater() is called on an object that lives in a thread with no running event loop, the object will be destroyed when the thread finishes.

Note that entering and leaving a new event loop (e.g., by opening a modal dialog) will not perform the deferred deletion; for the object to be deleted, the control must return to the event loop from which deleteLater() was called.

Note: It is safe to call this function more than once; when the first deferred deletion event is delivered, any pending events for the object are removed from the event queue.

See also destroyed() and QPointer.

pub unsafe fn block_signals(&self, b: bool) -> bool

If block is true, signals emitted by this object are blocked (i.e., emitting a signal will not invoke anything connected to it). If block is false, no such blocking will occur.

Calls C++ function: bool QObject::blockSignals(bool b).

C++ documentation:

If block is true, signals emitted by this object are blocked (i.e., emitting a signal will not invoke anything connected to it). If block is false, no such blocking will occur.

The return value is the previous value of signalsBlocked().

Note that the destroyed() signal will be emitted even if the signals for this object have been blocked.

Signals emitted while being blocked are not buffered.

See also signalsBlocked() and QSignalBlocker.

pub unsafe fn children(&self) -> Ref<QListOfQObject>

Returns a list of child objects. The QObjectList class is defined in the <QObject> header file as the following:

Calls C++ function: const QList<QObject*>& QObject::children() const.

C++ documentation:

Returns a list of child objects. The QObjectList class is defined in the <QObject> header file as the following:

  typedef QList<QObject*> QObjectList;

The first child added is the first object in the list and the last child added is the last object in the list, i.e. new children are appended at the end.

Note that the list order changes when QWidget children are raised or lowered. A widget that is raised becomes the last object in the list, and a widget that is lowered becomes the first object in the list.

See also findChild(), findChildren(), parent(), and setParent().

pub unsafe fn delete_later(&self)

Schedules this object for deletion.

Calls C++ function: [slot] void QObject::deleteLater().

C++ documentation:

Schedules this object for deletion.

The object will be deleted when control returns to the event loop. If the event loop is not running when this function is called (e.g. deleteLater() is called on an object before QCoreApplication::exec()), the object will be deleted once the event loop is started. If deleteLater() is called after the main event loop has stopped, the object will not be deleted. Since Qt 4.8, if deleteLater() is called on an object that lives in a thread with no running event loop, the object will be destroyed when the thread finishes.

Note that entering and leaving a new event loop (e.g., by opening a modal dialog) will not perform the deferred deletion; for the object to be deleted, the control must return to the event loop from which deleteLater() was called.

Note: It is safe to call this function more than once; when the first deferred deletion event is delivered, any pending events for the object are removed from the event queue.

See also destroyed() and QPointer.

pub unsafe fn disconnect_char_q_object_char( &self, signal: *const i8, receiver: impl CastInto<Ptr<QObject>>, member: *const i8 ) -> bool

This function overloads disconnect().

Calls C++ function: bool QObject::disconnect(const char* signal = …, const QObject* receiver = …, const char* member = …) const.

C++ documentation:

This function overloads disconnect().

Disconnects signal from method of receiver.

A signal-slot connection is removed when either of the objects involved are destroyed.

Note: This function is thread-safe.

pub unsafe fn disconnect_q_object_char( &self, receiver: impl CastInto<Ptr<QObject>>, member: *const i8 ) -> bool

This function overloads disconnect().

Calls C++ function: bool QObject::disconnect(const QObject* receiver, const char* member = …) const.

C++ documentation:

This function overloads disconnect().

Disconnects all signals in this object from receiver's method.

A signal-slot connection is removed when either of the objects involved are destroyed.

pub unsafe fn disconnect_char_q_object( &self, signal: *const i8, receiver: impl CastInto<Ptr<QObject>> ) -> bool

This function overloads disconnect().

Calls C++ function: bool QObject::disconnect(const char* signal = …, const QObject* receiver = …) const.

C++ documentation:

This function overloads disconnect().

Disconnects signal from method of receiver.

A signal-slot connection is removed when either of the objects involved are destroyed.

Note: This function is thread-safe.

pub unsafe fn disconnect_char(&self, signal: *const i8) -> bool

This function overloads disconnect().

Calls C++ function: bool QObject::disconnect(const char* signal = …) const.

C++ documentation:

This function overloads disconnect().

Disconnects signal from method of receiver.

A signal-slot connection is removed when either of the objects involved are destroyed.

Note: This function is thread-safe.

pub unsafe fn disconnect(&self) -> bool

This function overloads disconnect().

Calls C++ function: bool QObject::disconnect() const.

C++ documentation:

This function overloads disconnect().

Disconnects signal from method of receiver.

A signal-slot connection is removed when either of the objects involved are destroyed.

Note: This function is thread-safe.

pub unsafe fn disconnect_q_object( &self, receiver: impl CastInto<Ptr<QObject>> ) -> bool

This function overloads disconnect().

Calls C++ function: bool QObject::disconnect(const QObject* receiver) const.

C++ documentation:

This function overloads disconnect().

Disconnects all signals in this object from receiver's method.

A signal-slot connection is removed when either of the objects involved are destroyed.

pub unsafe fn dump_object_info_mut(&self)

Dumps information about signal connections, etc. for this object to the debug output.

Calls C++ function: void QObject::dumpObjectInfo().

C++ documentation:

Dumps information about signal connections, etc. for this object to the debug output.

Note: before Qt 5.9, this function was not const.

See also dumpObjectTree().

pub unsafe fn dump_object_info(&self)

Dumps information about signal connections, etc. for this object to the debug output.

Calls C++ function: void QObject::dumpObjectInfo() const.

C++ documentation:

Dumps information about signal connections, etc. for this object to the debug output.

Note: before Qt 5.9, this function was not const.

See also dumpObjectTree().

pub unsafe fn dump_object_tree_mut(&self)

Dumps a tree of children to the debug output.

Calls C++ function: void QObject::dumpObjectTree().

C++ documentation:

Dumps a tree of children to the debug output.

Note: before Qt 5.9, this function was not const.

See also dumpObjectInfo().

pub unsafe fn dump_object_tree(&self)

Dumps a tree of children to the debug output.

Calls C++ function: void QObject::dumpObjectTree() const.

C++ documentation:

Dumps a tree of children to the debug output.

Note: before Qt 5.9, this function was not const.

See also dumpObjectInfo().

pub unsafe fn dynamic_property_names(&self) -> CppBox<QListOfQByteArray>

Returns the names of all properties that were dynamically added to the object using setProperty().

Calls C++ function: QList<QByteArray> QObject::dynamicPropertyNames() const.

C++ documentation:

Returns the names of all properties that were dynamically added to the object using setProperty().

This function was introduced in Qt 4.2.

pub unsafe fn eq(&self, p: impl CastInto<Ref<QPointerOfQObject>>) -> bool

Returns true if c1 and c2 are the same Unicode character; otherwise returns false.

Calls C++ function: bool operator==(QObject* o, const QPointer<QObject>& p).

Warning: no exact match found in C++ documentation. Below is the C++ documentation for bool operator==(QChar c1, QChar c2):

Returns true if c1 and c2 are the same Unicode character; otherwise returns false.

pub unsafe fn event(&self, event: impl CastInto<Ptr<QEvent>>) -> bool

This virtual function receives events to an object and should return true if the event e was recognized and processed.

Calls C++ function: virtual bool QObject::event(QEvent* event).

C++ documentation:

This virtual function receives events to an object and should return true if the event e was recognized and processed.

The event() function can be reimplemented to customize the behavior of an object.

Make sure you call the parent event class implementation for all the events you did not handle.

Example:

class MyClass : public QWidget
{
      Q_OBJECT
public:
      MyClass(QWidget *parent = 0);
      ~MyClass();
      bool event(QEvent* ev)
      {
          if (ev->type() == QEvent::PolishRequest) {
              // overwrite handling of PolishRequest if any
              doThings();
              return true;
          } else  if (ev->type() == QEvent::Show) {
              // complement handling of Show if any
              doThings2();
              QWidget::event(ev);
              return true;
          }
          // Make sure the rest of events are handled
          return QWidget::event(ev);
      }
};

See also installEventFilter(), timerEvent(), QCoreApplication::sendEvent(), and QCoreApplication::postEvent().

pub unsafe fn event_filter( &self, watched: impl CastInto<Ptr<QObject>>, event: impl CastInto<Ptr<QEvent>> ) -> bool

Filters events if this object has been installed as an event filter for the watched object.

Calls C++ function: virtual bool QObject::eventFilter(QObject* watched, QEvent* event).

C++ documentation:

Filters events if this object has been installed as an event filter for the watched object.

In your reimplementation of this function, if you want to filter the event out, i.e. stop it being handled further, return true; otherwise return false.

Example:

class MainWindow : public QMainWindow
{
public:
      MainWindow();
protected:
      bool eventFilter(QObject obj, QEvent ev);
private:
      QTextEdit *textEdit;
};
MainWindow::MainWindow()
{
      textEdit = new QTextEdit;
      setCentralWidget(textEdit);
      textEdit->installEventFilter(this);
}
bool MainWindow::eventFilter(QObject obj, QEvent event)
{
      if (obj == textEdit) {
          if (event->type() == QEvent::KeyPress) {
              QKeyEvent keyEvent = static_cast<QKeyEvent>(event);
              qDebug() << “Ate key press” << keyEvent->key();
              return true;
          } else {
              return false;
          }
      } else {
          // pass the event on to the parent class
          return QMainWindow::eventFilter(obj, event);
      }
}

Notice in the example above that unhandled events are passed to the base class's eventFilter() function, since the base class might have reimplemented eventFilter() for its own internal purposes.

Warning: If you delete the receiver object in this function, be sure to return true. Otherwise, Qt will forward the event to the deleted object and the program might crash.

See also installEventFilter().

pub unsafe fn find_child_q_object_2a( &self, a_name: impl CastInto<Ref<QString>>, options: QFlags<FindChildOption> ) -> QPtr<QObject>

Returns the child of this object that can be cast into type T and that is called name, or 0 if there is no such object. Omitting the name argument causes all object names to be matched. The search is performed recursively, unless options specifies the option FindDirectChildrenOnly.

Calls C++ function: QObject* QObject::findChild<QObject*>(const QString& aName = …, QFlags<Qt::FindChildOption> options = …) const.

C++ documentation:

Returns the child of this object that can be cast into type T and that is called name, or 0 if there is no such object. Omitting the name argument causes all object names to be matched. The search is performed recursively, unless options specifies the option FindDirectChildrenOnly.

If there is more than one child matching the search, the most direct ancestor is returned. If there are several direct ancestors, it is undefined which one will be returned. In that case, findChildren() should be used.

This example returns a child QPushButton of parentWidget named "button1", even if the button isn't a direct child of the parent:

QPushButton button = parentWidget->findChild<QPushButton >(“button1”);

This example returns a QListWidget child of parentWidget:

QListWidget list = parentWidget->findChild<QListWidget >();

This example returns a child QPushButton of parentWidget (its direct parent) named "button1":

QPushButton button = parentWidget->findChild<QPushButton >(“button1”, Qt::FindDirectChildrenOnly);

This example returns a QListWidget child of parentWidget, its direct parent:

QListWidget list = parentWidget->findChild<QListWidget >(QString(), Qt::FindDirectChildrenOnly);

See also findChildren().

pub unsafe fn find_child_q_object_1a( &self, a_name: impl CastInto<Ref<QString>> ) -> QPtr<QObject>

Returns the child of this object that can be cast into type T and that is called name, or 0 if there is no such object. Omitting the name argument causes all object names to be matched. The search is performed recursively, unless options specifies the option FindDirectChildrenOnly.

Calls C++ function: QObject* QObject::findChild<QObject*>(const QString& aName = …) const.

C++ documentation:

Returns the child of this object that can be cast into type T and that is called name, or 0 if there is no such object. Omitting the name argument causes all object names to be matched. The search is performed recursively, unless options specifies the option FindDirectChildrenOnly.

If there is more than one child matching the search, the most direct ancestor is returned. If there are several direct ancestors, it is undefined which one will be returned. In that case, findChildren() should be used.

This example returns a child QPushButton of parentWidget named "button1", even if the button isn't a direct child of the parent:

QPushButton button = parentWidget->findChild<QPushButton >(“button1”);

This example returns a QListWidget child of parentWidget:

QListWidget list = parentWidget->findChild<QListWidget >();

This example returns a child QPushButton of parentWidget (its direct parent) named "button1":

QPushButton button = parentWidget->findChild<QPushButton >(“button1”, Qt::FindDirectChildrenOnly);

This example returns a QListWidget child of parentWidget, its direct parent:

QListWidget list = parentWidget->findChild<QListWidget >(QString(), Qt::FindDirectChildrenOnly);

See also findChildren().

pub unsafe fn find_child_q_object_0a(&self) -> QPtr<QObject>

Returns the child of this object that can be cast into type T and that is called name, or 0 if there is no such object. Omitting the name argument causes all object names to be matched. The search is performed recursively, unless options specifies the option FindDirectChildrenOnly.

Calls C++ function: QObject* QObject::findChild<QObject*>() const.

C++ documentation:

Returns the child of this object that can be cast into type T and that is called name, or 0 if there is no such object. Omitting the name argument causes all object names to be matched. The search is performed recursively, unless options specifies the option FindDirectChildrenOnly.

If there is more than one child matching the search, the most direct ancestor is returned. If there are several direct ancestors, it is undefined which one will be returned. In that case, findChildren() should be used.

This example returns a child QPushButton of parentWidget named "button1", even if the button isn't a direct child of the parent:

QPushButton button = parentWidget->findChild<QPushButton >(“button1”);

This example returns a QListWidget child of parentWidget:

QListWidget list = parentWidget->findChild<QListWidget >();

This example returns a child QPushButton of parentWidget (its direct parent) named "button1":

QPushButton button = parentWidget->findChild<QPushButton >(“button1”, Qt::FindDirectChildrenOnly);

This example returns a QListWidget child of parentWidget, its direct parent:

QListWidget list = parentWidget->findChild<QListWidget >(QString(), Qt::FindDirectChildrenOnly);

See also findChildren().

pub unsafe fn find_children_q_object_q_string_q_flags_find_child_option( &self, a_name: impl CastInto<Ref<QString>>, options: QFlags<FindChildOption> ) -> CppBox<QListOfQObject>

Returns all children of this object with the given name that can be cast to type T, or an empty list if there are no such objects. Omitting the name argument causes all object names to be matched. The search is performed recursively, unless options specifies the option FindDirectChildrenOnly.

Calls C++ function: QList<QObject*> QObject::findChildren<QObject*>(const QString& aName = …, QFlags<Qt::FindChildOption> options = …) const.

C++ documentation:

Returns all children of this object with the given name that can be cast to type T, or an empty list if there are no such objects. Omitting the name argument causes all object names to be matched. The search is performed recursively, unless options specifies the option FindDirectChildrenOnly.

The following example shows how to find a list of child QWidgets of the specified parentWidget named widgetname:

QList<QWidget > widgets = parentWidget.findChildren<QWidget >(“widgetname”);

This example returns all QPushButtons that are children of parentWidget:

QList<QPushButton > allPButtons = parentWidget.findChildren<QPushButton >();

This example returns all QPushButtons that are immediate children of parentWidget:

QList<QPushButton > childButtons = parentWidget.findChildren<QPushButton >(QString(), Qt::FindDirectChildrenOnly);

See also findChild().

pub unsafe fn find_children_q_object_q_reg_exp_q_flags_find_child_option( &self, re: impl CastInto<Ref<QRegExp>>, options: QFlags<FindChildOption> ) -> CppBox<QListOfQObject>

This function overloads findChildren().

Calls C++ function: QList<QObject*> QObject::findChildren<QObject*>(const QRegExp& re, QFlags<Qt::FindChildOption> options = …) const.

C++ documentation:

This function overloads findChildren().

Returns the children of this object that can be cast to type T and that have names matching the regular expression regExp, or an empty list if there are no such objects. The search is performed recursively, unless options specifies the option FindDirectChildrenOnly.

pub unsafe fn find_children_q_object_q_regular_expression_q_flags_find_child_option( &self, re: impl CastInto<Ref<QRegularExpression>>, options: QFlags<FindChildOption> ) -> CppBox<QListOfQObject>

This function overloads findChildren().

Calls C++ function: QList<QObject*> QObject::findChildren<QObject*>(const QRegularExpression& re, QFlags<Qt::FindChildOption> options = …) const.

C++ documentation:

This function overloads findChildren().

Returns the children of this object that can be cast to type T and that have names matching the regular expression re, or an empty list if there are no such objects. The search is performed recursively, unless options specifies the option FindDirectChildrenOnly.

This function was introduced in Qt 5.0.

pub unsafe fn find_children_q_object_q_string( &self, a_name: impl CastInto<Ref<QString>> ) -> CppBox<QListOfQObject>

Returns all children of this object with the given name that can be cast to type T, or an empty list if there are no such objects. Omitting the name argument causes all object names to be matched. The search is performed recursively, unless options specifies the option FindDirectChildrenOnly.

Calls C++ function: QList<QObject*> QObject::findChildren<QObject*>(const QString& aName = …) const.

C++ documentation:

Returns all children of this object with the given name that can be cast to type T, or an empty list if there are no such objects. Omitting the name argument causes all object names to be matched. The search is performed recursively, unless options specifies the option FindDirectChildrenOnly.

The following example shows how to find a list of child QWidgets of the specified parentWidget named widgetname:

QList<QWidget > widgets = parentWidget.findChildren<QWidget >(“widgetname”);

This example returns all QPushButtons that are children of parentWidget:

QList<QPushButton > allPButtons = parentWidget.findChildren<QPushButton >();

This example returns all QPushButtons that are immediate children of parentWidget:

QList<QPushButton > childButtons = parentWidget.findChildren<QPushButton >(QString(), Qt::FindDirectChildrenOnly);

See also findChild().

pub unsafe fn find_children_q_object(&self) -> CppBox<QListOfQObject>

Returns all children of this object with the given name that can be cast to type T, or an empty list if there are no such objects. Omitting the name argument causes all object names to be matched. The search is performed recursively, unless options specifies the option FindDirectChildrenOnly.

Calls C++ function: QList<QObject*> QObject::findChildren<QObject*>() const.

C++ documentation:

Returns all children of this object with the given name that can be cast to type T, or an empty list if there are no such objects. Omitting the name argument causes all object names to be matched. The search is performed recursively, unless options specifies the option FindDirectChildrenOnly.

The following example shows how to find a list of child QWidgets of the specified parentWidget named widgetname:

QList<QWidget > widgets = parentWidget.findChildren<QWidget >(“widgetname”);

This example returns all QPushButtons that are children of parentWidget:

QList<QPushButton > allPButtons = parentWidget.findChildren<QPushButton >();

This example returns all QPushButtons that are immediate children of parentWidget:

QList<QPushButton > childButtons = parentWidget.findChildren<QPushButton >(QString(), Qt::FindDirectChildrenOnly);

See also findChild().

pub unsafe fn find_children_q_object_q_reg_exp( &self, re: impl CastInto<Ref<QRegExp>> ) -> CppBox<QListOfQObject>

This function overloads findChildren().

Calls C++ function: QList<QObject*> QObject::findChildren<QObject*>(const QRegExp& re) const.

C++ documentation:

This function overloads findChildren().

Returns the children of this object that can be cast to type T and that have names matching the regular expression regExp, or an empty list if there are no such objects. The search is performed recursively, unless options specifies the option FindDirectChildrenOnly.

pub unsafe fn find_children_q_object_q_regular_expression( &self, re: impl CastInto<Ref<QRegularExpression>> ) -> CppBox<QListOfQObject>

This function overloads findChildren().

Calls C++ function: QList<QObject*> QObject::findChildren<QObject*>(const QRegularExpression& re) const.

C++ documentation:

This function overloads findChildren().

Returns the children of this object that can be cast to type T and that have names matching the regular expression re, or an empty list if there are no such objects. The search is performed recursively, unless options specifies the option FindDirectChildrenOnly.

This function was introduced in Qt 5.0.

pub unsafe fn inherits(&self, classname: *const i8) -> bool

Returns true if this object is an instance of a class that inherits className or a QObject subclass that inherits className; otherwise returns false.

Calls C++ function: bool QObject::inherits(const char* classname) const.

C++ documentation:

Returns true if this object is an instance of a class that inherits className or a QObject subclass that inherits className; otherwise returns false.

A class is considered to inherit itself.

Example:

QTimer *timer = new QTimer;         // QTimer inherits QObject
timer->inherits(“QTimer”);          // returns true
timer->inherits(“QObject”);         // returns true
timer->inherits(“QAbstractButton”); // returns false
// QVBoxLayout inherits QObject and QLayoutItem
QVBoxLayout *layout = new QVBoxLayout;
layout->inherits(“QObject”);        // returns true
layout->inherits(“QLayoutItem”);    // returns true (even though QLayoutItem is not a QObject)

If you need to determine whether an object is an instance of a particular class for the purpose of casting it, consider using qobject_cast<Type *>(object) instead.

See also metaObject() and qobject_cast().

pub unsafe fn install_event_filter( &self, filter_obj: impl CastInto<Ptr<QObject>> )

Installs an event filter filterObj on this object. For example:

Calls C++ function: void QObject::installEventFilter(QObject* filterObj).

C++ documentation:

Installs an event filter filterObj on this object. For example:

  monitoredObj->installEventFilter(filterObj);

An event filter is an object that receives all events that are sent to this object. The filter can either stop the event or forward it to this object. The event filter filterObj receives events via its eventFilter() function. The eventFilter() function must return true if the event should be filtered, (i.e. stopped); otherwise it must return false.

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

Here's a KeyPressEater class that eats the key presses of its monitored objects:

class KeyPressEater : public QObject
{
      Q_OBJECT
      ...
protected:
      bool eventFilter(QObject obj, QEvent event);
};
bool KeyPressEater::eventFilter(QObject obj, QEvent event)
{
      if (event->type() == QEvent::KeyPress) {
          QKeyEvent keyEvent = static_cast<QKeyEvent >(event);
          qDebug(“Ate key press %d”, keyEvent->key());
          return true;
      } else {
          // standard event processing
          return QObject::eventFilter(obj, event);
      }
}

And here's how to install it on two widgets:

KeyPressEater keyPressEater = new KeyPressEater(this);
QPushButton pushButton = new QPushButton(this);
QListView *listView = new QListView(this);
pushButton->installEventFilter(keyPressEater);
listView->installEventFilter(keyPressEater);

The QShortcut class, for example, uses this technique to intercept shortcut key presses.

Warning: If you delete the receiver object in your eventFilter() function, be sure to return true. If you return false, Qt sends the event to the deleted object and the program will crash.

Note that the filtering object must be in the same thread as this object. If filterObj is in a different thread, this function does nothing. If either filterObj or this object are moved to a different thread after calling this function, the event filter will not be called until both objects have the same thread affinity again (it is not removed).

See also removeEventFilter(), eventFilter(), and event().

pub unsafe fn is_widget_type(&self) -> bool

Returns true if the object is a widget; otherwise returns false.

Calls C++ function: bool QObject::isWidgetType() const.

C++ documentation:

Returns true if the object is a widget; otherwise returns false.

Calling this function is equivalent to calling inherits("QWidget"), except that it is much faster.

pub unsafe fn is_window_type(&self) -> bool

Returns true if the object is a window; otherwise returns false.

Calls C++ function: bool QObject::isWindowType() const.

C++ documentation:

Returns true if the object is a window; otherwise returns false.

Calling this function is equivalent to calling inherits("QWindow"), except that it is much faster.

pub unsafe fn kill_timer(&self, id: i32)

Kills the timer with timer identifier, id.

Calls C++ function: void QObject::killTimer(int id).

C++ documentation:

Kills the timer with timer identifier, id.

The timer identifier is returned by startTimer() when a timer event is started.

See also timerEvent() and startTimer().

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

Returns a pointer to the meta-object of this object.

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

C++ documentation:

Returns a pointer to the meta-object of this object.

A meta-object contains information about a class that inherits QObject, e.g. class name, superclass name, properties, signals and slots. Every QObject subclass that contains the Q_OBJECT macro will have a meta-object.

The meta-object information is required by the signal/slot connection mechanism and the property system. The inherits() function also makes use of the meta-object.

If you have no pointer to an actual object instance but still want to access the meta-object of a class, you can use staticMetaObject.

Example:

QObject *obj = new QPushButton;
obj->metaObject()->className();             // returns “QPushButton”
QPushButton::staticMetaObject.className();  // returns “QPushButton”

See also staticMetaObject.

pub unsafe fn move_to_thread(&self, thread: impl CastInto<Ptr<QThread>>)

Changes the thread affinity for this object and its children. The object cannot be moved if it has a parent. Event processing will continue in the targetThread.

Calls C++ function: void QObject::moveToThread(QThread* thread).

C++ documentation:

Changes the thread affinity for this object and its children. The object cannot be moved if it has a parent. Event processing will continue in the targetThread.

To move an object to the main thread, use QApplication::instance() to retrieve a pointer to the current application, and then use QApplication::thread() to retrieve the thread in which the application lives. For example:

myObject->moveToThread(QApplication::instance()->thread());

If targetThread is zero, all event processing for this object and its children stops.

Note that all active timers for the object will be reset. The timers are first stopped in the current thread and restarted (with the same interval) in the targetThread. As a result, constantly moving an object between threads can postpone timer events indefinitely.

A QEvent::ThreadChange event is sent to this object just before the thread affinity is changed. You can handle this event to perform any special processing. Note that any new events that are posted to this object will be handled in the targetThread.

Warning: This function is not thread-safe; the current thread must be same as the current thread affinity. In other words, this function can only "push" an object from the current thread to another thread, it cannot "pull" an object from any arbitrary thread to the current thread.

See also thread().

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

This property holds the name of this object

Calls C++ function: QString QObject::objectName() const.

C++ documentation:

This property holds the name of this object

You can find an object by name (and type) using findChild(). You can find a set of objects with findChildren().

qDebug(“MyClass::setPrecision(): (%s) invalid precision %f”,
         qPrintable(objectName()), newPrecision);

By default, this property contains an empty string.

Access functions:

QString	objectName() const
void	setObjectName(const QString &name)

Notifier signal:

void

objectNameChanged(const QString &objectName)

[see note below]

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

See also metaObject() and QMetaObject::className().

pub unsafe fn parent(&self) -> QPtr<QObject>

Returns a pointer to the parent object.

Calls C++ function: QObject* QObject::parent() const.

C++ documentation:

Returns a pointer to the parent object.

See also setParent() and children().

pub unsafe fn property(&self, name: *const i8) -> CppBox<QVariant>

Returns the value of the object's name property.

Calls C++ function: QVariant QObject::property(const char* name) const.

C++ documentation:

Returns the value of the object’s name property.

If no such property exists, the returned variant is invalid.

Information about all available properties is provided through the metaObject() and dynamicPropertyNames().

See also setProperty(), QVariant::isValid(), metaObject(), and dynamicPropertyNames().

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

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

pub unsafe fn qt_metacast(&self, arg1: *const i8) -> *mut c_void

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

pub unsafe fn remove_event_filter(&self, obj: impl CastInto<Ptr<QObject>>)

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

Calls C++ function: void QObject::removeEventFilter(QObject* obj).

C++ documentation:

Removes an event filter object obj 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 eventFilter() function).

See also installEventFilter(), eventFilter(), and event().

pub unsafe fn set_object_name(&self, name: impl CastInto<Ref<QString>>)

This property holds the name of this object

Calls C++ function: void QObject::setObjectName(const QString& name).

C++ documentation:

This property holds the name of this object

You can find an object by name (and type) using findChild(). You can find a set of objects with findChildren().

qDebug(“MyClass::setPrecision(): (%s) invalid precision %f”,
         qPrintable(objectName()), newPrecision);

By default, this property contains an empty string.

Access functions:

QString	objectName() const
void	setObjectName(const QString &name)

Notifier signal:

void

objectNameChanged(const QString &objectName)

[see note below]

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

See also metaObject() and QMetaObject::className().

pub unsafe fn set_parent(&self, parent: impl CastInto<Ptr<QObject>>)

Makes the object a child of parent.

Calls C++ function: void QObject::setParent(QObject* parent).

C++ documentation:

Makes the object a child of parent.

See also parent() and children().

pub unsafe fn set_property( &self, name: *const i8, value: impl CastInto<Ref<QVariant>> ) -> bool

Sets the value of the object's name property to value.

Calls C++ function: bool QObject::setProperty(const char* name, const QVariant& value).

C++ documentation:

Sets the value of the object’s name property to value.

If the property is defined in the class using Q_PROPERTY then true is returned on success and false otherwise. If the property is not defined using Q_PROPERTY, and therefore not listed in the meta-object, it is added as a dynamic property and false is returned.

Information about all available properties is provided through the metaObject() and dynamicPropertyNames().

Dynamic properties can be queried again using property() and can be removed by setting the property value to an invalid QVariant. Changing the value of a dynamic property causes a QDynamicPropertyChangeEvent to be sent to the object.

Note: Dynamic properties starting with "_q_" are reserved for internal purposes.

See also property(), metaObject(), dynamicPropertyNames(), and QMetaProperty::write().

pub unsafe fn signals_blocked(&self) -> bool

Returns true if signals are blocked; otherwise returns false.

Calls C++ function: bool QObject::signalsBlocked() const.

C++ documentation:

Returns true if signals are blocked; otherwise returns false.

Signals are not blocked by default.

See also blockSignals() and QSignalBlocker.

pub unsafe fn start_timer_2a(&self, interval: i32, timer_type: TimerType) -> i32

Starts a timer and returns a timer identifier, or returns zero if it could not start a timer.

Calls C++ function: int QObject::startTimer(int interval, Qt::TimerType timerType = …).

C++ documentation:

Starts a timer and returns a timer identifier, or returns zero if it could not start a timer.

A timer event will occur every interval milliseconds until killTimer() is called. If interval is 0, then the timer event occurs once every time there are no more window system events to process.

The virtual timerEvent() function is called with the QTimerEvent event parameter class when a timer event occurs. Reimplement this function to get timer events.

If multiple timers are running, the QTimerEvent::timerId() can be used to find out which timer was activated.

Example:

class MyObject : public QObject
{
      Q_OBJECT
public:
      MyObject(QObject *parent = 0);
protected:
      void timerEvent(QTimerEvent *event);
};
MyObject::MyObject(QObject *parent)
      : QObject(parent)
{
      startTimer(50);     // 50-millisecond timer
      startTimer(1000);   // 1-second timer
      startTimer(60000);  // 1-minute timer
      using namespace std::chrono;
      startTimer(milliseconds(50));
      startTimer(seconds(1));
      startTimer(minutes(1));
      // since C++14 we can use std::chrono::duration literals, e.g.:
      startTimer(100ms);
      startTimer(5s);
      startTimer(2min);
      startTimer(1h);
}
void MyObject::timerEvent(QTimerEvent *event)
{
      qDebug() << “Timer ID:” << event->timerId();
}

Note that QTimer's accuracy depends on the underlying operating system and hardware. The timerType argument allows you to customize the accuracy of the timer. See Qt::TimerType for information on the different timer types. Most platforms support an accuracy of 20 milliseconds; some provide more. If Qt is unable to deliver the requested number of timer events, it will silently discard some.

The QTimer class provides a high-level programming interface with single-shot timers and timer signals instead of events. There is also a QBasicTimer class that is more lightweight than QTimer and less clumsy than using timer IDs directly.

See also timerEvent(), killTimer(), and QTimer::singleShot().

pub unsafe fn start_timer_1a(&self, interval: i32) -> i32

Starts a timer and returns a timer identifier, or returns zero if it could not start a timer.

Calls C++ function: int QObject::startTimer(int interval).

C++ documentation:

Starts a timer and returns a timer identifier, or returns zero if it could not start a timer.

A timer event will occur every interval milliseconds until killTimer() is called. If interval is 0, then the timer event occurs once every time there are no more window system events to process.

The virtual timerEvent() function is called with the QTimerEvent event parameter class when a timer event occurs. Reimplement this function to get timer events.

If multiple timers are running, the QTimerEvent::timerId() can be used to find out which timer was activated.

Example:

class MyObject : public QObject
{
      Q_OBJECT
public:
      MyObject(QObject *parent = 0);
protected:
      void timerEvent(QTimerEvent *event);
};
MyObject::MyObject(QObject *parent)
      : QObject(parent)
{
      startTimer(50);     // 50-millisecond timer
      startTimer(1000);   // 1-second timer
      startTimer(60000);  // 1-minute timer
      using namespace std::chrono;
      startTimer(milliseconds(50));
      startTimer(seconds(1));
      startTimer(minutes(1));
      // since C++14 we can use std::chrono::duration literals, e.g.:
      startTimer(100ms);
      startTimer(5s);
      startTimer(2min);
      startTimer(1h);
}
void MyObject::timerEvent(QTimerEvent *event)
{
      qDebug() << “Timer ID:” << event->timerId();
}

Note that QTimer's accuracy depends on the underlying operating system and hardware. The timerType argument allows you to customize the accuracy of the timer. See Qt::TimerType for information on the different timer types. Most platforms support an accuracy of 20 milliseconds; some provide more. If Qt is unable to deliver the requested number of timer events, it will silently discard some.

The QTimer class provides a high-level programming interface with single-shot timers and timer signals instead of events. There is also a QBasicTimer class that is more lightweight than QTimer and less clumsy than using timer IDs directly.

See also timerEvent(), killTimer(), and QTimer::singleShot().

pub unsafe fn thread(&self) -> QPtr<QThread>

Returns the thread in which the object lives.

Calls C++ function: QThread* QObject::thread() const.

C++ documentation:

Returns the thread in which the object lives.

See also moveToThread().

Trait Implementations

impl CppDeletable for QGuiApplication

unsafe fn delete(&self)

Destructs the application.

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

C++ documentation:

Destructs the application.

impl Deref for QGuiApplication

fn deref(&self) -> &QCoreApplication

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

type Target = QCoreApplication

The resulting type after dereferencing.

impl DynamicCast<QGuiApplication> for QCoreApplication

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

impl StaticDowncast<QGuiApplication> for QCoreApplication

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

impl StaticUpcast<QCoreApplication> for QGuiApplication

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