PySide / PyQt detect if user trying to close window

Question

is there a way to detect if user trying to close window? For example, in Tkinter we can do something like this:

def exit_dialog():     #do stuff     pass  root = Tk() root.protocol("WM_DELETE_WINDOW", exit_dialog) root.mainloop() 

Thanks.

Answer 1

Override the closeEvent method of QWidget in your main window.

For example:

class MainWindow(QWidget): # or QMainWindow     ...      def closeEvent(self, event):         # do stuff         if can_exit:             event.accept() # let the window close         else:             event.ignore() 

Another possibility is to use the QApplication's aboutToQuit signal like this:

app = QApplication(sys.argv) app.aboutToQuit.connect(myExitHandler) # myExitHandler is a callable 

Answer 2

If you just have one window (i.e the last window) you want to detect then you can use the setQuitOnLastWindowClosed static function and the lastWindowClosed signal.

from PySide2 import QtGui import sys   def keep_alive():     print("ah..ah..ah..ah...staying alive...staying alive")     window.setVisibility(QtGui.QWindow.Minimized)   if __name__ == '__main__':     app = QtGui.QGuiApplication()     app.setQuitOnLastWindowClosed(False)     app.lastWindowClosed.connect(keep_alive)      window = QtGui.QWindow()     window.show()      sys.exit(app.exec_()) 

Hope that helps someone, it worked for me as on my first attempt I couldn't override closeEvent(), lack of experience!