Namespace,qobject,enum trick. How to get it to work?

[BadKnees]

As my post says, i have tried it as well with the results posted above. And in <qtsource>/src/corelib/global/qnamespace.h the troll do not inherit the QObject. I would really like to get this to work

[jpn]

Use Q_GADGET instead of Q_OBJECT.

[SnarlCat]

Use Q_GADGET instead of Q_OBJECT.

This doesn't seem to work, inheriting from QObject or not ...

Still complains about missing staticMetaObject...

[BadKnees]

I've given up. I've tried everything i can think of. I have examined the preprocessor output with MOC_RUN defined and without. In qtcore qnamespace.h compiles fine as a namespace with a metaobject. But i cant reproduce it in my project. So i, as a second choise, used Q_GADGET in my class. This at least enables me to use QMetaEnum with an object which does not inherit from QObject. It would have been cooler with a namespace. But i will supress my compulsions, and go on with my life

[jpn]

This doesn't seem to work, inheriting from QObject or not ...

Still complains about missing staticMetaObject...

First of all, Q_GADGET is meant for non-QObjects. Just don't forget to re-run qmake after adding or removing Q_GADGET. Just like you would do with Q_OBJECT. Furthermore, you need to include the moc file by hand if you have Q_GADGET or Q_OBJECT in a .cpp file (it should be in a header file to avoid that).

[SnarlCat]

Ok.. so time for a simplistic example:

// FILENAME: foo.h
#ifndef FOO_H
#define FOO_H
 
#include <QObject>
#ifdef Q_MOC_RUN
class foo {
  Q_GADGET
  Q_ENUMS(Direction)
public:
  enum Direction { Up, Down, Left, Right, Front, Back };
};
#else
namespace foo {
  enum Direction { Up, Down, Left, Right, Front, Back };
}
#endif
 
#endif // FOO_H
 
//FILENAME: bar.h
 
#include <QtCore>
#include "foo.h"
 
class bar: public QObject {
  Q_OBJECT
public:
  bar();
  foo::Direction getDirection() { return _dir; }
private:
  foo::Direction _dir;
};

// FILENAME: foo.h
#ifndef FOO_H
#define FOO_H

#include <QObject>
#ifdef Q_MOC_RUN
class foo {
  Q_GADGET
  Q_ENUMS(Direction)
public:
  enum Direction { Up, Down, Left, Right, Front, Back };
};
#else
namespace foo {
  enum Direction { Up, Down, Left, Right, Front, Back };
}
#endif

#endif // FOO_H

//FILENAME: bar.h

#include <QtCore>
#include "foo.h"

class bar: public QObject {
  Q_OBJECT
public:
  bar();
  foo::Direction getDirection() { return _dir; }
private:
  foo::Direction _dir;
};

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Moc seems to work (how would I know if it didn't?), but classes that include the header the above block is in, complain that "'staticMetaObject' is not a member of 'foo'" or "'staticMetaObject': undeclared identifier"

Thoughts on getting this working?

Thanks!

[jpn]

It's the macro which defines the member. In your code only moc can see the macro. You define a plain name space otherwise.

[SnarlCat]

So you think something like:

#ifdef Q_MOC_RUN
class foo {
  Q_GADGET
  Q_ENUMS(Direction)
public:
  enum Direction { Up, Down, Left, Right, Front, Back };
};
#else
namespace foo {
  Q_ENUMS(Direction)
  enum Direction { Up, Down, Left, Right, Front, Back };
}
#endif

#ifdef Q_MOC_RUN
class foo {
  Q_GADGET
  Q_ENUMS(Direction)
public:
  enum Direction { Up, Down, Left, Right, Front, Back };
};
#else
namespace foo {
  Q_ENUMS(Direction)
  enum Direction { Up, Down, Left, Right, Front, Back };
}
#endif

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...is what we're looking for?

This certainly wasn't evident in qnamespace.h ...

Thanks!

[jpn]

No, I meant just using a class. If you want to, you can fake it to be a namespace for doxygen, though.

[DragonEmbers]

Apologies for the necro-posting but since this is one of the top google hits:

http://comments.gmane.org/gmane.comp.lib.qt.user/5256

>> The real point is: is there some 'magic' qmake flag or something else
>> used in qnamespace.h for having
>> that working properly ?
>
> Yes, there's magic hardcoded in moc and in QMetaObject:roperty.



src/tools/moc/moc.cpp:653:

if (def.classname != "Qt" && def.classname != "QObject" && def.superclassList.isEmpty())
    error("Class contains Q_OBJECT macro but does not inherit from QObject");

if (def.classname != "Qt" && def.classname != "QObject" && def.superclassList.isEmpty())
    error("Class contains Q_OBJECT macro but does not inherit from QObject");

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