qtcast.cpp

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// Copyright (C) 2016 The Qt Company Ltd.
// SPDX-License-Identifier: LicenseRef-Qt-Commercial OR BSD-3-Clause
 
#include <QLabel>
#include <QPushButton>
 
#include "qtcast.h"
 
MyWidget::MyWidget()
{
//! [0]
    QObject *obj = new MyWidget;
//! [0]
 
//! [1]
    QWidget *widget = qobject_cast<QWidget *>(obj);
//! [1]
 
//! [2]
    MyWidget *myWidget = qobject_cast<MyWidget *>(obj);
//! [2]
 
//! [3]
    QLabel *label = qobject_cast<QLabel *>(obj);
//! [3] //! [4]
    // label is nullptr
//! [4]
 
//! [5]
    if (QLabel *label = qobject_cast<QLabel *>(obj)) {
//! [5] //! [6]
        label->setText(tr("Ping"));
    } else if (QPushButton *button = qobject_cast<QPushButton *>(obj)) {
        button->setText(tr("Pong!"));
    }
//! [6]
}