Resetting a PySide6 Window after closing it

ccortez

I have been working on a desktop app with PySide6 and have just now caught something that I am not sure how to fix.

On my GUI I have some windows that open, on the click of a button that's in my 'home' page. The thing that I have noticed is that whenever I open a window, close it, and then open it again, it is in the same state that it was in prior to closing.

So for example, I have a window that opens that allows the user to make some selections. When I close it and reopen it, all those selections are still there.

My goal is for the state of that window to reset every time it is closed. I think that in the background, the Qt application is keeping the reference alive and I am not sure how to make sure that the state and everything get destroyed every time I close out a window.

From what I have googled, I haven't really been able to find a direct solution to this, but I am also fairly new to Qt.

Any guide or answers would be helpful. Here is a small sample of what my code looks like, if it helps:

class MainWindow(QMainWindow):
 def __init__(self):
     super(MainWindow, self).__init__()
     # Set settings for main window to pop up on top left of screen
     self.setWindowTitle('Main window')
     #self.setStyleSheet("background-color: #1F4388;")
     self.resize(640, 380)
     left = QScreen.availableGeometry(QApplication.primaryScreen()).topLeft()
     geo = self.frameGeometry()
     geo.moveTopLeft(left)
     self.move(geo.topLeft())
     
    # Button that opens up other window
     self.button = QPushButton(self)       
     self.button.setGeometry(150, 150, 150, 40)       
     self.button.setText('Data Visualization')       
     self.button.setStyleSheet('font-size:15px')       
     self.datavis = DataPlotting()
     self.button.clicked.connect(self.datavis.show)

class DataPlotting1(QMainWindow):
 def __init__(self):
     super(DataPlotting1, self).__init__()
     # Adjusting dimensions of window and the title text size
     self.setWindowTitle('Data Visualization')
     self.resize(640, 900)
     self.label = QLabel(self)
     self.label.setGeometry(120, 0, 400, 100)
     self.label.setText('Data Visualization')
     self.label.setAlignment(Qt.AlignCenter)
     self.label.setStyleSheet('font-size:40px')

if __name__ == '__main__':
 app = QApplication(sys.argv)
 ex = MainWindow()
 ex.show()
 sys.exit(app.exec())

JonB

@ccortez
Normally hiding a window will remember its content if re-opened but closing it will destroy it and its content. You may have to set the Qt.WA_DeleteOnClose attribute on it (https://doc.qt.io/qt-5/qt.html#WidgetAttribute-enum).

The situation in Python is complicated, because it likes to keep references to objects and retain the object. You show self.datavis = DataPlotting() in your __init__(), that will maintain a reference to that window throughout the lifetime of your MainWindow. Setting that to None, and/or using Qt.WA_DeleteOnClose, are probably required to free the reference properly.

To fully "reset the state of the window when it is closed" you need to delete it as above and create a new instance when you re-open it. Or, you have to write your own method to reset the size, every widget etc. in it which you call before opening.

ccortez

@JonB Thank you for this, it helped me solve my issues!