Pyqt5: Dialogue box disappears immediately after appearing

Question

I have a situation in which I want a dialogue box to appear when a button is clicked. I used Qt designer to create a main window as well as a dialogue box. By looking at some online tutorials and answers on StackOverflow I managed to write this code

from PyQt5 import QtCore, QtGui, QtWidgets

class Ui_MainWindow(object):
    def setupUi(self, MainWindow):
        MainWindow.setObjectName("MainWindow")
        MainWindow.resize(557, 383)
        self.centralwidget = QtWidgets.QWidget(MainWindow)
        self.centralwidget.setObjectName("centralwidget")

        self.pushButton = QtWidgets.QPushButton(self.centralwidget)
        self.pushButton.setGeometry(QtCore.QRect(180, 70, 201, 81))
        self.pushButton.setObjectName("pushButton")
        self.pushButton.clicked.connect(self.newWindow)


        MainWindow.setCentralWidget(self.centralwidget)
        self.menubar = QtWidgets.QMenuBar(MainWindow)
        self.menubar.setGeometry(QtCore.QRect(0, 0, 557, 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.setText(_translate("MainWindow", "new window"))

    def newWindow(self):
        dialog = QtWidgets.QDialog() 
        self.myOtherWindow = Ui_Dialog()
        self.myOtherWindow.setupUi(dialog)
        dialog.show()

class Ui_Dialog(object):
    def setupUi(self, Dialog):
        Dialog.setObjectName("Dialog")
        Dialog.resize(400, 300)

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

    def retranslateUi(self, Dialog):
        _translate = QtCore.QCoreApplication.translate
        Dialog.setWindowTitle(_translate("Dialog", "Dialog"))

if __name__ == "__main__":
    import sys
    if not QtWidgets.QApplication.instance():
        app = QtWidgets.QApplication(sys.argv)
    else:
        app = QtWidgets.QApplication.instance()
    MainWindow = QtWidgets.QMainWindow()
    ui = Ui_MainWindow()
    ui.setupUi(MainWindow)
    MainWindow.show()
    sys.exit(app.exec_())

The problem is that when I click the pushbutton, the dialogue box appears for an instance and then disappears. What am I missing?

Thanks for your answer. Now I have added a button to the dialogue and I want the dialogue to close when I click on it. Do you have any suggestions on how to do this? — Utkarsh Ranjan, Jun 25 '18 at 08:17
When I add your_button.clicked.connect(your_dialog.close) to the code, the dialogue box never appears! — Utkarsh Ranjan, Jun 25 '18 at 09:04
That has nothing to do with my comment, if you comment that line appears the dialogue ?, Do you get an error message? — eyllanesc, Jun 25 '18 at 09:06
Do you get an error message? have you executed it in the CMD? — eyllanesc, Jun 25 '18 at 09:07
AttributeError: 'QDialog' object has no attribute 'pushButton'. I have defined pushButton — Utkarsh Ranjan, Jun 25 '18 at 09:10
hahaha, the error is clear, you do not have a button called pushbutton as a member of QDialog, how did you create the button ?, I assume that you have created the button and I only refer you to answer the main task, goodbye, I think I am wasting my time, take a book, read the documentation, read tutorials, do not run if you do not know how to crawl. :) — eyllanesc, Jun 25 '18 at 09:13
I stress, read tutorials, even a lot of them in the network, so it will save time and will do it to us — eyllanesc, Jun 25 '18 at 09:17
@eyllanesc i had a similar problem, why does `self.dialog` work and not simply `dialog`? — Marvin Effing, Jul 03 '20 at 09:30

score 0 · Answer 1 · edited Jun 21 '18 at 15:55

WARNING! Never change the  .ui  file

All changes made in this file will be lost!

from PyQt5 import QtCore, QtGui, QtWidgets

class Ui_MainWindow(object):
    def setupUi(self, MainWindow):
        MainWindow.setObjectName("MainWindow")
        MainWindow.resize(557, 383)
        self.centralwidget = QtWidgets.QWidget(MainWindow)
        self.centralwidget.setObjectName("centralwidget")

        self.pushButton = QtWidgets.QPushButton(self.centralwidget)
        self.pushButton.setGeometry(QtCore.QRect(180, 70, 201, 81))
        self.pushButton.setObjectName("pushButton")
        self.pushButton.clicked.connect(self.newWindow)


        MainWindow.setCentralWidget(self.centralwidget)
        self.menubar = QtWidgets.QMenuBar(MainWindow)
        self.menubar.setGeometry(QtCore.QRect(0, 0, 557, 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.setText(_translate("MainWindow", "new window"))

    """ 
    def newWindow(self):
        self.dialog = QtWidgets.QDialog() 
        self.myOtherWindow = Ui_Dialog()
        self.myOtherWindow.setupUi(self.dialog)
        self.dialog.show()
    """

class MainWindow(QtWidgets.QMainWindow, Ui_MainWindow):
    def __init__(self, parent=None):
        super(MainWindow, self).__init__(parent)

        self.setupUi(self)

    def newWindow(self):
        dialog = QtWidgets.QDialog() 
        dialog.setWindowTitle("Dialog")
        dialog.setGeometry(800, 300, 400, 300)
        dialog.exec_()


if __name__ == "__main__":
    import sys
    if not QtWidgets.QApplication.instance():
        app = QtWidgets.QApplication(sys.argv)
    else:
        app = QtWidgets.QApplication.instance()
    window = MainWindow()
    window.show()
    sys.exit(app.exec_())

Pyqt5: Dialogue box disappears immediately after appearing

1 Answers1