> Message: 1 > Date: Sun, 01 Apr 2012 13:04:30 +0200 > From: Detlev Offenbach <det...@die-offenbachs.de> > To: pyqt@riverbankcomputing.com > Subject: [PyQt] Strange behavior with new-style signals and slots > Message-ID: <1362374.ZZnnlU3EYs@jupiter> > Content-Type: text/plain; charset="us-ascii" > > Hallo, > > I am observing a strange behavior related to new-style signal and slots. > Here > is the situation. > > My program calls this line twice in a class (via different code paths). > > > self.project.projectPropertiesChanged.connect(self.__projectPropertiesChanged) > > The disconnect is only issued once when the class (the editor) is closed. > > > self.project.projectPropertiesChanged.disconnect(self.__projectPropertiesChanged) > > If the signal is emitted thereafter, I get a RuntimeError saying, that the > underlying C/C++ object has been destroyed. I suspect, that the Python > wrapper > for the Qt object (here it is a QScintilla object) is still kept alive by > some > reference counter (possibly caused by the double connection). > > Is this a bug in PyQt/sip or do I have to avoid such a situation? If the > later > is the case, is it possible to check, if a signal is already connected, > e.g. > something like > > > self.project.projectPropertiesChanged.is_connected(self.__projectPropertiesChanged) > > Another consequence of the double connection is, that the slot is called > twice > when the signal is emitted. > > Regards, > Detlev > -- > Detlev Offenbach > det...@die-offenbachs.de > > Detlev,
Perhaps you want to make use of Qt::UniqueConnection as the connection type. Note that I believe this will only work correctly on a slot decorated with pyqtSlot (or that was previously the case anyhow) - MH
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