/****************************************************************************+
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**+
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** Copyright (C) 2010 Nokia Corporation and/or its subsidiary(-ies).+
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** All rights reserved.+
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** Contact: Nokia Corporation (qt-info@nokia.com)+
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**+
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** This file is part of the QtGui module of the Qt Toolkit.+
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**+
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** $QT_BEGIN_LICENSE:LGPL$+
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** No Commercial Usage+
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** This file contains pre-release code and may not be distributed.+
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** You may use this file in accordance with the terms and conditions+
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** contained in the Technology Preview License Agreement accompanying+
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** this package.+
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**+
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** GNU Lesser General Public License Usage+
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** Alternatively, this file may be used under the terms of the GNU Lesser+
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** General Public License version 2.1 as published by the Free Software+
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** Foundation and appearing in the file LICENSE.LGPL included in the+
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** packaging of this file.  Please review the following information to+
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** ensure the GNU Lesser General Public License version 2.1 requirements+
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** will be met: http://www.gnu.org/licenses/old-licenses/lgpl-2.1.html.+
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**+
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** In addition, as a special exception, Nokia gives you certain additional+
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** rights.  These rights are described in the Nokia Qt LGPL Exception+
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** version 1.1, included in the file LGPL_EXCEPTION.txt in this package.+
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**+
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** If you have questions regarding the use of this file, please contact+
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** Nokia at qt-info@nokia.com.+
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**+
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**+
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**+
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**+
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**+
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**+
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**+
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**+
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** $QT_END_LICENSE$+
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**+
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****************************************************************************/+
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+
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#include "qstackedlayout.h"+
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#include "qlayout_p.h"+
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+
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#include <qlist.h>+
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#include <qwidget.h>+
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#include "private/qlayoutengine_p.h"+
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+
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QT_BEGIN_NAMESPACE+
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+
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class QStackedLayoutPrivate : public QLayoutPrivate+
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{+
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    Q_DECLARE_PUBLIC(QStackedLayout)+
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public:+
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    QStackedLayoutPrivate() : index(-1), stackingMode(QStackedLayout::StackOne) {}+
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    QList<QLayoutItem *> list;+
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    int index;+
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    QStackedLayout::StackingMode stackingMode;+
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};+
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+
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/*!+
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    \class QStackedLayout+
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+
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    \brief The QStackedLayout class provides a stack of widgets where+
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    only one widget is visible at a time.+
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+
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    \ingroup geomanagement+
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+
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    QStackedLayout can be used to create a user interface similar to+
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    the one provided by QTabWidget. There is also a convenience+
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    QStackedWidget class built on top of QStackedLayout.+
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+
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    A QStackedLayout can be populated with a number of child widgets+
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    ("pages"). For example:+
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+
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    \snippet doc/src/snippets/qstackedlayout/main.cpp 0+
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    \codeline+
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    \snippet doc/src/snippets/qstackedlayout/main.cpp 2+
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    \snippet doc/src/snippets/qstackedlayout/main.cpp 3+
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+
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    QStackedLayout provides no intrinsic means for the user to switch+
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    page. This is typically done through a QComboBox or a QListWidget+
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    that stores the titles of the QStackedLayout's pages. For+
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    example:+
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+
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    \snippet doc/src/snippets/qstackedlayout/main.cpp 1+
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+
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    When populating a layout, the widgets are added to an internal+
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    list. The indexOf() function returns the index of a widget in that+
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    list. The widgets can either be added to the end of the list using+
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    the addWidget() function, or inserted at a given index using the+
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    insertWidget() function. The removeWidget() function removes the+
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    widget at the given index from the layout. The number of widgets+
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    contained in the layout, can be obtained using the count()+
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    function.+
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+
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    The widget() function returns the widget at a given index+
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    position. The index of the widget that is shown on screen is given+
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    by currentIndex() and can be changed using setCurrentIndex(). In a+
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    similar manner, the currently shown widget can be retrieved using+
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    the currentWidget() function, and altered using the+
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    setCurrentWidget() function.+
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+
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    Whenever the current widget in the layout changes or a widget is+
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    removed from the layout, the currentChanged() and widgetRemoved()+
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    signals are emitted respectively.+
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+
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    \sa QStackedWidget, QTabWidget+
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*/+
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+
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/*!+
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    \fn void QStackedLayout::currentChanged(int index)+
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+
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    This signal is emitted whenever the current widget in the layout+
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    changes.  The \a index specifies the index of the new current+
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    widget, or -1 if there isn't a new one (for example, if there+
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    are no widgets in the QStackedLayout)+
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+
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    \sa currentWidget(), setCurrentWidget()+
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*/+
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+
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/*!+
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    \fn void QStackedLayout::widgetRemoved(int index)+
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+
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    This signal is emitted whenever a widget is removed from the+
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    layout. The widget's \a index is passed as parameter.+
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+
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    \sa removeWidget()+
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*/+
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+
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/*!+
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    \fn QWidget *QStackedLayout::widget()+
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    \internal+
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*/+
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+
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/*!+
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    Constructs a QStackedLayout with no parent.+
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+
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    This QStackedLayout must be installed on a widget later on to+
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    become effective.+
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+
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    \sa addWidget(), insertWidget()+
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*/+
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QStackedLayout::QStackedLayout()+
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    : QLayout(*new QStackedLayoutPrivate, 0, 0)+
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{+
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}+
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+
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/*!+
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    Constructs a new QStackedLayout with the given \a parent.+
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+
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    This layout will install itself on the \a parent widget and+
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    manage the geometry of its children.+
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*/+
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QStackedLayout::QStackedLayout(QWidget *parent)+
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    : QLayout(*new QStackedLayoutPrivate, 0, parent)+
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{+
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}+
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+
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/*!+
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    Constructs a new QStackedLayout and inserts it into+
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    the given \a parentLayout.+
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*/+
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QStackedLayout::QStackedLayout(QLayout *parentLayout)+
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    : QLayout(*new QStackedLayoutPrivate, parentLayout, 0)+
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{+
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}+
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+
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/*!+
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    Destroys this QStackedLayout. Note that the layout's widgets are+
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    \e not destroyed.+
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*/+
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QStackedLayout::~QStackedLayout()+
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{+
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    Q_D(QStackedLayout);+
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    qDeleteAll(d->list);+
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}+
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+
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/*!+
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    Adds the given \a widget to the end of this layout and returns the+
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    index position of the \a widget.+
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+
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    If the QStackedLayout is empty before this function is called,+
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    the given \a widget becomes the current widget.+
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+
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    \sa insertWidget(), removeWidget(), setCurrentWidget()+
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*/+
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int QStackedLayout::addWidget(QWidget *widget)+
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{+
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    Q_D(QStackedLayout);+
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    return insertWidget(d->list.count(), widget);+
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}+
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+
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/*!+
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    Inserts the given \a widget at the given \a index in this+
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    QStackedLayout. If \a index is out of range, the widget is+
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    appended (in which case it is the actual index of the \a widget+
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    that is returned).+
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+
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    If the QStackedLayout is empty before this function is called, the+
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    given \a widget becomes the current widget.+
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+
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    Inserting a new widget at an index less than or equal to the current index+
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    will increment the current index, but keep the current widget.+
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+
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    \sa addWidget(), removeWidget(), setCurrentWidget()+
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*/+
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int QStackedLayout::insertWidget(int index, QWidget *widget)+
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{+
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    Q_D(QStackedLayout);+
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    addChildWidget(widget);+
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    index = qMin(index, d->list.count());+
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    if (index < 0)+
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        index = d->list.count();+
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    QWidgetItem *wi = QLayoutPrivate::createWidgetItem(this, widget);+
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    d->list.insert(index, wi);+
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    invalidate();+
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    if (d->index < 0) {+
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        setCurrentIndex(index);+
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    } else {+
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        if (index <= d->index)+
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            ++d->index;+
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        if (d->stackingMode == StackOne)+
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            widget->hide();+
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        widget->lower();+
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    }+
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    return index;+
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}+
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+
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/*!+
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    \reimp+
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*/+
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QLayoutItem *QStackedLayout::itemAt(int index) const+
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{+
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    Q_D(const QStackedLayout);+
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    return d->list.value(index);+
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}+
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+
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// Code that enables proper handling of the case that takeAt() is+
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// called somewhere inside QObject destructor (can't call hide()+
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// on the object then)+
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+
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class QtFriendlyLayoutWidget : public QWidget+
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{+
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public:+
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    inline bool wasDeleted() const { return d_ptr->wasDeleted; }+
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};+
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+
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static bool qt_wasDeleted(const QWidget *w) { return static_cast<const QtFriendlyLayoutWidget*>(w)->wasDeleted(); }+
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+
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+
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/*!+
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    \reimp+
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*/+
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QLayoutItem *QStackedLayout::takeAt(int index)+
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{+
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    Q_D(QStackedLayout);+
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    if (index <0 || index >= d->list.size())+
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        return 0;+
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    QLayoutItem *item = d->list.takeAt(index);+
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    if (index == d->index) {+
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        d->index = -1;+
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        if ( d->list.count() > 0 ) {+
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            int newIndex = (index == d->list.count()) ? index-1 : index;+
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            setCurrentIndex(newIndex);+
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        } else {+
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            emit currentChanged(-1);+
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        }+
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    } else if (index < d->index) {+
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        --d->index;+
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    }+
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    emit widgetRemoved(index);+
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    if (item->widget() && !qt_wasDeleted(item->widget()))+
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        item->widget()->hide();+
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    return item;+
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}+
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+
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/*!+
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    \property QStackedLayout::currentIndex+
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    \brief the index position of the widget that is visible+
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+
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    The current index is -1 if there is no current widget.+
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+
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    \sa currentWidget(), indexOf()+
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*/+
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void QStackedLayout::setCurrentIndex(int index)+
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{+
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    Q_D(QStackedLayout);+
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    QWidget *prev = currentWidget();+
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    QWidget *next = widget(index);+
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    if (!next || next == prev)+
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        return;+
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+
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    bool reenableUpdates = false;+
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    QWidget *parent = parentWidget();+
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+
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    if (parent && parent->updatesEnabled()) {+
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        reenableUpdates = true;+
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        parent->setUpdatesEnabled(false);+
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    }+
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+
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    QWidget *fw = parent ? parent->window()->focusWidget() : 0;+
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    if (prev) {+
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        prev->clearFocus();+
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        if (d->stackingMode == StackOne)+
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            prev->hide();+
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    }+
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+
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    d->index = index;+
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    next->raise();+
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    next->show();+
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+
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    // try to move focus onto the incoming widget if focus+
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    // was somewhere on the outgoing widget.+
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+
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    if (parent) {+
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        if (fw && (prev && prev->isAncestorOf(fw))) { // focus was on old page+
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            // look for the best focus widget we can find+
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            if (QWidget *nfw = next->focusWidget())+
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                nfw->setFocus();+
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            else {+
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                // second best: first child widget in the focus chain+
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                QWidget *i = fw;+
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                while ((i = i->nextInFocusChain()) != fw) {+
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                    if (((i->focusPolicy() & Qt::TabFocus) == Qt::TabFocus)+
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                        && !i->focusProxy() && i->isVisibleTo(next) && i->isEnabled()+
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                        && next->isAncestorOf(i)) {+
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                        i->setFocus();+
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                        break;+
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                    }+
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                }+
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                // third best: incoming widget+
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                if (i == fw )+
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                    next->setFocus();+
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            }+
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        }+
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    }+
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    if (reenableUpdates)+
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        parent->setUpdatesEnabled(true);+
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    emit currentChanged(index);+
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}+
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+
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int QStackedLayout::currentIndex() const+
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{+
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    Q_D(const QStackedLayout);+
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    return d->index;+
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}+
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+
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+
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/*!+
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    \fn void QStackedLayout::setCurrentWidget(QWidget *widget)+
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+
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    Sets the current widget to be the specified \a widget. The new+
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    current widget must already be contained in this stacked layout.+
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+
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    \sa setCurrentIndex(), currentWidget()+
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 */+
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void QStackedLayout::setCurrentWidget(QWidget *widget)+
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{+
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    int index = indexOf(widget);+
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    if (index == -1) {+
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        qWarning("QStackedLayout::setCurrentWidget: Widget %p not contained in stack", widget);+
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        return;+
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    }+
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    setCurrentIndex(index);+
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}+
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+
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+
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/*!+
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    Returns the current widget, or 0 if there are no widgets in this+
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    layout.+
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+
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    \sa currentIndex(), setCurrentWidget()+
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*/+
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QWidget *QStackedLayout::currentWidget() const+
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{+
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    Q_D(const QStackedLayout);+
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    return d->index >= 0 ? d->list.at(d->index)->widget() : 0;+
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}+
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+
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/*!+
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    Returns the widget at the given \a index, or 0 if there is no+
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    widget at the given position.+
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+
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    \sa currentWidget(), indexOf()+
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*/+
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QWidget *QStackedLayout::widget(int index) const+
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{+
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    Q_D(const QStackedLayout);+
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     if (index < 0 || index >= d->list.size())+
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        return 0;+
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    return d->list.at(index)->widget();+
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}+
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+
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/*!+
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    \property QStackedLayout::count+
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    \brief the number of widgets contained in the layout+
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+
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    \sa currentIndex(), widget()+
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*/+
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int QStackedLayout::count() const+
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{+
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    Q_D(const QStackedLayout);+
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    return d->list.size();+
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}+
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+
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+
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/*!+
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    \reimp+
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*/+
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void QStackedLayout::addItem(QLayoutItem *item)+
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{+
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    QWidget *widget = item->widget();+
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    if (widget) {+
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        addWidget(widget);+
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        delete item;+
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    } else {+
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        qWarning("QStackedLayout::addItem: Only widgets can be added");+
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    }+
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}+
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+
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/*!+
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    \reimp+
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*/+
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QSize QStackedLayout::sizeHint() const+
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{+
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    Q_D(const QStackedLayout);+
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    QSize s(0, 0);+
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    int n = d->list.count();+
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+
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    for (int i = 0; i < n; ++i)+
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        if (QWidget *widget = d->list.at(i)->widget()) {+
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            QSize ws(widget->sizeHint());+
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            if (widget->sizePolicy().horizontalPolicy() == QSizePolicy::Ignored)+
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                ws.setWidth(0);+
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            if (widget->sizePolicy().verticalPolicy() == QSizePolicy::Ignored)+
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                ws.setHeight(0);+
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            s = s.expandedTo(ws);+
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        }+
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    return s;+
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}+
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+
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/*!+
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    \reimp+
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*/+
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QSize QStackedLayout::minimumSize() const+
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{+
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    Q_D(const QStackedLayout);+
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    QSize s(0, 0);+
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    int n = d->list.count();+
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+
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    for (int i = 0; i < n; ++i)+
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        if (QWidget *widget = d->list.at(i)->widget())+
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            s = s.expandedTo(qSmartMinSize(widget));+
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    return s;+
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}+
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+
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/*!+
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    \reimp+
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*/+
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void QStackedLayout::setGeometry(const QRect &rect)+
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{+
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    Q_D(QStackedLayout);+
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    switch (d->stackingMode) {+
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    case StackOne:+
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        if (QWidget *widget = currentWidget())+
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            widget->setGeometry(rect);+
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        break;+
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    case StackAll:+
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        if (const int n = d->list.count())+
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            for (int i = 0; i < n; ++i)+
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                if (QWidget *widget = d->list.at(i)->widget())+
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                    widget->setGeometry(rect);+
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        break;+
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    }+
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}+
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+
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/*!+
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    \enum QStackedLayout::StackingMode+
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    \since 4.4+
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+
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    This enum specifies how the layout handles its child widgets+
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    regarding their visibility.+
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+
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    \value StackOne+
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           Only the current widget is visible. This is the default.+
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+
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    \value StackAll+
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           All widgets are visible. The current widget is merely raised.+
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*/+
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+
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+
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/*!+
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    \property QStackedLayout::stackingMode+
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    \brief determines the way visibility of child widgets are handled.+
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    \since 4.4+
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+
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    The default value is StackOne. Setting the property to StackAll+
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    allows you to make use of the layout for overlay widgets+
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    that do additional drawing on top of other widgets, for example,+
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    graphical editors.+
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*/+
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+
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QStackedLayout::StackingMode QStackedLayout::stackingMode() const+
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{+
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    Q_D(const QStackedLayout);+
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    return d->stackingMode;+
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}+
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+
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void QStackedLayout::setStackingMode(StackingMode stackingMode)+
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{+
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    Q_D(QStackedLayout);+
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    if (d->stackingMode == stackingMode)+
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        return;+
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    d->stackingMode = stackingMode;+
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+
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    const int n = d->list.count();+
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    if (n == 0)+
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        return;+
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+
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    switch (d->stackingMode) {+
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    case StackOne:+
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        if (const int idx = currentIndex())+
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            for (int i = 0; i < n; ++i)+
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                if (QWidget *widget = d->list.at(i)->widget())+
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                    widget->setVisible(i == idx);+
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        break;+
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    case StackAll: { // Turn overlay on: Make sure all widgets are the same size+
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        QRect geometry;+
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        if (const QWidget *widget = currentWidget())+
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            geometry = widget->geometry();+
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        for (int i = 0; i < n; ++i)+
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            if (QWidget *widget = d->list.at(i)->widget()) {+
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                if (!geometry.isNull())+
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                    widget->setGeometry(geometry);+
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                widget->setVisible(true);+
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            }+
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    }+
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        break;+
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    }+
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}+
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+
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QT_END_NAMESPACE+
−