在 Jupyter Notebooks 中使用 PyQt5 时出现死内核

Question

我有一个烦人的问题，每当我运行从 PyQt5 导入的代码时，都会不断弹出指示“死内核”的错误消息。正如您可能在下面所说的那样，我正在使用 Jupyter Notebooks 并且肯定刚刚开始学习 Python。

这是命令提示符下面的错误信息；

Warning: QT_DEVICE_PIXEL_RATIO is deprecated. Instead use:
   QT_AUTO_SCREEN_SCALE_FACTOR to enable platform plugin controlled per-screen factors.
   QT_SCREEN_SCALE_FACTORS to set per-screen factors.
   QT_SCALE_FACTOR to set the application global scale factor.
This application failed to start because it could not find or load the Qt platform plugin "windows"
in "".

Reinstalling the application may fix this problem.
[I 14:35:25.311 NotebookApp] KernelRestarter: restarting kernel (1/5), keep random ports
kernel eb77c837-9e3a-46c2-9815-c8fdae756b12 restarted
[I 14:37:07.075 NotebookApp] Saving file at /Jupyter/Untitled2.ipynb

我使用QT Designer创建了一个非常简单的gui，代码如下所示。

from PyQt5 import QtCore, QtGui, QtWidgets

class Ui_MainWindow(object):
    def setupUi(self, MainWindow):
        MainWindow.setObjectName("MainWindow")
        MainWindow.resize(803, 609)
        self.centralwidget = QtWidgets.QWidget(MainWindow)
        self.centralwidget.setObjectName("centralwidget")
        self.button1 = QtWidgets.QPushButton(self.centralwidget)
        self.button1.setGeometry(QtCore.QRect(300, 370, 181, 51))
        self.button1.setObjectName("button1")
        self.label1 = QtWidgets.QLabel(self.centralwidget)
        self.label1.setGeometry(QtCore.QRect(330, 90, 211, 51))
        self.label1.setAlignment(QtCore.Qt.AlignRight|QtCore.Qt.AlignTrailing|QtCore.Qt.AlignVCenter)
        self.label1.setObjectName("label1")
        MainWindow.setCentralWidget(self.centralwidget)
        self.menubar = QtWidgets.QMenuBar(MainWindow)
        self.menubar.setGeometry(QtCore.QRect(0, 0, 803, 26))
        self.menubar.setObjectName("menubar")
        self.menuFile = QtWidgets.QMenu(self.menubar)
        self.menuFile.setObjectName("menuFile")
        MainWindow.setMenuBar(self.menubar)
        self.statusbar = QtWidgets.QStatusBar(MainWindow)
        self.statusbar.setObjectName("statusbar")
        MainWindow.setStatusBar(self.statusbar)
        self.menubar.addAction(self.menuFile.menuAction())

        self.retranslateUi(MainWindow)
        QtCore.QMetaObject.connectSlotsByName(MainWindow)

    def retranslateUi(self, MainWindow):
        _translate = QtCore.QCoreApplication.translate
        MainWindow.setWindowTitle(_translate("MainWindow", "MainWindow"))
        self.button1.setText(_translate("MainWindow", "Press Me!"))
        self.label1.setText(_translate("MainWindow", "Hello, my name is Bob"))
        self.menuFile.setTitle(_translate("MainWindow", "File"))


if __name__ == "__main__":
    import sys
    app = QtWidgets.QApplication(sys.argv)
    MainWindow = QtWidgets.QMainWindow()
    ui = Ui_MainWindow()
    ui.setupUi(MainWindow)
    MainWindow.show()
    sys.exit(app.exec_())

到目前为止我尝试了什么？

很遗憾，以下内容对我不起作用；

1.

 if __name__ == '__main__':
        import sys
        from PyQt5 import QtWidgets
        if not QtWidgets.QApplication.instance():
            app = QtWidgets.QApplication(sys.argv)
        else:
            app = QtWidgets.QApplication.instance() 
        main = Main()
        main.show()
        sys.exit(app.exec_())

from os import environ

def suppress_qt_warnings():
    environ["QT_DEVICE_PIXEL_RATIO"] = "0"
    environ["QT_AUTO_SCREEN_SCALE_FACTOR"] = "1"
    environ["QT_SCREEN_SCALE_FACTORS"] = "1"
    environ["QT_SCALE_FACTOR"] = "1"

if __name__ == "__main__":
    suppress_qt_warnings()

令人尴尬的是，我花了几个小时在互联网上寻找解决问题的方法，所以任何帮助都会非常有帮助。

谢谢！

Answer 1

对我来说，当您替换最后一行时，PyQt5 脚本在 Jupyter Notebook 中工作：

sys.exit(app.exec_())

与：

app.exec_()
del app