Thanks for the catch, Blair
On Wed, May 23, 2012 at 5:26 PM, Blair Zajac <[email protected]> wrote: > <nitpick> > > According to PEP-8, don't compare using == to singletons: > > http://www.python.org/dev/**peps/pep-0008/#programming-**recommendations<http://www.python.org/dev/peps/pep-0008/#programming-recommendations> > > """Comparisons to singletons like None should always be done with is or is > not, never the equality operators.""" > > app = QApplication.instance() > if app is None: > app = QApplication(sys.argv) > </nitpick> > > Blair > > > On 05/23/2012 02:19 PM, Jason Augustyn wrote: > >> Thanks, Nathan, after poking around a bit more I found a similar solution: >> >> app = QApplication.instance() >> if app == None: >> app = QApplication(sys.argv) >> >> This works! >> >> >> >> On Wed, May 23, 2012 at 5:03 PM, Nathan Smith <[email protected] >> <mailto:[email protected]**>> wrote: >> >> Hi Jason, >> >> PySide only supports creating a single persistent instance of >> QApplication. This singleton exists forever and cannot be deleted. >> If you have a function that tries to create a QApplication, then I >> recommend placing that creation inside of a try/except block: >> >> try: >> app = QtGui.QApplication(sys.argv) >> except RuntimeError: >> app = QtCore.QCoreApplication.**instance() >> >> >> This will either create a new QApplication instance if one does not >> exist, or return the current QApplication instance if one already >> does exist. >> >> Nathan >> >> On Wed, May 23, 2012 at 3:21 PM, Jason Augustyn >> <[email protected] <mailto:[email protected]>**> wrote: >> >> Hi all, I am new to using PySide and have been working through >> the novice tutorials, which are great. One problem - I cannot >> re-run a script without exiting the Python shell altogether. >> Re-running gives the RuntimeError: A QApplication instance >> already exists. >> >> I have searched for a solution and found an old bug tracker >> ticket from someone with a similar problem. The suggested >> solution was to upgrade to PySide 1.0.4 and the ticket was >> marked as invalid. Obviously that doesn;t work, as I'm running >> the newest version of PySide and still have the problem. Any >> suggestions? I am using IPython on a Mac OSX 10.7. >> >> Thanks! >> >> Jason >> >> ______________________________**_________________ >> PySide mailing list >> [email protected] <mailto:[email protected]> >> >> http://lists.qt-project.org/**mailman/listinfo/pyside<http://lists.qt-project.org/mailman/listinfo/pyside> >> >> >> >> >> >> >> ______________________________**_________________ >> PySide mailing list >> [email protected] >> http://lists.qt-project.org/**mailman/listinfo/pyside<http://lists.qt-project.org/mailman/listinfo/pyside> >> > >
_______________________________________________ PySide mailing list [email protected] http://lists.qt-project.org/mailman/listinfo/pyside
