A QApplication instance already exists

Question

I\'m doing some simple PySide on 3Dsmax 2015.

This is my error:

python.ExecuteFile \"C:\\Program Files\\Autodesk\\3ds Max 2015\\scripts\\Python\\dem         


        

Answer 1

You're creating an instance of QApplication in the line:

app = QApplication(sys.argv)

And getting that error because there's another instance of QApplication created somewhere before that (presumably somewhere in "3Dsmax 2015 Listener") and you're only allowed one.

See:

QT documentation on QApplication