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java.awt
public class: SystemTray [javadoc | source]
java.lang.Object
   java.awt.SystemTray
The SystemTray class represents the system tray for a desktop. On Microsoft Windows it is referred to as the "Taskbar Status Area", on Gnome it is referred to as the "Notification Area", on KDE it is referred to as the "System Tray". The system tray is shared by all applications running on the desktop.

On some platforms the system tray may not be present or may not be supported, in this case SystemTray#getSystemTray() throws UnsupportedOperationException . To detect whether the system tray is supported, use SystemTray#isSupported .

The SystemTray may contain one or more TrayIcons , which are added to the tray using the #add method, and removed when no longer needed, using the #remove . TrayIcon consists of an image, a popup menu and a set of associated listeners. Please see the TrayIcon class for details.

Every Java application has a single SystemTray instance that allows the app to interface with the system tray of the desktop while the app is running. The SystemTray instance can be obtained from the #getSystemTray method. An application may not create its own instance of SystemTray.

The following code snippet demonstrates how to access and customize the system tray:

    TrayIcon  trayIcon = null;
    if (SystemTray.isSupported()) {
        // get the SystemTray instance
        SystemTray tray = SystemTray.#getSystemTray ;
        // load an image
        java.awt.Image  image =  Toolkit.getDefaultToolkit().getImage (...);
        // create a action listener to listen for default action executed on the tray icon
        java.awt.event.ActionListener  listener = new ActionListener () {
            public void  actionPerformed (java.awt.event.ActionEvent  e) {
                // execute default action of the application
                // ...
            }
        };
        // create a popup menu
        java.awt.PopupMenu  popup = new  PopupMenu ();
        // create menu item for the default action
        MenuItem defaultItem = new MenuItem(...);
        defaultItem.addActionListener(listener);
        popup.add(defaultItem);
        /// ... add other items
        // construct a TrayIcon
        trayIcon = new  TrayIcon (image, "Tray Demo", popup);
        // set the TrayIcon properties
        trayIcon. addActionListener (listener);
        // ...
        // add the tray image
        try {
            tray. add (trayIcon);
        } catch (AWTException e) {
            System.err.println(e);
        }
        // ...
    } else {
        // disable tray option in your application or
        // perform other actions
        ...
    }
    // ...
    // some time later
    // the application state has changed - update the image
    if (trayIcon != null) {
        trayIcon. setImage (updatedImage);
    }
    // ...
Method from java.awt.SystemTray Summary:
add,   addNotify,   addPropertyChangeListener,   checkSystemTrayAllowed,   getPropertyChangeListeners,   getSystemTray,   getTrayIconSize,   getTrayIcons,   isSupported,   remove,   removePropertyChangeListener
Methods from java.lang.Object:
clone,   equals,   finalize,   getClass,   hashCode,   notify,   notifyAll,   toString,   wait,   wait,   wait
Method from java.awt.SystemTray Detail:
 public  void add(TrayIcon trayIcon) throws AWTException 
    Adds a TrayIcon to the SystemTray. The tray icon becomes visible in the system tray once it is added. The order in which icons are displayed in a tray is not specified - it is platform and implementation-dependent.

    All icons added by the application are automatically removed from the SystemTray upon application exit and also when the desktop system tray becomes unavailable.

 synchronized  void addNotify() 
 public synchronized  void addPropertyChangeListener(String propertyName,
    PropertyChangeListener listener) 
    Adds a {@code PropertyChangeListener} to the list of listeners for the specific property. The following properties are currently supported:

    Property Description
    {@code trayIcons} The {@code SystemTray}'s array of {@code TrayIcon} objects. The array is accessed via the #getTrayIcons method.
    This property is changed when a tray icon is added to (or removed from) the system tray.
    For example, this property is changed when the system tray becomes unavailable on the desktop
    and the tray icons are automatically removed.
    {@code systemTray} This property contains {@code SystemTray} instance when the system tray is available or null otherwise.
    This property is changed when the system tray becomes available or unavailable on the desktop.
    The property is accessed by the #getSystemTray method.

    The {@code listener} listens to property changes only in this context.

    If {@code listener} is {@code null}, no exception is thrown and no action is performed.

 static  void checkSystemTrayAllowed() 
 public synchronized PropertyChangeListener[] getPropertyChangeListeners(String propertyName) 
    Returns an array of all the listeners that have been associated with the named property.

    Only the listeners in this context are returned.

 public static SystemTray getSystemTray() 
    Gets the SystemTray instance that represents the desktop's tray area. This always returns the same instance per application. On some platforms the system tray may not be supported. You may use the #isSupported method to check if the system tray is supported.

    If a SecurityManager is installed, the AWTPermission {@code accessSystemTray} must be granted in order to get the {@code SystemTray} instance. Otherwise this method will throw a SecurityException.

 public Dimension getTrayIconSize() 
    Returns the size, in pixels, of the space that a tray icon will occupy in the system tray. Developers may use this methods to acquire the preferred size for the image property of a tray icon before it is created. For convenience, there is a similar method TrayIcon#getSize in the TrayIcon class.
 public TrayIcon[] getTrayIcons() 
    Returns an array of all icons added to the tray by this application. You can't access the icons added by another application. Some browsers partition applets in different code bases into separate contexts, and establish walls between these contexts. In such a scenario, only the tray icons added from this context will be returned.

    The returned array is a copy of the actual array and may be modified in any way without affecting the system tray. To remove a TrayIcon from the SystemTray, use the #remove(TrayIcon) method.

 public static boolean isSupported() 
    Returns whether the system tray is supported on the current platform. In addition to displaying the tray icon, minimal system tray support includes either a popup menu (see TrayIcon#setPopupMenu(PopupMenu) ) or an action event (see TrayIcon#addActionListener(ActionListener) ).

    Developers should not assume that all of the system tray functionality is supported. To guarantee that the tray icon's default action is always accessible, add the default action to both the action listener and the popup menu. See the example for an example of how to do this.

    Note: When implementing SystemTray and TrayIcon it is strongly recommended that you assign different gestures to the popup menu and an action event. Overloading a gesture for both purposes is confusing and may prevent the user from accessing one or the other.

 public  void remove(TrayIcon trayIcon) 
    Removes the specified TrayIcon from the SystemTray.

    All icons added by the application are automatically removed from the SystemTray upon application exit and also when the desktop system tray becomes unavailable.

    If trayIcon is null or was not added to the system tray, no exception is thrown and no action is performed.

 public synchronized  void removePropertyChangeListener(String propertyName,
    PropertyChangeListener listener) 
    Removes a {@code PropertyChangeListener} from the listener list for a specific property.

    The {@code PropertyChangeListener} must be from this context.

    If {@code propertyName} or {@code listener} is {@code null} or invalid, no exception is thrown and no action is taken.