[PyKDE] Newbie question on QWidget.focusOutEvent

Hans-Peter Jansen hpj at urpla.net
Mon Sep 26 08:58:43 BST 2005

Am Montag, 26. September 2005 08:04 schrieb Volker Lenhardt:
> Hi Pete,
> I thought I'd got the knack of it. But I haven't succeeded yet.
> This is the relevant part of my script:
> class DlgTourn(QDialog):
>      def __init__(self, tourn):
> 	QDialog.__init__(self, None, None, True, 1)
>          self.layout=QVBoxLayout(self)
> 	self.inputLayout=QGridLayout(self.layout, 1, 1, 5)
> 	for i in (4, 5):
> 	    for j in (1, 3):
> 		s+=1
> 		cmb=Combo(s, True, self)
> 		cmb.installEventFilter(self)
> 		for p in self.playerList:
> 		    cmb.insertItem(p, -1)
> 		self.wCmbList.append(cmb)
> 		self.inputLayout.addWidget(cmb, i, j)
> class Combo(QComboBox):
>      def __init__(self, p, *args):
> 	QComboBox.__init__(self, *args)
> 	self.setFocusPolicy(QWidget.StrongFocus)
> 	self.p=p
>      def eventFilter(self, o, e):
> 	if e and o:
> 	    if e.type()==QEvent.FocusOut:
> 		if o==self:
> #		if o==self.lineEdit():
> 		    QMessageBox.information(self, "Info", str(self.p))
> #		    return True
> 	return False

Hmm, I always put eventFilter() in the class, where I installed it, and 
that's what the o parameter is for (in my understanding). Note, that I 
derive such code from C++ examples, which is quite easy, thanks to 
Phils tight adaption of Qt via the powers of sip.

> If I have o==self, no message box appears, but I have to double click
> (on my PDA!) to make my choice of item.
> If I have o==self.lineEdit() I get 2(!) message boxes when I leave
> the lineEdit, and on clicking it away the program crashes with
> segmentation fault.

I cannot explain these effects, sorry. See below.

> No difference whether return True or False within the if-condition.

If you want to consume this event, return True, otherwise False.

> Any hint?

You finally reached the point, where a minimum self containing example 
script would be most helpful.


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