On 2/22/2007 5:32 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.
But I don't see why it's receiving a QWidget* -- the return type of the
functions i'm calling are explicitly A*.
Because elsewhere, in a point of your code that you are probably
ignoring, the instance is being returned as QWidget*. SIP executes the
%ConvertToSubClassCode *once* and create a Python object of type
QWidget; it register this Python an object within a hash table. After
that, every time the instance is returned by *any* method, it's looked
up in the hash table, and the Python wrapper (already constructed) is found.
Nevertheless, I implemented %ConvertToSubClassCode in class A (and class B
which inherits QWidget) using sipMapStringToClass/sipStringTypeClassMap, and
a QWidget is still being returned.
Can you show us this code please?
--
Giovanni Bajo
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