[PyQt] How do I subclass QTextEdit without warnings on close?

[Zoltan Szalai]

Hi Brad,

He means that you should call the focusOutEvent of the base class in 
your reimplementation of focusOutEvent.
It's desired because QTextEdit reimplements focusOutEvent from QWidget.

Something like this:
     def focusOutEvent(self, e):
         QtGui.QTextEdit.focusOutEvent(self, e)
         val = self.toHtml()
         self.textEdited.emit(val)

or using super:

     def focusOutEvent(self, e):
         super(MyQTextEdit, self).focusOutEvent(e)
         val = self.toHtml()
         self.textEdited.emit(val)

Either way, I don't get any error or warning at close.
(Win7, 32bit, python: 2.6.5, pyqt: 4.8.3, qt: 4.7.1, sip: 4.12.1)

regards
Zoli


On 2011.05.03. 4:49, Brad Ralph wrote:
> Hi Pete,
>
> Thanks for you reply but I don't understand what you are suggesting as a
> solution. I tried to take you at your suggestion and replace the line
> 'def  focusOutEvent(self, e):' with 'QtGui.QTextEdit.focusOutEvent(self, e)'
> but it did not work. (Invalid syntax error). I even tried variations like 'def
> QtGui.QTextEdit.focusOutEvent(self, e)' just in case I was stupidly not
> understanding you.
>
> I also experimented with my real application instead of the test app I
> included in my email.  From my understanding of your diagnosis, if the event
> does not get time to finish before the program ends, then I should be able to
> enter into a different widget (which fires the event) then wait for a few
> seconds (even 5 mins) for it to finish, before closing the program.  When I do
> this the error still occurs, but only if I fire the event by entering into the
> QTextEdit subclass.  This leads me to think that I have no clue what is going
> on.  How can the event not finish when several seconds have passed after it was
> fired?
>
> I also wonder what is the correct way to subclass a Qt4 widget in this case.I
> have been using the method in PyQt3 and it has always worked, so I guess I
> need to do it differently now.
>
> I also would like to know why you suggest using Super()?  I seem to remember
> that there were warnings in the PyQt docs that using it in certain cases could
> cause problems, so I've always avoided it.  I also tend to think that it
> breaks the 'explicit is better than implicit rule' but that is just an
> opinion.
>
> Thanks in advance for your help.
>
> Regards,
> Brad
>
> On Mon, 2 May 2011 11:36:44 PM Hans-Peter Jansen wrote:
>
> [snip ...]
>
>>> ########################################
>>>
>>> #!/bin/env python
>>> # -*- coding: utf-8 -*-
>>> import sys
>>> from PyQt4 import QtCore, QtGui
>>>
>>> try:
>>>      _fromUtf8 = QtCore.QString.fromUtf8
>>>
>>> except AttributeError:
>>>      _fromUtf8 = lambda s: s
>>>
>>> class MyQTextEdit(QtGui.QTextEdit):
>>>      textEdited = QtCore.pyqtSignal('QString')
>>>
>>>      def __init__(self, *args):
>>>          QtGui.QTextEdit.__init__(self, *args)
>>>
>>>      def  focusOutEvent(self, e):
>>>          val = self.toHtml()
>>>          self.textEdited.emit(val)
>> The dtor of QTextEdit is called before the event finished.
>>
>> Try this:
>>
>> 	  QtGui.QTextEdit.focusOutEvent(self, e)
>>
>> You might want to switch to super() for calling into the base classes,
>> though.
>>
>>> class frmTest(QtGui.QMainWindow):
>>>      def __init__(self, app, *args):
>>>          QtGui.QMainWindow.__init__(self, *args)
>>>          self.app = app
>>>          self.mainWidget = QtGui.QFrame()
>>>          self.setCentralWidget(self.mainWidget)
>>>          self.fmeLayout = QtGui.QVBoxLayout(self.mainWidget)
>>>          self.teDesc1 = MyQTextEdit(self.mainWidget)
>>>          self.teDesc1.setObjectName(_fromUtf8("teDesc1"))
>>>          self.fmeLayout.addWidget(self.teDesc1)
>>>          self.teDesc2 = MyQTextEdit(self.mainWidget)
>>>          self.teDesc2.setObjectName(_fromUtf8("teDesc1"))
>>>          self.fmeLayout.addWidget(self.teDesc2)
>>>
>>> if "__main__"==__name__:
>>>      qapp = QtGui.QApplication(sys.argv)
>>>      view = frmTest(qapp)
>>>      view.show()
>>>      qapp.exec_()
>> Cheers,
>> Pete
>>