关于python：PyQT5程序仅在第一次编译运行期间返回错误

PyQT5 program returning error only during first compile run

以下示例在新的ipython控制台(spyder)中运行时返回"-1"，但仅在第一次尝试时返回。之后它似乎工作正常。

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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())

错误如下：

>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:\Users\xx\Documents\Anaconda\lib\site-packages\IPython\core\interactiveshell.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:\Users\xx\Documents\Anaconda\lib\site-packages\spyder_kernels\customize\spydercustomize.py", line 668, in runfile
execfile(filename, namespace)

File"C:\Users\xx\Documents\Anaconda\lib\site-packages\spyder_kernels\customize\spydercustomize.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

我不知道这可能是什么，但因为有一天这应该是一个独立的程序，我担心它可能会变得混乱，所以我宁愿修复它。我应该尝试什么？

没有GUI.py它是不可重现的，所以这里是：

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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"))

它似乎与此相关，应用程序永远不会在第一次运行中返回QCoreApplication。但是，将其移动到函数中是行不通的。我无法在控制台中重现实际使其在第二次运行中工作的行为。似乎有些东西会将QCorEApplication变成一个有效的。

在两个现在删除的答案(不起作用)中，建议使用if __name__ == '__main__':并将应用程序调用移动到新类中。这没效果。