Russian Qt Forum

#define PQ_OBJECT \
public:\
    QStringList myList;

class PQWidget;
class PQWidget : public QWidget {
    Q_OBJECT
    PQ_OBJECT

public:
    Q_INVOKABLE explicit PQWidget(QWidget *parent = 0)
        : QWidget(parent){}
    virtual ~PQWidget(){}
};

class PQPushButton;
class PQPushButton : public QPushButton {
    Q_OBJECT
    PQ_OBJECT

public:
    Q_INVOKABLE explicit PQPushButton(QWidget *parent = 0)
        : QPushButton(parent) {
        myList << "text1";
        myList << "text2";
    }
};

// QObject -> PQWidget
    QObject *button = new PQPushButton;
    PQWidget *pbutton = (PQWidget*) button;

    if(pbutton->myList.contains("text1")) {
        qDebug() << "Okay!";
    }

    qDebug() << "QObject -> PQWidget OK!";

class PQObject;
class PQObject : public QObject {
    Q_OBJECT
    PQ_OBJECT

public:
    Q_INVOKABLE explicit PQObject(QObject *parent = 0)
        : QObject(parent){}
    virtual ~PQObject(){}
};

class PQTimer;
class PQTimer : public QTimer {
    Q_OBJECT
    PQ_OBJECT

public:
    Q_INVOKABLE explicit PQTimer(QObject *parent = 0)
        : QTimer(parent) {
        myList << "text1";
        myList << "text2";
    }
};

// QObject -> PQObject
    QObject *timer = new PQTimer;
    PQObject *ptimer = (PQObject*) timer;

    if(ptimer->myList.contains("qwerty")) { // Segmentation fault
        qDebug() << "Okay!";
    }

    qDebug() << "QObject -> PQObject OK!";

// есть не только такой код:
QWidget *button= new PQPushButton;
PQWidget *pbutton = (PQWidget*) button;

// есть еще и такой:
QWidget *widget= new PQWidget;
PQWidget *pwidget= (PQWidget*) widget;

class PQObject : public QObject {
    Q_OBJECT

public:
    explicit PQObject(QObject *parent = 0)
        : QObject(parent){}

    virtual ~PQObject(){}

    QStringList myList;
};

class PQPushButton : public QPushButton, public PQObject {
public:
    explicit PQPushButton(QWidget *parent = 0)
        : QPushButton(parent)
    {
    }

    virtual ~PQPushButton(){}
};

QObject *button = new PQPushButton; // ошибка: 'QObject' is an ambiguous base of 'PQPushButton'

PQObject *button = new PQPushButton;