Qt cast : QObject « Qt « C++

1. C++
2. Qt
3. QObject

Qt cast

  

/****************************************************************************
**
** Copyright (C) 2009 Nokia Corporation and/or its subsidiary(-ies).
** All rights reserved.
** Contact: Nokia Corporation (qt-info@nokia.com)
**
** This file is part of the documentation of the Qt Toolkit.
**
** $QT_BEGIN_LICENSE:LGPL$
** Commercial Usage
** Licensees holding valid Qt Commercial licenses may use this file in
** accordance with the Qt Commercial License Agreement provided with the
** Software or, alternatively, in accordance with the terms contained in
** a written agreement between you and Nokia.
**
** 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 1.1, 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 have questions regarding the use of this file, please contact
** Nokia at qt-info@nokia.com.
** $QT_END_LICENSE$
**
****************************************************************************/

#ifndef QTCAST_H
#define QTCAST_H

#include <QWidget>

class MyWidget : public QWidget
{
    Q_OBJECT

public:
    MyWidget();
};

#endif










#include <QLabel>
#include <QPushButton>

#include "qtcast.h"

MyWidget::MyWidget()
{

    QObject *obj = new MyWidget;



    QWidget *widget = qobject_cast<QWidget *>(obj);



    MyWidget *myWidget = qobject_cast<MyWidget *>(obj);



    QLabel *label = qobject_cast<QLabel *>(obj);
 
    // label is 0



    if (QLabel *label = qobject_cast<QLabel *>(obj)) {
 
        label->setText(tr("Ping"));
    } else if (QPushButton *button = qobject_cast<QPushButton *>(obj)) {
        button->setText(tr("Pong!"));
    }

}

int main()
{
    return 0;
}

   
    
  

Related examples in the same category