qwidget.3qt

Trolltech公司发布的基于C++图形开发环境

This enum used to determine how fonts and palette changes are propagated to children of a widget.
.SH MEMBER FUNCTION DOCUMENTATION
.SH "QWidget::QWidget ( QWidget * parent=0, const char * name=0, WFlags f=0 )"
Constructs a widget which is a child of \fIparent,\fR with the name \fIname\fR and widget flags set to \fIf.\fR
.PP
If \fIparent\fR is 0, the new widget becomes a top-level window. If \fIparent\fR is another widget, this widget becomes a child window inside \fIparent.\fR The new widget is deleted when \fIparent\fR is.
.PP
The \fIname\fR is sent to the QObject constructor.
.PP
The widget flags argument \fIf\fR is normally 0, but it can be set to customize the window frame of a top-level widget (i.e. \fIparent\fR must be zero). To customize the frame, set the \fCWStyle_Customize\fR flag OR'ed with any of the Qt::WidgetFlags.
.PP
Note that the X11 version of Qt may not be able to deliver all combinations of style flags on all systems. This is because on X11, Qt can only ask the window manager, and the window manager can override the application's settings. On Windows, Qt can set whatever flags you want.
.PP
Example:
.PP
.nf
.br
    QLabel *spashScreen = new QLabel( 0, "mySplashScreen",
.br
                                  WStyle_Customize | WStyle_NoBorder |
.br
                                  WStyle_Tool );
.fi
.SH "QWidget::~QWidget ()"
Destructs the widget.
.PP
All children of this widget are deleted first. The application exits if this widget is (was) the main widget.
.SH "bool QWidget::acceptDrops () const"
Returns TRUE if drop events are enabled for this widget.
.PP
See also setAcceptDrops().
.SH "void QWidget::adjustSize () \fC[virtual]\fR"
Adjusts the size of the widget to fit the contents.
.PP
Uses sizeHint() if valid (i.e if the size hint's width and height are equal to or greater than 0), otherwise sets the size to the children rectangle (the union of all child widget geometries).
.PP
See also sizeHint() and childrenRect().
.PP
Examples:
.(l
xform/xform.cpp
.)l
.PP
Reimplemented in QMessageBox.
.SH "bool QWidget::autoMask () const"
Returns whether or not the widget has the auto mask feature enabled.
.PP
See also setAutoMask(), updateMask(), setMask() and clearMask().
.SH "const QColor & QWidget::backgroundColor () const"
Returns the background color of this widget, which is normally set implicitly by setBackgroundMode(), but can also be set explicitly by setBackgroundColor().
.PP
If there is a background pixmap (set using setBackgroundPixmap()), then the return value of this function is indeterminate.
.PP
See also setBackgroundColor(), foregroundColor(), colorGroup() and palette().
.PP
Examples:
.(l
xform/xform.cpp grapher/grapher.cpp
.)l
.SH "void QWidget::backgroundColorChange ( const QColor & oldBackgroundColor ) \fC[virtual protected]\fR"
This virtual function is called from setBackgroundColor(). \fIoldBackgroundColor\fR is the previous background color; you can get the new background color from backgroundColor().
.PP
Reimplement this function if your widget needs to know when its background color changes. You will almost certainly need to call this implementation of the function.
.PP
See also setBackgroundColor(), backgroundColor(), setPalette(), repaint() and update().
.SH "QWidget::BackgroundMode QWidget::backgroundMode() const"
Returns the mode most recently set by setBackgroundMode(). The default is PaletteBackground.
.PP
See also BackgroundMode and setBackgroundMode().
.SH "QWidget::BackgroundOrigin QWidget::backgroundOrigin() const"
Returns the current background origin.
.PP
See also setBackgroundOrigin().
.SH "const QPixmap * QWidget::backgroundPixmap () const"
Returns the background pixmap if one has been set. If the widget has backgroundMode() NoBackground, the return value is a pixmap for which QPixmao:isNull() is true. If the widget has no pixmap is the background, the return value is a null pointer.
.PP
See also setBackgroundPixmap() and setBackgroundMode().
.SH "void QWidget::backgroundPixmapChange ( const QPixmap & oldBackgroundPixmap ) \fC[virtual protected]\fR"
This virtual function is called from setBackgroundPixmap(). \fIoldBackgroundPixmap\fR is the previous background pixmap; you can get the new background pixmap from backgroundPixmap().
.PP
Reimplement this function if your widget needs to know when its background pixmap changes. You will almost certainly need to call this implementation of the function.
.PP
See also setBackgroundPixmap(), backgroundPixmap(), repaint() and update().
.SH "QSize QWidget::baseSize () const"
Returns the widget base size
.PP
The base size is used to calculate a proper widget size in case the widget defines sizeIncrement().
.PP
See also setBaseSize() and setSizeIncrement().
.SH "QString QWidget::caption () const"
Returns the widget caption. If no caption has been set (common for child widgets), this functions returns a null string.
.PP
See also setCaption(), icon(), iconText() and QString::isNull().
.PP
Examples:
.(l
i18n/main.cpp
.)l
.SH "QRect QWidget::childrenRect () const"
Returns the bounding rectangle of the widget's children.
.PP
Explicitely hidden children are excluded.
.PP
See also childrenRegion().
.SH "QRegion QWidget::childrenRegion () const"
Returns the combined region of the widget's children geometry().
.PP
Explicitely hidden children are excluded.
.PP
See also childrenRect().
.SH "void QWidget::clearFocus () \fC[slot]\fR"
Takes keyboard input focus from the widget.
.PP
If the widget has active focus, a focus out event is sent to this widget to tell it that it is about to lose the focus.
.PP
This widget must enable focus setting in order to get the keyboard input focus, i.e. it must call setFocusPolicy().
.PP
See also hasFocus(), setFocus(), focusInEvent(), focusOutEvent(), setFocusPolicy() and QApplication::focusWidget().
.SH "void QWidget::clearMask ()"
Removes any mask set by setMask().
.PP
See also setMask().
.SH "void QWidget::clearWFlags ( WFlags f ) \fC[protected]\fR"
Clears the widget flags \fIf.\fR
.PP
Widget flags are a combination of Qt::WidgetFlags.
.PP
See also testWFlags(), getWFlags() and setWFlags().
.SH "bool QWidget::close () \fC[slot]\fR"
Closes this widget. Returns TRUE if the widget was closed, otherwise FALSE.
.PP
First it sends the widget a QCloseEvent. The widget is hidden if it accepts the close event. The default implementation of QWidget::closeEvent() accepts the close event.
.PP
The QApplication::lastWindowClosed() signal is emitted when the last visible top level widget is closed.
.PP
See also close(bool).
.PP
Examples:
.(l
popup/popup.cpp
.)l
.SH "bool QWidget::close ( bool alsoDelete ) \fC[virtual]\fR"
Closes this widget. Returns TRUE if the widget was closed, otherwise FALSE.
.PP
If \fIalsoDelete\fR is TRUE or the widget has the \fCWDestructiveClose\fR widget flag, the widget is also deleted. The widget can prevent itself from being closed by rejecting the QCloseEvent it gets.
.PP
The QApplication::lastWindowClosed() signal is emitted when the last visible top level widget is closed.
.PP
Note that closing the QApplication::mainWidget() terminates the application.
.PP
See also closeEvent(), QCloseEvent, hide(), QApplication::quit(), QApplication::setMainWidget() and QApplication::lastWindowClosed().
.SH "void QWidget::closeEvent ( QCloseEvent * e ) \fC[virtual protected]\fR"
This event handler can be reimplemented in a subclass to receive widget close events.
.PP
The default implementation calls e->accept(), which hides this widget. See the QCloseEvent documentation for more details.
.PP
See also event(), hide(), close() and QCloseEvent.
.PP
Reimplemented in QDialog, QProgressDialog and QPopupMenu.
.SH "const QColorGroup & QWidget::colorGroup () const"
Returns the current color group of the widget palette.
.PP
The color group is determined by the state of the widget.
.PP
A disabled widget returns the QPalette::disabled() color group, a widget in the window with keyboard focus returns the QPalette::active() color group, and all inactive widgets return the QPalette::inactive() color group.
.PP
See also palette() and setPalette().
.SH "void QWidget::constPolish () const \fC[slot]\fR"
Ensures that the widget is properly initialized by calling polish().
.PP
Call constPolish() from functions like sizeHint() that depends on the widget being initialized, and that may be called before show().
.PP
\fBWarning:\fR Do not call constPolish() on a widget from inside that widget's constructor.
.PP
See also polish().
.SH "void QWidget::create ( WId window = 0, bool initializeWindow = TRUE, bool destroyOldWindow = TRUE ) \fC[virtual protected]\fR"
Creates a new widget window if \fIwindow\fR is null, otherwise sets the widget's window to \fIwindow.\fR
.PP
Initializes the window (sets the geometry etc.) if \fIinitializeWindow\fR is TRUE. If \fIinitializeWindow\fR is FALSE, no initialization is performed. This parameter makes only sense if \fIwindow\fR is a valid window.
.PP
Destroys the old window if \fIdestroyOldWindow\fR is TRUE. If \fIdestroyOldWindow\fR is FALSE, you are responsible for destroying the window yourself (using platform native code).
.PP
The QWidget constructor calls create(0,TRUE,TRUE) to create a window for this widget.
.SH "const QCursor & QWidget::cursor () const"
Returns the widget cursor. If no cursor has been set the parent widget's cursor is returned.
.PP
See also setCursor() and unsetCursor();.
.SH "void QWidget::customEvent ( QCustomEvent * ) \fC[virtual protected]\fR"
This event handler can be reimplemented in a subclass to receive custom events. Custom events are user-defined events with a type value at least as large as the "User" item of the QEvent::Type enum, and is typically a QCustomEvent or QCustomEvent subclass.
.PP
See also event() and QCustomEvent.
.SH "bool QWidget::customWhatsThis () const \fC[virtual]\fR"
Returns whether the widget wants to handle What's This help manually. The default implementation returns FALSE, which means the widget will not receive any events in Whats This mode.
.PP
The widget may leave Whats This mode by calling QWhatsThis::leaveWhatsThisMode(), with or without actually displaying any help text.
.PP
You may also reimplement customWhatsThis() if your widget is a so-called "passive interactor" that is supposed to work under all circumstances. Simply don't call QWhatsThis::leaveWhatsThisMode() in that case.
.PP
See also QWhatsThis::inWhatsThisMode() and QWhatsThis::leaveWhatsThisMode().
.PP
Reimplemented in QPopupMenu and QMenuBar.
.SH "void QWidget::destroy ( bool destroyWindow = TRUE, bool destroySubWindows = TRUE ) \fC[virtual protected]\fR"
Frees up window system resources. Destroys the widget window if \fIdestroyWindow\fR is TRUE.
.PP
destroy() calls itself recursively for all the child widgets, passing \fIdestroySubWindows\fR for the \fIdestroyWindow\fR parameter. To have more control over destruction of subwidgets, destroy subwidgets selectively first.
.PP
This function is usually called from the QWidget destructor.
.SH "void QWidget::dragEnterEvent ( QDragEnterEvent * ) \fC[virtual protected]\fR"
This event handler is called when a drag is in progress and the mouse enters this widget.
.PP
See the Drag-and-drop documentation for an overview of how to provide drag-and-drop in your application.
.PP
See also QTextDrag, QImageDrag and QDragEnterEvent.
.PP
Reimplemented in QLineEdit and QMultiLineEdit.
.SH "void QWidget::dragLeaveEvent ( QDragLeaveEvent * ) \fC[virtual protected]\fR"
This event handler is called when a drag is in progress and the mouse leaves this widget.
.PP
See the Drag-and-drop documentation for an overview of how to provide drag-and-drop in your application.
.PP
See also QTextDrag, QImageDrag and QDragLeaveEvent.
.PP
Reimplemented in QMultiLineEdit.
.SH "void QWidget::dragMoveEvent ( QDragMoveEvent * ) \fC[virtual protected]\fR"
This event handler is called when a drag is in progress and the mouse enters this widget, and whenever it moves within the widget.
.PP
See the Drag-and-drop documentation for an overview of how to provide drag-and-drop in your application.
.PP
See also QTextDrag, QImageDrag and QDragMoveEvent.
.PP
Reimplemented in QMultiLineEdit.
.SH "void QWidget::drawText ( int x, int y, const QString & str )"
Writes \fIstr\fR at position \fIx,y.\fR
.PP
The \fIy\fR position is the base line position of the text. The text is drawn using the default font and the default foreground color.
.PP
This function is provided for convenience. You will generally get more flexible results and often higher speed by using a a painter instead.
.PP
See also setFont(), foregroundColor() and QPainter::drawText().
.SH "void QWidget::drawText ( const QPoint & pos, const QString & str )"
This is an overloaded member function, provided for convenience. It differs from the above function only in what argument(s) it accepts.
.SH "void QWidget::dropEvent ( QDropEvent * ) \fC[virtual protected]\fR"
This event handler is called when the drag is dropped on this widget.
.PP
See the Drag-and-drop documentation for an overview of how to provide drag-and-drop in your application.
.PP
See also QTextDrag, QImageDrag and QDropEvent.
.PP
Reimplemented in QMultiLineEdit and QLineEdit.
.SH "void QWidget::enabledChange ( bool oldEnabled ) \fC[virtual protected]\fR"
This virtual function is called from setEnabled(). \fIoldEnabled\fR is the previous setting; you can get the new setting from isEnabled().
.PP
Reimplement this function if your widget needs to know when it becomes enabled or disabled. You will almost certainly need to update the widget using update().
.PP
The default implementation repaints the visible part of the widget.
.PP
See also setEnabled(), isEnabled(), repaint(), update() and visibleRect().
.PP
Reimplemented in QListView and QButton.
.SH "void QWidget::enterEvent ( QEvent * ) \fC[virtual protected]\fR"
This event handler can be reimplemented in a subclass to receive widget enter events.
.PP
An event is sent to the widget when the mouse cursor enters the widget.
.PP
See also leaveEvent(), mouseMoveEvent() and event().
.PP
Reimplemented in QToolButton.
.SH "void QWidget::erase ( const QRegion & reg )"
Erases the area defined by \fIreg,\fR without generating a paint event.
.PP
Child widgets are not affected.
.PP
Examples:
.(l
drawlines/connect.cpp
.)l
.SH "void QWidget::erase ( int x, int y, int w, int h )"
Erases the specified area \fI(x,y,w,h)\fR in the widget without generating a paint event.
.PP
If \fIw\fR is negative, it is replaced with \fCwidth() - x\fR. If \fIh\fR is negative, it is replaced width \fCheight() - y\fR.
.PP
Child widgets are not affected.
.PP
See also repaint().
.SH "void QWidget::erase ()"
This is an overloaded member function, provided for convenience. It differs from the above function only in what argument(s) it accepts.
.PP
This version erases the entire widget.
.SH "void QWidget::erase ( const QRect & r )"
This is an overloaded member function, provided for convenience. It differs from the above function only in what argument(s) it accepts.
.SH "bool QWidget::event ( QEvent * e ) \fC[virtual protected]\fR"
This is the main event handler. You may reimplement this function in a subclass, but we recommend using one of the specialized event handlers instead.
.PP
The main event handler first passes an event through all event filters that have been installed. If none of the filters intercept the event, it calls one of the specialized event handlers.
.PP
Key press/release events are treated differently from other events. event() checks for Tab and shift-Tab and tries to move the focus appropriately. If there is no widget to move the focus to (or the key press is not Tab or shift-Tab), event() calls keyPressEvent().
.PP
This function returns TRUE if it is able to pass the event over to someone, or FALSE if nobody wanted the event.
.PP
See also closeEvent(), focusInEvent(), focusOutEvent(), enterEvent(), keyPressEvent(), keyReleaseEvent(), leaveEvent(), mouseDoubleClickEvent(), mouseMoveEvent(), mousePressEvent(), mouseReleaseEvent(), moveEvent(), paintEvent(), resizeEvent(), QObject::event() and QObject::timerEvent().
.PP
Reimplemented from QObject.
.SH "QWidget * QWidget::find ( WId id ) \fC[static]\fR"
Returns a pointer to the widget with window identifer/handle \fIid.\fR
.PP
The window identifier type depends by the underlying window system, see qwindowdefs.h for the actual definition. If there is no widget with this identifier, a null pointer is returned.
.PP
See also wmapper() and winId().
.SH "QFocusData * QWidget::focusData () \fC[protected]\fR"
Returns a pointer to the focus data for this widget's top-level widget.
.PP
Focus data always belongs to the top-level widget. The focus data list contains all the widgets in this top-level widget that can accept focus, in tab order. An iterator points to the current focus widget (focusWidget() returns a pointer to this widget).
.PP
This information is useful for implementing advanced versions of focusNextPrevChild().
.SH "void QWidget::focusInEvent ( QFocusEvent * ) \fC[virtual protected]\fR"
This event handler can be reimplemented in a subclass to receive keyboard focus events (focus received) for the widget.
.PP
A widget normally must setFocusPolicy() to something other than NoFocus in order to receive focus events. (Note that the application programmer can call setFocus() on any widget, even those that do not normally accept focus.)
.PP
The default implementation updates the widget if it accepts focus (see focusPolicy()). It also calls setMicroFocusHint(), hinting any system-specific input tools about the focus of the user's attention.
.PP
See also focusOutEvent(), setFocusPolicy(), keyPressEvent(), keyReleaseEvent(), event() and QFocusEvent.
.PP