Delete Window Event

How to capture Delete Window Event

To capture the window delete event, you call the protocol method in the top-level widget of your UI and pass a callback function of the widget. Finally, you need to call the to destroy method on the top-level widget inside the callback.

Example when the root widget of your UI is a Frame:

demo1.py

demo1.ui

class Application:
    def __init__(self, master):
        self.builder = builder = pygubu.Builder()
        builder.add_from_file('demo1.ui')
        self.mainwindow = builder.get_object('mainwindow', master)
        # Connect Delete event to a toplevel window
        master.protocol("WM_DELETE_WINDOW", self.on_close_window)
        
    def on_close_window(self, event=None):
        print('On close window')
        
        # Call destroy on top-level to finish program
        self.mainwindow.master.destroy()


if __name__ == '__main__':
    root = tk.Tk()
    app = Application(root)
    root.mainloop()

Example when the root widget of your UI is a Toplevel:

demo2.py

demo2.ui

class Application:
    def __init__(self):
        self.builder = builder = pygubu.Builder()
        builder.add_from_file('demo2.ui')
        self.mainwindow = builder.get_object('mainwindow')

        # Connect Delete event to a toplevel window
        self.mainwindow.protocol("WM_DELETE_WINDOW", self.on_close_window)
        
    def on_close_window(self, event=None):
        print('On close window')
        
        # Call destroy on top-level to finish program
        self.mainwindow.destroy()
        
    def run(self):
        self.mainwindow.mainloop()


if __name__ == '__main__':
    app = Application()
    app.run()