- Qt 5.5
- Qt QML
- Extending QML - Signal Support Example
- main.cpp Example File
- Qt 5.5.1 Reference Documentation

# main.cpp Example File

referenceexamples/signal/main.cpp

    /****************************************************************************
    **
    ** Copyright (C) 2015 The Qt Company Ltd.
    ** Contact: http://www.qt.io/licensing/
    **
    ** This file is part of the examples of the Qt Toolkit.
    **
    ** $QT_BEGIN_LICENSE:BSD$
    ** You may use this file under the terms of the BSD license as follows:
    **
    ** "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
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    **     from this software without specific prior written permission.
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    #include <QCoreApplication>
    #include <QQmlEngine>
    #include <QQmlComponent>
    #include <QDebug>
    #include "birthdayparty.h"
    #include "person.h"

    int main(int argc, char ** argv)
    {
        QCoreApplication app(argc, argv);

        qmlRegisterType<BirthdayPartyAttached>();
        qmlRegisterType<BirthdayParty>("People", 1,0, "BirthdayParty");
        qmlRegisterType<ShoeDescription>();
        qmlRegisterType<Person>();
        qmlRegisterType<Boy>("People", 1,0, "Boy");
        qmlRegisterType<Girl>("People", 1,0, "Girl");

        QQmlEngine engine;
        QQmlComponent component(&engine, QUrl("qrc:example.qml"));
        BirthdayParty *party = qobject_cast<BirthdayParty *>(component.create());

        if (party && party->host()) {
            qWarning() << party->host()->name() << "is having a birthday!";

            if (qobject_cast<Boy *>(party->host()))
                qWarning() << "He is inviting:";
            else
                qWarning() << "She is inviting:";

            for (int ii = 0; ii < party->guestCount(); ++ii) {
                Person *guest = party->guest(ii);

                QDate rsvpDate;
                QObject *attached =
                    qmlAttachedPropertiesObject<BirthdayParty>(guest, false);
                if (attached)
                    rsvpDate = attached->property("rsvp").toDate();

                if (rsvpDate.isNull())
                    qWarning() << "   " << guest->name() << "RSVP date: Hasn't RSVP'd";
                else
                    qWarning() << "   " << guest->name() << "RSVP date:" << qPrintable(rsvpDate.toString());
            }

            party->startParty();
        } else {
            qWarning() << component.errors();
        }

        return 0;
    }