[PyQt] Subclass of QGraphicsObject does not have the correct class name listed in QGraphicsScene.items()

[Selim Tuvi]

Hi Phil, thanks for the explanation. The issue came up where I need to 
do special processing based on the type of the item. I'll rely on my own 
"itemtype" property instead.
-Selim

Phil Thompson wrote:
> On Thu, 19 May 2011 14:42:47 -0700, Selim Tuvi
> <Selim.Tuvi at pdi.dreamworks.com> wrote:
>   
>> The code below outputs:
>>
>> [<__main__.Edge object at 0x2aaab0395830>, <PyQt4.QtGui.QGraphicsItem 
>> object at 0x2aaab03958c0>]
>>
>> which lists the Node instance as having the class QGraphicsItem when it 
>> should say <__main__.Node object at ...>.
>>
>> Tested on (Qt 4.7.2, PyQt 4.8.3) and (Qt 4.6.1, PyQt 4.7.2)
>>
>> Thanks
>> -Selim
>>
>> from PyQt4 import QtGui, QtCore
>>
>> class Node(QtGui.QGraphicsObject):
>>     def __init__(self):
>>         QtGui.QGraphicsObject.__init__(self)
>>        
>>     def paint(self, painter, option, widget):
>>         pass
>>        
>>     def boundingRect(self):
>>         return QtCore.QRectF()
>>
>> class Edge(QtGui.QGraphicsItem):
>>     def __init__(self):
>>         QtGui.QGraphicsItem.__init__(self)
>>
>>     def paint(self, painter, option, widget):
>>         pass
>>
>>     def boundingRect(self):
>>         return QtCore.QRectF()
>>
>> if __name__ == '__main__':
>>     import sys
>>     app = QtGui.QApplication(sys.argv)
>>     print QtCore.QT_VERSION_STR, QtCore.PYQT_VERSION_STR
>>     view = QtGui.QGraphicsView()
>>     scene = QtGui.QGraphicsScene()
>>     view.setScene(scene)
>>     scene.addItem(Node())
>>     scene.addItem(Edge())
>>     print scene.items()
>>     view.show()
>>     sys.exit(app.exec_())
>>     
>
> It's because QGraphicsObject inherits both QObject and QGraphicsItem.
> items() returns a list of QGraphicsItems which, for a QGraphicsObject, has
> a different C++ address than the original QGraphicsObject. PyQt doesn't
> recognise that the QGraphicsItem is a cast of the QGraphicsObject. I don't
> think there is anything I can (sensibly) do about this.
>
> Phil
>   
-------------- next part --------------
An HTML attachment was scrubbed...
URL: <http://www.riverbankcomputing.com/pipermail/pyqt/attachments/20110520/ad11d9a0/attachment.html>
-------------- next part --------------
A non-text attachment was scrubbed...
Name: Selim_Tuvi.vcf
Type: text/x-vcard
Size: 390 bytes
Desc: not available
URL: <http://www.riverbankcomputing.com/pipermail/pyqt/attachments/20110520/ad11d9a0/attachment.vcf>