QVariant to/from QFlag

shavera

I'm unit testing a function for a table model, where it emits 'headerDataChanged'. One of the fields in this signal is a 'Qt::Orientation' flag. When a QSignalSpy picks it up, the QVariant for the orientation field is an invalid one. I can't cast back to Qt::Orientation. Do I have to locally declare orientation as a metatype? It seems odd it wouldn't just treat it as an int or something.

SGaist

Hi,

Can you show the code from that part ?

mrjj

Hi
In Qt 5.7 it seems happy about it
alt text

  QVariant test;
  test.setValue(Qt::Orientation::Vertical);
  Qt::Orientation back = test.value<Qt::Orientation >();
  qDebug() << "i see " << back;

shavera

This post is deleted!

shavera

@mrjj It may be that 5.7 has the appropriate behaviour, but 5.5 doesn't seem to. For now, my project seems to be settled on 5.5, so maybe this is just a limitation I have to deal with, but is already fixed in newer Qt versions.

For a little tester I made a class:

class Dummy : public QObject
{
    Q_OBJECT
public:
    enum DummyOpt{
        Alpha = 0b01,
        Beta = 0b10
    };
    Q_DECLARE_FLAGS(DummyOpts, DummyOpt)

    explicit Dummy(QObject *parent = nullptr);

signals:
    void optionsChanged(DummyOpts);

public slots:
    void setDummyOpts(DummyOpts o);
};

Q_DECLARE_OPERATORS_FOR_FLAGS(Dummy::DummyOpts);

setDummyOpts just emits the optionsChanged signal. In main, I hooked up a QSignalSpy like:

    Dummy d;
    QSignalSpy optionsSpy{&d, &Dummy::optionsChanged};
    d.setDummyOpts(Dummy::Alpha);

    QVariant variant = optionsSpy.at(0).at(0);

    qDebug() << variant.value<Dummy::DummyOpts>();

And when I compile, I get:

error: static assertion failed: Type is not registered, please use the Q_DECLARE_METATYPE macro to make it known to Qt's meta-object system
Q_STATIC_ASSERT_X(QMetaTypeId2<T>::Defined, "Type is not registered, please use the Q_DECLARE_METATYPE macro to make it known to Qt's meta-object system");

mrjj

@shavera said in QVariant to/from QFlag:

Q_DECLARE_METATYPE

I dont see you register your own enum anywhere?
Q_DECLARE_METATYPE (Dummy::DummyOpt);