WindowListener does not work as expected

Question

I want my GUI to make some checks when a JOptionPane appears. Because I can\'t find any other way, I though I can do those each time the application window loses focus(its j

Answer 1

I'm not going to go into why you are doing what you are doing, but it is not working as you expect for the following reason:

WindowAdapter is a convenience class so you can create one listener and register it for multiple types of events. You have only registered it for one set of events, you need to also register it for focus events via: Window.addWindowFocusListener()

WindowAdapter adapter = new WindowAdapter() {
        @Override
        public void windowLostFocus(WindowEvent e) {
            System.out.println("Focus Lost");
        }
        @Override
        public void windowClosing(WindowEvent e) {
            //some other stuff here that work
        }
    };
appFrame.addWindowListener(adapter);
appFrame.addWindowFocusListener(adapter);