I am currently trying to troubleshoot an issue I am running into with a Qt application I am developing in Python. I only have a simple Main Window and a modal QDialog setup to collect user input after triggering a menu action on the Main Window. The QDialog is behaving as expected, since I've been able to confirm the test print is executed upon the QDialog returning Accepted, but the application will completely crash, without an error message, following the print statement. The same behavior occurs when QDialog returns Rejected. To clarify, the Main Window is shown for a couple seconds and the application crashes with no error messages. I would expect the function to return focus to the Main Window (with it still being open to operate on), after receiving either result from the Process function below.
I have also tried making the QDialog modeless (using show) and the accept/reject functions from the QDialog seem to return back to the main window as expected, but calling the function that brings up the QDialog again crashes the application. I am using pyqt 5.9 for this project, but I have used an essentially identical setup to the code below in a number of other projects in pyqt 5.6 without this happening. I am trying to figure out if there are any known issues with pyqt 5.9 that could be contributing to this issue, or if I have an error in my code somewhere that is causing this crash to occur. I was considering rolling back to 5.6 to see if that would get rid of the issue, but I feel like there may be something I am misunderstanding that is causing this to occur.
I am running the code out of Anaconda prompt (Anaconda 4.8.3, Python 3.7) on Windows 10, since Qt applications still have issues being run repeatedly within Spyder. I am using the pyqt that comes with Anaconda and haven't done any additional pip installs of pyqt.
Main Window Code
import sys
from PyQt5.QtCore import Qt
from PyQt5.QtWidgets import QApplication, QMainWindow, QWidget, QGridLayout, QHBoxLayout, QVBoxLayout, QAction, QLabel
from PyQt5.QtWidgets import QDialog, QListWidget, QListWidgetItem, QAbstractItemView, QPushButton, QLineEdit, QSpacerItem, QSizePolicy
class FirstWindow(QMainWindow):
def __init__(self):
QMainWindow.__init__(self)
self.title = 'Window 1'
self.left = 350
self.top = 150
self.width = 800
self.height = 500
self.setWindowTitle(self.title)
self.setGeometry(self.left,self.top,self.width,self.height)
widget = QWidget()
self.setCentralWidget(widget)
grid = QGridLayout()
widget.setLayout(grid)
mainMenu = self.menuBar()
mainMenu.setNativeMenuBar(False)
subMenu = mainMenu.addMenu('File')
modifyDB = QAction('Test',self)
subMenu.addAction(modifyDB)
modifyDB.triggered.connect(self.Process)
self.statusBar().showMessage('Ready')
def Process(self):
dialog = DialogWin()
if dialog.exec_() == QDialog.Accepted:
print('test passed')
if __name__ == '__main__':
if not QApplication.instance():
app = QApplication(sys.argv)
else:
app = QApplication.instance()
mainWin = FirstWindow()
mainWin.show()
app.exec_()
Dialog Code
class DialogWin(QDialog):
def __init__(self,parent=None):
super(DialogWin,self).__init__(parent)
self.title = 'Database Table Name Selection'
self.left = 350
self.top = 150
self.width = 300
self.height = 300
self.setWindowTitle(self.title)
self.setGeometry(self.left,self.top,self.width,self.height)
vbox = QVBoxLayout()
spacer = QSpacerItem(10,10,QSizePolicy.Expanding,QSizePolicy.Expanding)
self.list_exp = QLabel('Select Existing Table to Overwrite')
vbox.addWidget(self.list_exp)
self.table_list = QListWidget()
self.table_list.setSelectionMode(QAbstractItemView.SingleSelection)
vbox.addWidget(self.table_list)
hbox = QHBoxLayout()
hbox.addItem(spacer)
self.option_exp = QLabel('<span style="font-size:8pt; font-weight:600; color:#aa0000;">OR</span>')
hbox.addWidget(self.option_exp)
hbox.addItem(spacer)
vbox.addLayout(hbox)
self.new_name = QLineEdit(placeholderText='Enter New Source Name')
vbox.addWidget(self.new_name)
hbox = QHBoxLayout()
self.okButton = QPushButton('OK')
hbox.addWidget(self.okButton)
self.okButton.clicked.connect(self.accept)
self.cancelButton = QPushButton('Cancel')
hbox.addWidget(self.cancelButton)
self.cancelButton.clicked.connect(self.reject)
vbox.addLayout(hbox)
self.setLayout(vbox)
item = QListWidgetItem('No Tables Available...')
item.setFlags(item.flags() ^ Qt.ItemIsSelectable)
self.table_list.addItem(item)
Any input on this issue would be tremendously helpful. I've spent a lot of hours trying to understand how this setup could be working for me in one application and not in another.
