QVariant is not working for user defined datatype

[narinder83]

Hello There,

I am facing difficulty with QVariant class. I've defined a sub class of QDateTime and trying to assign it to QVariant and read back. Q_DECLARE_METATYPE(myClass) and qRegisterMetaType declarations are in place still QVariant is not getting initialized with my defined class. Please suggest what is wrong here.

#include <QCoreApplication>
#include <QDateTime>
#include <QVariant>
#include <qdebug.h>

class myClass:public QDateTime
{


};

Q_DECLARE_METATYPE(myClass)

int main(int argc, char *argv[])
{
    QCoreApplication a(argc, argv);

    qRegisterMetaType<myClass>("myClass");

    myClass mc;
    mc.setDate (QDateTime::currentDateTime().date ());
    mc.setTime (QDateTime::currentDateTime() .time ());

    qDebug() << mc.date().day () << mc.date().month()  << mc.date().year () ;

    QVariant vc;
   vc.setValue (mc);

    myClass dateTime = vc.value<myClass>();

    qDebug() << dateTime.date().day () << dateTime.date().month()  << dateTime.date().year () ;

    return a.exec();
}

[VRonin]

@narinder83 said in QVariant is not working for user defined datatype:

myClass dateTime = vc.value<myClass>();

it might just be a problem of the default copy constructor. try defining it.

class myClass : public QDateTime
{
public:
myClass() = default;
~myClass() = default;
myClass(myClass&& other)
:QDateTime(static_cast<QDateTime&&>(other))
{}
myClass(const myClass& other)
:QDateTime(static_cast<const QDateTime&>(other))
{}
myClass& operator=(const myClass& other){
QDateTime::operator=(static_cast<const QDateTime&>(other));
return *this;
}
myClass& operator=(myClass&& other){
QDateTime::operator=(static_cast<QDateTime&&>(other));
return *this;
}
};