[PyKDE] QWidgetFactory and classes defined in Python

[Yann Cointepas]

I am sorry, there is an error in the example code I sent. The las line of 
testQWidgetFactory.py should have been:

w.child( 'myCustomWidget1' ).pythonMethod()

The behaviour is different on various PyQt/sip versions. The problem is 
related to the deletion of the Python version of MyCustomWidget instance 
which is local to MyWidgetFactory.createWidget(). If I keep a reference on 
this widget (for example in a global variable), the link between the C++ 
QWidget and its Python counterpart is never lost.

Is it mandatory to always keep somewhere a Python reference on a QWidget to be 
able to get this Python object from pure C++ methods returning QWidget * ?

> Hi,
>
> PyQt loose the link between a Python QWidget subclass and the corresponding
> C++ object when using QWidgetFactory.
>
> In the following example, a simple custom widget for designer is created in
> Python. QWidgetFactory is specialized to create custom widget instances and
> registered it with  QWidgetFactory.addFactory. Then a simple .ui file is
> using this custom widget. It almost work but the widget returned by
> QWidgetFactory.create() do not have access to the Python methods defined in
> its class. Is there a way to go around this problem ?
>
> Regards,
>
>       Yann Cointepas
>
>
> The example is composed of form1.ui and testQWidgetFactory.py and produces
> the following output:
>
> $> python testQWidgetFactory.py
> MyCustomWidget.__init__ <__main__.MyCustomWidget object at 0xb7efaaac>
> Created widget from .ui file: <qt.QWidget object at 0xb7efaaac>
> Traceback (most recent call last):
>   File "testQWidgetFactory.py", line 22, in ?
>     w.pythonMethod()
> AttributeError: pythonMethod
>
> ---------- testQWidgetFactory.py ----------
> import sys
> import qt
> import qtui
>
> class MyCustomWidget( qt.QWidget ):
>   def __init__( self, parent=None, name=None ):
>     qt.QWidget.__init__( self, parent, name )
>     print 'MyCustomWidget.__init__', self
>
>   def pythonMethod( self ):
>     print 'in MyCustomWidget.pythonMethod()'
>
> class MyWidgetFactory( qtui.QWidgetFactory ):
>   def createWidget( self, className, parent, name ):
>     if className == 'MyCustomWidget':
>       return MyCustomWidget( parent, name )
>
> qApp = qt.QApplication( sys.argv )
> qtui.QWidgetFactory.addWidgetFactory( MyWidgetFactory() )
> w = qtui.QWidgetFactory.create( 'form1.ui' )
> print 'Created widget from .ui file:', w
> w.pythonMethod()
>
>
> ---------- form1.ui ----------
> <!DOCTYPE UI><UI version="3.3" stdsetdef="1">
> <class>Form1</class>
> <widget class="QWidget">
>     <property name="name">
>         <cstring>Form1</cstring>
>     </property>
>     <property name="geometry">
>         <rect>
>             <x>0</x>
>             <y>0</y>
>             <width>600</width>
>             <height>480</height>
>         </rect>
>     </property>
>     <property name="caption">
>         <string>Form1</string>
>     </property>
>     <widget class="MyCustomWidget">
>         <property name="name">
>             <cstring>myCustomWidget1</cstring>
>         </property>
>         <property name="geometry">
>             <rect>
>                 <x>170</x>
>                 <y>110</y>
>                 <width>261</width>
>                 <height>161</height>
>             </rect>
>         </property>
>     </widget>
> </widget>
> <customwidgets>
>     <customwidget>
>         <class>MyCustomWidget</class>
>         <header location="local">mywidget.h</header>
>         <sizehint>
>             <width>-1</width>
>             <height>40</height>
>         </sizehint>
>         <container>0</container>
>         <sizepolicy>
>             <hordata>5</hordata>
>             <verdata>5</verdata>
>             <horstretch>0</horstretch>
>             <verstretch>0</verstretch>
>         </sizepolicy>
>         <pixmap>image0</pixmap>
>     </customwidget>
> </customwidgets>
> <images>
>     <image name="image0">
>         <data format="PNG"
> length="1125">89504e470d0a1a0a0000000d4948445200000016000000160806000000c4b
>46c3b0000042c49444154388db5954f6c14551cc73fefcd7476b65bdaae4bb78bb5502a14d40
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> </image>
> </images>
> <layoutdefaults spacing="6" margin="11"/>
> <includehints>
>     <includehint>mycustomwidget.h</includehint>
> </includehints>
> </UI>

-- 
Yann Cointepas                         Tel: +33 1 69 86 78 52
CEA - SHFJ                             Fax: +33 1 69 86 77 86
4, place du Général Leclerc
91401 Orsay Cedex France