Qt-interest Archive, January 2008
Re: Q_ENUMS: howto register 'external' enums
Message 1 in thread
This does not work for me in (Qt 4.3).
I have a lot of enumerated types defined in a non-QObject base class
(not a namespace)
that I want to multiply inherit in other classes. Some of these will
indirectly inherit from QObject themselves, so I don't want my
QiGlobal class to inherit also, causing multiple inheritance from
qobject.
But I looked at the qnamespace.h and thought I'd try out that trick of
conditionally including the Q_OBJECT and Q_ENUM macro only from moc. I
enclosed the qobject macros in conditional compilation directives:
class QiGlobal {
#ifdef Q_MOC_RUN
Q_OBJECT
Q_ENUMS(QiWideKeyAction)
Q_ENUMS(QiCellDecorationStyle)
Q_ENUMS(QiCopyPolicy)
Q_ENUMS(QiClearPolicy)
Q_ENUMS(QiSortMode)
#endif
/// all my enums definitions go here
}
But when I try to build it, I get:
Error: Class contains Q_OBJECT macro but does not inherit from QObject.
Why does it work for qnamespace but not for me? I'm not sure. Why does
Qt forbid this anyway? I can imagine many situations where one might
want to use the Q_ENUMS to define a few enumerators in a non-QObject
class that one can use for inheritance in other classes.
Is there a straightforward way to locate enumerators in one place that
is not a QObject class, but instead just a regular class that one can
multiply inherit from? That would make these Q_ENUMS so much more
useful.
On Jul 31, 2007 5:37 AM, Richard Moore <richmoore44@xxxxxxxxx> wrote:
> On 7/31/07, veronique.lefrere@xxxxxx <veronique.lefrere@xxxxxx> wrote:
> > maybe it's stupid but... why don't you do, like in qt qnamespace.h ?
> > you register and declare you enums and just include this .h in class file
> > you want to use them.
>
> Qt uses some magic to make this work:
>
> #ifndef Q_MOC_RUN
> namespace
> #else
> class Q_CORE_EXPORT
> #endif
> Qt {
> #ifdef Q_MOC_RUN
> Q_OBJECT
> Q_ENUMS(Orientation TextFormat BackgroundMode DateFormat
> ScrollBarPolicy FocusPolicy ContextMenuPolicy CaseSensitivi
> ty LayoutDirection ArrowType ShortcutContext)
>
> Looking at this appears that sometimes the namespace is treated as a
> namespace, and other times as class. I don't see any reason why this
> shouldn't work though it seems a bit evil.
>
> Cheers
>
> Rich.
>
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> To unsubscribe - send a mail to qt-interest-request@xxxxxxxxxxxxx with "unsubscribe" in the subject or the body.
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>
>
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Message 2 in thread
> > Looking at this appears that sometimes the namespace is treated as a
> > namespace, and other times as class. I don't see any reason why this
> > shouldn't work though it seems a bit evil.
Why don't you do the same with your class, i.e. in the normal case have
QiGlobal be your custom class,
but in the Q_MOC_RUN case, have it inherit from QObject.
Cheers,
Peter
--
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Message 3 in thread
I think you can use Q_GADGET instead of Q_OBJECT to get it to let you
use Q_ENUMS without inheriting QObject.
Katrina
Le 25 janv. 08 à 18:05, Alan Ezust a écrit :
> This does not work for me in (Qt 4.3).
>
> I have a lot of enumerated types defined in a non-QObject base class
> (not a namespace)
> that I want to multiply inherit in other classes. Some of these will
> indirectly inherit from QObject themselves, so I don't want my
> QiGlobal class to inherit also, causing multiple inheritance from
> qobject.
>
> But I looked at the qnamespace.h and thought I'd try out that trick of
> conditionally including the Q_OBJECT and Q_ENUM macro only from moc. I
> enclosed the qobject macros in conditional compilation directives:
>
> class QiGlobal {
> #ifdef Q_MOC_RUN
> Q_OBJECT
> Q_ENUMS(QiWideKeyAction)
> Q_ENUMS(QiCellDecorationStyle)
> Q_ENUMS(QiCopyPolicy)
> Q_ENUMS(QiClearPolicy)
> Q_ENUMS(QiSortMode)
> #endif
> /// all my enums definitions go here
>
> }
>
> But when I try to build it, I get:
>
> Error: Class contains Q_OBJECT macro but does not inherit from
> QObject.
>
> Why does it work for qnamespace but not for me? I'm not sure. Why does
> Qt forbid this anyway? I can imagine many situations where one might
> want to use the Q_ENUMS to define a few enumerators in a non-QObject
> class that one can use for inheritance in other classes.
>
> Is there a straightforward way to locate enumerators in one place that
> is not a QObject class, but instead just a regular class that one can
> multiply inherit from? That would make these Q_ENUMS so much more
> useful.
>
>
> On Jul 31, 2007 5:37 AM, Richard Moore <richmoore44@xxxxxxxxx> wrote:
>> On 7/31/07, veronique.lefrere@xxxxxx <veronique.lefrere@xxxxxx>
>> wrote:
>>> maybe it's stupid but... why don't you do, like in qt
>>> qnamespace.h ?
>>> you register and declare you enums and just include this .h in
>>> class file
>>> you want to use them.
>>
>> Qt uses some magic to make this work:
>>
>> #ifndef Q_MOC_RUN
>> namespace
>> #else
>> class Q_CORE_EXPORT
>> #endif
>> Qt {
>> #ifdef Q_MOC_RUN
>> Q_OBJECT
>> Q_ENUMS(Orientation TextFormat BackgroundMode DateFormat
>> ScrollBarPolicy FocusPolicy ContextMenuPolicy CaseSensitivi
>> ty LayoutDirection ArrowType ShortcutContext)
>>
>> Looking at this appears that sometimes the namespace is treated as a
>> namespace, and other times as class. I don't see any reason why this
>> shouldn't work though it seems a bit evil.
>>
>> Cheers
>>
>> Rich.
>>
>> --
>> To unsubscribe - send a mail to qt-interest-request@xxxxxxxxxxxxx
>> with "unsubscribe" in the subject or the body.
>> List archive and information: http://lists.trolltech.com/qt-interest/
>>
>>
>
> --
> To unsubscribe - send a mail to qt-interest-request@xxxxxxxxxxxxx
> with "unsubscribe" in the subject or the body.
> List archive and information: http://lists.trolltech.com/qt-interest/
>
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