How to trap the Window minimizing event?

Question

I want to create a JFrame instance and on the click of its minimize button, I would like to hide it to the System Tray which is usually the taskbar of windows.

I'd come to know that by using SystemTray class in java.awt package I can do so but neither I'm getting any tutorial on it nor any working program example.

I'd asked this question here to either get the link to tutorial site for SystemTray class or if any body knows how to trap the window minimizing event, a working example.

Answer 1

The WindowListener interface and JFrame's addWindowListener() method should help you determine when the frame has been minimised.

Answer 2

This will trap the window minimized event and will create a tray icon. It will also remove the window from the taskbar and it will add a listener on the tray icon so that a mouseclick would restore the window. The code is a bit scrappy but should be good enough for your learning purposes:

public class Qwe extends JFrame {

public static void main(String[] args) {
    final Qwe qwe = new Qwe();

    qwe.addWindowStateListener(new WindowStateListener() {
        public void windowStateChanged(WindowEvent e) {
            if (e.getNewState() == ICONIFIED) {
                try {
                    final TrayIcon trayIcon = new TrayIcon(new ImageIcon("/usr/share/icons/gnome/16x16/emotes/face-plain.png").getImage());
                    trayIcon.addMouseListener(new MouseAdapter() {
                        @Override
                        public void mouseClicked(MouseEvent e) {
                            qwe.setVisible(true);
                            SystemTray.getSystemTray().remove(trayIcon);
                        }
                    });
                    SystemTray.getSystemTray().add(trayIcon);
                    qwe.setVisible(false);
                } catch (AWTException e1) {
                    e1.printStackTrace();
                }
            }
        }
    });
    qwe.setSize(200, 200);
    qwe.setVisible(true);
}

}

Answer 3

best way would be create follows

1) SystemTray

2) add JPopopMenu to the SystemTray's Icon

3) set DefaultCloseOperation for TopLevelContainer (in your case JFrame)

• by using WindowListener setDefaultCloseOperation(JFrame.DO_NOTHING_ON_CLOSE);

• in other cases always works setDefaultCloseOperation(JFrame.HIDE_ON_CLOSE);

• notice don't forget declare System.exit(1) to the SystemTray's JpopupMenu, from JMenuItem or another Action/Event, because in this form currenet JVM never gone from Native OS until PC power-off or restart

Answer 4

private void windowStateChanged(java.awt.event.WindowEvent evt) {
    // Use getExtendedstate here.
}

• WindowStateListener docs
• Frame.getExtendedState() docs