doc/src/snippets/signalsandslots/signalsandslots.cpp
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     1 /****************************************************************************
       
     2 **
       
     3 ** Copyright (C) 2009 Nokia Corporation and/or its subsidiary(-ies).
       
     4 ** All rights reserved.
       
     5 ** Contact: Nokia Corporation (qt-info@nokia.com)
       
     6 **
       
     7 ** This file is part of the documentation of the Qt Toolkit.
       
     8 **
       
     9 ** $QT_BEGIN_LICENSE:LGPL$
       
    10 ** No Commercial Usage
       
    11 ** This file contains pre-release code and may not be distributed.
       
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    13 ** contained in the Technology Preview License Agreement accompanying
       
    14 ** this package.
       
    15 **
       
    16 ** GNU Lesser General Public License Usage
       
    17 ** Alternatively, this file may be used under the terms of the GNU Lesser
       
    18 ** General Public License version 2.1 as published by the Free Software
       
    19 ** Foundation and appearing in the file LICENSE.LGPL included in the
       
    20 ** packaging of this file.  Please review the following information to
       
    21 ** ensure the GNU Lesser General Public License version 2.1 requirements
       
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    24 ** In addition, as a special exception, Nokia gives you certain additional
       
    25 ** rights.  These rights are described in the Nokia Qt LGPL Exception
       
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    28 ** If you have questions regarding the use of this file, please contact
       
    29 ** Nokia at qt-info@nokia.com.
       
    30 **
       
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    32 **
       
    33 **
       
    34 **
       
    35 **
       
    36 **
       
    37 **
       
    38 ** $QT_END_LICENSE$
       
    39 **
       
    40 ****************************************************************************/
       
    41 
       
    42 #include <QAbstractButton>
       
    43 
       
    44 #include "signalsandslots.h"
       
    45 
       
    46 //! [0]
       
    47 void Counter::setValue(int value)
       
    48 {
       
    49     if (value != m_value) {
       
    50         m_value = value;
       
    51         emit valueChanged(value);
       
    52     }
       
    53 }
       
    54 //! [0]
       
    55 
       
    56 int main()
       
    57 {
       
    58 //! [1]
       
    59     Counter a, b;
       
    60 //! [1] //! [2]
       
    61     QObject::connect(&a, SIGNAL(valueChanged(int)),
       
    62                      &b, SLOT(setValue(int)));
       
    63 //! [2]
       
    64 
       
    65 //! [3]
       
    66     a.setValue(12);     // a.value() == 12, b.value() == 12
       
    67 //! [3] //! [4]
       
    68     b.setValue(48);     // a.value() == 12, b.value() == 48
       
    69 //! [4]
       
    70 
       
    71 
       
    72     QWidget *widget = reinterpret_cast<QWidget *>(new QObject(0));
       
    73 //! [5]
       
    74     if (widget->inherits("QAbstractButton")) {
       
    75         QAbstractButton *button = static_cast<QAbstractButton *>(widget);
       
    76         button->toggle();
       
    77 //! [5] //! [6]
       
    78     }
       
    79 //! [6]
       
    80 
       
    81 //! [7]
       
    82     if (QAbstractButton *button = qobject_cast<QAbstractButton *>(widget))
       
    83         button->toggle();
       
    84 //! [7]
       
    85 }