PySide2 not closing correctly with basic example

问题

When I run the basic script:

import sys
from PySide2.QtWidgets import QApplication, QLabel

app = QApplication(sys.argv)
label = QLabel("Hello World")
label.show()
app.exec_()

forthe first time it all works fine. However, if I run it a second time I get:

File "../script.py", line 17, in <module>
app = QApplication(sys.argv)

RuntimeError: Please destroy the QApplication singleton before creating a new QApplication instance.

I am running the scripts in an Ubuntu machine. I get the same error in python2 and python3.

Thanks !

回答1:

Probably your IDE has already created a QApplication, so the solution is to create a QApplication if it does not exist:

app = QApplication.instance()
if app is None: 
    app = QApplication(sys.argv)

来源：https://stackoverflow.com/questions/54281439/pyside2-not-closing-correctly-with-basic-example