com.trolltech.qt.gui
Class QApplication

java.lang.Object
  extended by com.trolltech.qt.internal.QSignalEmitterInternal
      extended by com.trolltech.qt.QSignalEmitter
          extended by com.trolltech.qt.QtJambiObject
              extended by com.trolltech.qt.core.QObject
                  extended by com.trolltech.qt.core.QCoreApplication
                      extended by com.trolltech.qt.gui.QApplication
All Implemented Interfaces:
QtJambiInterface

public class QApplication
extends QCoreApplication

The QApplication class manages the GUI application's control flow and main settings. It 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. It also handles most system-wide and application-wide settings.

For any GUI application that uses Qt, there is precisely one QApplication object, no matter whether the application has 0, 1, 2 or more windows at any time. For non-GUI Qt applications, use QCoreApplication instead, which doesn't depend on the QtGui library.

The QApplication object is accessible through the instance() function which return a pointer equivalent to the global qApp pointer.

QApplication's main areas of responsibility are:

Since the QApplication object does so much initialization, it must be created before any other objects related to the user interface are created.

Since it also deals with common command line arguments, 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(), cursorFlashTime(), setCursorFlashTime(), doubleClickInterval(), setDoubleClickInterval(), setKeyboardInputInterval(), wheelScrollLines(), setWheelScrollLines(), palette(), setPalette(), font(), setFont(), fontMetrics().
Event handling exec(), processEvents(), exit(), quit(). sendEvent(), postEvent(), sendPostedEvents(), removePostedEvents(), hasPendingEvents(), notify(), macEventFilter(), qwsEventFilter(), x11EventFilter(), x11ProcessEvent(), winEventFilter().
GUI Styles style(), setStyle().
Color usage colorSpec(), setColorSpec(), qwsSetCustomColors().
Text handling installTranslator(), removeTranslator()translate().
Widgets allWidgets(), topLevelWidgets(), desktop(), activePopupWidget(), activeModalWidget(), clipboard(), focusWidget(), winFocus(), activeWindow(), widgetAt().
Advanced cursor handling overrideCursor(), setOverrideCursor(), restoreOverrideCursor().
X Window System synchronization flushX(), syncX().
Session management isSessionRestored(), sessionId(), commitData(), saveState().
Miscellaneous closeAllWindows(), startingUp(), closingDown(), type().

See also:
QCoreApplication, QAbstractEventDispatcher, QEventLoop, and QSettings.


Nested Class Summary
static class QApplication.ColorSpec
          See setColorSpec() for full details.
static class QApplication.Type
           
 
Nested classes/interfaces inherited from class com.trolltech.qt.core.QCoreApplication
QCoreApplication.Encoding
 
Nested classes/interfaces inherited from class com.trolltech.qt.QSignalEmitter
QSignalEmitter.AbstractSignal, QSignalEmitter.PrivateSignal0, QSignalEmitter.PrivateSignal1, QSignalEmitter.PrivateSignal2, QSignalEmitter.PrivateSignal3, QSignalEmitter.PrivateSignal4, QSignalEmitter.PrivateSignal5, QSignalEmitter.PrivateSignal6, QSignalEmitter.PrivateSignal7, QSignalEmitter.PrivateSignal8, QSignalEmitter.PrivateSignal9, QSignalEmitter.Signal0, QSignalEmitter.Signal1, QSignalEmitter.Signal2, QSignalEmitter.Signal3, QSignalEmitter.Signal4, QSignalEmitter.Signal5, QSignalEmitter.Signal6, QSignalEmitter.Signal7, QSignalEmitter.Signal8, QSignalEmitter.Signal9
 
Nested classes/interfaces inherited from class com.trolltech.qt.internal.QSignalEmitterInternal
com.trolltech.qt.internal.QSignalEmitterInternal.AbstractSignalInternal
 
Field Summary
 QSignalEmitter.Signal1 commitDataRequest
          This signal takes 1 generic argument(s).
 QSignalEmitter.Signal2 focusChanged
          This signal takes 2 generic argument(s).
 QSignalEmitter.Signal0 fontDatabaseChanged
          This signal is emitted when application fonts are loaded or removed.
 QSignalEmitter.Signal0 lastWindowClosed
          This signal is emitted from QApplication.:exec() when the last visible primary window (i.
 QSignalEmitter.Signal1 saveStateRequest
          This signal takes 1 generic argument(s).
 
Fields inherited from class com.trolltech.qt.core.QCoreApplication
aboutToQuit, m_instance, unixSignal
 
Fields inherited from class com.trolltech.qt.internal.QSignalEmitterInternal
currentSender
 
Constructor Summary
QApplication(java.lang.String[] args)
          Creates a QApplication with the specified command line arguments.
 
Method Summary
static void aboutQt()
          Displays a simple message box about Qt.
static void aboutQtJambi()
          Displays a simple message box about Qt Jambi.
static QWidget activeModalWidget()
          Returns the active modal widget.
static QWidget activePopupWidget()
          Returns the active popup widget.
static QWidget activeWindow()
          Returns the application top-level window that has the keyboard input focus, or 0 if no application window has the focus.
static void alert(QWidget widget)
          Causes an alert to be shown for widget if the window is not the active window.
static void alert(QWidget widget, int duration)
          Causes an alert to be shown for widget if the window is not the active window.
static java.util.List allWidgets()
          Returns a list of all the widgets in the application.
static void beep()
          Sounds the bell, using the default volume and sound.
static void changeOverrideCursor(QCursor arg__1)
          Changes the currently active application override cursor to cursor.
static QClipboard clipboard()
          Returns a pointer to the application global clipboard.
static void closeAllWindows()
          Closes all top-level windows.
static int colorSpec()
          Returns the color specification.
 void commitData(QSessionManager sm)
          This function deals with session management.
static int cursorFlashTime()
          This property holds the text cursor's flash (blink) time in milliseconds.
static QDesktopWidget desktop()
          Returns the desktop widget (also called the root window).
static boolean desktopSettingsAware()
          Returns true if Qt is set to use the system's standard colors, fonts, etc.
static int doubleClickInterval()
          This property holds the time limit in milliseconds that distinguishes a double click from two consecutive mouse clicks.
static QWidget focusWidget()
          Returns the application widget that has the keyboard input focus, or 0 if no widget in this application has the focus.
static QFont font()
          Returns the default application font.
static QFont font(QWidget arg__1)
          This is an overloaded member function, provided for convenience.
static QFontMetrics fontMetrics()
          Returns display (screen) font metrics for the application font.
static QSize globalStrut()
          This property holds the minimum size that any GUI element that the user can interact with should have.
 QInputContext inputContext()
          Returns the QInputContext instance used by the application.
static QApplication instance()
          Returns the unique QApplication instance.
static boolean isEffectEnabled(Qt.UIEffect arg__1)
          Returns true if effect is enabled; otherwise returns false.
static boolean isLeftToRight()
          Returns true if the application's layout direction is Qt::LeftToRight ; otherwise returns false.
static boolean isRightToLeft()
          Returns true if the application's layout direction is Qt::RightToLeft ; otherwise returns false.
 boolean isSessionRestored()
          Returns true if the application has been restored from an earlier session; otherwise returns false.
static Qt.LayoutDirection keyboardInputDirection()
          Returns the current keyboard input direction.
static int keyboardInputInterval()
          This property holds the time limit in milliseconds that distinguishes a key press from two consecutive key presses.
static QLocale keyboardInputLocale()
          Returns the current keyboard input locale.
static Qt.KeyboardModifiers keyboardModifiers()
          Returns the current state of the modifier keys on the keyboard.
static Qt.LayoutDirection layoutDirection()
          This property holds the default layout direction for this application.
static Qt.MouseButtons mouseButtons()
          Returns the current state of the buttons on the mouse.
static QCursor overrideCursor()
          Returns the active application override cursor.
static QPalette palette()
          Returns the application palette.
static QPalette palette(QWidget arg__1)
          This is an overloaded member function, provided for convenience.
static boolean quitOnLastWindowClosed()
          This property holds whether the application implicitly quits when the last window is closed.
static void restoreOverrideCursor()
          Undoes the last setOverrideCursor().
 void saveState(QSessionManager sm)
          This function deals with session management.
 java.lang.String sessionId()
          Returns the current session's identifier.
 java.lang.String sessionKey()
          Returns the session key in the current session.
static void setActiveWindow(QWidget act)
          Sets the active window to the active widget in response to a system event.
static void setColorSpec(int arg__1)
          Sets the color specification for the application to spec.
static void setCursorFlashTime(int arg__1)
          This property holds the text cursor's flash (blink) time in milliseconds.
static void setDesktopSettingsAware(boolean arg__1)
          Sets whether Qt should use the system's standard colors, fonts, etc.
static void setDoubleClickInterval(int arg__1)
          This property holds the time limit in milliseconds that distinguishes a double click from two consecutive mouse clicks.
static void setEffectEnabled(Qt.UIEffect arg__1)
          Enables the UI effect effect if enable is true, otherwise the effect will not be used.
static void setEffectEnabled(Qt.UIEffect arg__1, boolean enable)
          Enables the UI effect effect if enable is true, otherwise the effect will not be used.
static void setFont(QFont font)
          Changes the default application font to font.
static void setGlobalStrut(QSize arg__1)
          This property holds the minimum size that any GUI element that the user can interact with should have.
 void setInputContext(QInputContext arg__1)
          This function replaces the QInputContext instance used by the application with inputContext.
static void setKeyboardInputInterval(int arg__1)
          This property holds the time limit in milliseconds that distinguishes a key press from two consecutive key presses.
static void setLayoutDirection(Qt.LayoutDirection direction)
          This property holds the default layout direction for this application.
static void setOverrideCursor(QCursor arg__1)
          Sets the application override cursor to cursor.
static void setPalette(QPalette palette)
          Changes the default application palette to palette.
static void setQuitOnLastWindowClosed(boolean quit)
          This property holds whether the application implicitly quits when the last window is closed.
static void setStartDragDistance(int l)
          If you support drag and drop in your application, and want to start a drag and drop operation after the user has moved the cursor a certain distance with a button held down, you should use this property's value as the minimum distance required.
static void setStartDragTime(int ms)
          This property holds the time in milliseconds that a mouse button must be held down before a drag and drop operation will begin.
static void setStyle(QStyle arg__1)
          Sets the application's GUI style to style.
static QStyle setStyle(java.lang.String arg__1)
          This is an overloaded member function, provided for convenience.
 void setStyleSheet(java.lang.String sheet)
          This property holds the application style sheet.
static void setWheelScrollLines(int arg__1)
          This property holds the number of lines to scroll a widget, when the mouse wheel is rotated.
static void setWindowIcon(QIcon icon)
          This property holds the default window icon.
static int startDragDistance()
          If you support drag and drop in your application, and want to start a drag and drop operation after the user has moved the cursor a certain distance with a button held down, you should use this property's value as the minimum distance required.
static int startDragTime()
          This property holds the time in milliseconds that a mouse button must be held down before a drag and drop operation will begin.
static QStyle style()
          Returns the application's style object.
 java.lang.String styleSheet()
          This property holds the application style sheet.
static void syncX()
          Synchronizes with the X server in the X11 implementation.
static QWidget topLevelAt(int x, int y)
          This is an overloaded member function, provided for convenience.
static QWidget topLevelAt(QPoint p)
          Returns the top-level widget at the given point; returns 0 if there is no such widget.
static java.util.List topLevelWidgets()
          Returns a list of the top-level widgets (windows) in the application.
static QApplication.Type type()
          Returns the type of application (Tty , GuiClient , or GuiServer ).
static int wheelScrollLines()
          This property holds the number of lines to scroll a widget, when the mouse wheel is rotated.
static QWidget widgetAt(int x, int y)
          This is an overloaded member function, provided for convenience.
static QWidget widgetAt(QPoint p)
          Returns the widget at global screen position point, or 0 if there is no Qt widget there.
static QIcon windowIcon()
          This property holds the default window icon.
 
Methods inherited from class com.trolltech.qt.core.QCoreApplication
addLibraryPath, applicationDirPath, applicationFilePath, applicationName, applicationPid, applicationVersion, arguments, closingDown, exec, exit, exit, flush, hasPendingEvents, initialize, installTranslator, invokeAndWait, invokeLater, invokeLater, libraryPaths, notify, organizationDomain, organizationName, postEvent, postEvent, processEvents, processEvents, processEvents, processEvents, quit, removeLibraryPath, removePostedEvents, removePostedEvents, removeTranslator, sendEvent, sendPostedEvents, sendPostedEvents, setApplicationName, setApplicationVersion, setAttribute, setAttribute, setLibraryPaths, setOrganizationDomain, setOrganizationName, startingUp, testAttribute, translate, translate, translate
 
Methods inherited from class com.trolltech.qt.core.QObject
childEvent, children, connectSlotsByName, customEvent, disposeLater, dumpObjectInfo, dumpObjectTree, dynamicPropertyNames, event, eventFilter, findChild, findChild, findChild, findChildren, findChildren, findChildren, findChildren, indexOfProperty, installEventFilter, isWidgetType, killTimer, moveToThread, objectName, parent, properties, property, removeEventFilter, setObjectName, setParent, setProperty, startTimer, timerEvent, toString, userProperty
 
Methods inherited from class com.trolltech.qt.QtJambiObject
dispose, disposed, equals, finalize, reassignNativeResources, tr, tr, tr
 
Methods inherited from class com.trolltech.qt.QSignalEmitter
blockSignals, disconnect, disconnect, signalsBlocked, signalSender, thread
 
Methods inherited from class com.trolltech.qt.internal.QSignalEmitterInternal
__qt_signalInitialization
 
Methods inherited from class java.lang.Object
clone, getClass, hashCode, notify, notifyAll, wait, wait, wait
 
Methods inherited from interface com.trolltech.qt.QtJambiInterface
disableGarbageCollection, nativeId, nativePointer, reenableGarbageCollection, setJavaOwnership
 

Field Detail

commitDataRequest

public final QSignalEmitter.Signal1 commitDataRequest

This signal takes 1 generic argument(s). We list their type and the name they go by in the description of this signal. <com.trolltech.qt.gui.QSessionManager(named: manager)>:

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.

Note that you should not exit the application when called. 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.

See also:
isSessionRestored(), sessionId(), saveState(), and Session Management.


focusChanged

public final QSignalEmitter.Signal2 focusChanged

This signal takes 2 generic argument(s). We list their type and the name they go by in the description of this signal. <com.trolltech.qt.gui.QWidget(named: old), com.trolltech.qt.gui.QWidget(named: now)>:

This signal is emitted when the widget that has keyboard focus changed from old to now, i. . because the user pressed the tab-key, clicked into a widget or changed the active window. Note that both old and now can be the null-pointer.

The signal is emitted after both widget have been notified about the change through QFocusEvent.

See also:
QWidget::setFocus(), QWidget::clearFocus(), and Qt::FocusReason .


fontDatabaseChanged

public final QSignalEmitter.Signal0 fontDatabaseChanged
This signal is emitted when application fonts are loaded or removed.

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


lastWindowClosed

public final QSignalEmitter.Signal0 lastWindowClosed
This signal is emitted from QApplication.:exec() when the last visible primary window (i. . window with no parent) with the Qt::WA_QuitOnClose attribute set is closed.

By default,

This feature be turned off by setting quitOnLastWindowClosed to false.

See also:
QWidget::close().


saveStateRequest

public final QSignalEmitter.Signal1 saveStateRequest

This signal takes 1 generic argument(s). We list their type and the name they go by in the description of this signal. <com.trolltech.qt.gui.QSessionManager(named: manager)>:

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.

Note that 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 function, 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.

See also:
isSessionRestored(), sessionId(), commitData(), and Session Management.

Constructor Detail

QApplication

public QApplication(java.lang.String[] args)
Creates a QApplication with the specified command line arguments.

Method Detail

inputContext

public final QInputContext inputContext()
Returns the QInputContext instance used by the application.

See also:
setInputContext().


isSessionRestored

public final boolean isSessionRestored()
Returns true if the application has been restored from an earlier session; otherwise returns false.

See also:
sessionId(), commitData(), and saveState().


sessionId

public final java.lang.String sessionId()
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(), commitData(), and saveState().


sessionKey

public final java.lang.String sessionKey()
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 with every call of commitData() or saveState().

See also:
isSessionRestored(), sessionId(), commitData(), and saveState().


setInputContext

public final void setInputContext(QInputContext arg__1)
This function replaces the QInputContext instance used by the application with inputContext.

See also:
inputContext().


setStyleSheet

public final void setStyleSheet(java.lang.String sheet)
This property holds the application style sheet. By default, this property returns an empty string unless the user specifies the -stylesheet option on the command line when running the application.

See also:
QWidget::setStyle(), and Qt Style Sheets.


styleSheet

public final java.lang.String styleSheet()
This property holds the application style sheet. By default, this property returns an empty string unless the user specifies the -stylesheet option on the command line when running the application.

See also:
QWidget::setStyle(), and Qt Style Sheets.


commitData

public void commitData(QSessionManager sm)
This function deals with session management. It is invoked 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.

Note that you should not exit the application within this function. Instead, the session manager may or may not do this afterwards, depending on the context.

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

The default implementation requests interaction and sends a close event to all visible top-level widgets. If any event was rejected, the shutdown is canceled.

See also:
isSessionRestored(), sessionId(), saveState(), and Session Management.


saveState

public void saveState(QSessionManager sm)
This function 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.

Note that you should never exit the application within this function. 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 function, no user interaction is possible, unless you ask the manager for explicit permission. See QSessionManager::allowsInteraction() and QSessionManager::allowsErrorInteraction() for details.

See also:
isSessionRestored(), sessionId(), commitData(), and Session Management.


aboutQt

public static void aboutQt()
Displays a simple message box about Qt. The message includes the version number of Qt being used by the application.

This is useful for inclusion in the Help menu of an application, as shown in the Menus example.

This function is a convenience slot for QMessageBox::aboutQt().


activeModalWidget

public static QWidget activeModalWidget()
Returns the active modal widget.

A modal widget is a special top-level widget which is a subclass of QDialog that specifies the modal parameter of the constructor as true. A modal widget must be closed before the user can continue with other parts of the program.

Modal widgets are organized in a stack. This function returns the active modal widget at the top of the stack.

See also:
activePopupWidget(), and topLevelWidgets().


activePopupWidget

public static QWidget activePopupWidget()
Returns the active popup widget.

A popup widget is a special top-level widget that sets the Qt::WType_Popup widget flag, e.g. the QMenu widget. When the application opens a popup widget, all events are sent to the popup. Normal widgets and modal widgets cannot be accessed before the popup widget is closed.

Only other popup widgets may be opened when a popup widget is shown. The popup widgets are organized in a stack. This function returns the active popup widget at the top of the stack.

See also:
activeModalWidget(), and topLevelWidgets().


activeWindow

public static QWidget activeWindow()
Returns the application top-level window that has the keyboard input focus, or 0 if no application window has the focus. Note that there might be an activeWindow() even if there is no focusWidget(), for example if no widget in that window accepts key events.

See also:
setActiveWindow(), QWidget::setFocus(), QWidget::hasFocus(), and focusWidget().


alert

public static void alert(QWidget widget)
Causes an alert to be shown for widget if the window is not the active window. The alert is shown for msec miliseconds. If msec is zero (the default), then the alert is shown indefinitely until the window becomes active again.

Currently this function does nothing on Qt for Embedded Linux.

On Mac OS X, this works more at the application level and will cause the application icon to bounce in the dock.

On Windows this causes the window's taskbar entry to flash for a time. If msec is zero, the flashing will stop and the taskbar entry will turn a different color (currently orange).

On X11, this will cause the window to be marked as "demands attention", the window must not be hidden (i.e. not have hide() called on it, but be visible in some sort of way) in order for this to work.


alert

public static void alert(QWidget widget,
                         int duration)
Causes an alert to be shown for widget if the window is not the active window. The alert is shown for msec miliseconds. If msec is zero (the default), then the alert is shown indefinitely until the window becomes active again.

Currently this function does nothing on Qt for Embedded Linux.

On Mac OS X, this works more at the application level and will cause the application icon to bounce in the dock.

On Windows this causes the window's taskbar entry to flash for a time. If msec is zero, the flashing will stop and the taskbar entry will turn a different color (currently orange).

On X11, this will cause the window to be marked as "demands attention", the window must not be hidden (i.e. not have hide() called on it, but be visible in some sort of way) in order for this to work.


allWidgets

public static java.util.List allWidgets()
Returns a list of all the widgets in the application.

The list is empty (QList::isEmpty()) if there are no widgets.

Note that some of the widgets may be hidden.

Example:

        public final void updateAllWidgets() {
            for (QWidget widget : QApplication.allWidgets())
                widget.update();
        }

See also:
topLevelWidgets(), and QWidget::isVisible().


beep

public static void beep()
Sounds the bell, using the default volume and sound. The function is not available in Qt for Embedded Linux.


changeOverrideCursor

public static void changeOverrideCursor(QCursor arg__1)
Changes the currently active application override cursor to cursor.

This function has no effect if setOverrideCursor() wasn't called.

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


clipboard

public static QClipboard clipboard()
Returns a pointer to the application global clipboard.

Note: The QApplication object should already be constructed before accessing the clipboard.


closeAllWindows

public static void closeAllWindows()
Closes all top-level windows.

This function is particularly useful for applications with many top-level windows. It could, for example, be connected to a Exit entry in the File menu:

The following code example is written in c++.

    exitAct = new QAction(tr("E&xit"), this);
    exitAct->setShortcut(tr("Ctrl+Q"));
    exitAct->setStatusTip(tr("Exit the application"));
    connect(exitAct, SIGNAL(triggered()), qApp, SLOT(closeAllWindows()));
The windows are closed in random order, until one window does not accept the close event. The application quits when the last window was successfully closed; this can be turned off by setting quitOnLastWindowClosed to false.

See also:
quitOnLastWindowClosed, lastWindowClosed() , QWidget::close(), QWidget::closeEvent(), lastWindowClosed() , quit(), topLevelWidgets(), and QWidget::isWindow().


colorSpec

public static int colorSpec()
Returns the color specification.

See also:
QApplication::setColorSpec().


cursorFlashTime

public static int cursorFlashTime()
This property holds the text cursor's flash (blink) time in milliseconds. The flash time is the time required to display, invert and restore the caret display. Usually the text cursor is displayed for half the cursor flash time, then hidden for the same amount of time, but this may vary.

The default value on X11 is 1000 milliseconds. On Windows, the control panel value is used. Widgets should not cache this value since it may be changed at any time by the user changing the global desktop settings.

Note that on Microsoft Windows, setting this property sets the cursor flash time for all applications.


desktop

public static QDesktopWidget desktop()
Returns the desktop widget (also called the root window).

Note that the desktop may be composed of multiple screens, so it would be incorrect, for example, to attempt to center some widget in the desktop's geometry. QDesktopWidget has various functions for obtaining useful geometries upon the desktop, such as QDesktopWidget::screenGeometry() and QDesktopWidget::availableGeometry().

On X11, it is also possible to draw on the desktop.


desktopSettingsAware

public static boolean desktopSettingsAware()
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().


doubleClickInterval

public static int doubleClickInterval()
This property holds the time limit in milliseconds that distinguishes a double click from two consecutive mouse clicks. The default value on X11 is 400 milliseconds. On Windows and Mac OS X, the operating system's value is used.

On Microsoft Windows, calling this function sets the double click interval for all applications.


focusWidget

public static QWidget focusWidget()
Returns the application widget that has the keyboard input focus, or 0 if no widget in this application has the focus.

See also:
QWidget::setFocus(), QWidget::hasFocus(), activeWindow(), and focusChanged() .


font

public static QFont font()
Returns the default application font.

See also:
setFont(), fontMetrics(), and QWidget::font().


font

public static QFont font(QWidget arg__1)
This is an overloaded member function, provided for convenience.

Returns the default font for the widget.

See also:
fontMetrics(), and QWidget::setFont().


fontMetrics

public static QFontMetrics fontMetrics()
Returns display (screen) font metrics for the application font.

See also:
font(), setFont(), QWidget::fontMetrics(), and QPainter::fontMetrics().


globalStrut

public static QSize globalStrut()
This property holds the minimum size that any GUI element that the user can interact with should have. For example, no button should be resized to be smaller than the global strut size. The strut size should be considered when reimplementing GUI controls that may be used on touch-screens or similar I/O devices.

Example:

        public static QSize sizeHint() {
            return new QSize(80, 25).expandedTo(QApplication.globalStrut());
        }
By default, this property contains a QSize object with zero width and height.


isEffectEnabled

public static boolean isEffectEnabled(Qt.UIEffect arg__1)
Returns true if effect is enabled; otherwise returns false.

By default, Qt will try to use the desktop settings. Call setDesktopSettingsAware(false) to prevent this.

Note: All effects are disabled on screens running at less than 16-bit color depth.

See also:
setEffectEnabled(), and Qt::UIEffect .


isLeftToRight

public static boolean isLeftToRight()
Returns true if the application's layout direction is Qt::LeftToRight ; otherwise returns false.

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


isRightToLeft

public static boolean isRightToLeft()
Returns true if the application's layout direction is Qt::RightToLeft ; otherwise returns false.

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


keyboardInputDirection

public static Qt.LayoutDirection keyboardInputDirection()
Returns the current keyboard input direction.


keyboardInputInterval

public static int keyboardInputInterval()
This property holds the time limit in milliseconds that distinguishes a key press from two consecutive key presses. The default value on X11 is 400 milliseconds. On Windows and Mac OS X, the operating system's value is used.


keyboardInputLocale

public static QLocale keyboardInputLocale()
Returns the current keyboard input locale.


keyboardModifiers

public static Qt.KeyboardModifiers keyboardModifiers()
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().


layoutDirection

public static Qt.LayoutDirection layoutDirection()
This property holds the default layout direction for this application. On system start-up, the default layout direction depends on the application's language.

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


mouseButtons

public static Qt.MouseButtons mouseButtons()
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::MousePress and QEvent::MouseRelease events).

It should be noted this may not reflect the actual buttons held on theinput 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().


palette

public static QPalette palette()
Returns the application palette.

See also:
setPalette(), and QWidget::palette().


palette

public static QPalette palette(QWidget arg__1)
This is an overloaded member function, provided for convenience.

If a widget is passed, the default palette for the widget's class is returned. This may or may not be the application palette. In most cases there isn't a special palette for certain types of widgets, but one notable exception is the popup menu under Windows, if the user has defined a special background color for menus in the display settings.

See also:
setPalette(), and QWidget::palette().


quitOnLastWindowClosed

public static boolean quitOnLastWindowClosed()
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) with the Qt::WA_QuitOnClose attribute set is closed. By default this attribute is set for all widgets except for sub-windows. Refer to Qt::WindowType for a detailed list of Qt::Window objects.

See also:
quit(), and QWidget::close().


restoreOverrideCursor

public static void restoreOverrideCursor()
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().


setActiveWindow

public static void setActiveWindow(QWidget act)
Sets the active window to the active widget in response to a system event. The function is called from the platform specific event handlers.

Warning: This function does not set the keyboard focus to the active widget. Call QWidget::activateWindow() instead.

It sets the activeWindow() and focusWidget() attributes and sends proper WindowActivate /WindowDeactivate and FocusIn /FocusOut events to all appropriate widgets. The window will then be painted in active state (e.g. cursors in line edits will blink), and it will have tool tips enabled.

See also:
activeWindow(), and QWidget::activateWindow().


setColorSpec

public static void setColorSpec(int arg__1)
Sets the color specification for the application to spec.

The color specification controls how the application allocates colors when run on a display with a limited amount of colors, e.g. 8 bit / 256 color displays.

The color specification must be set before you create the QApplication object.

The options are:

Be aware that the CustomColor and ManyColor choices may lead to colormap flashing: The foreground application gets (most) of the available colors, while the background windows will look less attractive.

Example:

        public static void main(String args[]) {
            QApplication.setColorSpec(QApplication.ColorSpec.ManyColor.value());
            QApplication.initialize(args);

             ... 
            QApplication.exec();
        }

See also:
colorSpec().


setCursorFlashTime

public static void setCursorFlashTime(int arg__1)
This property holds the text cursor's flash (blink) time in milliseconds. The flash time is the time required to display, invert and restore the caret display. Usually the text cursor is displayed for half the cursor flash time, then hidden for the same amount of time, but this may vary.

The default value on X11 is 1000 milliseconds. On Windows, the control panel value is used. Widgets should not cache this value since it may be changed at any time by the user changing the global desktop settings.

Note that on Microsoft Windows, setting this property sets the cursor flash time for all applications.


setDesktopSettingsAware

public static void setDesktopSettingsAware(boolean arg__1)
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 QApplication object, like this:

        public static void main(String args[]) {
            QApplication.setDesktopSettingsAware(false);
            QApplication.initialize(args);

             ... 

            QApplication.exec();
        }

See also:
desktopSettingsAware().


setDoubleClickInterval

public static void setDoubleClickInterval(int arg__1)
This property holds the time limit in milliseconds that distinguishes a double click from two consecutive mouse clicks. The default value on X11 is 400 milliseconds. On Windows and Mac OS X, the operating system's value is used.

On Microsoft Windows, calling this function sets the double click interval for all applications.


setEffectEnabled

public static void setEffectEnabled(Qt.UIEffect arg__1)
Enables the UI effect effect if enable is true, otherwise the effect will not be used.

Note: All effects are disabled on screens running at less than 16-bit color depth.

See also:
isEffectEnabled(), Qt::UIEffect , and setDesktopSettingsAware().


setEffectEnabled

public static void setEffectEnabled(Qt.UIEffect arg__1,
                                    boolean enable)
Enables the UI effect effect if enable is true, otherwise the effect will not be used.

Note: All effects are disabled on screens running at less than 16-bit color depth.

See also:
isEffectEnabled(), Qt::UIEffect , and setDesktopSettingsAware().


setGlobalStrut

public static void setGlobalStrut(QSize arg__1)
This property holds the minimum size that any GUI element that the user can interact with should have. For example, no button should be resized to be smaller than the global strut size. The strut size should be considered when reimplementing GUI controls that may be used on touch-screens or similar I/O devices.

Example:

        public static QSize sizeHint() {
            return new QSize(80, 25).expandedTo(QApplication.globalStrut());
        }
By default, this property contains a QSize object with zero width and height.


setKeyboardInputInterval

public static void setKeyboardInputInterval(int arg__1)
This property holds the time limit in milliseconds that distinguishes a key press from two consecutive key presses. The default value on X11 is 400 milliseconds. On Windows and Mac OS X, the operating system's value is used.


setLayoutDirection

public static void setLayoutDirection(Qt.LayoutDirection direction)
This property holds the default layout direction for this application. On system start-up, the default layout direction depends on the application's language.

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


setOverrideCursor

public static void setOverrideCursor(QCursor arg__1)
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(new QCursor(Qt.CursorShape.WaitCursor));
        calculateHugeMandelbrot();              // lunch time...
        QApplication.restoreOverrideCursor();

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


setQuitOnLastWindowClosed

public static void setQuitOnLastWindowClosed(boolean quit)
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) with the Qt::WA_QuitOnClose attribute set is closed. By default this attribute is set for all widgets except for sub-windows. Refer to Qt::WindowType for a detailed list of Qt::Window objects.

See also:
quit(), and QWidget::close().


setStartDragDistance

public static void setStartDragDistance(int l)
If you support drag and drop in your application, and want to start a drag and drop operation after the user has moved the cursor a certain distance with a button held down, you should use this property's value as the minimum distance required.

For example, if the mouse position of the click is stored in startPos and the current position (e.g. in the mouse move event) is currentPos, you can find out if a drag should be started with code like this:

            if (startPos.subtract(currentPos).manhattanLength() >=
                QApplication.startDragDistance()) {
                startTheDrag();
            }
Qt uses this value internally, e.g. in QFileDialog.

The default value is 4 pixels.

See also:
startDragTime(), QPoint::manhattanLength(), and Drag and Drop.


setStartDragTime

public static void setStartDragTime(int ms)
This property holds the time in milliseconds that a mouse button must be held down before a drag and drop operation will begin. If you support drag and drop in your application, and want to start a drag and drop operation after the user has held down a mouse button for a certain amount of time, you should use this property's value as the delay.

Qt also uses this delay internally, e.g. in QTextEdit and QLineEdit, for starting a drag.

The default value is 500 ms.

See also:
startDragDistance(), and Drag and Drop.


setStyle

public static void setStyle(QStyle arg__1)
Sets the application's GUI style to style. Ownership of the style object is transferred to QApplication, so QApplication will delete the style object on application exit or when a new style is set and the old style is still the parent of the application object.

Example usage:

        QApplication.setStyle(new QWindowsStyle());
When switching application styles, the color palette is set back to the initial colors or the system defaults. This is necessary since certain styles have to adapt the color palette to be fully style-guide compliant.

Note that setting the style before a palette has been set (i.e. before creating QApplication) will cause the application to use QStyle::standardPalette() for the palette.

Warning: Qt style sheets are currently not supported for custom QStyle subclasses. We plan to address this in some future release.

See also:
style(), QStyle, setPalette(), and desktopSettingsAware().


setStyle

public static QStyle setStyle(java.lang.String arg__1)
This is an overloaded member function, provided for convenience.

Requests a QStyle object for style from the QStyleFactory.

The string must be one of the QStyleFactory::keys(), typically one of "windows", "motif", "cde", "plastique", "windowsxp", or "macintosh". Style names are case insensitive.

Returns 0 if an unknown style is passed, otherwise the QStyle object returned is set as the application's GUI style.

Warning: To ensure that the application's style is set correctly, it is best to call this function before the QApplication constructor, if possible.


setWheelScrollLines

public static void setWheelScrollLines(int arg__1)
This property holds the number of lines to scroll a widget, when the mouse wheel is rotated. If the value exceeds the widget's number of visible lines, the widget should interpret the scroll operation as a single page up or page down. If the widget is an item view class, then the result of scrolling one line depends on the setting of the widget's scroll mode. Scroll one line can mean scroll one item or scroll one pixel .

By default, this property has a value of 3.


setWindowIcon

public static void setWindowIcon(QIcon icon)
This property holds the default window icon.

See also:
QWidget::setWindowIcon(), and Setting the Application Icon.


startDragDistance

public static int startDragDistance()
If you support drag and drop in your application, and want to start a drag and drop operation after the user has moved the cursor a certain distance with a button held down, you should use this property's value as the minimum distance required.

For example, if the mouse position of the click is stored in startPos and the current position (e.g. in the mouse move event) is currentPos, you can find out if a drag should be started with code like this:

            if (startPos.subtract(currentPos).manhattanLength() >=
                QApplication.startDragDistance()) {
                startTheDrag();
            }
Qt uses this value internally, e.g. in QFileDialog.

The default value is 4 pixels.

See also:
startDragTime(), QPoint::manhattanLength(), and Drag and Drop.


startDragTime

public static int startDragTime()
This property holds the time in milliseconds that a mouse button must be held down before a drag and drop operation will begin. If you support drag and drop in your application, and want to start a drag and drop operation after the user has held down a mouse button for a certain amount of time, you should use this property's value as the delay.

Qt also uses this delay internally, e.g. in QTextEdit and QLineEdit, for starting a drag.

The default value is 500 ms.

See also:
startDragDistance(), and Drag and Drop.


style

public static QStyle style()
Returns the application's style object.

See also:
setStyle(), and QStyle.


syncX

public static void syncX()
Synchronizes with the X server in the X11 implementation. This normally takes some time. Does nothing on other platforms.


topLevelAt

public static QWidget topLevelAt(QPoint p)
Returns the top-level widget at the given point; returns 0 if there is no such widget.


topLevelAt

public static QWidget topLevelAt(int x,
                                 int y)
This is an overloaded member function, provided for convenience.

Returns the top-level widget at the point (x, y); returns 0 if there is no such widget.


topLevelWidgets

public static java.util.List topLevelWidgets()
Returns a list of the top-level widgets (windows) in the application.

Note that some of the top-level widgets may be hidden, for example a tooltip if no tooltip is currently shown.

Example:

        public final void showAllHiddenTopLevelWidgets() {
            for (QWidget widget : QApplication.topLevelWidgets()) {
                if (widget.isHidden())
                    widget.show();
            }
        }

See also:
allWidgets(), QWidget::isWindow(), and QWidget::isHidden().


type

public static QApplication.Type type()
Returns the type of application (Tty , GuiClient , or GuiServer ). The type is set when constructing the QApplication object.


wheelScrollLines

public static int wheelScrollLines()
This property holds the number of lines to scroll a widget, when the mouse wheel is rotated. If the value exceeds the widget's number of visible lines, the widget should interpret the scroll operation as a single page up or page down. If the widget is an item view class, then the result of scrolling one line depends on the setting of the widget's scroll mode. Scroll one line can mean scroll one item or scroll one pixel .

By default, this property has a value of 3.


widgetAt

public static QWidget widgetAt(QPoint p)
Returns the widget at global screen position point, or 0 if there is no Qt widget there.

This function can be slow.

See also:
QCursor::pos(), QWidget::grabMouse(), and QWidget::grabKeyboard().


widgetAt

public static QWidget widgetAt(int x,
                               int y)
This is an overloaded member function, provided for convenience.

Returns the widget at global screen position (x, y), or 0 if there is no Qt widget there.


windowIcon

public static QIcon windowIcon()
This property holds the default window icon.

See also:
QWidget::setWindowIcon(), and Setting the Application Icon.


aboutQtJambi

public static void aboutQtJambi()
Displays a simple message box about Qt Jambi. The message includes the version number of Qt being used by the application.

This is useful for inclusion in the Help menu of an application.


instance

public static QApplication instance()
Returns the unique QApplication instance.


setFont

public static void setFont(QFont font)
Changes the default application font to font.


setPalette

public static void setPalette(QPalette palette)
Changes the default application palette to palette.


overrideCursor

public static QCursor overrideCursor()
Returns the active application override cursor.

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