How to detect dialog's close event?

Question

Hi everyone.

I am making a GUI application using python3.4, PyQt5 in windows 7.

Application is very sample. User clicks a main window's button, information dialog pops up. And when a user clicks information dialog's close button (window's X button), system shows confirm message. This is all.

Here's my code.

# coding: utf-8

import sys
from PyQt5.QtWidgets import QApplication, QMainWindow, QPushButton, QDialog, QLabel

class mainClass(QMainWindow):
    def __init__(self):
        super().__init__()
        self.initUI()

    def initUI(self):
        openDlgBtn = QPushButton("openDlg", self)
        openDlgBtn.clicked.connect(self.openChildDialog)
        openDlgBtn.move(50, 50)

        self.setGeometry(100, 100, 200, 200)
        self.show()

    def openChildDialog(self):
        childDlg = QDialog(self)
        childDlgLabel = QLabel("Child dialog", childDlg)

        childDlg.resize(100, 100)
        childDlg.show()


if __name__ == "__main__":
    app = QApplication(sys.argv)
    mc = mainClass()
    sys.exit(app.exec_())

Result screen shot is...

In this situation, I've added these code in mainClass class.

def closeEvent(self, event):
    print("X is clicked")

This code works only when the main window is closed. But what I want is closeEvent function works when childDlg is to closed. Not main window.

What should I do?

Answer 1

You have added, the method closeEvent in the class mainClass. So you have reimplemented the method closeEvent of your QMainwindow and not the method closeEvent of your childDlg. To do it, you have to subclass your chilDlg like this:

# coding: utf-8

import sys
from PyQt5.QtWidgets import QApplication, QMainWindow, QPushButton, QDialog, QLabel

class ChildDlg(QDialog):
   def closeEvent(self, event):
      print("X is clicked")

class mainClass(QMainWindow):
    def __init__(self):
        super().__init__()
        self.initUI()

    def initUI(self):
        openDlgBtn = QPushButton("openDlg", self)
        openDlgBtn.clicked.connect(self.openChildDialog)
        openDlgBtn.move(50, 50)

        self.setGeometry(100, 100, 200, 200)
        self.show()

    def openChildDialog(self):
        childDlg = ChildDlg(self)
        childDlgLabel = QLabel("Child dialog", childDlg)

        childDlg.resize(100, 100)
        childDlg.show()


if __name__ == "__main__":
    app = QApplication(sys.argv)
    mc = mainClass()
    sys.exit(app.exec_())

Answer 2

import sys
from PyQt5.QtWidgets import QApplication, QMainWindow, QPushButton, QDialog, QLabel

class mainClass(QMainWindow):
    def __init__(self):
        super().__init__()
        self.initUI()

    def initUI(self):
        openDlgBtn = QPushButton("openDlg", self)
        openDlgBtn.clicked.connect(self.openChildDialog)
        openDlgBtn.move(50, 50)

        self.setGeometry(100, 100, 200, 200)
        self.show()

    def openChildDialog(self):
        childDlg = QDialog(self)
        childDlgLabel = QLabel("Child dialog", childDlg)

        childDlg.closeEvent = self.CloseEvent

        childDlg.resize(100, 100)
        childDlg.show()

    def CloseEvent(self, event):
        print("X is clicked")

if __name__ == "__main__":
    app = QApplication(sys.argv)
    mc = mainClass()
    sys.exit(app.exec_())