Ndtyjky

The following example, when run in a new ipython console (spyder) returns "-1", but only at the first try. After that it seems to work fine.

from PyQt5 import QtWidgets, QtGui, QtCore



from GUI import Ui_MainWindow  # importing our generated file



import sys

import numpy as np



class mywindow(QtWidgets.QMainWindow):



    def __init__(self):



        super(mywindow, self).__init__()



        self.ui = Ui_MainWindow()



        self.ui.setupUi(self)



app = QtCore.QCoreApplication.instance()

if app is None:

    app = QtWidgets.QApplication(sys.argv)



application = mywindow()



application.show()



sys.exit(app.exec())

The error is as follows:

>runfile('C:/Users/xxx.py', wdir='C:/Users/xx/Documents/3dPackaging')
An exception has occurred, use %tb to see the full traceback.

SystemExit: -1

C:UsersxxDocumentsAnacondalibsite-packagesIPythoncoreinteractiveshell.py:2969: UserWarning: To exit: use 'exit', 'quit', or Ctrl-D.
warn("To exit: use 'exit', 'quit', or Ctrl-D.", stacklevel=1)

%tb
Traceback (most recent call last):

File "", line 1, in
runfile('C:/Users/xxx.py', wdir='C:/Users/xx')

File "C:UsersxxDocumentsAnacondalibsite-packagesspyder_kernelscustomizespydercustomize.py", line 668, in runfile
execfile(filename, namespace)

File "C:UsersxxDocumentsAnacondalibsite-packagesspyder_kernelscustomizespydercustomize.py", line 108, in execfile
exec(compile(f.read(), filename, 'exec'), namespace)

File "C:/Users/xx/Documents/3dPackaging/VersandkartonsPacken.py", line 64, in
sys.exit(app.exec())

SystemExit: -1

I have no idea what this could be, but as this is supposed to be a standalone program one day, I'm afraid it might be messy then, so i'd rather fix it. Anything I should try?

It's not reproducible without the GUI.py, so here it is:

from PyQt5 import QtCore, QtGui, QtWidgets



class Ui_MainWindow(object):

    def setupUi(self, MainWindow):

        MainWindow.setObjectName("MainWindow")

        MainWindow.resize(1127, 910)

        self.centralwidget = QtWidgets.QWidget(MainWindow)

        self.centralwidget.setObjectName("centralwidget")

        self.pushButton_schliessen = QtWidgets.QPushButton(self.centralwidget)

        self.pushButton_schliessen.setGeometry(QtCore.QRect(930, 770, 75, 23))

        self.pushButton_schliessen.setObjectName("pushButton_schliessen")

        self.label = QtWidgets.QLabel(self.centralwidget)

        self.label.setGeometry(QtCore.QRect(440, 20, 421, 31))

        font = QtGui.QFont()

        font.setPointSize(20)

        self.label.setFont(font)

        self.label.setObjectName("label")

        self.pushButton = QtWidgets.QPushButton(self.centralwidget)

        self.pushButton.setGeometry(QtCore.QRect(170, 770, 75, 23))

        self.pushButton.setObjectName("pushButton")

        self.tableWidget_input = QtWidgets.QTableWidget(self.centralwidget)

        self.tableWidget_input.setGeometry(QtCore.QRect(160, 80, 421, 671))

        self.tableWidget_input.setObjectName("tableWidget_input")

        self.tableWidget_input.setColumnCount(0)

        self.tableWidget_input.setRowCount(0)

        self.tableWidget_output = QtWidgets.QTableWidget(self.centralwidget)

        self.tableWidget_output.setGeometry(QtCore.QRect(650, 80, 441, 671))

        self.tableWidget_output.setObjectName("tableWidget_output")

        self.tableWidget_output.setColumnCount(0)

        self.tableWidget_output.setRowCount(0)

        MainWindow.setCentralWidget(self.centralwidget)

        self.menubar = QtWidgets.QMenuBar(MainWindow)

        self.menubar.setGeometry(QtCore.QRect(0, 0, 1127, 21))

        self.menubar.setObjectName("menubar")

        MainWindow.setMenuBar(self.menubar)

        self.statusbar = QtWidgets.QStatusBar(MainWindow)

        self.statusbar.setObjectName("statusbar")

        MainWindow.setStatusBar(self.statusbar)



        self.retranslateUi(MainWindow)

        QtCore.QMetaObject.connectSlotsByName(MainWindow)



    def retranslateUi(self, MainWindow):

        _translate = QtCore.QCoreApplication.translate

        MainWindow.setWindowTitle(_translate("MainWindow", "MainWindow"))

        self.pushButton_schliessen.setText(_translate("MainWindow", "Schliessen"))

        self.label.setText(_translate("MainWindow", "Versandkartons Packen"))

        self.pushButton.setText(_translate("MainWindow", "Berechnen"))

It seems to be related to this, app is never none but already returns a QCoreApplication in the first run. However , moving it into a function doesn't work. And I can't reproduce in the console the behaviour that actually makes it work in the second run. Something seems to change the QCorEApplication into a working one.

In two now deleted answers (didn't work), it was suggested to use if __name__ == '__main__': and move the application call into a new class. That hasn't worked.

This must be related to a peculiarity of the local system. We (commenters on the original question) have not been able to reproduce the error when installing the requirements from scratch in a clean environment (even when the environment very closely matches the affected system).

Please try reinstalling your environment, or running this on a different system, and see if the problem persists.

I use conda which might be related to the issue. I just upgraded PyQT5 with pip install PyQt5, making this issue disappear. So that seems to be the easiest solution.