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 getSystemTray()
 throws UnsupportedOperationException.  To detect whether the
 system tray is supported, use isSupported().
 
The SystemTray may contain one or more TrayIcons, which are added to the tray using the add(java.awt.TrayIcon) method, and removed when no longer needed, using the
 remove(java.awt.TrayIcon).  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
         Image image = Toolkit.getDefaultToolkit().getImage(...);
         // create a action listener to listen for default action executed on the tray icon
         ActionListener listener = new ActionListener() {
             public void actionPerformed(ActionEvent e) {
                 // execute default action of the application
                 // ...
             }
         };
         // create a popup menu
         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);
     }
     // ...
 
 - Since:
- 1.6
- See Also:
- 
Method SummaryModifier and TypeMethodDescriptionvoidAdds aTrayIconto theSystemTray.voidaddPropertyChangeListener(String propertyName, PropertyChangeListener listener) Adds aPropertyChangeListenerto the list of listeners for the specific property.getPropertyChangeListeners(String propertyName) Returns an array of all the listeners that have been associated with the named property.static SystemTrayGets theSystemTrayinstance that represents the desktop's tray area.TrayIcon[]Returns an array of all icons added to the tray by this application.Returns the size, in pixels, of the space that a tray icon will occupy in the system tray.static booleanReturns whether the system tray is supported on the current platform.voidRemoves the specifiedTrayIconfrom theSystemTray.voidremovePropertyChangeListener(String propertyName, PropertyChangeListener listener) Removes aPropertyChangeListenerfrom the listener list for a specific property.
- 
Method Details- 
getSystemTrayGets theSystemTrayinstance 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 theisSupported()method to check if the system tray is supported.If a SecurityManager is installed, the AWTPermission accessSystemTraymust be granted in order to get theSystemTrayinstance. Otherwise this method will throw a SecurityException.- Returns:
- the SystemTrayinstance that represents the desktop's tray area
- Throws:
- UnsupportedOperationException- if the system tray isn't supported by the current platform
- HeadlessException- if- GraphicsEnvironment.isHeadless()returns- true
- SecurityException- if- accessSystemTraypermission is not granted
- See Also:
 
- 
isSupportedpublic 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 (seeTrayIcon.setPopupMenu(PopupMenu)) or an action event (seeTrayIcon.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 examplefor an example of how to do this.Note: When implementing SystemTrayandTrayIconit 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.- Returns:
- falseif no system tray access is supported; this method returns- trueif the minimal system tray access is supported but does not guarantee that all system tray functionality is supported for the current platform
- See Also:
 
- 
addAdds aTrayIconto theSystemTray. 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 SystemTrayupon application exit and also when the desktop system tray becomes unavailable.- Parameters:
- trayIcon- the- TrayIconto be added
- Throws:
- NullPointerException- if- trayIconis- null
- IllegalArgumentException- if the same instance of a- TrayIconis added more than once
- AWTException- if the desktop system tray is missing
- See Also:
 
- 
removeRemoves the specifiedTrayIconfrom theSystemTray.All icons added by the application are automatically removed from the SystemTrayupon application exit and also when the desktop system tray becomes unavailable.If trayIconisnullor was not added to the system tray, no exception is thrown and no action is performed.- Parameters:
- trayIcon- the- TrayIconto be removed
- See Also:
 
- 
getTrayIconsReturns 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 TrayIconfrom theSystemTray, use theremove(TrayIcon)method.- Returns:
- an array of all tray icons added to this tray, or an empty array if none has been added
- See Also:
 
- 
getTrayIconSizeReturns the size, in pixels, of the space that a tray icon will occupy in the system tray. Developers may use this method to acquire the preferred size for the tray icon before it is created. For convenience, there is a similar methodTrayIcon.getSize()in theTrayIconclass.- Returns:
- the default size of a tray icon, in pixels
- See Also:
 
- 
addPropertyChangeListenerAdds aPropertyChangeListenerto the list of listeners for the specific property. The following properties are currently supported:SystemTray properties Property Description trayIconsThe SystemTray's array ofTrayIconobjects. The array is accessed via thegetTrayIcons()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.systemTrayThis property contains SystemTrayinstance when the system tray is available ornullotherwise. This property is changed when the system tray becomes available or unavailable on the desktop. The property is accessed by thegetSystemTray()method.The listenerlistens to property changes only in this context.If listenerisnull, no exception is thrown and no action is performed.- Parameters:
- propertyName- the specified property
- listener- the property change listener to be added
- See Also:
 
- 
removePropertyChangeListenerRemoves aPropertyChangeListenerfrom the listener list for a specific property.The PropertyChangeListenermust be from this context.If propertyNameorlistenerisnullor invalid, no exception is thrown and no action is taken.- Parameters:
- propertyName- the specified property
- listener- the PropertyChangeListener to be removed
- See Also:
 
- 
getPropertyChangeListenersReturns an array of all the listeners that have been associated with the named property.Only the listeners in this context are returned. - Parameters:
- propertyName- the specified property
- Returns:
- all of the PropertyChangeListeners associated with the named property; if no such listeners have been added or ifpropertyNameisnullor invalid, an empty array is returned
- See Also:
 
 
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