Returns the application top-level window that has the keyboard input focus, or nullptr if no application window has the focus. See also activeModalWidget() and topLevelWidgets(). This function returns the active popup widget at the top of the stack. The popup widgets are organized in a stack. Only other popup widgets may be opened when a popup widget is shown. Normal widgets and modal widgets cannot be accessed before the popup widget is closed. When the application opens a popup widget, all events are sent to the popup. QWidget *QApplication:: activePopupWidget()Ī popup widget is a special top-level widget that sets the Qt::WType_Popup widget flag, e.g. See also activePopupWidget() and topLevelWidgets(). This function returns the active modal widget at the top of the stack. A modal widget must be closed before the user can continue with other parts of the program. QWidget *QApplication:: activeModalWidget()Ī modal widget is a special top-level widget which is a subclass of QDialog that specifies the modal parameter of the constructor as true. This function is a convenience slot for QMessageBox::aboutQt(). This is useful for inclusion in the Help menu of an application, as shown in the Menus example. The message includes the version number of Qt being used by the application. void QApplication:: aboutQt()ĭisplays a simple message box about Qt. Sets the global variable qApp to nullptr. QApplication:: ~QApplication()Ĭleans up any window system resources that were allocated by this application. The value must be of format port:1234, where block is optional and will make the application wait until a debugger connects to it. -qmljsdebugger=, activates the QML/JS debugger with a specified port.-reverse, sets the application's layout direction to Qt::RightToLeft.-widgetcount, prints debug message at the end about number of widgets left undestroyed and maximum number of widgets existed at the same time.-stylesheet stylesheet, is the same as listed above.Note: Relative URLs in the Style Sheet file are relative to the Style Sheet file's path. Hence, it is usually a good idea to create it before any interpretation or modification of argv is done in the application itself. QApplication also deals with common command line arguments. Since the QApplication object does so much initialization, it must be created before any other objects related to the user interface are created. It manages the application's mouse cursor handling, see setOverrideCursor().You can ask which widget is at a certain position using widgetAt(), get a list of topLevelWidgets() and closeAllWindows(), etc. It knows about the application's windows.It provides some magical objects like the clipboard().It provides localization of strings that are visible to the user via translate().This can be changed at runtime with setStyle(). It defines the application's look and feel, which is encapsulated in a QStyle object.See the constructor documentation below for more details. It parses common command line arguments and sets its internal state accordingly.By using sendEvent() and postEvent() you can send your own events to widgets. It performs event handling, meaning that it receives events from the underlying window system and dispatches them to the relevant widgets.It keeps track of these properties in case the user changes the desktop globally, for example through some kind of control panel. It initializes the application with the user's desktop settings such as palette(), font() and doubleClickInterval().QApplication's main areas of responsibility are: The QApplication object is accessible through the instance() function that returns a pointer equivalent to the global qApp pointer. QCoreApplication * createApplication( int &argc, char *argv )įor ( int i = 1 i app(createApplication(argc, argv)) SetPalette(const QPalette & palette, const char * className = nullptr) SetNavigationMode(Qt::NavigationMode mode) SetFont(const QFont & font, const char * className = nullptr) SetEffectEnabled(Qt::UIEffect effect, bool enable = true)
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