[PyKDE] SIP automatically casting up to a QWidget

[Giovanni Bajo]

On 2/22/2007 2:53 PM, Paul Giannaros wrote:

> I have a class A that i'm wrapping with SIP. The class inherits from a bunch 
> of other classes. One of the classes it inherits from also in turn inherits 
> from QWidget. When I import the created module, whenever I call a method that 
> is meant to return an instance of class A I get a QWidget instead. I can use 
> sip.cast to get the QWidget back to an A instance, but that's not a very 
> friendly solution.
> Can someone suggest why this is happening, or how to fix it?

SIP needs to know the correct run-time type of your class: otherwise 
when it receives a QWidget* it cannot know what type the class really is.

Have a look at how %ConvertToSubClassCode is implemented in 
QtCore/qobject.sip and QtGui/qapplication.sip (assuming you're using 
Qt4). Within your a.sip, you must add your own %ConvertToSubClassCode 
that verifies if a generic QObject* is an instance of your type (class 
A). SIP then knows how to "chain" all the other %ConvertToSubClassCode 
in the object hierarchy, so your code needs only to verify your own class.
-- 
Giovanni Bajo