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diff --git a/doc/src/porting4.qdoc b/doc/src/porting4.qdoc deleted file mode 100644 index 4efb7be32..000000000 --- a/doc/src/porting4.qdoc +++ /dev/null @@ -1,4231 +0,0 @@ -/**************************************************************************** -** -** Copyright (C) 2009 Nokia Corporation and/or its subsidiary(-ies). -** Contact: Nokia Corporation (qt-info@nokia.com) -** -** This file is part of the documentation of the Qt Toolkit. -** -** $QT_BEGIN_LICENSE:LGPL$ -** No Commercial Usage -** This file contains pre-release code and may not be distributed. -** You may use this file in accordance with the terms and conditions -** contained in the either Technology Preview License Agreement or the -** Beta Release License Agreement. -** -** GNU Lesser General Public License Usage -** Alternatively, this file may be used under the terms of the GNU Lesser -** General Public License version 2.1 as published by the Free Software -** Foundation and appearing in the file LICENSE.LGPL included in the -** packaging of this file. Please review the following information to -** ensure the GNU Lesser General Public License version 2.1 requirements -** will be met: http://www.gnu.org/licenses/old-licenses/lgpl-2.1.html. -** -** In addition, as a special exception, Nokia gives you certain -** additional rights. These rights are described in the Nokia Qt LGPL -** Exception version 1.0, included in the file LGPL_EXCEPTION.txt in this -** package. -** -** GNU General Public License Usage -** Alternatively, this file may be used under the terms of the GNU -** General Public License version 3.0 as published by the Free Software -** Foundation and appearing in the file LICENSE.GPL included in the -** packaging of this file. Please review the following information to -** ensure the GNU General Public License version 3.0 requirements will be -** met: http://www.gnu.org/copyleft/gpl.html. -** -** If you are unsure which license is appropriate for your use, please -** contact the sales department at http://qt.nokia.com/contact. -** $QT_END_LICENSE$ -** -****************************************************************************/ - -/*! - \page porting4.html - \title Porting to Qt 4 - \contentspage {Porting Guides}{Contents} - \previouspage Porting Guides - \nextpage Porting to Qt 4 - Virtual Functions - \ingroup porting - \brief An overview of issues and techniques to consider when porting from Qt 3 to Qt 4. - -\omit - ### QFileInfo::PermissionSpec -> QFile::Permission(s?) - ### refer to porting4-renamedfunctions.qdoc - ### QApplication library mutex is gone - ### no integral conversion for containers? strings? - ### QVector etc. are initialized to 0 by default? - ### How to port from Qt 2.3 to Qt 4. - ### missing sort() functions? - ### QToolTipGroup - ### QServerSocket -> Q3ServerSocket - - ### remove these when the classes are re-ported - - ### QApplication::eventLoop() - - \row \o void QCheckListItem::paintCell(QPainter *, const QColorGroup &, int, int, int)\row \o void Q3CheckListItem::paintCell(QPainter *, const QPalette &, int, int, int) - \row \o void QCheckListItem::paintFocus(QPainter *, const QColorGroup &, const QRect &) \o void Q3CheckListItem::paintFocus(QPainter *, const QPalette &, const QRect &) - \row \o QDataTable: a whole bunch of virtual functions have a different signature - - < Function: void QIconViewItem::paintFocus(QPainter *, const QColorGroup &) - > Function: void QIconViewItem::paintFocus(QPainter *, const QPalette &) - - < Function: void QIconViewItem::paintItem(QPainter *, const QColorGroup &) - > Function: void QIconViewItem::paintItem(QPainter *, const QPalette &) - - < Function: bool QUrlOperator::checkValid() - - < Function: void QWSInputMethod::setFont(const QFont &) - - ### OpenMode or OpenMode - - ### QWSDecoration -\endomit - - This document describes the process of porting applications from - Qt 3 to Qt 4. - If you haven't yet made the decision about porting, or are unsure - about whether it is worth it, take a look at the \l{What's New in - Qt 4}{key features} offered by Qt 4. See also - \l{Moving from Qt 3 to Qt 4} for tips on how to write Qt 3 code - that is easy to port to Qt 4. - - \bold{Other porting guides:} - - \list - \o \l{Moving from Qt 3 to Qt 4} \mdash covers some high level topics relevant - to developers porting from Qt 3 to Qt 4. - \o \l{Porting to Qt 4 - Drag and Drop} \mdash covers differences in the - way drag and drop is handled between Qt 3 and Qt 4. - \o \l{Porting UI Files to Qt 4} \mdash describes the new format used to - describe forms created with \QD. - \o \l{Porting to Graphics View} \mdash provides a class-by-class overview - of the differences between Qt 3's canvas API and Qt 4's Graphics - View framework. - \o \l{qt3to4 - The Qt 3 to 4 Porting Tool} \mdash provides an overview - of a tool aimed at helping developers start the process of porting an - application to Qt 4. - \endlist - - The Qt 4 series is not binary compatible with the 3 series. This - means programs compiled for Qt 3 must be recompiled to work with - Qt 4. Qt 4 is also not completely \e source compatible with 3, - however nearly all points of incompatibility cause compiler - errors or run-time messages (rather than mysterious results). Qt - 4 includes many additional features and discards obsolete - functionality. Porting from Qt 3 to Qt 4 requires some effort, - but once completed the considerable additional power and - flexibility of Qt 4 is available for use in your applications. - - To port code from Qt 3 to Qt 4: - - \list 1 - - \o Briefly read the porting notes below to get an idea of what to expect. - - \o Be sure that your code compiles and runs well on all your target - platforms with Qt 3. - - \o Add the line \c{QT += qt3support} to your \c .pro file if you use - \c qmake; otherwise, edit your makefile or project file to - link against the Qt3Support library and add \c -DQT3_SUPPORT to your - compiler flags. (You might also need to specify other - libraries. See \l{What's New in Qt 4} for details.) - - \o Run the \l qt3to4 porting tool. The tool will go through your - source code and adapt it to Qt 4. - - \o Follow the instructions in the \l{Porting UI Files to Qt 4} - page to port Qt Designer files. - - \o Recompile with Qt 4. For each error, search below for related - identifiers (e.g., function names, class names). This document - mentions all relevant identifiers to help you get the information - you need at the cost of being a little verbose. - - \endlist - - The \l qt3to4 porting tool replaces occurrences of Qt 3 classes - that don't exist anymore in Qt 4 with the corresponding Qt 3 - support class; for example, \c QListBox is turned into \c - Q3ListBox. - - At some point, you might want to stop linking against the Qt 3 - support library (\l{Qt3Support}) and take advantage of Qt 4's - new features. The instructions below explain how to do that for - each compatibility class. - - In addition to the Qt3Support classes (such as \c Q3Action, \c - Q3ListBox, and \c Q3ValueList), Qt 4 provides compatibility - functions when it's possible for an old API to cohabit with the - new one. For example, QString provides a - QString::simplifyWhiteSpace() compatibility function that's - implemented inline and that simply calls QString::simplified(). - \bold{The compatibility functions are not documented here; instead, - they are documented for each class.} - - If you have the line \c{QT += qt3support} in your \c .pro file, \c - qmake will automatically define the \c QT3_SUPPORT symbol, turning - on compatibility function support. You can also define the symbol - manually (e.g., if you don't want to link against the \c - Qt3Support library), or you can define \c QT3_SUPPORT_WARNINGS - instead, telling the compiler to emit a warning when a - compatibility function is called. (This works only with GCC 3.2+ - and MSVC 7.) - - If you get stuck, ask on the - \l{http://qt.nokia.com/lists/qt-interest/}{qt-interest} - mailing list. If you are a licensed customer, you can also contact - Qt's technical support team. - -\omit - ### what to do with slots that aren't slots anymore - ### what to do with virtual functions that aren't virtual anymore - ### what to do with virtual functions that changed signature -\endomit - -\omit - ### <qtl.h> -- stuff that vanished? - ### implicit sharing - ### uint -> int indexes -\endomit - - Table of contents: - - \tableofcontents{4} - -\omit - \section1 Header Files - - ### New style of headers - - \table - \header \o Old header \o New header - \row \o \c{<qtl.h>} \o \c{<qalgorithms.h>} or \c{<QtAlgorithms>} - \endtable - - ### Some headers don't include each other anymore... -\endomit - - \section1 Casting and Object Types - - In Qt 3, it was possible to use the \c qt_cast() function to determine - whether instances of QObject subclasses could be safely cast to derived - types of those subclasses. For example, if a QFrame instance is passed - to a function whose signature specifies a QWidget pointer as its argument, - \c qt_cast() could be used to obtain a QFrame pointer so that the - instance's functions can be accessed. - - In Qt 4, much of this functionality is provided by the qobject_cast() - function, and additional functions also provide similar functionality for - certain non-QObject types: - - \table - \header \o Qt 3 function \o Qt 4 function - \row \o T *qt_cast<T *>(QObject *) \o \l{qobject_cast()}{T *qobject_cast<T *>(QObject *)} - \row \o \o \l{qgraphicsitem_cast()}{T qgraphicsitem_cast<T>(QGraphicsItem *)} - \row \o \o \l{qstyleoption_cast()}{T qstyleoption_cast<T>(QStyleOption *)} - \row \o \o \l{qvariant_cast()}{T qvariant_cast<T>(const QVariant &)} - \row \o \o \l{qdbus_cast()}{T qdbus_cast(const QDBusArgument &)} - \endtable - -\omit - \section1 Global Functions - - \table - \header \o Qt 3 function \o Qt 4 function - \row \o cstrcmp() \o strcmp() - \row \o cstrcpy() \o strcpy() - \row \o cstrlen() \o strlen() - \row \o cstrncmp() \o strncmp() - \row \o qmemmove() \o memmove() - \endtable - - qGLVersion() ### - - copyBlt() ### - bitBlt() - - #ifdef compat classes: - * QLayoutIterator - * QColorGroup - * QMenuItem - - QWidget visibleRect property compat - QWidget::BackgroundOrigin compat -\endomit - - \section1 Type Names - - The table below lists the classes that have been renamed in Qt 4. - If you compile your applications with \c QT3_SUPPORT defined, the - old names will be available. - - Whenever you see an occurrence of the name on the left, you can - safely replace it with the Qt 4 equivalent in your program. The - \l qt3to4 tool performs the conversion automatically. - - \table - \header \o Qt 3 class name \o Qt 4 class name - \input porting4-renamedclasses.qdocinc - \endtable - - The table below lists the enums and typedefs that have been - renamed in Qt 4. If you compile your applications with \c - QT3_SUPPORT defined, the old names will be available. - - Whenever you see an occurrence of the name on the left, you can - safely replace it with the Qt 4 equivalent in your program. The - \l qt3to4 tool performs the conversion - automatically. - - \table - \header \o Qt 3 type name \o Qt 4 type name - \input porting4-renamedtypes.qdocinc - \endtable - - \omit - ### - \row \o QButton::ToggleState \o Use QCheckBox::ToggleState instead. - \endomit - - \section1 Enum Values - - The table below lists the enum values that have been renamed in - Qt 4. If you compile your applications with \c QT3_SUPPORT defined, - the old names will be available. - - Whenever you see an occurrence of the name on the left, you can - safely replace it with the Qt 4 equivalent in your program. The - \l qt3to4 tool performs the conversion automatically. - - \table - \header \o Qt 3 enum value name \o Qt 4 enum value name - \input porting4-renamedenumvalues.qdocinc - \endtable - - In addition, the following \l{Qt::WindowFlags}{window flags} have - been either replaced with \l{Qt::WidgetAttribute}{widget - attributes} or have been deprecated: - - \table - \header \o Qt 3 type \o Qt 4 equivalent - \row \o Qt::WDestructiveClose \o Use QWidget::setAttribute(Qt::WA_DeleteOnClose) instead. - \row \o Qt::WStaticContents \o{1,2} Use QWidget::setAttribute(Qt::WA_StaticContents) instead. - \row \o Qt::WNorthWestGravity - \row \o Qt::WNoAutoErase \o{1,3} Use QWidget::setAttribute(Qt::WA_NoBackground) instead. - \row \o Qt::WResizeNoErase - \row \o Qt::WRepaintNoErase - \row \o Qt::WPaintClever \o Unnecessary in Qt 4. - \omit ### Check with Matthias \endomit - \row \o Qt::WMacNoSheet \o Unnecessary in Qt 4. - \omit ### Check with Sam \endomit - \endtable - - In Qt 4.1, the widget flags used to determine window modality were - replaced by a single enum that can be used to specify the modal - behavior of top-level widgets: - - \table - \header \o Qt 3 type \o Qt 4 equivalent - \row \o Qt::WShowModal \o Use QWidget::setWindowModality(Qt::ApplicationModal) instead. - \row \o Qt::WGroupLeader \o Use QWidget::setWindowModality(Qt::WindowModal) - for each child dialog of the group leader, but do not change the modality - of the group leader itself. - \endtable - - \target properties - \section1 Properties - - Some properties have been renamed in Qt 4, to make Qt's API more - consistent and more intuitive. For example, QWidget's \c caption - property has been renamed \c windowTitle to make it clear that it - refers to the title shown in the window's title bar. - - In addition, the property system has been extended to allow - properties to be redefined in subclasses with the \l Q_PROPERTY() - macro, removing the need for a \c Q_OVERRIDE() macro. - - The table below lists the Qt properties that have been renamed in - Qt 4. Occurrences of these in \e{Qt Designer} UI files are - automatically converted to the new name by \c uic. - - \table - \header \o Qt 3 name \o Qt 4 name - \row \o QButton::accel \o QButton::shortcut - \row \o QButton::on \o QButton::checked - \row \o QButton::toggleButton \o QAbstractButton::checkable - \row \o QDial::lineStep \o QDial::singleStep - \row \o QDial::maxValue \o QDial::maximum - \row \o QDial::minValue \o QDial::minimum - \row \o QDialog::modal \o QDialog::isModal - \row \o QLineEdit::edited \o QLineEdit::modified - \row \o QLineEdit::hasMarkedText \o QLineEdit::hasSelectedText - \row \o QLineEdit::markedText \o QLineEdit::selectedText - \row \o QObject::name \o QObject::objectName - \row \o QProgressDialog::progress \o QProgressDialog::value - \row \o QProgressDialog::totalSteps \o QProgressDialog::maximum - \row \o QProgressDialog::wasCancelled \o QProgressDialog::wasCanceled - \row \o QPushButton::iconSet \o QPushButton::icon - \row \o QScrollBar::draggingSlider \o QScrollBar::sliderDown - \row \o QScrollBar::lineStep \o QScrollBar::singleStep - \row \o QScrollBar::maxValue \o QScrollBar::maximum - \row \o QScrollBar::minValue \o QScrollBar::minimum - \row \o QSlider::lineStep \o QSlider::singleStep - \row \o QSlider::maxValue \o QSlider::maximum - \row \o QSlider::minValue \o QSlider::minimum - \row \o QSpinBox::lineStep \o QSpinBox::singleStep - \row \o QSpinBox::maxValue \o QSpinBox::maximum - \row \o QSpinBox::minValue \o QSpinBox::minimum - \row \o QTabBar::currentTab \o QTabBar::currentIndex - \row \o QTabWidget::currentPage \o QTabWidget::currentWidget - \row \o QToolButton::iconSet \o QToolButton::icon - \row \o QToolButton::textLabel \o QToolButton::text - \row \o QWidget::caption \o QWidget::windowTitle - \row \o QWidget::icon \o QWidget::windowIcon - \row \o QWidget::iconText \o QWidget::windowIconText - \endtable - - A handful of properties in Qt 3 are no longer properties in Qt 4, - but the access functions still exist as part of the Qt 4 API. - These are not used by \e{Qt Designer}; the only case where you - need to worry about them is in highly dynamic applications that - use Qt's meta-object system to access properties. Here's the list - of these properties with the read and write functions that you - can use instead: - - \table - \header \o Qt 3 property \o Qt 4 read function \o Qt 4 write function - \row \o QSqlDatabase::connectOptions \o QSqlDatabase::connectOptions() \o QSqlDatabase::setConnectOptions() - \row \o QSqlDatabase::databaseName \o QSqlDatabase::databaseName() \o QSqlDatabase::setDatabaseName() - \row \o QSqlDatabase::hostName \o QSqlDatabase::hostName() \o QSqlDatabase::setHostName() - \row \o QSqlDatabase::password \o QSqlDatabase::password() \o QSqlDatabase::setPassword() - \row \o QSqlDatabase::port \o QSqlDatabase::port() \o QSqlDatabase::setPort() - \row \o QSqlDatabase::userName \o QSqlDatabase::userName() \o QSqlDatabase::setUserName() - \endtable - - Some properties have been removed from Qt 4, but the associated - access functions are provided if \c QT3_SUPPORT is defined to help - porting to Qt 4. When converting Qt 3 UI files to Qt 4, \c uic - generates calls to the Qt 3 compatibility functions. Note that - this only applies to the properties of the Qt3Support library, - i.e. \c QT3_SUPPORT properties of the other libraries must be - ported manually when converting Qt 3 UI files to Qt 4. - - The table below lists these properties with the read and write - functions that you can use instead. The documentation for the - individual functions explains how to replace them with - non-compatibility Qt 4 functions. - - \table - \header \o Qt 3 property \o Qt 4 read function (\c QT3_SUPPORT)\o Qt 4 write function (\c QT3_SUPPORT) - \row \o QMenuBar::separator \o QMenuBar::separator() \o QMenuBar::setSeparator() - \row \o QPushButton::menuButton \o QPushButton::isMenuButton() \o N/A - \row \o QTabWidget::margin \o QTabWidget::margin() \o QTabWidget::setMargin() - \row \o QTextEdit::textFormat \o QTextEdit::textFormat() \o QTextEdit::setTextFormat() - \row \o QWidget::backgroundBrush \o QWidget::backgroundBrush() \o N/A - \row \o QWidget::backgroundMode \o QWidget::backgroundMode() \o QWidget::setBackgroundMode() - \row \o QWidget::backgroundOrigin \o QWidget::backgroundOrigin() \o QWidget::setBackgroundOrigin() - \row \o QWidget::colorGroup \o QWidget::colorGroup() \o QWidget::setColorGroup() - \row \o QWidget::customWhatsThis \o QWidget::customWhatsThis() \o QWidget::setCustomWhatsThis() - \row \o QWidget::inputMethodEnabled \o QWidget::inputMethodEnabled() \o QWidget::setInputMethodEnabled() - \row \o QWidget::ownCursor \o QWidget::ownCursor() \o N/A - \row \o QWidget::ownFont \o QWidget::ownFont() \o N/A - \row \o QWidget::ownPalette \o QWidget::ownPalette() \o N/A - \row \o QWidget::paletteBackgroundColor \o QWidget::paletteBackgroundColor() \o QWidget::setPaletteBackgroundColor() - \row \o QWidget::paletteBackgroundPixmap \o QWidget::paletteBackgroundPixmap() \o QWidget::setPaletteBackgroundPixmap() - \row \o QWidget::paletteForegroundColor \o QWidget::paletteForegroundColor() \o QWidget::setPaletteForegroundColor() - \row \o QWidget::underMouse \o QWidget::underMouse() \o N/A - \endtable - - The following Qt 3 properties and their access functions are no - longer available in Qt 4. In most cases, Qt 4 provides similar - functionality. - - \table - \header \o Qt 3 property \o Qt 4 equivalent - \row \o QButton::autoRepeat \o N/A - \row \o QButton::autoResize \o Call QWidget:setFixedSize(QWidget::sizeHint()) whenever you change the contents. - \row \o QButton::exclusiveToggle \o See \l QAbstractButton::autoExclusive. - \row \o QButton::pixmap \o Use QAbstractButton::icon instead. - \row \o QButton::toggleState \o Use QCheckBox::setState() and QCheckBox::state() instead. - \row \o QButton::toggleType \o Use QCheckBox::setTristate() instead. - \row \o QComboBox::autoResize \o Call QWidget:setFixedSize(QWidget::sizeHint()) whenever you change the contents. - \row \o QFrame::contentsRect \o Use Q3Frame::contentsRect() instead. - \row \o QFrame::margin \o Use QWidget::setContentsMargins() instead. - \row \o QTabBar::keyboardFocusTab \o N/A - \row \o QToolButton::offIconSet \o Use the \l{QIcon::Off}{off component} of QAbstractButton::icon instead. - \row \o QToolButton::onIconSet \o Use the \l{QIcon::On}{on component} of QAbstractButton::icon instead. - \row \o QWidget::microFocusHint \o N/A - \row \o QMimeSource::serialNumber () \o N/A - \endtable - -\omit - \section1 Inheritance Chain - - ### QMenuBar, etc. - - \section1 Null vs. Empty - - ### -\endomit - - \section1 Explicit Sharing - - Qt 4 is the first version of Qt that contains no \link - http://qt.nokia.com/doc/3.3/shclass.html explicitly shared - \endlink classes. All classes that were explicitly shared in Qt 3 - are \e implicitly shared in Qt 4: - - \list - \o QImage - \o QBitArray - \o QByteArray - \o Q3PointArray - \endlist - - This means that if you took a copy of an instance of the class - (using operator=() or the class's copy constructor), any - modification to the copy would affect the original and vice - versa. Needless to say, this behavior is rarely desirable. - - Fortunately, nearly all Qt 3 applications don't rely on explicit - sharing. When porting, you typically only need to remove calls to - detach() and/or copy(), which aren't necessary anymore. - - If you deliberately rely on explicit sharing in your application, - you can use pointers or references to achieve the same result in - Qt 4. - - \oldcode - void asciify(QByteArray array) - { - for (int i = 0; i < (int)array.size(); ++i) { - if ((uchar)array[i] >= 128) - array[i] = '?'; - } - } - \newcode - void asciify(QByteArray &array) - { - for (int i = 0; i < array.size(); ++i) { - if ((uchar)array[i] >= 128) - array[i] = '?'; - } - } - \endcode - - (Notice the \c & in the parameter declaration.) - -\omit - \section1 Qt Designer UI Files - - ### -\endomit - - \section1 Painting and Redrawing Widgets - - When implementing custom widgets in Qt 3, it was possible to use - QPainter to draw on a widget outside paint events. This made it - possible to integrate Qt applications with third party libraries - and tools that impose their own rendering models. For example, - a widget might be repainted in a slot using data obtained from - an external source. - - In Qt 4, it is only possible to paint on a widget from within its - \l{QWidget::}{paintEvent()} handler function. This restriction simplifies - Qt's interaction with native window systems, improves the performance - of applications by reducing the number of redraw operations, and - also enables features to be implemented to improve the appearance of - widgets, such as a backing store. - - Generally, we recommend redesigning applications to perform all - painting operations in \l{QWidget::}{paintEvent()} functions, deferring - actual painting until the next time this function is called. - Applications can post paint events to trigger repaints, and it may be - possible to examine your widget's internal state to determine which - part of the widget needs to be repainted. - - If asynchronous repaints are used extensively by your application, - and it is not practical to redesign the rendering model to perform - all painting operations from within a widget's \l{QWidget::}{paintEvent()} - function, it may be necessary to consider using an intermediate painting - step. In this approach, one or more images can be updated asynchronously - and painted on the widget in the paint event. To avoid excessive - buffering, it may be worthwhile disabling the backing store by setting - the widget's Qt::WA_PaintOnScreen widget attribute. - - On certain platforms, the Qt::WA_PaintOutsidePaintEvent widget attribute - can be set to allow a widget to be painted from outside paint events. - - \note Setting widget attributes to disable key features of Qt's widget - rendering model may also cause other features to be disabled. - - \section1 Compatibility Signals and Slots - - When \c QT3_SUPPORT is defined, the default connection type for signals - and slots is the Qt::AutoCompatConnection type. This allows so-called - \e compatibility signals and slots (defined in Qt 3 support mode to provide - Qt 3 compatibility features) to be connected to other signals and - slots. - - However, if Qt is compiled with debugging output enabled, and the - developer uses other connection types to connect to compatibility - signals and slots (perhaps by building their application without Qt 3 - support enabled), then Qt will output warnings to the console to - indicate that compatibility connections are being made. This is intended - to be used as an aid in the process of porting a Qt 3 application to Qt 4. - - \section1 QAccel - - The \c QAccel class has been renamed Q3Accel and moved to the - Qt3Support module. In new applications, you have three options: - - \list 1 - \o You can use QAction and set a key sequence using QAction::setShortcut(). - \o You can use QShortcut, a class that provides similar - functionality to Q3Accel. - \o You can use QWidget::grabShortcut() and process "shortcut" - events by reimplementing QWidget::event(). - \endlist - - The Q3Accel class also supports multiple accelerators using the - same object, by calling Q3Accel::insertItem() multiple times. In - Qt 4, the solution is to create multiple QShortcut objects. - - \section1 QAccessibleInterface - - The QAccessibleInterface class has undergone some API changes in - Qt 4, to make it more consistent with the rest of the Qt API. - - If you have classes that inherit QAccessibleInterface or one of - its subclasses (QAccessibleObject, QAccessibleWidget, etc.), you - must port them the new QAccessibleInterface API. - - See \l{Porting to Qt 4 - Virtual Functions}{Virtual Functions} - for a list of QAccessibleInterface virtual member functions in - Qt 3 that are no longer virtual in Qt 4. - - \section1 QAccessibleTitleBar - - The \c QAccessibleTitleBar has been renamed Q3AccessibleTitleBar - and moved to the Qt3Support library. - - \target qaction.section - \section1 QAction - - The QAction class has been redesigned in Qt 4 to integrate better - with the rest of the menu system. It unifies the old \c QMenuItem - class and the old \c QAction class into one class, avoiding - unnecessary data duplication and the need to learn two different - APIs. - - The old \c QAction and \c QActionGroup classes have been renamed - Q3Action and Q3ActionGroup and moved to Qt3Support. In addition, - the new QAction class has compatibility functions to ease - transition to Qt 4. Note that when using Q3ToolBar and - Q3PopupMenu, their actions must be \l {Q3Action}s. - - See \l{Porting to Qt 4 - Virtual Functions}{Virtual Functions} - for a list of QAction virtual member functions in Qt 3 that are - no longer virtual in Qt 4. - - \section1 QActionGroup - - The QAction class has been completely redesigned in Qt 4 to - integrate better with the rest of the menu system. See the - \l{#qaction.section}{section on QAction} for details. - - \section1 QApplication - - The QApplication class has been split into two classes: - QCoreApplication and QApplication. The new QApplication class - inherits QCoreApplication and adds GUI-related functionality. In - practice, this has no consequences for existing Qt applications. - - In addition, the following API changes were made: - - \list 1 - \o QApplication::allWidgets() and QApplication::topLevelWidgets() - used to return a pointer to a QWidgetList. Now they return a - QWidgetList. - - Also, QWidgetList has changed from being a typedef for - QPtrList<QWidget> to being a typedef for QList<QWidget *>. - See the \l{#qwidgetlist.section}{section on QWidgetList} below - for details. - - \oldcode - QWidgetList *list = QApplication::topLevelWidgets(); - QWidgetListIt it(*list); - QWidget *widget; - while ((widget = it.current())) { - if (widget->inherits("MainWindow")) - ((MainWindow *)widget)->updateRecentFileItems(); - ++it; - } - delete list; - \newcode - QWidgetList list = QApplication::topLevelWidgets(); - for (int i = 0; i < list.size(); ++i) { - if (MainWindow *mainWin = qobject_cast<MainWindow *>(list.at(i))) - mainWin->updateRecentFileItems(); - } - \endcode - \o QApplication::setMainWidget() is no longer used. When all an application's - windows are closed, the application will exit normally. - \endlist - - \section1 QAquaStyle - - The \c QAquaStyle class first appeared in Qt 3.0, when the Qt for - Mac OS X port was first released. It emulated Apple's "Aqua" theme. - In Qt 3.1, QAquaStyle was obsoleted by QMacStyle, which uses Appearance - Manager to perform its drawing. - - The \c QAquaStyle class is no longer provided in Qt 4. Use - QMacStyle instead. - - \target qasciidict.section - \section1 QAsciiCache<T> - - \c QAsciiCache<T> has been renamed Q3AsciiCache<T> and moved to - the Qt3Support library. It has been replaced by - QCache<QByteArray, T>. - - For details, read the \l{#qcache.section}{section on QCache<T>}, - mentally substituting QByteArray for QString. - - \section1 QAsciiDict<T> - - QAsciiDict<T> and QAsciiDictIterator<T> have been renamed - Q3AsciiDict<T> and Q3AsciiDictIterator<T> and moved to the - Qt3Support library. They have been replaced by the - more modern QHash<Key, T> and QMultiHash<Key, T> classes and - their associated iterator classes. - - When porting old code that uses Q3AsciiDict<T> to Qt 4, there are - four classes that you can use: - - \list - \o QMultiHash<QByteArray, T *> - \o QMultiHash<QByteArray, T> - \o QHash<QByteArray, T *> - \o QHash<QByteArray, T> - \endlist - - For details, read the \l{#qdict.section}{section on QDict<T>}, - mentally substituting QByteArray for QString. - - \section1 QAsyncIO - - The \c QAsyncIO class was used internally in Qt 2.x in - conjunction with QImageConsumer. It was obsoleted in Qt 3.0. - - \input porting4-obsoletedmechanism.qdocinc - - \section1 QBackInsertIterator - - The undocumented \c QBackInsertIterator class has been removed - from the Qt library. If you need it in your application, feel - free to copy the source code from the Qt 3 \c <qtl.h> header - file. - - \section1 QBitArray - - In Qt 3, QBitArray inherited from QByteArray. In Qt 4, QBitArray - is a totally independent class. This makes very little difference - to the user, except that the new QBitArray doesn't provide any of - QByteArray's byte-based API anymore. These calls will result in a - compile-time error, except calls to QBitArray::truncate(), whose - parameter was a number of \e bytes in Qt 3 and a number of bits - in Qt 4. - - QBitArray was an explicitly shared class in Qt 3. See \l{Explicit - Sharing} for more information. - - The \c QBitVal class has been renamed QBitRef. - - \section1 QButton - - The \c QButton class has been replaced by QAbstractButton in Qt - 4. Classes like QPushButton and QRadioButton inherit from - QAbstractButton. As a help when porting older Qt applications, - the Qt3Support library contains a Q3Button class - implemented in terms of the new QAbstractButton. - - If you used the \c QButton class as a base class for your own - button type and want to port your code to the newer - QAbstractButton, you need to be aware that QAbstractButton has no - equivalent for the Q3Button::drawButton(QPainter *) virtual - function. The solution is to reimplement QWidget::paintEvent() in - your QAbstractButton subclass as follows: - - \snippet doc/src/snippets/code/doc_src_porting4.qdoc 0 - - \table - \header \o Q3Button function \o QAbstractButton equivalent - \row \o Q3Button::autoResize() \o Call QWidget:setFixedSize(QWidget::sizeHint()) whenever you change the contents. - \row \o Q3Button::isExclusiveToggle() \o Use QAbstractButton::group() or QAbstractButton::autoExclusive() instead. - \row \o Q3Button::pixmap() const \o QAbstractButton::icon() - \row \o Q3Button::setAutoResize() \o N/A - \row \o Q3Button::setPixmap(const QPixmap &) \o QAbstractButton::setIcon(const QIcon &) - \row \o Q3Button::setState(ToggleState) \o See remark below - \row \o Q3Button::setToggleType(ToggleType) \o See remark below - \row \o Q3Button::state() \o See remark below - \row \o Q3Button::stateChanged(int) \o See remark below - \row \o Q3Button::toggleType() \o See remark below - \endtable - - Remarks: - - \list 1 - \o In Qt 3, \c QButton had a "toggle type", which could be - QButton::SingleShot, QButton::Toggle, or QButton::Tristate. - The new QAbstractButton class doesn't support "tristate" - directly; this feature is implemented in QCheckBox instead. - The two other "toggle types" (\c QButton::SingleShot and \c - QButton::Toggle) are replaced by a QAbstractButton::checkable - property. - \o In Qt 3, QButton had a "toggle state", which could be \c - QButton::Off, \c QButton::NoChange, or \c QButton::On. In Qt - 4, this mechanism has been moved to QCheckBox. - \endlist - - See \l{Porting to Qt 4 - Virtual Functions}{Virtual Functions} for - a list of \c QButton virtual member functions in Qt 3 that aren't - virtual in Qt 4. - - See \l{#properties}{Properties} for a list of \c QButton properties - in Qt 3 that have changed in Qt 4. - - \section1 QButtonGroup - - The \c QButtonGroup class has been completely redesigned in Qt 4. - For compatibility, the old \c QButtonGroup class has been renamed - Q3ButtonGroup and has been moved to Qt3Support. - Likewise, the \c QHButtonGroup and \c QVButtonGroup convenience - subclasses have been renamed \c Q3HButtonGroup and \c Q3VButtonGroup and - moved to the Qt3Support library. - - The old \c QButtonGroup, as well as Q3ButtonGroup, can be used in two ways: - - \list 1 - \o The button group is the parent widget of a number of buttons, - i.e. the button group is the parent argument in the button - constructor. The buttons are assigned identifiers 0, 1, 2, etc., - in the order they are created. A Q3ButtonGroup can display a frame - and a title because it inherits Q3GroupBox. - \o The button group is an invisible widget and the contained - buttons have some other parent widget. In this usage, each - button must be manually inserted, using - Q3ButtonGroup::insert(), into the button group and given an - ID number. - \endlist - - Unlike Q3ButtonGroup, the new QButtonGroup doesn't inherit - QWidget. It is very similar to a "hidden Q3ButtonGroup". - - If you use a Q3ButtonGroup, Q3HButtonGroup, or Q3VButtonGroup as - a widget and want to port to Qt 4, you can replace it with - QGroupBox. In Qt 4, radio buttons with the same parent are - automatically part of an exclusive group, so you normally don't - need to do anything else. See also the - \l{#qgroupbox.section}{section on QGroupBox} below. - - See \l{Porting to Qt 4 - Virtual Functions}{Virtual Functions} for - a list of QButtonGroup virtual member functions in Qt 3 that are no - longer virtual in Qt 4. - - \target qbytearray.section - \section1 QByteArray - - In Qt 3, QByteArray was simply a typedef for QMemArray<char>. In - Qt 4, QByteArray is a class in its own right, with a higher-level - API in the style of QString. - - Here are the main issues to be aware of when porting to Qt 4: - - \list 1 - \o The QMemArray(int size) constructor has been replaced with - QByteArray(int size, char ch). The second argument specifies - which character should be used for initializing the array; - pass '\\0' if you have no specific needs. - - \oldcode - QByteArray ba(64); - \newcode - QByteArray ba(64, '\0'); - \endcode - - \o QMemArray::at() returned a non-const reference, whereas the - new QByteArray::at() returns a const value. Code like - - \snippet doc/src/snippets/code/doc_src_porting4.qdoc 1 - - will no longer compile. Instead, use QByteArray::operator[]: - - \snippet doc/src/snippets/code/doc_src_porting4.qdoc 2 - - \o The QMemArray::contains(char) function has been renamed - QByteArray::count(char). In addition, there now exists a - QByteArray::contains(char) function that returns a boolean - value. Replace old calls to contains() with either count() or - contains(), depending on whether you care about the specific - number of occurrences of a character in the byte array or - only care about whether the array contains that character or - not. - - \o The new QByteArray has no assign() function. Calls to - QMemArray::assign(const QMemArray &) can be replaced by calls - to QByteArray::operator=(). Calls to QMemArray::assign(const - T *, uint) have no equivalent in Qt 4; if you use it, the - solution is either to use QByteArray::fromRawData() and to - call free() yourself to avoid a memory leak, or to use the - QByteArray(const char *, int) constructor, which will take a - deep copy of the data. - - \o QMemArray::bsearch() and QMemArray::sort() have no equivalent - in the new QByteArray class. Use \l qBinaryFind() and \l qSort() - if you need that functionality. - \endlist - - QByteArray was an explicitly shared class in Qt 3. See - \l{Explicit Sharing} for more information. - - \target qcache.section - \section1 QCache<T> - - QCache<T> has been renamed Q3Cache<T> and moved to Qt3Support. - The new QCache class has a different API, and takes different - template parameters: QCache<Key, T>. - - When porting to Qt 4, QCache<QString, T> is the obvious - substitute for Q3Cache<T>. The following table summarizes the API - differences. - - \table - \header \o Q3Cache<T> function \o QCache<QString, T> equivalent - \row \o Q3Cache::Q3Cache(int maxCost, int size, bool caseSensitive) \o See remark below - \row \o Q3Cache::autoDelete() \o N/A - \row \o Q3Cache::count() \o QCache::count() or QCache::size() (equivalent) - \row \o Q3Cache::setAutoDelete() \o See remark below - \row \o Q3Cache::size() \o N/A - \row \o Q3Cache::statistics() \o N/A - \row \o Q3Cache::operator=() \o See remark below - \endtable - - Remarks: - - \list 1 - \o Q3Cache requires the user to allocate a specific number of - buckets by passing a prime number (17 by default) to the - constructor. In contrast, the new QCache's hash table - automatically grows and shrinks as needed, and the - constructor doesn't take a prime number. - - \o Q3Cache supportes case-insensitive lookups by passing false as - second argument to the constructor. This feature has no - equivalent in QMultiHash. Instead, call QString::toLower() - before you insert or lookup a key in the hash. - - \o The Q3Cache::insert() function returns a \c bool value that - indicates whether or not the item actually was inserted in - the cache. If the item wasn't inserted, it was the caller's - responsibility to delete the item. The new QCache::insert() - function returns \c void and either adds it to the cache or - deletes it right away. Old code like - - \snippet doc/src/snippets/code/doc_src_porting4.qdoc 3 - - becomes - - \snippet doc/src/snippets/code/doc_src_porting4.qdoc 4 - - \o The new QCache class \e always takes ownership of the items - it stores (i.e. auto-delete is always on). If you use Q3Cache - with auto-delete turned off (the rarely useful default), you - cannot use QCache as a direct substitute. One unelegant trick - that works well in practice is to use QCache<QString, T *> - instead of QCache<QString, T>. In that case, QCache owns the - pointers, not the objects that the pointers refer to. For - example, - - \snippet doc/src/snippets/code/doc_src_porting4.qdoc 5 - - becomes - - \snippet doc/src/snippets/code/doc_src_porting4.qdoc 6 - - An alternative is to stick to using Q3Cache. - \endlist - - QCacheIterator<T> has been renamed Q3CacheIterator<T> and moved - to the Qt3Support library. The new QCache class - doesn't offer any iterator types. - - \section1 QCanvas - - The canvas module classes have been - renamed and moved to the Qt3Support library. - - \table - \header \o Qt 3 class name \o Compatibility class in Qt 4 - \row \o \c QCanvas \o Q3Canvas - \row \o \c QCanvasEllipse \o Q3CanvasEllipse - \row \o \c QCanvasItem \o Q3CanvasItem - \row \o \c QCanvasItemList \o Q3CanvasItemList - \row \o \c QCanvasLine \o Q3CanvasLine - \row \o \c QCanvasPixmap \o Q3CanvasPixmap - \row \o \c QCanvasPixmapArray \o Q3CanvasPixmapArray - \row \o \c QCanvasPolygon \o Q3CanvasPolygon - \row \o \c QCanvasPolygonalItem \o Q3CanvasPolygonalItem - \row \o \c QCanvasRectangle \o Q3CanvasRectangle - \row \o \c QCanvasSpline \o Q3CanvasSpline - \row \o \c QCanvasSprite \o Q3CanvasSprite - \row \o \c QCanvasText \o Q3CanvasText - \row \o \c QCanvasView \o Q3CanvasView - \endtable - - \l{The Graphics View Framework} replaces QCanvas. For more on porting to - Graphics View, see \l{Porting to Graphics View}. - - \section1 QColor - - In Qt 4, QColor is a value type like QPoint or QRect. Graphics - system-specific code has been implemented in QColormap. - - The \c QColor::maxColors() function has been replaced - by QColormap::size(). - - The \c QColor::numBitPlanes() function has been replaced - by QColormap::depth(). - - The \c QColor::setNamedColor() function no longer supports - the named color in the same way as Qt 3. Qt 4's - \l{QColor::}{setNamedColor()} uses the new W3C convention - as stated - \l{http://www.w3.org/TR/SVG/types.html#ColorKeywords}{here}. - - \table - \header \o{4,1} Predefined Qt Colors - \row \o Qt::color0 \o Qt::color1 \o Qt::black \o Qt::white - \row \o Qt::darkGray \o Qt::gray \o Qt::lightGray \o Qt::red - \row \o Qt::green \o Qt::blue \o Qt::cyan \o Qt::magenta - \row \o Qt::yellow \o Qt::darkRed \o Qt::darkGreen \o Qt::darkBlue - \row \o Qt::darkCyan \o Qt::darkMagenta \o Qt::darkYellow \o Qt::transparent - \endtable - - The predefined colors listed in the table above were static - QColor objects in Qt 3. In Qt 4, they are enum values of type - Qt::GlobalColor. Thanks to the implicit QColor(Qt::GlobalColor) - constructor, the enum values are automatically converted to - \l{QColor}s in most contexts. Occasionally, you might need a - cast. - - \oldcode - QColor lightCyan = Qt::cyan.light(180); - \newcode - QColor lightCyan = QColor(Qt::cyan).light(180); - \endcode - - \section1 QColorGroup - - In Qt 3, a QPalette consisted of three QColorGroup objects. In Qt - 4, the (rarely used) QColorGroup abstraction has been eliminated. - For source compatibility, a QColorGroup class is available when - \c QT3_SUPPORT is defined. - - The new QPalette still works in terms of color groups, specified - through enum values (QPalette::Active, QPalette::Disabled, and - QPalette::Inactive). It also has the concept of a \e current - color group, which you can set using - QPalette::setCurrentColorGroup(). - - The QPalette object returned by QWidget::palette() returns a - QPalette initialized with the correct current color group for the - widget. This means that if you had code like - - \badcode - painter.setBrush(colorGroup().brush(QColorGroup::Text)); - \endcode - - you can simply replace colorGroup() with palette(): - - \snippet doc/src/snippets/code/doc_src_porting4.qdoc 7 - - \section1 QColorDrag - - The \c QColorDrag class has been renamed Q3ColorDrag and moved to - the Qt3Support library. In Qt 4, use QMimeData - instead and call QMimeData::setColor() to set the color. - - \section1 QComboBox - - In Qt 3, the list box used to display the contents of a \c QComboBox - widget could be accessed by using the \c listBox() function. In Qt 4, - the standard list box is provided by a QListView widget, and can be - accessed with the \l{QComboBox::view()}{view()} function. - - \omit ### \endomit - - See \l{Porting to Qt 4 - Virtual Functions}{Virtual Functions} for - a list of QComboBox virtual member functions in Qt 3 that are no longer - virtual in Qt 4. - - \section1 QCString - - In Qt 3, QCString inherited from QByteArray. The main drawback - of this approach is that the user had the responsibility of - ensuring that the string is '\\0'-terminated. Another important - issue was that conversions between \c QCString and QByteArray often - gave confusing results. (See the - \l{http://qt.nokia.com/doc/qq/qq05-achtung.html#qcstringisastringofchars}{Achtung! - Binary and Character Data} article in \e{Qt Quarterly} for an - overview of the pitfalls.) - - Qt 4 solves that problem by merging the QByteArray and \c QCString - classes into one class called QByteArray. Most functions that - were in \c QCString previously have been moved to QByteArray. The - '\\0' issue is handled by having QByteArray allocate one extra - byte that it always sets to '\\0'. For example: - - \snippet doc/src/snippets/code/doc_src_porting4.qdoc 8 - - The Qt3Support library contains a class called - Q3CString that inherits from the new QByteArray class and that - extends it to provide an API that is as close to the old \c QCString - class as possible. Note that the following functions aren't - provided by Q3CString: - - \list - \o QCString::find(const QRegExp &, int) - \o QCString::findRev(const QRegExp &, int) - \o QCString::contains(const QRegExp &) - \o QCString::replace(const QRegExp &, const char *) - \endlist - - The following functions have lost their last parameter, which - specified whether the search was case sensitive or not: - - \list - \o QByteArray::find(char, int) - \o QByteArray::find(const char *, int) - \o QByteArray::findRev(char, int) - \o QByteArray::findRev(const char *, int) - \o QByteArray::contains(char) - \o QByteArray::contains(const char *) - \endlist - - In both cases, the solution is to convert the \c QCString to a - QString and use the corresponding QString functions instead. - - Also be aware that \c QCString::size() (inherited from - QByteArray) used to return the size of the character data \e - including the '\\0'-terminator, whereas the new - QByteArray::size() is just a synonym for QByteArray::length(). - This brings QByteArray in line with QString. - - When porting to Qt 4, occurrences of \c QCString should be - replaced with QByteArray or QString. The following table - summarizes the API differences between the Q3CString - class and the Qt 4 QByteArray and QString classes: - - \table - \header \o Q3CString function \o Qt 4 equivalent - \row \o Q3CString::Q3CString(const char *, uint) \o See remark below - \row \o Q3CString::Q3CString(int) \o QByteArray::QByteArray(int, char) - \row \o Q3CString::leftJustify() \o QString::leftJustified() - \row \o Q3CString::length() \o QByteArray::length() or QByteArray::size() (equivalent) - \row \o Q3CString::lower() \o QByteArray::toLower() - \row \o Q3CString::rightJustify() \o QString::rightJustified() - \row \o Q3CString::setExpand() \o See remark below - \row \o Q3CString::simplifyWhiteSpace() \o QByteArray::simplified() - \row \o Q3CString::sprintf() \o QString::sprintf() - \row \o Q3CString::stripWhiteSpace() \o QByteArray::trimmed() - \row \o Q3CString::toDouble() \o QString::toDouble() - \row \o Q3CString::toFloat() \o QString::toFloat() - \row \o Q3CString::toInt() \o QString::toInt() - \row \o Q3CString::toLong() \o QString::toLong() - \row \o Q3CString::toShort() \o QString::toShort() - \row \o Q3CString::toUInt() \o QString::toUInt() - \row \o Q3CString::toULong() \o QString::toULong() - \row \o Q3CString::toUShort() \o QString::toUShort() - \row \o Q3CString::upper() \o QByteArray::toUpper() - \endtable - - Remarks: - - \list 1 - \o Q3CString(const char *str, uint max) constructs a string of - length strlen(str) or \e max - 1, whichever is shorter. - QByteArray(const char *data, int size) constructs a byte - array containing exactly \e size bytes. - - \oldcode - QCString str1("Hello", 4); // "Hel" - QCString str2("Hello world!", n); - \newcode - QByteArray str1("Hello", 3); - QByteArray str2("Hello world!"); - str2.truncate(n - 1); - \endcode - - \o Q3CString::setExpand(uint index, char ch) has no equivalent in - Qt 4. - - \oldcode - QCString str("Hello world"); - str.setExpand(16, '\n'); // "Hello world \n" - \newcode - QByteArray str("Hello world"); - while (str.size() < 16) - str += ' '; - str += '\n'; - \endcode - \endlist - - Since the old \c QCString class inherited from QByteArray, - everything that is said in the \l{#qbytearray.section}{QByteArray - section} applies for \c QCString as well. - - \section1 QCustomEvent - - In Qt 3, developers could create a custom event by constructing - a new QCustomEvent, and send relevant data to other components in - the application by passing a void pointer, either on construction or - using the setData() function. Objects could receive custom events - by reimplementing the \l{QObject::customEvent()}{customEvent()} - function, and access the stored data using the event's data() - function. - - In Qt 4, custom events are created by subclassing - QEvent. Event-specific data can be stored in a way that is - appropriate for your application. Custom events are still - delivered to each object's - \l{QObject::customEvent()}{customEvent()} handler function, but as - QEvent objects rather than as deprecated QCustomEvent objects. - - \section1 QDataBrowser - - The \c QDataBrowser class has been renamed Q3DataBrowser and - moved to the Qt3Support library. In Qt 4.2, you should use the - QDataWidgetMapper class to create data-aware forms. - - See \l{QtSql Module} for an overview of the new SQL - classes. - - \section1 QDataPump - - The \c QDataPump class was used internally in Qt 2.x in - conjunction with QImageConsumer. It was obsoleted in Qt 3.0. - - \input porting4-obsoletedmechanism.qdocinc - - \section1 QDataSink - - The \c QDataSink class was used internally in Qt 2.x in conjunction - with QImageConsumer. It was obsoleted in Qt 3.0. - - \input porting4-obsoletedmechanism.qdocinc - - \section1 QDataSource - - The \c QDataSource class was used internally in Qt 2.x in - conjunction with QImageConsumer. It was obsoleted in Qt 3.0. - \input porting4-obsoletedmechanism.qdocinc - - \section1 QDataTable - - The \c QDataTable class has been renamed Q3DataTable and moved to - the Qt3Support library. In Qt 4.2, you should use the - QDataWidgetMapper class to create data-aware forms. - - See \l{QtSql Module} for an overview of the new SQL classes. - - \section1 QDataView - - The \c QDataView class has been renamed Q3DataView and moved to - the Qt3Support library. In Qt 4.2, you should use the - QDataWidgetMapper class to create data-aware forms. - - See \l{QtSql Module} for an overview of the new SQL classes. - - \section1 QDateEdit - - The QDateEdit class in Qt 4 is a convenience class based on - QDateTimeEdit. The old class has been renamed Q3DateEdit and moved - to the Qt3Support library. - - See \l{Porting to Qt 4 - Virtual Functions}{Virtual Functions} for - a list of \c QDateEdit virtual member functions in Qt 3 that are - no longer virtual in Qt 4. - - \section1 QDateTimeEditBase - - The \c QDateTimeEditBase class has been renamed - Q3DateTimeEditBase and moved to Qt3Support. Use QDateTimeEdit or - QAbstractSpinBox instead. - - \section1 QDateTimeEdit - - The old \c QDateTimeEdit class has been renamed - Q3DateTimeEditBase and moved to Qt3Support. The new QDateTimeEdit - in Qt 4 has been rewritten from scratch to provide a more - flexible and powerful API. - - See \l{Porting to Qt 4 - Virtual Functions}{Virtual Functions} for - a list of QDateTimeEdit virtual member functions in Qt 3 that are no - longer virtual in Qt 4. - - \section1 QDeepCopy<T> - - The \c QDeepCopy<T> class in Qt 3 provided a means of ensuring that - implicitly shared and explicitly shared classes referenced unique - data. This was necessary because the reference counting in Qt's - container classes was done in a thread-unsafe manner. - - With Qt 4, \c QDeepCopy<T> has been renamed Q3DeepCopy<T> and - moved to the Qt3Support library. Removing it from - existing code is straightforward. - - \oldcode - QString str1 = "I am a string"; - QDeepCopy<QString> str2 = str1; - QString str3 = QDeepCopy<QString>(str2); - \newcode - QString str1 = "I am a string"; - QString str2 = str1; - QString str3 = str2; - \endcode - - \section1 QDial - - See \l{Porting to Qt 4 - Virtual Functions}{Virtual Functions} for - a list of QDial virtual member functions in Qt 3 that are no longer - virtual in Qt 4. - - See \l{#properties}{Properties} for a list of QDial properties in - Qt 3 that have changed in Qt 4. - - \target qdict.section - \section1 QDict<T> - - \c QDict<T> has been renamed Q3Dict<T> and moved to Qt3Support. - It has been replaced by the more modern QHash<Key, T> and - QMultiHash<Key, T> classes. - - When porting old code that uses QDict<T> to Qt 4, there are four - classes that you can use: - - \table - \header \o Qt 4 class \o When to use it - \row \o QMultiHash<QString, T *> - - \o Since Q3Dict<T> is pointer-based and allows duplicate - keys, this is usually the most straightforward conversion. - - \row \o QMultiHash<QString, T> - - \o If type \c T is an \l{assignable data type}, you can use - \c T as the value type rather than \c{T *}. This often - leads to nicer code. - - \row \o QHash<QString, T *> - - \o{1,2} If you don't use duplicate keys, you can use QHash - instead of QMultiHash. QMultiHash inherits from QHash. - - \row \o QHash<QString, T> - \endtable - - The APIs of Q3Dict<T> and QMultiHash<QString, T *> are quite - similar. The main issue is that Q3Dict supports auto-delete - whereas QMultiHash doesn't. - - \omit - (See \l{What's Wrong with - Auto-Delete} for an explanation of why the Qt 4 containers don't - offer that feature.) - \endomit - - The following table summarizes the API differences between the - two classes: - - \table - \header \o Q3Dict function \o QMultiHash equivalent - \row \o Q3Dict::Q3Dict(int size, bool caseSensitive) \o See remarks below - \row \o Q3Dict::autoDelete() \o N/A - \row \o Q3Dict::count() \o QMultiHash::count() or QMultiHash::size() (equivalent) - \row \o Q3Dict::find(const QString &) \o QMultiHash::value(const QString &) - \row \o Q3Dict::remove(const QString &) \o QMultiHash::take(const QString &) - \row \o Q3Dict::resize(uint) \o QMultiHash::reserve(int) - \row \o Q3Dict::setAutoDelete() \o See discussion below - \row \o Q3Dict::size() \o QMultiHash::capacity() - \row \o Q3Dict::statistics() \o N/A - \row \o Q3Dict::operator[](const QString &) \o See remark below - \endtable - - Remarks: - - \list 1 - \o Q3Dict requires the user to allocate a specific number of - buckets by passing a prime number (17 by default) to the - constructor and/or calling Q3Dict::resize() later on. In - contrast, QMultiHash's hash table automatically grows and - shrinks as needed, and the constructor doesn't take a prime - number. - - \o Q3Dict supportes case-insensitive lookups by passing false as - second argument to the constructor. This feature has no - equivalent in QMultiHash. Instead, call QString::toLower() - before you insert or lookup a key in the hash. - - \o Q3Dict::size() and QMultiHash::size() have different semantics. - The former returns the number of buckets in the container, whereas - the latter returns the number of \e items in the container. - - \o If there are multiple items with the same key, - Q3Dict::remove() removes only the most recently inserted item, - whereas QMultiHash::remove() removes all items that share a - particular key. To remove only the most recently inserted item, - call QMultiHash::take(). - - \o Q3Dict has only one [] operator (Q3Dict::operator[]()), - providing const access to an item's value. QMultiHash also - has a non-const overload that can be used on the left side of - the assignment operator. If you use the [] operator on a - non-const QHash with an unexisting item, QHash will created - an element and initialize it to be a null pointer. For that - reason, Q3Dict::operator[] should be converted to - QMultiHash::value(), not QMultiHash::operator[]. - - \endlist - - If you use Q3Dict's auto-delete feature (by calling - Q3Dict::setAutoDelete(true)), you need to do some more work. You - have two options: Either you call \c delete yourself whenever you - remove an item from the container, or you use - QMultiHash<QString, T> instead of QMultiHash<QString, T *> (i.e. - store values directly instead of pointers to values). Here, we'll - see when to call \c delete. - - The following table summarizes the idioms that you need to watch - out for if you want to call \c delete yourself. - - \table - \header \o Q3Dict idiom \o QMultiHash idiom - \row - \o - \snippet doc/src/snippets/code/doc_src_porting4.qdoc 9 - \o - \snippet doc/src/snippets/code/doc_src_porting4.qdoc 10 - \row - \o - \snippet doc/src/snippets/code/doc_src_porting4.qdoc 11 - \o - \snippet doc/src/snippets/code/doc_src_porting4.qdoc 12 - \row - \o - \snippet doc/src/snippets/code/doc_src_porting4.qdoc 13 - - (also called from Q3Dict's destructor) - - \o - \snippet doc/src/snippets/code/doc_src_porting4.qdoc 14 - - In 99% of cases, the following idiom also works: - - \snippet doc/src/snippets/code/doc_src_porting4.qdoc 15 - - However, it may lead to crashes if \c hash is referenced from - the value type's destructor, because \c hash contains - dangling pointers until clear() is called. - \endtable - - Be aware that Q3Dict's destructor automatically calls clear(). If - you have a Q3Dict data member in a custom class and use the - auto-delete feature, you will need to call \c delete on all the - items in the container from your class destructor to avoid a - memory leak. - - Finally, \c QDictIterator<T> (renamed Q3DictIterator<T>) must - also be ported. There are no fewer than four iterator classes - that can be used as a replacement: QHash::const_iterator, - QHash::iterator, QHashIterator, and QMutableHashIterator. The - most straightforward class to use when porting is - QHashIterator<QString, T *>. The following table summarizes the - API differences: - - \table - \header \o Q3DictIterator functions \o Qt 4 equivalent - \row \o Q3DictIterator::count() \o QHash::count() or QHash::size() - \row \o Q3DictIterator::current() \o QHashIterator::value() - \row \o Q3DictIterator::currentKey() \o QHashIterator::key() - \row \o Q3DictIterator::isEmpty() \o QHash::isEmpty() - \row \o Q3DictIterator::toFirst() \o QHashIterator::toFront() - \row \o Q3DictIterator::operator()() \o QHashIterator::value() - \row \o Q3DictIterator::operator*() \o QHashIterator::value() - \row \o Q3DictIterator::operator++() \o See remark below - \endtable - - Be aware that QHashIterator has a different way of iterating than - Q3DictIterator. A typical loop with Q3DictIterator looks like this: - - \snippet doc/src/snippets/code/doc_src_porting4.qdoc 16 - - Here's the equivalent QHashIterator loop: - - \snippet doc/src/snippets/code/doc_src_porting4.qdoc 17 - - See \l{Java-style iterators} for details. - - \section1 QDir - - The following functions used to have a boolean \c{acceptAbsPath} - parameter that defaulted to true: - - \list - \i QDir::filePath() - \i QDir::absFilePath() - \i QDir::cd() - \i QDir::mkdir() - \i QDir::rmdir() - \i QDir::remove() - \i QDir::rename() - \i QDir::exists() - \endlist - - In Qt 3, if \c acceptAbsPath is true, a file name starting with - '/' is be returned without change; if \c acceptAbsPath is false, - an absolute path is prepended to the file name. For example: - - \table - \header \i Current directory \i File name \i \c acceptAbsPath \i File path - \row \i{1,2} /home/tsmith \i{1,2} index.html \i true \i /home/tsmith/index.html - \row \i false \i /home/tsmith/index.html - \row \i{1,2} /home/tsmith \i{1,2} /index.html \i true \i /index.html - \row \i false \i /home/tsmith/index.html - \endtable - - In Qt 4, this parameter is no longer available. If you use it - in your code, you can check that QDir::isRelativePath() returns - false instead. - - \oldcode - QDir dir("/home/tsmith"); - QString path = dir.filePath(fileName, false); - \newcode - QDir dir("/home/tsmith"); - QString path; - if (dir.isRelativePath(fileName)) - path = dir.filePath(fileName); - else - path = fileName; - \endcode - - QDir::encodedEntryList() has been removed. - - fileInfoList(), entryInfoList(), and drives() now return a QList<QFileInfo> - and not a QPtrList<QFileInfo> *. Code using these methods will not work with - the Qt3Support library and must be adapted instead. - - See \l{Porting to Qt 4 - Virtual Functions}{Virtual Functions} for - a list of QDir virtual member functions in Qt 3 that are no longer - virtual in Qt 4. - - QDir::match() now always matches case insensitively. - - QDir::homeDirPath() has been removed. Use QDir::home() instead, and - extract the path separately. - - \section1 QDns - - Qt 3 used its own implementation of the DNS protocol and provided - a low-level \c QDns class. Qt 4's QHostInfo class uses the system's \c - gethostbyname() function from a thread instead. - - The old \c QDns class has been renamed Q3Dns and moved to the - Qt3Support library. The new QHostInfo class has a - radically different API: It consists mainly of two static - functions, one of which is blocking (QHostInfo::fromName()), the - other non-blocking (QHostInfo::lookupHost()). See the QHostInfo - class documentation for details. - - \section1 QDockArea - - The \c QDockArea class has been renamed Q3DockArea and moved to - the Qt3Support library. In Qt 4, QMainWindow handles - the dock and toolbar areas itself. See the QMainWindow - documentation for details. - - \section1 QDockWindow - - The old \c QDockWindow class has been renamed Q3DockWindow and - moved to the Qt3Support library. In Qt 4, there is a - new QDockWidget class with a different API. See the class - documentation for details. - - See \l{Porting to Qt 4 - Virtual Functions}{Virtual Functions} for - a list of QDockWidget virtual member functions in Qt 3 that are no - longer virtual in Qt 4. - - \note \l{Q3DockWindow}'s - \l{Q3DockWindow::setHorizontallyStretchable()}{horizontallyStretchable} - property can be achieved in QDockWidget with - \l{QWidget#Size Hints and Size Policies}{size policies}. - - \section1 QDragObject - - The \c QDragObject class has been renamed Q3DragObject and - moved to the Qt3Support library. In Qt 4, it has been - replaced by the QMimeData class. See the class documentation for - details. - - Note that the Q3DragObject::DragCopyOrMove drag and drop mode is - interpreted differently to Qt 3's QDragObject::DragCopyOrMove mode. - In Qt 3, a move operation was performed by default, and the user had - to hold down the \key{Ctrl} key to perform a copy operation. - In Qt 4, a copy operation is performed by default; the user has to - hold down the \key{Shift} key to perform a move operation. - - See \l{Porting to Qt 4 - Drag and Drop} for a comparison between - the drag and drop APIs in Qt 3 and Qt 4. - - \section1 QDropSite - - The \c QDropSite class has been renamed Q3DropSite and moved to - the Qt3Support library. - - The QDropSite class has been obsolete ever since Qt 2.0. The only - thing it does is call QWidget::setAcceptDrops(true). - - \oldcode - class MyWidget : public QWidget, public QDropSite - { - public: - MyWidget(const QWidget *parent) - : QWidget(parent), QDropSite(this) - { - } - ... - } - \newcode - class MyWidget : public QWidget - { - public: - MyWidget(const QWidget *parent) - : QWidget(parent) - { - setAcceptDrops(true); - } - ... - } - \endcode - - See \l{Porting to Qt 4 - Drag and Drop} for a comparison between - the drag and drop APIs in Qt 3 and Qt 4. - - \section1 QEditorFactory - - The \c QEditorFactory class has been renamed Q3EditorFactory and - moved to the Qt3Support library. - - See \l{QtSql Module} for an overview of the new SQL classes. - - \section1 QEventLoop - - In Qt 3, \c QEventLoop combined the Qt event loop and the event - dispatching. In Qt 4, these tasks are now assigned to two - distinct classes: QEventLoop and QAbstractEventDispatcher. - - If you subclassed QEventLoop to integrate with another library's - event loop, you must subclass QAbstractEventDispatcher instead. See - the class documentation for details. - - Developers using \c{QEventLoop::loopLevel()} in Qt 3 should use - QCoreApplication::loopLevel() instead. Note that this function is - marked as obsolete, but it is expected to be available for the - lifetime of Qt 4. - \omit ### mention virtual functions that aren't virtual anymore \endomit - - \omit - \section1 QFile - - The QFile::readLine(QString&, Q_ULONG) method from qt3 has been removed - in qt4, but this change in the QFile interface is not documented in the - porting documentation as of qt-4.0.0-b1. - \endomit - - \section1 QFileDialog - - The QFileDialog class in Qt 4 has been totally rewritten. It - provides most of the functionality of the old \c QFileDialog - class, but with a different API. Some functionality, such as the - ability to preview files, is expected to be added in a later Qt 4 - release. - - The old \c QFileDialog, \c QFileIconProvider, and \c QFilePreview - classes has been renamed Q3FileDialog, Q3FileIconProvider, and - Q3FilePreview and have been moved to Qt3Support. You can use them - if you need some functionality not provided yet by the new - QFileDialog class. - - The following table lists which functions have been renamed or - removed in Qt 4. - - \table - \header \o Old function \o Qt 4 equivalent - \row \o Q3FileDialog::addFilter(const QString &) \o See remark below - \row \o Q3FileDialog::addLeftWidget(QWidget *) \o N/A - \row \o Q3FileDialog::addRightWidget(QWidget *) \o N/A - \row \o Q3FileDialog::addToolButton(QAbstractButton *, bool separator) \o N/A - \row \o Q3FileDialog::addWidgets(QLabel *, QWidget *, QPushButton *) \o N/A - \row \o Q3FileDialog::dir() \o QFileDialog::directory() - \row \o Q3FileDialog::dirPath() \o QFileDialog::directory().path() - \row \o Q3FileDialog::iconProvider() \o N/A - \row \o Q3FileDialog::isContentsPreviewEnabled() \o N/A - \row \o Q3FileDialog::isInfoPreviewEnabled() \o N/A - \row \o Q3FileDialog::previewMode() \o N/A - \row \o Q3FileDialog::rereadDir() \o N/A - \row \o Q3FileDialog::resortDir() \o N/A - \row \o Q3FileDialog::selectAll(bool) \o N/A - \row \o Q3FileDialog::setContentsPreview(QWidget *, Q3FilePreview *) \o N/A - \row \o Q3FileDialog::setContentsPreviewEnabled(bool) \o N/A - \row \o Q3FileDialog::setDir(const QString &) \o QFileDialog::setDirectory(const QString &) - \row \o Q3FileDialog::setFilters(const char **) \o Q3FileDialog::setFilters(const QStringList &) - \row \o Q3FileDialog::setIconProvider(Q3FileIconProvider *) \o N/A - \row \o Q3FileDialog::setInfoPreview(QWidget *, Q3FilePreview *) \o N/A - \row \o Q3FileDialog::setInfoPreviewEnabled(bool) \o N/A - \row \o Q3FileDialog::setPreviewMode(PreviewMode) \o N/A - \row \o Q3FileDialog::setSelectedFilter(const QString &) \o QFileDialog::selectFilter(const QString &) - \row \o Q3FileDialog::setSelectedFilter(int) \o See remark below - \row \o Q3FileDialog::setSelection(const QString &) \o QFileDialog::selectFile(const QString &) - \row \o Q3FileDialog::setShowHiddenFiles(bool) \o showHidden() - \row \o Q3FileDialog::setUrl(const QUrlOperator &) \o N/A - \row \o Q3FileDialog::showHiddenFiles() \o N/A - \row \o Q3FileDialog::url() \o QUrl::fromLocalFile(QFileDialog::directory()) - \header \o Old signals \o Qt 4 equivalent - \row \o Q3FileDialog::fileHighlighted(const QString &) \o N/A - \row \o Q3FileDialog::fileSelected(const QString &) \o QFileDialog::filesSelected(const QStringList &) - \row \o Q3FileDialog::dirEntered(const QString &) \o N/A - \row \o Q3FileDialog::filterSelected(const QString &) \o N/A - \endtable - - Remarks: - - \list 1 - \o The Q3FileDialog::addFilter(const QString &) function has no - direct equivalent in the new QFileDialog. Use - QFileDialog::setFilters() instead. - - \oldcode - fileDialog->addFilter(tr("JPEG files (*.jpg *.jpeg)")); - \newcode - QStringList filters = fileDialog->filters(); - filters << tr("JPEG files (*.jpg *.jpeg)"); - fileDialog->setFilters(filters); - \endcode - - \o The Q3FileDialog::setSelectedFilter(int) overload has no direct - equivalent in the new QFileDialog. Use - QFileDialog::selectFilter(const QString &) instead. - - \oldcode - fileDialog->setSelectedFilter(3); - \newcode - fileDialog->selectFilter(fileDialog->filters().at(3)); - \endcode - \endlist - - There are no equivalent virtual functions to the two - Q3FileDialog::setSelectedFilter() virtual functions in the QFileDialog - API. In addition, these functions have been renamed or removed, as - described above. - - \section1 QFocusData - - The QFocusData class is not available in Qt 4. Some of its - functionality is available via the QWidget::nextInFocusChain() - and QWidget::focusNextPrevChild() functions. - - \section1 QFocusEvent - - The setReason() function is no longer present in Qt 4. It is - necessary to define the reason when constructing a focus event. - - \section1 QFont - - \c QFont::Script has been moved to QFontDatabase::WritingSystem. - - \section1 QFrame - - The QFrame class has been made more lightweight in Qt 4, by - reducing the number of properties and virtual functions. The - reduction in the number of virtual functions is significant - because QFrame is the base class of many Qt classes. - - Here's an overview of the changes: - - \list - \o QFrame no longer has a \c margin property (which wasn't - honored by Qt's layout managers anyway). - - \o QFrame no longer has a frameChanged() function, reimplement - QFrame::resizeEvent() instead. - - \o QFrame used to have drawFrame(QPainter *) and - drawContents(QPainter *) virtual functions. These are now - gone. In Qt 4, the frame is drawn by the QFrame::paintEvent() - function. If you want to change the way QFrame paints itself, - reimplement this function. To draw the contents of the frame, - reimplement QFrame:paintEvent() and call the base class - implementation of the function before you use the - \l {QWidget::}{contentsRect()} function inherited from QWidget, - to retrieve the rectangle to paint on. - - \endlist - - To help with porting, the Qt3Support library contains a Q3Frame - class that inherits QFrame and provides a similar API to the old - QFrame class. If you derived from QFrame in your application, you - might want to use Q3Frame as a base class as a first step in the - porting process, and later move on to the new QFrame class. - - See \l{Porting to Qt 4 - Virtual Functions}{Virtual Functions} for - a list of QFrame virtual member functions in Qt 3 that are no longer - virtual in Qt 4. - - \section1 QFtp - - QFtp no longer inherits from QNetworkProtocol. See the - \l{#qnetworkprotocol.section}{section on QNetworkProtocol} for - details. - - The old \c QFtp class has been renamed Q3Ftp and moved to the - Qt3Support library. - - \target qglayoutiterator.section - \section1 QGLayoutIterator - - The QGLayoutIterator class no longer exists in Qt 4. This makes - only a difference if you implemented custom layout managers - (i.e., QLayout subclasses). - - The new approach is much simpler: It consists in reimplementing - QLayout::itemAt() and QLayout::takeAt(). These functions operate - on indexes, eliminating the need for a layout iterator class. - - \section1 QGrid - - The \c QGrid class is now only available as Q3Grid in Qt 4. You - can achieve the same result as \c QGrid by creating a QWidget - with a grid layout: - - \oldcode - QGrid *grid = new QGrid(2, Qt::Horizontal); - QPushButton *child1 = new QPushButton(grid); - QPushButton *child2 = new QPushButton(grid); - QPushButton *child3 = new QPushButton(grid); - QPushButton *child4 = new QPushButton(grid); - \newcode - QWidget *grid = new QWidget; - QPushButton *child1 = new QPushButton(grid); - QPushButton *child2 = new QPushButton(grid); - QPushButton *child3 = new QPushButton(grid); - QPushButton *child4 = new QPushButton(grid); - - QVBoxLayout *layout = new QVBoxLayout; - layout->addWidget(child1, 0, 0); - layout->addWidget(child2, 0, 1); - layout->addWidget(child3, 1, 0); - layout->addWidget(child4, 1, 1); - grid->setLayout(layout); - \endcode - - \section1 QGridLayout - - See \l{Porting to Qt 4 - Virtual Functions}{Virtual Functions} for - a list of QGridLayout virtual member functions in Qt 3 that are no - longer virtual in Qt 4. - - \section1 QGridView - - The \c QGridView class has been renamed Q3GridView and moved to - the Qt3Support library. In Qt 4, we recommend that - you use QTableView or QAbstractItemView for presenting tabular - data. - - See \l{Model/View Programming} for an overview of the new item - view classes. - - \target qgroupbox.section - \section1 QGroupBox - - The QGroupBox class has been redesigned in Qt 4. Many of the - features of the old \c QGroupBox class can be obtained by using - the Q3GroupBox class from the Qt3Support library. - - The new QGroupBox is more lightweight. It doesn't attempt to - duplicate functionality already provided by QGridLayout, and it - does not inherit from QFrame. As a result, the following members - have been removed: - - \list - \o Q3GroupBox::setColumns(), Q3GroupBox::columns() - \o Q3GroupBox::setOrientation(), Q3GroupBox::orientation() - \o Q3GroupBox::setInsideMargin(), Q3GroupBox::insideMargin() - \o Q3GroupBox::addSpace() - \endlist - - Naturally, the \c columns and \c orientation properties have also - been removed. - - If you rely on some of the missing functionality in your - application, you can use Q3GroupBox instead of QGroupBox as a - help to porting. - - See \l{Porting to Qt 4 - Virtual Functions}{Virtual Functions} for - a list of QGroupBox virtual member functions in Qt 3 that are no - longer virtual in Qt 4. - - \section1 QHBox - - The \c QHBox class is now only available as Q3HBox in Qt 4. You - can achieve the same result as \c QHBox by creating a QWidget - with an horizontal layout: - - \oldcode - QHBox *hbox = new QHBox; - QPushButton *child1 = new QPushButton(hbox); - QPushButton *child2 = new QPushButton(hbox); - \newcode - QWidget *hbox = new QWidget; - QPushButton *child1 = new QPushButton; - QPushButton *child2 = new QPushButton; - - QHBoxLayout *layout = new QHBoxLayout; - layout->addWidget(child1); - layout->addWidget(child2); - hbox->setLayout(layout); - \endcode - - Note that child widgets are not automatically placed into the widget's - layout; you will need to manually add each widget to the QHBoxLayout. - - \section1 QHeader - - The \c QHeader class has been renamed Q3Header and moved to - the Qt3Support library. In Qt 4, it is replaced - by the QHeaderView class. - - See \l{Model/View Programming} for an overview of the new item - view classes. - - \section1 QHGroupBox - - The \c QHGroupBox class has been renamed Q3HGroupBox and moved to - the Qt3Support library. - Qt 4 does not provide a specific replacement class for \c QHGroupBox - since QGroupBox is designed to be a generic container widget. As a - result, you need to supply your own layout for any child widgets. - - See \l{#QGroupBox} for more information about porting code that uses - group boxes. - - \section1 QHttp - - QHttp no longer inherits from QNetworkProtocol. See the See the - \l{#qnetworkprotocol.section}{section on QNetworkProtocol} for - details. - - The old \c QHttp, \c QHttpHeader, \c QHttpRequestHeader, and \c - QHttpResponseHeader classes have been renamed Q3Http, - Q3HttpHeader, Q3HttpRequestHeader, and Q3HttpResponseHeader and - have been moved to the Qt3Support library. - - \section1 QIconFactory - - The QIconFactory class is no longer part of Qt. It has been replaced by - the QIconEngine class. - - \section1 QIconSet - - The QIconSet class is no longer part of Qt. It has been replaced by - the QIcon class. - - \section1 QIconView - - The \c QIconView, \c QIconViewItem, \c QIconDrag, and \c - QIconDragItem classes has been renamed Q3IconView, - Q3IconViewItem, Q3IconDrag, and Q3IconDragItem and moved to the - Qt3Support library. New Qt applications should use - QListWidget or its base class QListView instead, and call - QListView::setViewMode(QListView::IconMode) to obtain an "icon - view" look. - - See \l{Model/View Programming} for an overview of the new item - view classes. - - \omit - ### - - \section1 QImage - - QImage::fromMimeSource(const QString &) -> qImageFromMimeSource(const QString &) - \endomit - - \section1 QImageDrag - - The \c QImageDrag class has been renamed Q3ImageDrag and moved to - the Qt3Support library. In Qt 4, use QMimeData - instead and call QMimeData::setImage() to set the image. - - See \l{Porting to Qt 4 - Drag and Drop} for a comparison between - the drag and drop APIs in Qt 3 and Qt 4. - - \section1 QImageIO - - The \c QImageIO class has been split into two classes: - QImageReader and QImageWriter. The table below shows the - correspondance between the two APIs: - - \table - \header \o Qt 3 function \o Qt 4 equivalents - \row \o QImageIO::description() \o QImageWriter::text() - \row \o QImageIO::fileName() \o QImageReader::fileName() and QImageWriter::fileName() - \row \o QImageIO::format() \o QImageReader::format() and QImageWriter::format() - \row \o QImageIO::gamma() \o QImageWriter::gamma() - \row \o QImageIO::image() \o Return value of QImageReader::read() - \row \o QImageIO::inputFormats() \o QImageReader::supportedImageFormats() - \row \o QImageIO::ioDevice() \o QImageReader::device() and QImageWriter::device() - \row \o QImageIO::outputFormats() \o QImageWriter::supportedImageFormats() - \row \o QImageIO::parameters() \o N/A - \row \o QImageIO::quality() \o QImageWriter::quality() - \row \o QImageIO::read() \o QImageReader::read() - \row \o QImageIO::setDescription() \o QImageWriter::setText() - \row \o QImageIO::setFileName() \o QImageReader::setFileName() and QImageWriter::setFileName() - \row \o QImageIO::setFormat() \o QImageReader::setFormat() and QImageWriter::setFormat() - \row \o QImageIO::setGamma() \o QImageWriter::setGamma() - \row \o QImageIO::setIODevice() \o QImageReader::setDevice() and QImageWriter::setDevice() - \row \o QImageIO::setImage() \o Argument to QImageWriter::write() - \row \o QImageIO::setParameters() \o N/A - \row \o QImageIO::setQuality() \o QImageWriter::setQuality() - \row \o QImageIO::setStatus() \o N/A - \row \o QImageIO::status() \o QImageReader::error() and QImageWriter::error() - \row \o QImageIO::write() \o QImageWriter::write() - \endtable - - \section1 QIntCache<T> - - QIntCache<T> has been moved to Qt3Support. It has been replaced - by QCache<int, T>. - - For details, read the \l{#qcache.section}{section on QCache<T>}, - mentally substituting \c int for QString. - - \section1 QIntDict<T> - - QIntDict<T> and QIntDictIterator<T> have been moved to - Qt3Support. They have been replaced by the more modern QHash<Key, - T> and QMultiHash<Key, T> classes and their associated iterator - classes. - - When porting old code that uses QIntDict<T> to Qt 4, there are - four classes that you can use: - - \list - \o QMultiHash<int, T *> - \o QMultiHash<int, T> - \o QHash<int, T *> - \o QHash<int, T> - \endlist - - For details, read the \l{#qdict.section}{section on QDict<T>}, - mentally substituting \c int for QString. - - \target qiodevice.section - \section1 QIODevice - - The QIODevice class's API has been simplified to make it easier - to subclass and to make it work more smoothly with asynchronous - devices such as QTcpSocket and QProcess. - - The following virtual functions have changed name or signature: - - \table - \header \o Qt 3 function \o Comment - \row \o QIODevice::at() const \o Renamed QIODevice::pos(). - \row \o QIODevice::at(Offset) \o Renamed QIODevice::seek(). - \row \o QIODevice::open(int) \o The parameter is now of type QIODevice::OpenMode. - \row \o QIODevice::readBlock(char *, Q_ULONG) \o QIODevice::read(char *, qint64) - \row \o QIODevice::writeBlock(const char *, Q_ULONG) \o QIODevice::write(const char *, qint64) - \endtable - - \note QIODevice::open(QIODevice::OpenMode) is no longer pure virtual. - - The following functions are no longer virtual or don't exist anymore: - - \table - \row \o QIODevice::getch() \o Renamed QIODevice::getChar() and implemented in terms of QIODevice::readData(). - \row \o QIODevice::putch(int) \o Renamed QIODevice::putChar() and implemented in terms of QIODevice::writeData(). - \row \o QIODevice::readAll() \o Implemented in terms of QIODevice::readData(). - \row \o QIODevice::readLine(char *, Q_ULONG) \o Implemented in terms of QIODevice::readData() - \row \o QIODevice::ungetch(int) \o Renamed QIODevice::ungetChar() and simulated using an internal unget buffer. - \endtable - - The \c IO_xxx flags have been revised, and the protected setFlags() - function removed. Most of the flags have been - eliminated because errors are best handled by implementing certain - functions in QIODevice subclasses rather than through the base classes. - The file access flags, such as \c IO_ReadOnly and \c IO_WriteOnly, have - been moved to the QIODevice class to avoid polluting the global - namespace. The table below shows the correspondence between the - Qt 3 \c IO_xxx flags and the Qt 4 API: - - \table - \header \o Qt 3 constant \o Qt 4 equivalent - \row \o IO_Direct \o Use !QIODevice::isSequential() instead (notice the \e not). - \row \o IO_Sequential \o Use QIODevice::isSequential() instead. - \row \o IO_Combined \o N/A - \row \o IO_TypeMask \o N/A - \row \o IO_Raw \o QIODevice::Unbuffered - \row \o IO_Async \o N/A - \row \o IO_ReadOnly \o QIODevice::ReadOnly - \row \o IO_WriteOnly \o QIODevice::WriteOnly - \row \o IO_ReadWrite \o QIODevice::ReadWrite - \row \o IO_Append \o QIODevice::Append - \row \o IO_Truncate \o QIODevice::Truncate - \row \o IO_Translate \o QIODevice::Text - \row \o IO_ModeMask \o N/A - \row \o IO_Open \o Use QIODevice::isOpen() instead. - \row \o IO_StateMask \o N/A - \row \o IO_Ok \o N/A - \row \o IO_ReadError \o N/A - \row \o IO_WriteError \o N/A - \row \o IO_FatalError \o N/A - \row \o IO_ResourceError \o N/A - \row \o IO_OpenError \o N/A - \row \o IO_ConnectError \o N/A - \row \o IO_AbortError \o N/A - \row \o IO_TimeOutError \o N/A - \row \o IO_UnspecifiedError \o N/A - \endtable - - \section1 QIODeviceSource - - The QIODeviceSource class was used internally in Qt 2.x in - conjunction with QImageConsumer. It was obsoleted in Qt 3.0. - \input porting4-obsoletedmechanism.qdocinc - - \section1 QLabel - - QLabel doesn't enable word-wrap automatically anymore when rich - text is used. You can enable it by calling - QLabel::setWordWrap() or by setting the - \l{QLabel::wordWrap}{wordWrap} property. The reason for this - change is that the old behavior was confusing to many users. - - Also, QLabel no longer offers an \c autoResize property. Instead, - you can call QWidget::setFixedSize() on the label, with - QLabel::sizeHint() as the argument, whenever you change the - contents of the QLabel. - - See also \l{Porting to Qt 4 - Virtual Functions}{Virtual Functions} - for a list of QLabel virtual member functions in Qt 3 that are no - longer virtual in Qt 4. - - \section1 QLayout - - In Qt 4, margins are always handled by layouts; there is no - QLayout::setSupportsMargin() function anymore. - - The deleteAllItems() function is now only available if - \c QT3_SUPPORT is defined. If you maintain a QList of layout - items, you can use qDeleteAll() to remove all the items in one - go. - - In Qt 3, it was possible to change the resizing behavior for layouts - in top-level widgets by adjusting the layout's \c resizeMode property. - In Qt 4, this property has been replaced by the QLayout::sizeConstraint - property which provides more control over how the layout behaves when - resized. - - See also the \l{#qlayoutiterator.section}{section on - QLayoutIterator} and the \l{#qglayoutiterator.section}{section on - QGLayoutIterator}. - - \target qlayoutiterator.section - \section1 QLayoutIterator - - The QLayoutIterator class is obsoleted in Qt 4. It is available - only if \c QT3_SUPPORT is defined. It can be replaced by the - QLayout::itemAt() and QLayout::takeAt() functions, which operate - on indexes. - - \oldcode - QLayoutIterator it = layout()->iterator(); - QLayoutItem *child; - while ((child = it.current()) != 0) { - if (child->widget() == myWidget) { - it.takeCurrent(); - return; - ++it; - } - \newcode - int i = 0; - QLayoutItem *child; - while ((child = layout()->itemAt(i)) != 0) { - if (child->widget() == myWidget) { - layout()->takeAt(i); - return; - } - ++i; - } - \endcode - - \section1 QLineEdit - - See \l{#properties}{Properties} for a list of QLineEdit - properties in Qt 3 that have changed in Qt 4. - - The default value of QLineEdit's \l{QLineEdit::dragEnabled()}{dragEnabled} - property was \c true in Qt 3. In Qt 4, the default value is \c false. - - Note that QLineEdit in Qt 4 is no longer a subclass of QFrame. - If you need to visually style a line edit with a frame, we recommend - either using a QFrame as a container for a QLineEdit or customizing - the line edit with a \l{Qt Style Sheets}{style sheet}. - - \section1 QListBox - - The \c QListBox, \c QListBoxItem, \c QListBoxText, and \c - QListBoxPixmap classes have been renamed Q3ListBox, - Q3ListBoxItem, Q3ListBoxText, and Q3ListBoxPixmap and have been - moved to the Qt3Support library. New Qt applications - should use QListWidget or its base class QListView instead. - - See \l{Model/View Programming} for an overview of the new item - view classes. - - \section1 QListView - - The \c QListView, \c QListViewItem, \c QCheckListItem, and \c - QListViewItemIterator classes have been renamed Q3ListView, - Q3ListViewItem, Q3CheckListItem, and Q3ListViewItemIterator, and - have been moved to the Qt3Support library. New Qt - applications should use one of the following four classes - instead: QTreeView or QTreeWidget for tree-like structures; - QListWidget or the new QListView class for one-dimensional lists. - - See \l{Model/View Programming} for an overview of the new item - view classes. - - \section1 QLocalFs - - The \c QLocalFs class is no longer part of the public Qt API. It - has been renamed Q3LocalFs and moved to Qt3Support. Use QDir, - QFileInfo, or QFile instead. - - \section1 QMainWindow - - The QMainWindow class has been redesigned in Qt 4 to provide a - more modern look and feel and more flexibility. The API has - changed to reflect that. The old \c QMainWindow class has been - renamed Q3MainWindow and moved to Qt3Support. See the QMainWindow - class documentation for details. - - \omit ### More detail \endomit - - \target qmemarray.section - \section1 QMemArray<T> - - QMemArray<T> has been moved to Qt3Support. It has been replaced - by the QVector<T> class. - - The following table summarizes the API differences between the - two classes. - - \table - \row \o QMemArray::assign(const QMemArray<T> &) \o QVector::operator=() - \row \o QMemArray::assign(const T *, uint) \o See remark below - \row \o QMemArray::duplicate(const QMemArray &) \o QVector::operator=() - \row \o QMemArray::duplicate(const T *, uint) \o See remark below - \row \o QMemArray::setRawData(const T *, uint) \o N/A - \row \o QMemArray::resetRawData(const T *, uint) \o N/A - \row \o QMemArray::find(const T &, uint) \o QVector::indexOf(const T &, int) - \row \o QMemArray::contains(const T &) \o QVector::count(const T &) - \row \o QMemArray::sort() \o \l qSort() - \row \o QMemArray::bsearch(const T &d) \o \l qBinaryFind() - \row \o QMemArray::at(uint) \o QVector::operator[]() - \row \o QMemArray::operator const T *() \o QVector::constData() - \endtable - - Remarks: - - \list 1 - \o QMemArray::assign(const T *, uint) and QMemArray::duplicate(const T *, uint) - can be replaced by QVector::resize() and qCopy(). - - \oldcode - QMemArray<QSize> array; - ... - array.assign(data, size); - \newcode - QVector<QSize> vector; - ... - vector.resize(size); - qCopy(data, data + size, vector.begin()); - \endcode - - \o QMemArray is an explicitly shared class, whereas QVector is - implicitly shared. See \l{Explicit Sharing} for more - information. - \endlist - - \section1 QMenuBar - - In Qt 3, QMenuBar inherited from QFrame and QMenuData; in Qt 4, it is - a direct subclass of QWidget. Applications that provided customized - menu bars will need to take advantage of the styling features described - in the \l{Qt Style Sheets} document. - - It is not possible to add widgets to menu bars in Qt 4. - - \section1 QMenuData - - In Qt 4, the QMenu class provides a menu widget that can be used in all - the places where menus are used in an application. Unlike \c QMenuData, - QMenu is designed around the concept of actions, provided by the QAction - class, instead of the identifiers used in Qt 3. - - In Qt 3, it was possible to insert widgets directly into menus by using - a specific \c QMenuData::insertItem() overload. In Qt 4.2 and later, - the QWidgetAction class can be used to wrap widgets for use in Qt 4's - action-based APIs. - - \section1 QMessageBox - - The QMessageBox::iconPixmap() function used to return a "const - QPixmap *". In Qt 4, it returns a QPixmap. - - \section1 QMimeSourceFactory - - The \c QMimeSourceFactory has been renamed Q3MimeSourceFactory - and moved to the Qt3Support library. New Qt applications should - use Qt 4's \l{Resource System} instead. - - \section1 QMovie - - The QMovie API has been revised in Qt 4 to make it more - consistent with the other Qt classes (notably QImageReader). The - table below summarizes the changes. - - \table - \header \o Qt 3 function \o Qt 4 equivalent - \row \o QMovie::connectResize() \o Connect to QMovie::resized() - \row \o QMovie::connectStatus() \o Connect to QMovie::stateChanged() - \row \o QMovie::connectUpdate() \o Connect to QMovie::updated() - \row \o QMovie::disconnectResize() \o Disconnect from QMovie::resized() - \row \o QMovie::disconnectStatus() \o Disconnect from QMovie::stateChanged() - \row \o QMovie::disconnectUpdate() \o Disconnect from QMovie::updated() - \row \o QMovie::finished() \o Use QMovie::state() instead - \row \o QMovie::frameImage() \o Use QMovie::currentImage() instead - \row \o QMovie::frameNumber() \o Use QMovie::currentFrameNumber() instead - \row \o QMovie::framePixmap() \o Use QMovie::currentPixmap() instead - \row \o QMovie::getValidRect() \o Use frameRect() instead - \row \o QMovie::isNull() \o Use QMovie::isValid() instead - \row \o QMovie::pause() \o Use QMovie::setPaused(true) instead - \row \o QMovie::paused() \o Use QMovie::state() instead - \row \o QMovie::pushData() \o N/A - \row \o QMovie::pushSpace() \o N/A - \row \o QMovie::restart() \o Use QMovie::jumpToFrame(0) instead - \row \o QMovie::running() \o Use QMovie::state() instead - \row \o QMovie::step() \o Use QMovie::jumpToFrame() and QMovie::setPaused() instead - \row \o QMovie::step() \o Use QMovie::jumpToNextFrame() instead - \row \o QMovie::steps() \o Use QMovie::currentFrameNumber() and QMovie::frameCount() instead - \row \o QMovie::unpause() \o Use QMovie::setPaused(false) instead - \endtable - - \section1 QMultiLineEdit - - The \c QMultiLineEdit class in Qt 3 was a convenience QTextEdit - subclass that provided an interface compatible with Qt 2's - QMultiLineEdit class. In Qt 4, it is called Q3MultiLineEdit, it - inherits Q3TextEdit, and it is part of Qt3Support. Use QTextEdit - in new code. - - \target qnetworkprotocol.section - \section1 QNetworkProtocol - - The QNetworkProtocol, QNetworkProtocolFactoryBase, - QNetworkProtocolFactory<T>, and QNetworkOperation classes are no - longer part of the public Qt API. They have been renamed - Q3NetworkProtocol, Q3NetworkProtocolFactoryBase, - Q3NetworkProtocolFactory<T>, and Q3NetworkOperation and have been - moved to the Qt3Support library. - - In Qt 4 applications, you can use classes like QFtp and - QNetworkAccessManager directly to perform file-related actions on - a remote host. - - \section1 QObject - - QObject::children() now returns a QObjectList instead of a - pointer to a QObjectList. See also the comments on QObjectList - below. - - Use QObject::findChildren() (or qFindChildren() if you need MSVC 6 - compatibility) instead of QObject::queryList(). For example: - - \snippet doc/src/snippets/code/doc_src_porting4.qdoc 18 - - QObject::killTimers() has been removed because it was unsafe to - use in subclass. (A subclass normally doesn't know whether the - base class uses timers or not.) - - The \c QObject::name property has been renamed - QObject::objectName. - - \c QObject::objectTrees() has been removed. If you are primarly - interested in widgets, use QApplication::allWidgets() or - QApplication::topLevelWidgets(). - - \section1 QObjectDictionary - - The QObjectDictionary class is a synonym for - QAsciiDict<QMetaObject>. See the \l{#qasciidict.section}{section - on QAsciiDict<T>}. - - \section1 QObjectList - - In Qt 3, the QObjectList class was a typedef for - QPtrList<QObject>. In Qt 4, it is a typedef for QList<QObject *>. - See the \l{#qptrlist.section}{section on QPtrList<T>}. - - \section1 QPaintDevice - - To reimplement painter backends one previously needed to reimplement - the virtual function QPaintDevice::cmd(). This function is taken out - and should is replaced with the function QPaintDevice::paintEngine() - and the abstract class QPaintEngine. QPaintEngine provides virtual - functions for all drawing operations that can be performed on a - painter backend. - - bitBlt() and copyBlt() are now only compatibility functions. Use - QPainter::drawPixmap() instead. - - \section1 QPaintDeviceMetrics - - All functions that used to be provided by the \c - QPaintDeviceMetrics class have now been moved to QPaintDevice. - - \oldcode - QPaintDeviceMetrics metrics(widget); - int deviceDepth = metrics.depth(); - \newcode - int deviceDepth = widget->depth(); - \endcode - - For compatibility, the old \c QPaintDeviceMetrics class has been - renamed Q3PaintDeviceMetrics and moved to Qt3Support. - - \section1 QPainter - - The QPainter class has undergone some changes in Qt 4 because of - the way rectangles are drawn. In Qt 4, the result of drawing a - QRect with a pen width of 1 pixel is 1 pixel wider and 1 pixel - taller than in Qt 3. - - For compatibility, we provide a Q3Painter class in Qt3Support - that provides the old semantics. See the Q3Painter documentation - for details and for the reasons why we had to make this change. - - The \l{http://qt.nokia.com/doc/3.3/qpainter.html#CoordinateMode-enum}{QPainter::CoordinateMode} - enum has been removed in Qt 4. All clipping - operations are now defined using logical coordinates and are subject - to transformation operations. - - The - \l{http://qt.nokia.com/doc/3.3/qpainter.html#RasterOP-enum}{QPainter::RasterOP} - enum has been replaced with QPainter::CompositionMode. - - \section1 QPicture - - In Qt 3, a QPicture could be saved in the SVG file format. In Qt - 4, the SVG support is provided by the QtSvg module, which - includes classes for \e displaying the contents of SVG files. - - If you would like to generate SVG files, you can use the Q3Picture - compatibility class or the QSvgGenerator class introduced in Qt 4.3. - - \section1 QPixmap - - The mask() function has been changed to return a reference to a QBitmap - rather than a pointer. As a result, it is no longer possible simply to - test for a null pointer when determining whether a pixmap has a mask. - Instead, you need to explicitly test whether the mask bitmap is null or - not. - - \oldcode - if (pixmap.mask()) - widget->setMask(*pixmap.mask()); - \newcode - if (!pixmap.mask().isNull()) - widget->setMask(pixmap.mask()); - \endcode - - The \c QPixmap::setOptimization() and \c QPixmap::setDefaultOptimization() - mechanism is no longer available in Qt 4. - -\omit - QPixmap::fromMimeSource(const QString &) -> qPixmapFromMimeSource(const QString &) -\endomit - - \section1 QPointArray - - The \c QPointArray class has been renamed QPolygon in Qt 4 and - has undergone significant changes. In Qt 3, \c QPointArray - inherited from QMemArray<QPoint>. In Qt 4, QPolygon inherits from - QVector<QPoint>. Everything mentioned in the - \l{#qmemarray.section}{section on QMemArray<T>} apply for - QPointArray as well. - - The Qt3Support library contains a Q3PointArray class - that inherits from QPolygon and provides a few functions that - existed in \c QPointArray but no longer exist in QPolygon. These - functions include Q3PointArray::makeArc(), - Q3PointArray::makeEllipse(), and Q3PointArray::cubicBezier(). - In Qt 4, we recommend that you use QPainterPath for representing - arcs, ellipses, and Bezier curves, rather than QPolygon. - - The QPolygon::setPoints() and QPolygon::putPoints() functions - return \c void in Qt 4. The corresponding Qt 3 functions returned - a \c bool indicating whether the array was successfully resized - or not. This can now be checked by checking QPolygon::size() - after the call. - -\omit - X11 Specific: - - ::appDisplay() -> QX11Info::display() - QPaintDevice::x11Display() -> QX11Info::display() - QPaintDevice::x11AppDisplay() -> QX11Info::display() - QPaintDevice::x11Screen() -> QX11Info::appScreen() - QPaintDevice::x11AppScreen() -> ??? - QPaintDevice::x11Depth() -> QX11Info::appDepth() - QPaintDevice::x11ColorMap() -> QX11Info::appColorMap() - QPaintDevice::x11DefaultColorMap() -> ??? - QPaintDevice::x11Visual() -> QX11Info::appVisual() - QPaintDevice::x11DefaultVisual() -> ??? - - QPaintDevice::x11AppDpiX() -> QX11Info::appDpiX() - QPaintDevice::x11AppDpiY() -> QX11Info::appDpiY() - QPaintDevice::x11SetAppDpiX() -> QX11Info::setAppDpiX() - QPaintDevice::x11SetAppDpiY() -> QX11Info::setAppDpiY() - - QPaintDevice::x11AppDepth() -> ??? - QPaintDevice::x11AppCells() -> ??? - QPaintDevice::x11AppRootWindow() -> ??? - QPaintDevice::x11AppColorMap() -> ??? - QPaintDevice::x11AppDefaultColorMap() -> ??? - QPaintDevice::x11AppVisual() -> ??? - QPaintDevice::x11AppDefaultVisual() -> ??? - - End of X11 Specific -\endomit - - \section1 QPopupMenu - - For most purposes, QPopupMenu has been replaced by QMenu in Qt - 4. For compatibility with older applications, Q3PopupMenu provides - the old API and features that are specific to pop-up menus. Note - that, when using Q3PopupMenu, the menu's actions must be \l - {Q3Action}s. - - In Qt 3, it was common practice to add entries to pop-up menus using the - insertItem() function, maintaining identifiers for future use; for - example, to dynamically change menu items. - In Qt 4, menu entries are completely represented - by actions for consistency with other user interface components, such as - toolbar buttons. Create new menus with the QMenu class, and use the - overloaded QMenu::addAction() functions to insert new entries. - If you need to manage a set of actions created for a particular menu, - we suggest that you construct a QActionGroup and add them to that. - - The \l{Qt Examples#Main Windows}{Main Window examples} provided - show how to use Qt's action system to construct menus, toolbars, and other - common user interface elements. - - \section1 QPrinter - - The QPrinter class now expects printing to be set up from a - QPrintDialog. - - \section1 QProcess - - The QProcess class has undergone major improvements in Qt 4. It - now inherits QIODevice, which makes it possible to combine - QProcess with a QTextStream or a QDataStream. - - The old \c QProcess class has been renamed Q3Process and moved to - the Qt3Support library. - - \section1 QProgressBar - - The QProgressBar API has been significantly improved in Qt 4. The - old \c QProgressBar API is available as Q3ProgressBar in the - Qt3Support library. - - \section1 QProgressDialog - - The QProgressDialog API has been significantly improved in Qt 4. - The old \c QProgressDialog API is available as Q3ProgressDialog - in the Qt3Support library. - - See \l{#properties}{Properties} for a list of QProgressDialog - properties in Qt 3 that have changed in Qt 4. - - \section1 QPtrCollection<T> - - The \c QPtrCollection<T> abstract base class has been renamed - Q3PtrCollection<T> moved to the Qt3Support library. - There is no direct equivalent in Qt 4. - - \omit - ### - The QPtrCollection entry is unsatisfactory. The xref is missing - its list and saying "no direct equivalent" with so suggestions - seems feeble. - \endomit - - See \l{Generic Containers} for a list of Qt 4 containers. - - \section1 QPtrDict<T> - - \c QPtrDict<T> and \c QPtrDictIterator<T> have been renamed - Q3PtrDict<T> and Q3PtrDictIterator<T> and have been moved to the - Qt3Support library. They have been replaced by the - more modern QHash<Key, T> and QMultiHash<Key, T> classes and - their associated iterator classes. - - When porting old code that uses Q3PtrDict<T> to Qt 4, there are - four classes that you can use: - - \list - \o QMultiHash<void *, T *> - \o QMultiHash<void *, T> - \o QHash<void *, T *> - \o QHash<void *, T> - \endlist - - (You can naturally use other types than \c{void *} for the key - type, e.g. \c{QWidget *}.) - - To port Q3PtrDict<T> to Qt 4, read the \l{#qdict.section}{section - on QDict<T>}, mentally substituting \c{void *} for QString. - - \target qptrlist.section - \section1 QPtrList<T> - - QPtrList<T>, QPtrListIterator<T>, and QPtrListStdIterator<T> have - been moved to the Qt3Support library. They have been - replaced by the more modern QList and QLinkedList classes and - their associated iterator classes. - - When porting to Qt 4, you have the choice of using QList<T> or - QLinkedList<T> as alternatives to QValueList<T>. QList<T> has an - index-based API and provides very fast random access - (QList::operator[]), whereas QLinkedList<T> has an iterator-based - API. - - The following table summarizes the API differences between - QPtrList<T> and QList<T *>: - - \table - \header \o QPtrList function \o QList equivalent - \row \o QPtrList::contains(const T *) \o QList::count(T *) - \row \o QPtrList::containsRef(const T *) \o QList::count(T *) - \row \o QPtrList::find(const T *) \o See remark below - \row \o QPtrList::findRef(const T *) \o See remark below - \row \o QPtrList::getFirst() \o QList::first() - \row \o QPtrList::getLast() \o QList::last() - \row \o QPtrList::inSort(const T *) \o N/A - \row \o QPtrList::remove(const T *) \o QList::removeAll(T *) - \row \o QPtrList::remove(uint) \o QList::removeAt(int) - \row \o QPtrList::removeNode(QLNode *) \o N/A - \row \o QPtrList::removeRef(const T *) \o QList::removeAll(T *) - \row \o QPtrList::sort() \o See remark below - \row \o QPtrList::takeNode(QLNode *) \o N/A - \row \o QPtrList::toVector(QGVector *) \o See remark below - \endtable - - Remarks: - - \list 1 - \o QPtrList::toVector(QGVector *) can be replaced by - QVector::resize() and qCopy(). - - \oldcode - QPtrList<QWidget> list; - ... - QPtrVector<QWidget> vector; - list.toVector(&vector); - \newcode - QList<QWidget *> list; - ... - QVector<QWidget *> vector; - vector.resize(list.size()); - qCopy(list.begin(), list.end(), vector.begin()); - \endcode - - \o QPtrList::sort() relied on the virtual compareItems() to - sort items. In Qt 4, you can use \l qSort() instead and pass - your "compare item" function as an argument. - - \o QPtrList::find(const T *) returns an iterator, whereas - QList::indexOf(T *) returns an index. To convert an index - into an iterator, add the index to QList::begin(). - - \o QPtrList::removeFirst() and QPtrList::removeLast() return a \c - bool that indicates whether the element was removed or not. - The corresponding QList functions return \c void. You can - achieve the same result by calling QList::isEmpty() before - attempting to remove an item. - \endlist - - If you use QPtrList's auto-delete feature (by calling - QPtrList::setAutoDelete(true)), you need to do some more work. - You have two options: Either you call \c delete yourself whenever - you remove an item from the container, or you can use QList<T> - instead of QList<T *> (i.e. store values directly instead of - pointers to values). Here, we'll see when to call \c delete. - - \omit - (See \l{What's Wrong with Auto-Delete} for an explanation of why - the Qt 4 containers don't offer that feature.) - \endomit - - The following table summarizes the idioms that you need to watch - out for if you want to call \c delete yourself. - - \table - \header \o QPtrList idiom \o QList idiom - \row - \o - \snippet doc/src/snippets/code/doc_src_porting4.qdoc 19 - \o - \snippet doc/src/snippets/code/doc_src_porting4.qdoc 20 - \row - \o - \snippet doc/src/snippets/code/doc_src_porting4.qdoc 21 - \o - \snippet doc/src/snippets/code/doc_src_porting4.qdoc 22 - \row - \o - \snippet doc/src/snippets/code/doc_src_porting4.qdoc 23 - \o - \snippet doc/src/snippets/code/doc_src_porting4.qdoc 24 - \row - \o - \snippet doc/src/snippets/code/doc_src_porting4.qdoc 25 - \o - \snippet doc/src/snippets/code/doc_src_porting4.qdoc 26 - \row - \o - \snippet doc/src/snippets/code/doc_src_porting4.qdoc 27 - \o - \snippet doc/src/snippets/code/doc_src_porting4.qdoc 28 - \row - \o - \snippet doc/src/snippets/code/doc_src_porting4.qdoc 29 - (removes the current item) - - \o - \snippet doc/src/snippets/code/doc_src_porting4.qdoc 30 - \row - \o - \snippet doc/src/snippets/code/doc_src_porting4.qdoc 31 - - (also called from QPtrList's destructor) - - \o - \snippet doc/src/snippets/code/doc_src_porting4.qdoc 32 - - In 99% of cases, the following idiom also works: - - \snippet doc/src/snippets/code/doc_src_porting4.qdoc 33 - - However, it may lead to crashes if \c list is referenced from - the value type's destructor, because \c list contains - dangling pointers until clear() is called. - \endtable - - Be aware that QPtrList's destructor automatically calls clear(). - If you have a QPtrList data member in a custom class and use the - auto-delete feature, you will need to call \c delete on all the - items in the container from your class destructor to avoid a - memory leak. - - QPtrList had the concept of a "current item", which could be used - for traversing the list without using an iterator. When porting - to Qt 4, you can use the Java-style QListIterator<T *> (or - QMutableListIterator<T *>) class instead. The following table - summarizes the API differences: - - \table - \header \o QPtrList function \o QListIterator equivalent - \row \o QPtrList::at() \o N/A - \row \o QPtrList::current() \o QMutableListIterator::value() - \row \o QPtrList::currentNode() \o N/A - \row \o QPtrList::findNext(const T *) \o QListIterator::findNext(const T *) - \row \o QPtrList::findNextRef(const T *) \o QListIterator::findNext(const T *) - \row \o QPtrList::first() \o QPtrList::toFront() - \row \o QPtrList::last() \o QPtrList::toBack() - \row \o QPtrList::next() \o QPtrList::next() - \row \o QPtrList::prev() \o QPtrList::previous() - \row \o QPtrList::remove() \o QMutableListIterator::remove() - \row \o QPtrList::take() \o QMutableListIterator::remove() - \endtable - - Be aware that QListIterator has a different way of iterating than - QPtrList. A typical loop with QPtrList looks like this: - - \snippet doc/src/snippets/code/doc_src_porting4.qdoc 34 - - Here's the equivalent QListIterator loop: - - \snippet doc/src/snippets/code/doc_src_porting4.qdoc 35 - - Finally, QPtrListIterator<T> must also be ported. There are no - fewer than four iterator classes that can be used as a - replacement: QList::const_iterator, QList::iterator, - QListIterator, and QMutableListIterator. The most straightforward - class to use when porting is QMutableListIterator<T *> (if you - modify the list through the iterator) or QListIterator<T *> (if - you don't). The following table summarizes the API differences: - - \table - \header \o QPtrListIterator function \o Qt 4 equivalent - \row \o QPtrListIterator::atFirst() \o !QListIterator::hasPrevious() (notice the \c{!}) - \row \o QPtrListIterator::atLast() \o !QListIterator::hasNext() (notice the \c{!}) - \row \o QPtrListIterator::count() \o QList::count() or QList::size() - \row \o QPtrListIterator::current() \o QMutableListIterator::value() - \row \o QPtrListIterator::isEmpty() \o QList::isEmpty() - \row \o QPtrListIterator::toFirst() \o QListIterator::toFront() - \row \o QPtrListIterator::toLast() \o QListIterator::toBack() - \row \o QPtrListIterator::operator() \o QMutableListIterator::value() - \row \o QPtrListIterator::operator*() \o QMutableListIterator::value() - \endtable - - Again, be aware that QListIterator has a different way of - iterating than QPtrList. A typical loop with QPtrList looks like - this: - - \snippet doc/src/snippets/code/doc_src_porting4.qdoc 36 - - Here's the equivalent QListIterator loop: - - \snippet doc/src/snippets/code/doc_src_porting4.qdoc 37 - - Finally, QPtrListStdIterator<T> must also be ported. This is - easy, because QList also provides STL-style iterators - (QList::iterator and QList::const_iterator). - - \section1 QPtrQueue<T> - - QPtrQueue has been moved to the Qt3Support library. - It has been replaced by the more modern QQueue class. - - The following table summarizes the differences between - QPtrQueue<T> and QQueue<T *>: - - \table - \header \o QPtrQueue function \o QQueue equivalent - \row \o QPtrQueue::autoDelete() \o See discussion below - \row \o QPtrQueue::count() \o QQueue::count() or QQueue::size() (equivalent) - \row \o QPtrQueue::current() \o QQueue::head() - \row \o QPtrQueue::remove() \o QQueue::dequeue() - \row \o QPtrQueue::setAutoDelete() \o See discussion below - \endtable - - If you use QPtrQueue's auto-delete feature (by calling - QPtrQueue::setAutoDelete(true)), you need to do some more work. - You have two options: Either you call \c delete yourself whenever - you remove an item from the container, or you can use QQueue<T> - instead of QQueue<T *> (i.e. store values directly instead of - pointers to values). Here, we will show when to call \c delete. - - \omit - (See \l{What's Wrong with Auto-Delete} for an explanation of why - the Qt 4 containers don't offer that feature.) - \endomit - - \table - \header \o QPtrQueue idiom \o QQueue idiom - \row - \o - \snippet doc/src/snippets/code/doc_src_porting4.qdoc 38 - \o - \snippet doc/src/snippets/code/doc_src_porting4.qdoc 39 - \row - \o - \snippet doc/src/snippets/code/doc_src_porting4.qdoc 40 - \o - \snippet doc/src/snippets/code/doc_src_porting4.qdoc 41 - \row - \o - \snippet doc/src/snippets/code/doc_src_porting4.qdoc 42 - - (also called from QPtrQueue's destructor) - - \o - \snippet doc/src/snippets/code/doc_src_porting4.qdoc 43 - - In 99% of cases, the following idiom also works: - - \snippet doc/src/snippets/code/doc_src_porting4.qdoc 44 - - However, it may lead to crashes if \c queue is referenced - from the value type's destructor, because \c queue contains - dangling pointers until clear() is called. - \endtable - - \section1 QPtrStack<T> - - QPtrStack has been moved to the Qt3Support library. - It has been replaced by the more modern QStack class. - - The following table summarizes the differences between - QPtrStack<T> and QStack<T *>: - - \table - \header \o QPtrStack function \o QStack equivalent - \row \o QPtrStack::autoDelete() \o See discussion below - \row \o QPtrStack::count() \o QStack::count() or QStack::size() (equivalent) - \row \o QPtrStack::current() \o QStack::top() - \row \o QPtrStack::remove() \o QStack::pop() - \row \o QPtrStack::setAutoDelete() \o See discussion below - \endtable - - If you use QPtrStack's auto-delete feature (by calling - QPtrStack::setAutoDelete(true)), you need to do some more work. - You have two options: Either you call \c delete yourself whenever - you remove an item from the container, or you can use QStack<T> - instead of QStack<T *> (i.e. store values directly instead of - pointers to values). Here, we will show when to call \c delete. - - \omit - (See \l{What's Wrong with Auto-Delete} for an explanation of why - the Qt 4 containers don't offer that feature.) - \endomit - - \table - \header \o QPtrStack idiom \o QStack idiom - \row - \o - \snippet doc/src/snippets/code/doc_src_porting4.qdoc 45 - \o - \snippet doc/src/snippets/code/doc_src_porting4.qdoc 46 - \row - \o - \snippet doc/src/snippets/code/doc_src_porting4.qdoc 47 - \o - \snippet doc/src/snippets/code/doc_src_porting4.qdoc 48 - \row - \o - \snippet doc/src/snippets/code/doc_src_porting4.qdoc 49 - - (also called from QPtrStack's destructor) - - \o - \snippet doc/src/snippets/code/doc_src_porting4.qdoc 50 - - In 99% of cases, the following idiom also works: - - \snippet doc/src/snippets/code/doc_src_porting4.qdoc 51 - - However, it may lead to crashes if \c stack is referenced - from the value type's destructor, because \c stack contains - dangling pointers until clear() is called. - \endtable - - \section1 QPtrVector<T> - - QPtrVector<T> has been moved to Qt3Support. It has been replaced - by the more modern QVector class. - - When porting to Qt 4, you can use QVector<T *> as an alternative - to QPtrVector<T>. The APIs of QPtrVector<T> and QVector<T *> are - somewhat similar. The main issue is that QPtrVector supports - auto-delete whereas QVector doesn't. - - \omit - (See \l{What's Wrong with Auto-Delete} for an explanation of why - the Qt 4 containers don't offer that feature.) - \endomit - - The following table summarizes the API differences between the - two classes: - - \table - \header \o QPtrVector function \o QVector equivalent - \row \o QPtrVector::autoDelete() \o See discussion below - \row \o QPtrVector::bsearch(const T *) \o \l qBinaryFind() - \row \o QPtrVector::contains(const T *) \o QVector::count(T *) - \row \o QPtrVector::containsRef(const T *) \o QVector::count(T *) - \row \o QPtrVector::count() \o See remark below - \row \o QPtrVector::insert(uint, T *) \o See remark below - \row \o QPtrVector::isNull() \o N/A - \row \o QPtrVector::remove(uint) \o See remark below - \row \o QPtrVector::setAutoDelete() \o See discussion below - \row \o QPtrVector::sort() \o \l qSort() - \row \o QPtrVector::take(uint) \o See remark below - \row \o QPtrVector::toList(QGList *) \o QList::QList(const QVector &) - \endtable - - Remarks: - - \list 1 - \o QPtrVector::insert(uint, T *) sets an item to store a certain - pointer value. This is \e not the same as QVector::insert(int, T *), - which creates space for the item by moving following items by - one position. Use \c{vect[i] = ptr} to set a QVector item to - a particular value. - \o QPtrVector::remove(uint) sets an item to be 0. This is \e not - the same as QVector::removeAt(int), which entirely erases the - item, reducing the size of the vector. Use \c{vect[i] = 0} to - set a QVector item to 0. - \o Likewise, QPtrVector::take(uint) sets an item to be 0 and - returns the previous value of the item. Again, this is easy to - achieve using QVector::operator[](). - \o QPtrVector::count() returns the number of non-null items in - the vector, whereas QVector::count() (like QVector::size()) - returns the number of items (null or non-null) in the vector. - Fortunately, it's not too hard to simulate QPtrVector::count(). - - \oldcode - int numValidItems = vect.count(); - \newcode - int numValidItems = vect.size() - vect.count(0); - \endcode - \endlist - - If you use QVector's auto-delete feature (by calling - QVector::setAutoDelete(true)), you need to do some more work. You - have two options: Either you call \c delete yourself whenever you - remove an item from the container, or you use QVector<T> instead - of QVector<T *> (i.e. store values directly instead of pointers - to values). Here, we'll see when to call \c delete. - - The following table summarizes the idioms that you need to watch - out for if you want to call \c delete yourself. - - \table - \header \o QPtrVector idiom \o QVector idiom - \row - \o - \snippet doc/src/snippets/code/doc_src_porting4.qdoc 52 - \o - \snippet doc/src/snippets/code/doc_src_porting4.qdoc 53 - \row - \o - \snippet doc/src/snippets/code/doc_src_porting4.qdoc 54 - \o - \snippet doc/src/snippets/code/doc_src_porting4.qdoc 55 - \row - \o - \snippet doc/src/snippets/code/doc_src_porting4.qdoc 56 - \o - \snippet doc/src/snippets/code/doc_src_porting4.qdoc 57 - \row - \o - \snippet doc/src/snippets/code/doc_src_porting4.qdoc 58 - \o - \snippet doc/src/snippets/code/doc_src_porting4.qdoc 59 - \row - \o - \snippet doc/src/snippets/code/doc_src_porting4.qdoc 60 - - (also called from QPtrVector's destructor) - - \o - \snippet doc/src/snippets/code/doc_src_porting4.qdoc 61 - - In 99% of cases, the following idiom also works: - - \snippet doc/src/snippets/code/doc_src_porting4.qdoc 62 - - However, it may lead to crashes if \c vect is referenced from - the value type's destructor, because \c vect contains - dangling pointers until clear() is called. - \endtable - - Be aware that QPtrVector's destructor automatically calls - clear(). If you have a QPtrVector data member in a custom class - and use the auto-delete feature, you will need to call \c delete - on all the items in the container from your class destructor to - avoid a memory leak. - - \section1 QPushButton - - See \l{#properties}{Properties} for a list of QPushButton - properties in Qt 3 that have changed in Qt 4. - - \section1 QRangeControl - - In Qt 3, various "range control" widgets (QDial, QScrollBar, - QSlider, and QSpin) inherited from both QWidget and - \c QRangeControl. - - In Qt 4, \c QRangeControl has been replaced with the new - QAbstractSlider and QAbstractSpinBox classes, which inherit from - QWidget and provides similar functionality. Apart from eliminating - unnecessary multiple inheritance, the new design allows - QAbstractSlider to provide signals, slots, and properties. - - The old \c QRangeControl class has been renamed Q3RangeControl - and moved to the Qt3Support library, together with - the (undocumented) \c QSpinWidget class. - - If you use \c QRangeControl as a base class in your application, - you can switch to use QAbstractSlider or QAbstractSpinBox instead. - - \oldcode - class VolumeControl : public QWidget, public QRangeControl - { - ... - protected: - void valueChange() { - update(); - emit valueChanged(value()); - } - void rangeChange() { - update(); - } - void stepChange() { - update(); - } - }; - \newcode - class VolumeControl : public QAbstractSlider - { - ... - protected: - void sliderChange(SliderChange change) { - update(); - if (change == SliderValueChange) - emit valueChanged(value()); - } - }; - \endcode - - \section1 QRegExp - - The search() and searchRev() functions have been renamed to indexIn() - and lastIndexIn() respectively. - - \section1 QRegion - - The following changes have been made to QRegion in Qt 4: - - \list - \o There is no longer any difference between a \e null region and - an \e empty region. Use isEmpty() in most places where you - would have used a null QRegion. - \o QRegion::rects() used to return a QMemArray<QRect>. It now returns - a QVector<QRect>. - \endlist - - \section1 QScrollBar - - See \l{#properties}{Properties} for a list of QScrollBar - properties in Qt 3 that have changed in Qt 4. - - \section1 QScrollView - - The \c QScrollView class has been renamed Q3ScrollView and moved - to the Qt3Support library. It has been replaced by - the QAbstractScrollArea and QScrollArea classes. - - Note that Qt 4 in general uses the QScrollArea::widget() function - where Qt 3 used QScrollView::viewport(). The rationale for this is - that it is no longer possible to draw directly on a scroll - area. The QScrollArea::widget() function returns the widget set on - the scroll area. - - \c QScrollView was designed to work around the 16-bit limitation - on widget coordinates found on most window systems. In Qt 4, this - is done transparently for \e all widgets, so there is no longer a - need for such functionality in \c QScrollView. For that reason, - the new QAbstractScrollArea and QScrollArea classes are much more - lightweight, and concentrate on handling scroll bars. - - \section1 QServerSocket - - The \c QServerSocket class has been renamed Q3ServerSocket and - moved to the Qt3Support library. In Qt 4, it has been - replaced by QTcpServer. - - With Q3ServerSocket, connections are accepted by reimplementing a - virtual function (Q3ServerSocket::newConnection()). With - QTcpServer, on the other hand, you don't need to subclass. - Instead, simply connect to the QTcpServer::newConnection() - signal. - - \section1 QSettings - - The QSettings class has been rewritten to be more robust and to - respect existing standards (e.g., the INI file format). The API - has also been extensively revised. The old API is still provided - when Qt 3 support is enabled. - - Since the format and location of settings have changed between Qt - 3 and Qt 4, the Qt 4 version of your application won't recognize - settings written using Qt 3. - - \section1 QShared - - The \c QShared class has been obsoleted by the more powerful - QSharedData and QSharedDataPointer as a means of creating custom - implicitly shared classes. It has been renamed Q3Shared moved to - the Qt3Support library. - - An easy way of porting to Qt 4 is to include this class into your - project and to use it instead of \c QShared: - - \snippet doc/src/snippets/code/doc_src_porting4.qdoc 63 - - If possible, we recommend that you use QSharedData and - QSharedDataPointer instead. They provide thread-safe reference - counting and handle all the reference counting behind the scenes, - eliminating the risks of forgetting to increment or decrement the - reference count. - - \section1 QSignal - - The QSignal class has been renamed to Q3Signal and moved to the - Qt3Support library. The preferred approach is to create your own - QObject subclass with a signal that has the desired signature. - Alternatively, you can call QMetaObject::invokeMethod() if you - want to invoke a slot. - - \section1 QSimpleRichText - - QSimpleRichText has been obsoleted by QTextDocument. It has - bene renamed Q3SimpleRichText and moved to the Qt3Support - library. - - Previously, you would do the following with Q3SimpleRichText: - - \snippet doc/src/snippets/code/doc_src_porting4.qdoc 63a - - However, with QTextDocument, you use the following code instead: - - \snippet doc/src/snippets/code/doc_src_porting4.qdoc 63b - - See \l{Rich Text Processing} for an overview of the Qt 4 rich - text classes. - - \section1 QSlider - - The QSlider::sliderStart() and QSlider::sliderRect() functions - have been removed. - - The slider's rect can now be retrieved using the code snippet below: - - \snippet doc/src/snippets/code/doc_src_porting4.qdoc 63c - - In addition, the direction of a vertical QSlider has changed, - i.e. the bottom is now the minimum, and the top the maximum. You - can use the QAbstractSlider::invertedAppearance property to - control this behavior. - - See \l{#properties}{Properties} for a list of QSlider properties - in Qt 3 that have changed in Qt 4. - - \section1 QSocket - - The \c QSocket class has been renamed Q3Socket and moved to the - Qt3Support library. In Qt 4, it has been replaced by - the QTcpSocket class, which inherits most of its functionality - from QAbstractSocket. - - \section1 QSocketDevice - - The \c QSocketDevice class has been renamed Q3SocketDevice and - moved to the Qt3Support library. In Qt 4, there is no - direct equivalent to Q3SocketDevice: - - \list \o If you use Q3SocketDevice in a thread to perform blocking - network I/O (a technique encouraged by the \e{Qt Quarterly} - article \l{http://qt.nokia.com/doc/qq/qq09-networkthread.html} - {Unblocking Networking}), you can now use QTcpSocket, QFtp, or - QNetworkAccessManager, which can be used from non-GUI threads. - - \o If you use Q3SocketDevice for UDP, you can now use QUdpSocket instead. - - \o If you use Q3SocketDevice for other uses, Qt 4 offers no - alternative right now. However, there is a \c QAbstractSocketEngine - internal class that offers a low-level socket API similar to - Q3SocketDevice. Should the need for such functionality arise in - Qt 4 applications, we will consider making this class public in a - future release. - \endlist - - \section1 QSortedList - - The QSortedList<T> class has been deprecated since Qt 3.0. In Qt - 4, it has been moved to the Qt3Support library. - - In new code, we recommend that you use QList<T> instead and use - \l qSort() to sort the items. - - \section1 QSplitter - - The function setResizeMode() has been moved into Qt3Support. Set - the stretch factor in the widget's size policy to get equivalent - functionality. - - The obsolete function drawSplitter() has been removed. Use - QStyle::drawPrimitive() to acheive similar functionality. - - \section1 QSpinBox - - See \l{#properties}{Properties} for a list of QSpinBox properties - in Qt 3 that have changed in Qt 4. - - \section1 QSqlCursor - - The \c QSqlCursor class has been renamed Q3SqlCursor and moved to - the Qt3Support library. In Qt 4, you can use - QSqlQuery, QSqlQueryModel, or QSqlTableModel, depending on - whether you want a low-level or a high-level interface for - accessing databases. - - See \l{QtSql Module} for an overview of the new SQL classes. - - \section1 QSqlDatabase - - QSqlDatabase is now a smart pointer that is passed around by - value. Simply replace all QSqlDatabase pointers by QSqlDatabase - objects. - - \section1 QSqlEditorFactory - - The \c QSqlEditorFactory class has been renamed - Q3SqlEditorFactory and moved to Qt3Support. - - See \l{QtSql Module} for an overview of the new SQL classes. - - \section1 QSqlError - - The enum \c{Type} was renamed to \c{ErrorType}, The values were renamed as well: - - \list - \o None - use NoError instead - \o Connection - use ConnectionError instead - \o Statement - use StatementError instead - \o Transaction - use TransactionError instead - \o Unknown - use UnknownError instead - \endlist - - \section1 QSqlFieldInfo - - The QSqlFieldInfo class has been moved to Qt3Support. Its - functionality is now provided by the QSqlField class. - - See \l{QtSql Module} for an overview of the new SQL classes. - - \section1 QSqlForm - - The \c QSqlForm class has been renamed Q3SqlForm and moved to the - Qt3Support library. - - See \l{QtSql Module} for an overview of the new SQL classes. - - \section1 QSqlPropertyMap - - The \c QSqlPropertyMap class has been renamed Q3SqlPropertyMap - moved to the Qt3Support library. - - See \l{QtSql Module} for an overview of the new SQL classes. - - \section1 QSqlQuery - - QSqlQuery::prev() was renamed to QSqlQuery::previous(). - QSqlQuery::prev() remains, but it just calls previous(). - QSqlQuery no longer has any virtual methods, i.e., exec(), - value(), seek(), next(), prev(), first(), last(), and the - destructor are no longer virtual. - - \section1 QSqlRecord - - QSqlRecord behaves like a vector now, QSqlRecord::insert() will - actually insert a new field instead of replacing the existing - one. - - \section1 QSqlRecordInfo - - The QSqlRecordInfo class has been moved to Qt3Support. Its - functionality is now provided by the QSqlRecord class. - - See \l{QtSql Module} for an overview of the new SQL classes. - - \section1 QSqlSelectCursor - - The \c QSqlSelectCursor class has been renamed Q3SqlSelectCursor - and moved to the Qt3Support library. - - See \l{QtSql Module} for an overview of the new SQL classes. - - \section1 QStoredDrag - - The \c QStoredDrag class has been renamed Q3StoredDrag and moved - to the Qt3Support library. In Qt 4, use QMimeData - instead and call QMimeData::setData() to set the data. - - See \l{Porting to Qt 4 - Drag and Drop} for a comparison between - the drag and drop APIs in Qt 3 and Qt 4. - - \section1 QStr(I)List - - The QStrList and QStrIList convenience classes have been - deprecated since Qt 2.0. In Qt 4, they have been moved to the - Qt3Support library. If you used any of these, we - recommend that you use QStringList or QList<QByteArray> instead. - - \section1 QStr(I)Vec - - The QStrVec and QStrIVec convenience classes have been deprecated - since Qt 2.0. In Qt 4, they have been moved to Qt3Support. If you - used any of these, we recommend that you use QStringList or - QList<QByteArray> instead. - - \section1 QString - - Here are the main issues to be aware of when porting QString to - Qt 4: - - \list 1 - \o The QString::QString(QChar) constructor performed implicit - conversion in Qt 3. Now, you will need a cast to convert a - QChar to a QString. - - \o The QString::QString(const QByteArray &) constructor used to - stop at the first '\\0' it encountered, for compatibility - with Qt 1. This quirk has now been fixed; in Qt 4, the - resulting QString always has the same length as the - QByteArray that was passed to the constructor. - - \o The QString::null static constant has been deprecated in Qt - 4. For compatibility, Qt 4 provides a QString::null symbol - that behaves more or less the same as the old constant. The - new idiom is to write QString() instead of QString::null, or - to call clear(). - - \oldcode - str1 = QString::null; - if (str2 == QString::null) - do_something(QString::null); - \newcode - str1.clear(); - if (str2.isNull()) - do_something(QString()); - \endcode - - In new code, we recommend that you don't rely on the - distinction between a null string and a (non-null) empty - string. See \l{Distinction Between Null and Empty Strings} - for details. - - \o QString::latin1() and QString::ascii() have been replaced - with QString::toLatin1() and QString::toAscii(), which return - a QByteArray instead of a (non-reentrant) \c{const char *}. - For consistency, QString::utf8() and QString::local8Bit(), - which already returned a QByteArray (actually a \c QCString), - have been renamed QString::toUtf8() and - QString::toLocal8Bit(). - - To obtain a \c{const char *} pointer to ASCII or Latin-1 data, - use QString::toAscii() or QString::toLatin1() to obtain a - QByteArray containing the data, then call QByteArray::constData() - to access the character data directly. Note that the pointer - returned by this function is only valid for the lifetime of the - byte array; you should avoid taking a pointer to the data - contained in temporary objects. - - \snippet doc/src/snippets/code/doc_src_porting4.qdoc 64 - - In the above example, the \c goodData pointer is valid for the lifetime - of the \c asciiData byte array. If you need to keep a copy of the data - in a non-Qt data structure, use standard C memory allocation and string - copying functions to do so \e before destroying the byte array. - - \o QString::at() returned a non-const reference, whereas the - new QString::at() returns a const value. Code like - - \snippet doc/src/snippets/code/doc_src_porting4.qdoc 65 - - will no longer compile. Instead, use QString::operator[]: - - \snippet doc/src/snippets/code/doc_src_porting4.qdoc 66 - - \o The QString::contains(\e x) function (where \e x is a - character or a string) has been renamed QString::count(\e x). - In addition, there now exists a set of QString::contains() - functions that returns a boolean value. Replace old calls to - contains() with either count() or contains(), depending on - whether you care about the specific number of occurrences of - a character in the string or only care about whether the - string contains that character or not. - - \o Many functions in QString had a \c bool parameter that - specified case sensitivity. In Qt 4, in the interest of code - readability and maintainability, the \c bool parameters have - been replaced by the Qt::CaseSensitivity enum, which can take - the values Qt::CaseSensitive and Qt::CaseInsensitive. - - \oldcode - if (url.startsWith("http:", false)) - ... - \newcode - if (url.startsWith("http:", Qt::CaseInsensitive)) - ... - \endcode - - \o The QString::setExpand(uint, QChar) function, which already - was obsolete in Qt 3, is no longer available. Use - QString::operator[] instead. - - \oldcode - str.setExpand(32, '$'); - \newcode - str[32] = '$'; - \endcode - - \o The \c QT_NO_ASCII_CAST and \c QT_NO_CAST_ASCII macros have - been renamed \c QT_NO_CAST_TO_ASCII and \c - QT_NO_CAST_FROM_ASCII, respectively. - - \o The QString::data() used to return the same as - QString::ascii(). It now returns a pointer to the Unicode - data stored in the QString object. Call QString::ascii() if - you want the old behavior. - - \o QString::arg() now converts two-digit place markers, allowing - up to 99 place markers to be used in any given string. - - \o Comparisons between QStrings and \c NULL in order to determine - whether strings are empty are no longer allowed. - Use \l{QString::}{isEmpty()} instead. - - \endlist - - \section1 QStringList - - QStringList now inherits from QList<QString> and can no longer be - converted to a QValueList<QString>. Since QValueList inherits QList a - cast will work as expected. - - This change implies some API incompatibilities for QStringList. - For example, at() returns the string, not an iterator. See the - \l{#qvaluelist.section}{section on QValueList} for details. - - The static QStringList::split() function for splitting strings into - lists of smaller strings has been replaced by QString::split(), - which returns a QStringList. - - \section1 QStyle - - The QStyle API has been overhauled and improved. Most of the information on - why this change was done is described in \l{The Qt 4 Style API}{the QStyle overview}. - - Since QStyle is mostly used internally by Qt's widgets and styles and since - it is not essential to the good functioning of an application, there is no - compatibility path. This means that we have changed many enums and - functions and the qt3to4 porting tool will not change much in your qstyle - code. To ease the pain, we list some of the major changes here. - - QStyleOption has taken on a more central role and is no longer an optional - argument, please see the QStyleOption documentation for more information. - - The QStyle::StyleFlags have been renamed QStyle::StateFlags and are now prefixed State_ - instead of Style_, in addition the Style_ButtonDefault flag has moved to - QStyleOptionButton. - - The QStyle::PrimitiveElement enumeration has undergone extensive change. - Some of the enums were moved to QStyle::ControlElement, some were removed - and all were renamed. This renaming is not done by the qt3to4 porting tool, - so you must do it yourself. The table below shows how things look - now. - - \table - \header \o Old name \o New name \o Remark - \row \o \c PE_ButtonCommand \o QStyle::PE_PanelButtonCommand - \row \o \c PE_ButtonDefault \o QStyle::PE_FrameDefaultButton - \row \o \c PE_ButtonBevel \o QStyle::PE_PanelButtonBevel - \row \o \c PE_ButtonTool \o QStyle::PE_PanelButtonTool - \row \o \c PE_ButtonDropDown \o QStyle::PE_IndicatorButtonDropDown - \row \o \c PE_FocusRect \o QStyle::PE_FrameFocusRect - \row \o \c PE_ArrowUp \o QStyle::PE_IndicatorArrowUp - \row \o \c PE_ArrowDown \o QStyle::PE_IndicatorArrowDown - \row \o \c PE_ArrowRight \o QStyle::PE_IndicatorArrowRight - \row \o \c PE_ArrowLeft \o QStyle::PE_IndicatorArrowLeft - \row \o \c PE_SpinBoxUp \o QStyle::PE_IndicatorSpinUp - \row \o \c PE_SpinBoxDown \o QStyle::PE_IndicatorSpinDown - \row \o \c PE_SpinBoxPlus \o QStyle::PE_IndicatorSpinPlus - \row \o \c PE_SpinBoxMinus \o QStyle::PE_IndicatorSpinMinus - \row \o \c PE_SpinBoxSlider \o QStyle::CE_SpinBoxSlider \o uses QStyle::drawControl() - \row \o \c PE_Indicator \o QStyle::PE_IndicatorCheckBox - \row \o \c PE_IndicatorMask \o N/A \o use QStyle::styleHint() to retrieve mask - \row \o \c PE_ExclusiveIndicator \o QStyle::PE_IndicatorRadioButton - \row \o \c PE_ExclusiveIndicatorMask \o N/A \o use QStyle::styleHint() to retrieve mask - \row \o \c PE_DockWindowHandle \o QStyle::PE_IndicatorToolBarHandle - \row \o \c PE_DockWindowSeparator \o QStyle::PE_Q3DockWindowSeparator - \row \o \c PE_DockWindowResizeHandle \o QStyle::PE_IndicatorDockWindowResizeHandle - \row \o \c PE_DockWindowTitle \o QStyle::CE_DockWindowTitle \o uses QStyle::drawControl() - \row \o \c PE_Splitter \o QStyle::CE_Splitter \o uses QStyle::drawControl() - \row \o \c PE_Panel \o QStyle::PE_Frame - \row \o \c PE_PanelMenu \o QStyle::PE_FrameMenu - \row \o \c PE_PanelMenuBar \o QStyle::PE_PanelMenuBar - \row \o \c PE_PanelDockWindow \o QStyle::PE_FrameDockWindow - \row \o \c PE_TabBarBase \o QStyle::PE_FrameTabBarBase - \row \o \c PE_HeaderSection \o QStyle::CE_HeaderSection \o uses QStyle::drawControl() - \row \o \c PE_HeaderArrow \o QStyle::PE_IndicatorHeaderArrow - \row \o \c PE_StatusBarSection \o QStyle::PE_FrameStatusBar - \row \o \c PE_Separator \o QStyle::PE_Q3Separator - \row \o \c PE_SizeGrip \o QStyle::CE_SizeGrip \o uses QStyle::drawControl() - \row \o \c PE_CheckMark \o QStyle::PE_IndicatorMenuCheckMark - \row \o \c PE_ScrollBarAddLine \o QStyle::CE_ScrollBarAddLine \o uses QStyle::drawControl() - \row \o \c PE_ScrollBarSubLine \o QStyle::CE_ScrollBarSubLine \o uses QStyle::drawControl() - \row \o \c PE_ScrollBarAddPage \o QStyle::CE_ScrollBarAddPage \o uses QStyle::drawControl() - \row \o \c PE_ScrollBarSubPage \o QStyle::CE_ScrollBarSubPage \o uses QStyle::drawControl() - \row \o \c PE_ScrollBarSlider \o QStyle::CE_ScrollBarSlider \o uses QStyle::drawControl() - \row \o \c PE_ScrollBarFirst \o QStyle::CE_ScrollBarFirst \o uses QStyle::drawControl() - \row \o \c PE_ScrollBarLast \o QStyle::CE_ScrollBarLast \o uses QStyle::drawControl() - \row \o \c PE_ProgressBarChunk \o QStyle::PE_IndicatorProgressChunk - \row \o \c PE_PanelLineEdit \o QStyle::PE_FrameLineEdit - \row \o \c PE_PanelTabWidget \o QStyle::PE_FrameTabWidget - \row \o \c PE_WindowFrame \o QStyle::PE_FrameWindow - \row \o \c PE_CheckListController \o QStyle::PE_Q3CheckListController - \row \o \c PE_CheckListIndicator \o QStyle::PE_Q3CheckListIndicator - \row \o \c PE_CheckListExclusiveIndicato\o QStyle::PE_Q3CheckListExclusiveIndicator - \row \o \c PE_PanelGroupBox \o QStyle::PE_FrameGroupBox - \row \o \c PE_TreeBranch \o QStyle::PE_IndicatorBranch - \row \o \c PE_RubberBand \o QStyle::CE_RubberBand \o uses QStyle::drawControl() - \row \o \c PE_PanelToolBar \o QStyle::PE_PanelToolBar - \row \o \c PE_ToolBarHandle \o QStyle::PE_IndicatorToolBarHandle - \row \o \c PE_ToolBarSeparator \o QStyle::PE_IndicatorToolBarSeparator - \endtable - - The QStyle::drawControlMask() and QStyle::drawComplexControlMask() - functions have been removed. They are replaced with a style hint. - - The QStyle::drawItem() overloads that took both a pixmap and a string have - been removed. Use QStyle::drawItemText() and QStyle::drawItemPixmap() directly. - - The QStyle::itemRect() overload that took both a pixmap and a string is also removed, use - either QStyle::itemTextRect() or QStyle::itemPixmapRect() instead. - - \section1 QStyleSheet - - The QStyleSheet and QStyleSheetItem classes have been renamed - Q3StyleSheet and Q3StyleSheetItem, and have been moved to the - Qt3Support library. - - See \l{Rich Text Processing} for an overview of the Qt 4 rich - text classes, and \l{Qt Style Sheets} for a description of - CSS-like style sheet support in Qt 4.2 and above. - - \section1 QSyntaxHighlighter - - The \c QSyntaxHighlighter class from Qt 3 has been renamed - Q3SyntaxHighlighter and moved to the Qt3Support library. Since Qt - 4.1, it has been replaced by a new QSyntaxHighlighter class based - on Qt 4's new rich text engine. - - \section1 QTabBar - - See \l{#properties}{Properties} for a list of QTabBar properties - in Qt 3 that have changed in Qt 4. - - \section1 QTabDialog - - The \c QTabDialog class is no longer part of the public Qt API. - It has been renamed Q3TabDialog and moved to Qt3Support. In Qt 4 - applications, you can easily obtain the same result by combining - a QTabWidget with a QDialog and provide \l{QPushButton}s - yourself. - - See also the \l{dialogs/tabdialog} example, which shows how to - implement tab dialogs in Qt 4. - - \section1 QTabWidget - - See \l{#properties}{Properties} for a list of QTabWidget - properties in Qt 3 that have changed in Qt 4. - - \section1 QTable - - The \c QTable, \c QTableItem, \c QComboTableItem, \c - QCheckTableItem, and \c QTableSelection classes have been renamed - Q3Table, Q3TableItem, Q3ComboTableItem, Q3CheckTableItem, and - Q3TableSelection and moved to the Qt3Support library. - New Qt applications should use the new QTableWidget or QTableView - class instead. - - Some of these classes behave differently with respect to the way - they handle \c NULL pointers. For example, Q3TableItem::setPixmap() - no longer accepts \c NULL or 0 to indicate that the item should - contain a null pixmap; in this case, a null pixmap should be - constructed and passed explicitly to the function. - - See \l{Model/View Programming} for an overview of the new item - view classes. - - \section1 QTextCodec - - The loadCharmap() and loadCharmapFromFile() functions are no longer - available in Qt 4. You need to create your own codec if you want to - create a codec based on a POSIX2 charmap definition. - - \section1 QTextDrag - - The \c QTextDrag class has been renamed Q3TextDrag and moved to - the Qt3Support library. In Qt 4, use QMimeData - instead and call QMimeData::setText() to set the data. - - See \l{Porting to Qt 4 - Drag and Drop} for a comparison between - the drag and drop APIs in Qt 3 and Qt 4. - - \section1 QTextEdit - - The old QTextEdit and QTextBrowser classes have been renamed - Q3TextEdit and Q3TextBrowser, and have been moved to Qt3Support. - The new QTextEdit and QTextBrowser have a somewhat different API. - - The \c QTextEdit::setWrapPolicy() function has been renamed to \l{QTextEdit::setWordWrapMode()}{setWordWrapMode()} and the - \c QTextEdit::setWrapColumnOrWidth() function has been renamed to \l{QTextEdit::setLineWrapColumnOrWidth()} - {setLineWrapColumnOrWidth()}. The Q3TextEdit::setWrapPolicy() and Q3TextEdit::setWrapColumnOrWidth() still provide this - functionality in the Q3TextEdit class. - - - See \l{Rich Text Processing} for an overview of the Qt 4 rich - text classes. - - \section1 QTextIStream - - The QTextIStream convenience class is no longer provided in Qt 4. Use - QTextStream directly instead. - - \section1 QTextOStream - - The QTextOStream convenience class is no longer provided in Qt 4. Use - QTextStream directly instead. - - \section1 QTextOStreamIterator - - The undocumented \c QTextOStreamIterator class has been removed - from the Qt library. If you need it in your application, feel - free to copy the source code from the Qt 3 \c <qtl.h> header - file. - - \section1 QTextStream - - QTextStream has undergone a number of API and implementation enhancements, - and some of the changes affect QTextStream's behavior: - - \list - \o QTextStream now uses buffered writing, which means that you need to - call QTextStream::flush(), or use the streaming manipulators \c endl or - \c flush if you need QTextStream to flush its write buffer. The stream is - flushed automatically if QTextStream is deleted or when the device is - closed. - \o QTextStream now uses buffered reading, so if you read a line from the - stream, QTextStream will read as much as it can from the device to - fill up its internal read buffer. This speeds up reading significantly, - but Qt 3 code that mixed QTextStream access and direct device access - may need to be updated. - \o While QTextStream in Qt 3 always translated end-of-line characters from - Windows style ("\\r\\n") to Unix style ("\\n") on Windows, QTextStream in - Qt 4 only does this on devices opened with the \c{QIODevice::Text} mode - (formerly \c{IO_Translate}). - \endlist - - Note that when using a QTextStream on a QFile in Qt 4, calling - QIODevice::reset() on the QFile will not have the expected result - because QTextStream now buffers the file. Use the - QTextStream::seek() function instead. - - \section1 QTextView - - The \c QTextView class has been renamed Q3TextView and moved to the - Qt3Support library. - - \section1 QTimeEdit - - The QTimeEdit class in Qt 4 is a convenience class based on - QDateTimeEdit. The old class has been renamed Q3TimeEdit and moved - to the Qt3Support library. - - See \l{Porting to Qt 4 - Virtual Functions}{Virtual Functions} for - a list of \c QTimeEdit virtual member functions in Qt 3 that are no - longer virtual in Qt 4. - - \section1 QTimer - - Windows restricts the granularity of timers, but starting with Qt 4, - we emulate a finer time resolution. On Windows XP we use the - multimedia timer API, which gives us 1 millisecond resolution for - QTimer. - - Note that other versions of Windows have a lower timer resolution, - and that code relying on underlying system timer restrictions - encounters no such limitations using Qt 4 (e.g., setting an - interval of 0 millisecond results in Qt occupying all of the - processor time when no GUI events need processing). - - \section1 QToolBar - - The old \c QToolBar class, which worked with the old \c - QMainWindow and \c QDockArea classes and inherited from \c - QDockWindow, has been renamed Q3ToolBar and moved to - Qt3Support. Note that, when using Q3ToolBar, the toolbar's actions - must be \l {Q3Action}s. - - Use the new QToolBar class in new applications. - - \note \l{Q3ToolBar}'s - \l{Q3DockWindow::setHorizontallyStretchable()}{horizontallyStretchable} - property can be achieved in QToolBar with - \l{QWidget#Size Hints and Size Policies}{size policies}. - - \section1 QToolButton - - See \l{#properties}{Properties} for a list of QToolButton properties - in Qt 3 that have changed in Qt 4. - - Note that many of the properties that could previously be set in - the constructor must now be set separately. - - \section1 QToolTip - - The QToolTip::setGloballyEnabled() function no longer exists. - Tooltips can be disabled by \l{QObject::installEventFilter()}{installing - an event filter} on qApp (the unique QApplication object) to block events - of type QEvent::ToolTip. - - \section1 QUriDrag - - The \c QUriDrag class has been renamed Q3UriDrag and moved to the - Qt3Support library. In Qt 4, use QMimeData instead - and call QMimeData::setUrl() to set the URL. - - See \l{Porting to Qt 4 - Drag and Drop} for a comparison between - the drag and drop APIs in Qt 3 and Qt 4. - - \section1 QUrl - - The QUrl class has been rewritten from scratch in Qt 4 to be more - standard-compliant. The old QUrl class has been renamed Q3Url and - moved to the Qt3Support library. - - The new QUrl class provides an extensive list of compatibility - functions to ease porting from Q3Url to QUrl. A few functions - require you to change your code: - - \list - \o Q3Url::Q3Url(const Q3Url &, const QString &, bool) can be - simulated by combining the URLs manually (using - QString::operator+(), for example). - \o Q3Url::setEncodedPathAndQuery(const QString &) is replaced by - QUrl::setPath() and QUrl::setEncodedQuery(). - \o Q3Url::encodedPathAndQuery() is replaced by QUrl::path() and - QUrl::encodedQuery(). - \o Q3Url::isLocalFile() can be simulated by checking that - QUrl::protocol() is "file". - \o Q3Url::toString(bool, bool) is replaced by - QUrl::toString(int), where the \c int parameter specifies a - combination of \l{QUrl::FormattingOptions}{formatting - options}. - \endlist - - \section1 QUrlOperator - - The \c QUrlOperator class is no longer part of the public Qt API. - It has been renamed Q3UrlOperator and moved to Qt3Support. - - From Qt 4.4, the Network Access API provides a subset of the features - provided by \c QUrlOperator that are mostly intended for use with - applications that use the HTTP and FTP protocols. See the - QNetworkRequest, QNetworkReply, and QNetworkAccessManager documentation - for further details. - - \target qvaluelist.section - \section1 QValueList<T> - - The QValueList<T> class has been replaced by QList<T> and - QLinkedList<T> in Qt 4. As a help when porting older Qt - applications, the Qt3Support library contains a - QValueList<T> class implemented in terms of the new - QLinkedList<T>. Similarly, it contains QValueListIterator<T> and - QValueListConstIterator<T> classes implemented in terms of - QLinkedList<T>::iterator and QLinkedList<T>::const_iterator. - - When porting to Qt 4, you have the choice of using QList<T> or - QLinkedList<T> as alternatives to QValueList<T>. QList<T> has an - index-based API and provides very fast random access - (QList::operator[]), whereas QLinkedList<T> has an iterator-based - API. - - Here's a list of problem functions: - - \list - \o QValueList(const std::list<T> &) doesn't exist in QList or - QLinkedList. You can simulate it by calling - \l{QLinkedList::append()}{append()} in a loop. - - \o QValueList::insert(iterator, size_type, const T& x) doesn't - exist in QList or QLinkedList. Call - \l{QLinkedList::insert()}{insert()} repeatedly instead. - - \o QValueList::fromLast() doesn't exist in QList or QLinkedList. Use - QValueList::end() instead. - - \oldcode - for (QValueList<T>::iterator i = list.fromLast(); i != list.begin(); --i) - do_something(*i); - \newcode - QLinkedList<T>::iterator i = list.end(); - while (i != list.begin()) { - --i; // decrement i before using it - do_something(*i); - } - \endcode - - \o QValueList::append() and QValueList::prepend() return an - iterator to the inserted item. QList's and QLinkedList's - corresponding functions don't, but it's not a problem because - QValueList::prepend() always returns begin() and append() - always returns QValueList::end() - 1. - - \o QValueList::at(\e i) return an iterator to the item at index - \e i. This corresponds to QList::begin() + \e i. - - \o QValueList::contains(const T &) corresponds to - QList::count(const T &) and QLinkedList::count(const T &). - \endlist - - \section1 QValueVector<T> - - The QValueVector<T> class has been replaced by QVector<T> in Qt - 4. As a help when porting older Qt applications, the Qt3Support - library contains a Q3ValueVector<T> class implemented in terms of - the new QVector<T>. - - When porting from QValueVector<T> to QVector<T>, you might run - into the following incompatibilities: - - \list - \o QValueVector(const std::vector<T> &) doesn't exist in QVector. - You can simulate it by calling QVector::append()} in a loop. - \o QValueVector::resize(int, const T &) doesn't exist in QVector. - If you want the new items to be initialized with a particular - value, use QVector::insert() instead. - \o QValueVector::at() on a non-const vector returns a non-const - reference. This corresponds to QVector::operator[](). - \o Both QValueVector::at() functions have an \e ok parameter of - type \c{bool *} that is set to true if the index is within - bounds. This functionality doesn't exist in QVector; instead, - check the index against QVector::size() yourself. - \endlist - - See \l{Generic Containers} for an overview of the Qt 4 container - classes. - - \section1 QVariant - - Some changes to the rest of the Qt library have - implications on QVariant: - - \list 1 - \o The \c QVariant::ColorGroup enum value is defined only - if \c QT3_SUPPORT is defined. - \o The \c QVariant::IconSet enum value has been renamed - QVariant::Icon. - \o The \c QVariant::CString enum value is now a synonym for - QVariant::ByteArray. - \endlist - - Also, the QVariant(bool, int) constructor has been replaced by QVariant(bool). - Old code like QVariant(true, 0) should be replaced with QVariant(true); otherwise, - the QVariant(int, void *) overload might accidentally be triggered. - - Many of QVariant's convenience functions in Qt 3, such as toColor() and - toKeySequence(), have been removed to enable QVariant to be part of the - QtCore module. QVariant is still able to hold values of these types. - - Types which are not supported by any of the QVariant constructors can be - stored as variants with the QVariant::fromValue() function. Types with no - suitable convenience function for unpacking can be retrieved with the - QVariant::value() function or passed directly to classes that implement - the QVariant() operator. - - \table - \header \o Qt 3 function \o Qt 4 function - \input porting4-removedvariantfunctions.qdocinc - \endtable - - See the QVariant::Type enum for a list of types supported by QVariant. - - \section1 QVBox - - The \c QVBox class is now only available as Q3VBox in Qt 4. You - can achieve the same result as \c QVBox by creating a QWidget - with a vertical layout: - - \oldcode - QVBox *vbox = new QVBox; - QPushButton *child1 = new QPushButton(vbox); - QPushButton *child2 = new QPushButton(vbox); - \newcode - QWidget *vbox = new QWidget; - QPushButton *child1 = new QPushButton; - QPushButton *child2 = new QPushButton; - - QVBoxLayout *layout = new QVBoxLayout; - layout->addWidget(child1); - layout->addWidget(child2); - vbox->setLayout(layout); - \endcode - - Note that child widgets are not automatically placed into the widget's - layout; you will need to manually add each widget to the QVBoxLayout. - - \section1 QVGroupBox - - The \c QVGroupBox class has been renamed Q3VGroupBox and moved to - the Qt3Support library. - Qt 4 does not provide a specific replacement class for \c QVGroupBox - since QGroupBox is designed to be a generic container widget. As a - result, you need to supply your own layout for any child widgets. - - See \l{#QGroupBox} for more information about porting code that uses - group boxes. - - \section1 QWhatsThis - - The QWhatsThis class has been redesigned in Qt 4. The old \c - QWhatsThis class is available as Q3WhatsThis in Qt3Support. - - \section1 QWidget - - Widget background painting has been greatly improved, supporting - flicker-free updates and making it possible to have - semi-transparent widgets. This renders the following background - handling functions obsolete: - - \list - \o QWidget::repaint(bool noErase) - the \c noErase boolean parameter is gone - \o QWidget::setBackgroundMode(BackgroundMode m) - \o QWidget::backgroundBrush() const - \o QWidget::setBackgroundPixmap(const QPixmap &pm) - \o QWidget::backgroundPixmap() const - \o QWidget::setBackgroundColor(const QColor &c) - \o QWidget::backgroundColor() const - \o QWidget::foregroundColor() const - \o QWidget::eraseColor() const - \o QWidget::setEraseColor(const QColor &c) - \o QWidget::erasePixmap() const - \o QWidget::setErasePixmap(const QPixmap &p) - \o QWidget::paletteForegroundColor() - \o QWidget::setPaletteForegroundColor(const QColor &c) - \o QWidget::paletteBackgroundColor() - \o QWidget::setPaletteBackgroundColor(const QColor &c) - \o QWidget::paletteBackgroundPixmap() const - \o QWidget::setPaletteBackgroundPixmap(const QPixmap &p) - \o QWidget::erase() - \o QWidget::erase(const QRect &r) - \o QWidget::setBackgroundOrigin( BackgroundOrigin ) - \o QWidget::BackgroundOrigin backgroundOrigin() const - \o QWidget::backgroundOffset() - \endlist - - Sample code on how to do obtain similar behavior from Qt 4, previously - handled by some of the above functions can be found in the - \l{http://qt.nokia.com/doc/qwidget-qt3.html}{Qt 3 Support Members for QWidget} - page. - - A widget now receives change events in its QWidget::changeEvent() - handler. This makes the following virtual change handlers obsolete: - - \list - \o QWidget::styleChange - use QEvent::StyleChange - \o QWidget::enabledChange - use QEvent::EnabledChange - \o QWidget::paletteChange - use QEvent::PaletteChange - \o QWidget::fontChange - use QEvent::FontChange - \o QWidget::windowActivationChange - use QEvent::ActivationChange - \o QWidget::languageChange - use QEvent::LanguageChange - \endlist - - The following functions were slots, but are no more: - \list - \o QWidget::clearFocus() - \o QWidget::setMouseTracking() - \o QWidget::stackUnder(QWidget*) - \o QWidget::move(int x, int y) - \o QWidget::move(const QPoint &) - \o QWidget::resize(int w, int h) - \o QWidget::resize(const QSize &) - \o QWidget::setGeometry(int x, int y, int w, int h) - \o QWidget::setGeometry(const QRect &) - \o QWidget::adjustSize() - \o QWidget::update(int x, int y, int w, int h) - \o QWidget::update(const QRect&) - \o QWidget::repaint(bool erase) - \o QWidget::repaint(int x, int y, int w, int h, bool erase) - \o QWidget::repaint(const QRect &, bool erase) - \o QWidget::repaint(const QRegion &, bool erase) - \o QWidget::setCaption(const QString &) - \o QWidget::setIcon(const QPixmap &) - \o QWidget::setIconText(const QString &) - \endlist - - The following functions were incorrectly marked as virtual: - - \list - \o QWidget::close(bool alsoDelete) - \o QWidget::create(WId, bool, bool) - \o QWidget::destroy(bool) - \o QWidget::move(int x, int y) - \o QWidget::reparent(QWidget *parent, WFlags, const QPoint &, bool) - \o QWidget::resize(int w, int h) - \o QWidget::setAcceptDrops(bool on) - \o QWidget::setActiveWindow() - \o QWidget::setAutoMask(bool) - \o QWidget::setBackgroundColor(const QColor &) - \o QWidget::setBackgroundMode(BackgroundMode) - \o QWidget::setBackgroundOrigin(BackgroundOrigin) - \o QWidget::setBackgroundPixmap(const QPixmap &) - \o QWidget::setCaption(const QString &) - \o QWidget::setCursor(const QCursor &) - \o QWidget::setEnabled(bool) - \o QWidget::setEraseColor(const QColor &) - \o QWidget::setErasePixmap(const QPixmap &) - \o QWidget::setFocus() - \o QWidget::setFocusPolicy(FocusPolicy) - \o QWidget::setFocusProxy(QWidget *) - \o QWidget::setFont(const QFont &) - \o QWidget::setGeometry(const QRect &) - \o QWidget::setGeometry(int x, int y, int w, int h) - \o QWidget::setIcon(const QPixmap &) - \o QWidget::setIconText(const QString &) - \o QWidget::setKeyCompression(bool) - \o QWidget::setMask(const QBitmap &) - \o QWidget::setMask(const QRegion &) - \o QWidget::setMaximumSize(int maxw, int maxh) - \o QWidget::setMicroFocusHint(int x, int y, int w, int h, bool, QFont *f) - \o QWidget::setMinimumSize(int minw, int minh) - \o QWidget::setMouseTracking(bool enable) - \o QWidget::setPalette(const QPalette &) - \o QWidget::setPaletteBackgroundColor(const QColor &) - \o QWidget::setPaletteBackgroundPixmap(const QPixmap &) - \o QWidget::setSizeIncrement(int w, int h) - \o QWidget::setSizePolicy(QSizePolicy) - \o QWidget::setUpdatesEnabled(bool enable) - \o QWidget::setWState(uint) - \o QWidget::show() - \o QWidget::showFullScreen() - \o QWidget::showMaximized() - \o QWidget::showMinimized() - \o QWidget::showNormal() - \o QWidget::sizePolicy() - \o QWidget::unsetCursor() - \endlist - - The internal clearWState() function was removed. Use - QWidget::setAttribute() instead. - - setWFlags() was renamed QWidget::setWindowFlags(). - - clearWFlags() has no direct replacement. You can use - QWidget::setAttribute() instead. For example, - \c{setAttribute(..., false)} to clear an attribute. More information - is available \l{http://qt.nokia.com/doc/qwidget.html#setAttribute}{here}. - - testWFlags() was renamed to \l{QWidget::testAttribute()}{testAttribute()}. - - See \l{#properties}{Properties} for a list of QWidget properties - in Qt 3 that have changed in Qt 4. - - \section1 QWidgetFactory - - The \c QWidgetFactory class has been replaced by QFormBuilder in Qt 4. - - \section1 QWidgetIntDict - - The QWidgetIntDict class was a synonym for QIntDict<QWidget>. It - is no longer available in Qt 4. If you link against Qt3Support, - you can use Q3IntDict<QWidget> instead; otherwise, see the - \l{#qdict.section}{section on QDict<T>}. - - \target qwidgetlist.section - \section1 QWidgetList - - In Qt 3, the QWidgetList class was a typedef for - QPtrList<QWidget>. In Qt 4, it is a typedef for QList<QWidget *>. - See the \l{#qptrlist.section}{section on QPtrList<T>}. - - \section1 QWidgetPlugin - - The QWidgetPlugin class is no longer available in Qt 4. To create - custom widget plugins, subclass QDesignerCustomWidgetInterface to - provide information about the custom widget, and build a plugin in - the way described in the \l{designer/customwidgetplugin}{Custom - Widget Plugin} example. - - \section1 QWidgetStack - - The QWidgetStack class is no longer part of the Qt public API. It - has been renamed Q3WidgetStack and moved to Qt3Support. In Qt 4 - applications, you can use QStackedWidget instead to obtain the - same results. - - \section1 QWizard - - The \c QWizard class was reintroduced in Qt 4.3. See the - \l{Trivial Wizard Example}, \l{License Wizard Example} and - \l{Class Wizard Example} for more details. - - \section1 QWorkspace - - The \c QWorkspace in Qt 4 class requires explicit adding of MDI - windows with QWorkspace::addWindow(). -*/ - -/*! - \page porting4-virtual-functions.html - \title Porting to Qt 4 - Virtual Functions - \contentspage {Porting Guides}{Contents} - \previouspage Porting to Qt 4 - \nextpage Porting to Qt 4 - Drag and Drop - \ingroup porting - \brief An overview of changes to virtual functions in Qt 4. - - \section1 Virtual Functions - - Virtual functions that changed their signature in Qt 4: - - \table - \header \o Qt 3 function signature \o Qt 4 function signature - \input porting4-modifiedvirtual.qdocinc - \endtable - - Virtual functions that are not virtual in Qt 4: - - \table - \header \o Qt 3 function \o Comment - \input porting4-removedvirtual.qdocinc - \endtable -*/ |