C++/Qt/QObject
cpp with qobject
/*
* Copyright (c) 2006-2007, Johan Thelin
*
* All rights reserved.
*
* Redistribution and use in source and binary forms, with or without modification,
* are permitted provided that the following conditions are met:
*
* * Redistributions of source code must retain the above copyright notice,
* this list of conditions and the following disclaimer.
* * Redistributions in binary form must reproduce the above copyright notice,
* this list of conditions and the following disclaimer in the documentation
* and/or other materials provided with the distribution.
* * Neither the name of APress nor the names of its contributors
* may be used to endorse or promote products derived from this software
* without specific prior written permission.
*
* THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
* "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
* LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
* A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT OWNER OR
* CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL,
* EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO,
* PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR
* PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF
* LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING
* NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS
* SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
*
*/
#include <string>
using namespace std;
#include <QtDebug>
#include <QObject>
class MyClass : public QObject
{
public:
MyClass( const string &text, QObject *parent = 0 );
const string &text();
void setText( const string &text );
int getLengthOfText();
private:
string m_text;
};
MyClass::MyClass( const string &text, QObject *parent ) : QObject( parent )
{
m_text = text;
}
const string &MyClass::text() { return m_text; }
void MyClass::setText( const string &text ) { m_text = text; }
int MyClass::getLengthOfText() { return m_text.size(); }
int main( int argc, char **argv )
{
QObject parent;
MyClass *a, *b, *c;
a = new MyClass( "foo", &parent );
b = new MyClass( "ba-a-ar", &parent );
c = new MyClass( "baz", &parent );
qDebug() << QString::fromStdString(a->text()) << " (" << a->getLengthOfText() << ")";
a->setText( b->text() );
qDebug() << QString::fromStdString(a->text()) << " (" << a->getLengthOfText() << ")";
return a->getLengthOfText() - c->getLengthOfText();
}
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;
}