Sergei Sizov – Software Engineer Agile Software Development with Java and PHP

SystemTray Icon for Java Swing Application

Sometimes we need our application to be launched hidden in background. Applications like Skype or ICQ are running in background and waiting for incoming messages. These applications both having their icon in the System Tray and you can easily activate them by double-clicking on their system tray icon. This tutorial shows how to create the System Tray Icon for your Java Swing Application.

One problem, however, is that you need to have JRE 6 installed. Previous versions of Java VM do not support System Tray.

Creating SystemTray Icon

Firstly, we need to have the following packages imported:

import java.awt.SystemTray;
import java.awt.TrayIcon;
import java.awt.TrayIcon.MessageType;

Let's declare a SystemTray variable

TrayIcon trayIcon = null;

Then we need to check if the SystemTray is supported.

if (SystemTray.isSupported()) ...

If it is, then we will create a new TrayIcon. To create the TrayIcon we need to specify the Icon (or you can use the standard Java Icon), application name and a PopupMenu to be shown on right click.

// getting image to be used as icon for our TrayIcon

URL iconURL = getClass().getResource("/graphics/rss.png");
ImageIcon icon = new ImageIcon(iconURL);

// Creating popup menu to be shown on right click
trayMenu = new PopupMenu();
// Shows or hides main frame
popupShowHide = new MenuItem("Show/Hide");
popupShowHide.addActionListener(new ActionListener() {
  public void actionPerformed(ActionEvent event) {
   frame.setVisible(!frame.isVisible());
  }
});
 trayMenu.add(popupShowHide);
// close application
 MenuItem popupExit = new MenuItem("Exit");
 popupExit.addActionListener(new ActionListener() {
 public void actionPerformed(ActionEvent event) {
 closeApplication();
 }
 });
 trayMenu.add(popupExit);

// Create TrayIcon
trayIcon = new TrayIcon(icon.getImage(), // Image
"My Application", // Caption Text
trayMenu // Popup Menu
);
// shrink image to the size of the tray icon
trayIcon.setImageAutoSize(true);

// instance of SystemTray
SystemTray systemTray = SystemTray.getSystemTray();

// trying to add the TrayIcon
try {
 systemTray.add(trayIcon);
} catch (AWTException ignore) {
 // ignore
}

Also, you can catch the left double click on the TrayIcon. Say, for example you want to activate your application on left double click. Just add and ActionListener like this.

trayIcon.addActionListener(new ActionListener() {
 public void actionPerformed(ActionEvent event) {
  frame.setVisible(!frame.isVisible());
 }
});

SystemTray notifications

SystemTray allows you to show notifications about some events that has occured.

public void showInformation(String message) {

 trayIcon.displayMessage("My Application", // Application Title
 message, // Message to be shown
 MessageType.INFO // Type of the message - INFO
 );

}

For more information visit java.sun.com website.