QVariant and Enums: different behavior in Qt 5.7 and Qt 5.6.1

tga2450

Hi all,

I am trying to use QVariant with enum types. My issue is that I have different behaviors when building with Qt 5.7 (run on computer) and building with Qt 5.6.1 (run on embedded target).

Here is an example code :

#include <QCoreApplication>
#include <QMetaType>
#include <QMetaEnum>
#include <QVariant>
#include <QDebug>

enum Test
{
    Test1,
    Test2,
    Test3
};
Q_DECLARE_METATYPE(Test)

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

    Test t = Test2;
    QVariant v(t);

    qDebug()<<"Can convert: "+QString("%1").arg(v.canConvert<Test>());
    Test t2 = v.value<Test>();
    qDebug()<<"Value of t2: "+QString("%1").arg(t2);


    return a.exec();
}

Built under Qt 5.7 and running on computer it returns

Can convert: 1
Value of t2: 1

Built under Qt 5.6.1 and running on my embedded target it returns

Can convert: 0
Value of t2: 0

I cannot figure out why QVariant::canConvert always return false with all enums on my target.

Thank you for your help.

VRonin

can you try using Q_ENUM?

globalenums.h

class GlobalEnums{
Q_GADGET
Q_DISABLE_COPY(GlobalEnums)
GlobalEnums() = delete;
~GlobalEnums() = delete;
public:
enum Test
{
    Test1,
    Test2,
    Test3
};
Q_ENUM(Test)
};

main.cpp

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

    GlobalEnums::Test t = GlobalEnums::Test2;
    QVariant v(t);

    qDebug()<<"Can convert: " << v.canConvert<GlobalEnums::Test>();
    GlobalEnums::Test t2 = v.value<GlobalEnums::Test>();
    qDebug()<<"Value of t2: "<< t2;


    return a.exec();
}

tga2450

Thank you VRonin for your help.

I tried your suggestion but it didn't change the results on my target. Conversion from QVariant to Test enum is still refused.

Chris Kawa

Could be related: QTBUG-53384.
Can you check with Qt 5.6.2?