Guarded transition depending on an object (not a type)

[ClintEastwood]

Hello all,

I'm trying to implement a Guarded Transition for a QStateMachine following this example:

class CheckedTransition : public QSignalTransition
 {
public:
    CheckedTransition(QCheckBox *check)
        : QSignalTransition(check, SIGNAL(stateChanged(int)))  {}
protected:
    bool eventTest(QEvent *e)  {
        if (!QSignalTransition::eventTest(e))
            return false;
        QStateMachine::SignalEvent *se = static_cast<QStateMachine::SignalEvent*>(e);
        return (se->arguments().at(0).toInt() == Qt::Checked);
    }
};
 
...
 
QCheckBox *check = new QCheckBox();
check->setTristate(true);
 
QState *s1 = new QState();
QState *s2 = new QState();
CheckedTransition *t1 = new CheckedTransition(check);
t1->setTargetState(s2);
s1->addTransition(t1);

class CheckedTransition : public QSignalTransition
 {
public:
    CheckedTransition(QCheckBox *check)
        : QSignalTransition(check, SIGNAL(stateChanged(int)))  {}
protected:
    bool eventTest(QEvent *e)  {
        if (!QSignalTransition::eventTest(e))
            return false;
        QStateMachine::SignalEvent *se = static_cast<QStateMachine::SignalEvent*>(e);
        return (se->arguments().at(0).toInt() == Qt::Checked);
    }
};
 
...
 
QCheckBox *check = new QCheckBox();
check->setTristate(true);
 
QState *s1 = new QState();
QState *s2 = new QState();
CheckedTransition *t1 = new CheckedTransition(check);
t1->setTargetState(s2);
s1->addTransition(t1);

To copy to clipboard, switch view to plain text mode 

However, in my case, instead of the signal stateChanged(int) with only an int argument, I have a signal with two arguments: an object and an enum type, and depending on the state of the object the eventTest will return true or false. This is my signal:

void newMessage(Message, System);

void newMessage(Message, System);

To copy to clipboard, switch view to plain text mode 

System is an enum type so I can access it as if it were an int value, but Message is a class... and I do not know how to access to this argument through the SignalEvent instance. So, my problem is exactly in this expression:

se->arguments().at(0).toInt()

se->arguments().at(0).toInt()

To copy to clipboard, switch view to plain text mode 

I have tried to cast the QVariant object to a Message instance but it generated an error. Does anyone know any solution? Is it possible to do what I want?

Thanks in advance,

[wysota]

Does Message inherit QObject? Is it registered with QVariant?

[ClintEastwood]

No, Message does not inherit QObject neither it is registered with QVariant. Do I have to do these things to achieve what I want? Can you outline me a little more those two points?

Thanks,

[wysota]

If you want to get this kind of object as a stored argument then it has to be registered with QVariant.