[PyQt] PyQt4 question

[Phil Thompson]

On Sunday 27 May 2007 11:50 am, Detlev Offenbach wrote:
> On Sonntag, 27. Mai 2007, Phil Thompson wrote:
> > On Saturday 26 May 2007 9:07 pm, Detlev Offenbach wrote:
> > > On Samstag, 26. Mai 2007, Phil Thompson wrote:
> > > > On Saturday 26 May 2007 7:58 pm, Detlev Offenbach wrote:
> > > > > On Samstag, 26. Mai 2007, Phil Thompson wrote:
> > > > > > On Saturday 26 May 2007 4:52 pm, Detlev Offenbach wrote:
> > > > > > > Hi,
> > > > > > >
> > > > > > > is there a PyQt equivalent to "qobject_cast<T*>(object)"?
> > > > > >
> > > > > > sip.cast()?
> > > > > >
> > > > > > But it shouldn't be necessary if the sub-class conversion code
> > > > > > has been properly implemented.
> > > > >
> > > > > How do I do that. I haven't wrapped complicated stuff like this so
> > > > > far. The situation is as follows. I have the following code:
> > > > >
> > > > >
> > > > > self.plugins.extend(self.designer.pluginManager().instances()) for
> > > > > plugin in self.plugins:
> > > > >             if isinstance(plugin,
> > > > > QDesignerFormEditorPluginInterface): if not plugin.isInitialized():
> > > > >                     plugin.initialze(self.designer)
> > > > >
> > > > >
> > > > > "self.designer.pluginManager().instances()" returns a list of
> > > > > QObject. The first if statement shall check, wether the returned
> > > > > QObject is of type QDesignerFormEditorPluginInterface. In C++ you
> > > > > would do it with code like
> > > > >
> > > > > if ( (qobject_cast<QDesignerFormEditorPluginInterface*>(plugin)) )
> > > > >
> > > > > How can the problem be solved with PyQt4 and Python?
> > > > >
> > > > > Note: self.designer.pluginManager() returns an object of type
> > > > > QDesignerPluginManager.
> > > >
> > > > The wrapper for QDesignerFormEditorPluginInterface must define
> > > > some %ConvertToSubClassCode which will use RTTI provided by the
> > > > instance to identify the right Python type object. See how PyQt does
> > > > it for QObject and QEvent. If the instance doesn't provide any RTTI
> > > > then you're stuck.
> > >
> > > Mustn't the %ConvertToSubClassCode go into the more general class (e.g.
> > > QObject)?
> >
> > No - just in a QObject sub-class in the module.
> >
> > > Is there a way to extend the QObject wrapper?
> >
> > That's what sip does under the covers.
>
> I am stuck at the moment due to my lack of sip know how. Below is the
> wrapper code in question. How does the %ConvertToSubClassCode have to be?
>
> ---------------------------------------------------------------------------
>- class QDesignerFormEditorPluginInterface
> {
>
> %TypeHeaderCode
> #include <abstractformeditorplugin.h>
> %End
>
> public:
>     virtual ~QDesignerFormEditorPluginInterface();
>
>     virtual bool isInitialized() const = 0;
>     virtual void initialize(QDesignerFormEditorInterface *core) = 0;
>     virtual QAction *action() const = 0;
>
>     virtual QDesignerFormEditorInterface *core() const = 0;
> };
> ---------------------------------------------------------------------------

What RTTI is available for the code to determine what the class really is? I 
can't see anything that is obviously suitable - in which case you are stuck.

Phil