public class SystemTray extends Object
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);
}
// ...
TrayIcon| Modifier and Type | Method and Description |
|---|---|
void |
add(TrayIcon trayIcon)
Adds a
TrayIcon to the SystemTray. |
void |
addPropertyChangeListener(String propertyName,
PropertyChangeListener listener)
Adds a
PropertyChangeListener to the list of listeners for the
specific property. |
PropertyChangeListener[] |
getPropertyChangeListeners(String propertyName)
Returns an array of all the listeners that have been associated
with the named property.
|
static SystemTray |
getSystemTray()
Gets the
SystemTray instance that represents the
desktop's tray area. |
TrayIcon[] |
getTrayIcons()
Returns an array of all icons added to the tray by this
application.
|
Dimension |
getTrayIconSize()
Returns the size, in pixels, of the space that a tray icon will
occupy in the system tray.
|
static boolean |
isSupported()
Returns whether the system tray is supported on the current
platform.
|
void |
remove(TrayIcon trayIcon)
Removes the specified
TrayIcon from the
SystemTray. |
void |
removePropertyChangeListener(String propertyName,
PropertyChangeListener listener)
Removes a
PropertyChangeListener from the listener list
for a specific property. |
public static SystemTray getSystemTray()
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
accessSystemTray must be granted in order to get the
SystemTray instance. Otherwise this method will throw a
SecurityException.
SystemTray instance that represents
the desktop's tray areaUnsupportedOperationException - if the system tray isn't
supported by the current platformHeadlessException - if
GraphicsEnvironment.isHeadless() returns trueSecurityException - if accessSystemTray permission
is not grantedadd(TrayIcon),
TrayIcon,
isSupported(),
SecurityManager.checkPermission(java.security.Permission),
AWTPermissionpublic static boolean isSupported()
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.
false if no system tray access is supported; this
method returns true if the minimal system tray access is
supported but does not guarantee that all system tray
functionality is supported for the current platformgetSystemTray()public void add(TrayIcon trayIcon) throws AWTException
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.
trayIcon - the TrayIcon to be addedNullPointerException - if trayIcon is
nullIllegalArgumentException - if the same instance of
a TrayIcon is added more than onceAWTException - if the desktop system tray is missingremove(TrayIcon),
getSystemTray(),
TrayIcon,
Imagepublic void remove(TrayIcon trayIcon)
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.
trayIcon - the TrayIcon to be removedadd(TrayIcon),
TrayIconpublic TrayIcon[] getTrayIcons()
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.
add(TrayIcon),
TrayIconpublic Dimension getTrayIconSize()
TrayIcon.getSize() in the TrayIcon class.TrayIcon.setImageAutoSize(boolean),
Image,
TrayIcon.getSize()public void addPropertyChangeListener(String propertyName, PropertyChangeListener listener)
PropertyChangeListener to the list of listeners for the
specific property. The following properties are currently supported:
| Property | Description |
|---|---|
trayIcons |
The SystemTray's array of 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. |
systemTray |
This property contains 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 listener listens to property changes only in this context.
If listener is null, no exception is thrown
and no action is performed.
propertyName - the specified propertylistener - the property change listener to be addedremovePropertyChangeListener(java.lang.String, java.beans.PropertyChangeListener),
getPropertyChangeListeners(java.lang.String)public void removePropertyChangeListener(String propertyName, PropertyChangeListener listener)
PropertyChangeListener from the listener list
for a specific property.
The PropertyChangeListener must be from this context.
If propertyName or listener is null or invalid,
no exception is thrown and no action is taken.
propertyName - the specified propertylistener - the PropertyChangeListener to be removedaddPropertyChangeListener(java.lang.String, java.beans.PropertyChangeListener),
getPropertyChangeListeners(java.lang.String)public PropertyChangeListener[] getPropertyChangeListeners(String propertyName)
Only the listeners in this context are returned.
propertyName - the specified propertyPropertyChangeListeners associated with
the named property; if no such listeners have been added or
if propertyName is null or invalid, an empty
array is returnedaddPropertyChangeListener(java.lang.String, java.beans.PropertyChangeListener),
removePropertyChangeListener(java.lang.String, java.beans.PropertyChangeListener) Submit a bug or feature
For further API reference and developer documentation, see Java SE Documentation. That documentation contains more detailed, developer-targeted descriptions, with conceptual overviews, definitions of terms, workarounds, and working code examples.
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