Class Taskbar

public class Taskbar
extends Object

The Taskbar class allows a Java application to interact with the system task area (taskbar, Dock, etc.).

There are a variety of interactions depending on the current platform such as displaying progress of some task, appending user-specified menu to the application icon context menu, etc.

Implementation Note:
Linux support is currently limited to Unity. However to make these features work on Unity, the app should be run from a .desktop file with specified java.desktop.appName system property set to this .desktop file name: Exec=java -Djava.desktop.appName=MyApp.desktop -jar /path/to/myapp.jar see https://help.ubuntu.com/community/UnityLaunchersAndDesktopFiles
Since:
9

Nested Classes

Modifier and Type Class Description
static class  Taskbar.Feature

List of provided features.
static class  Taskbar.State

Kinds of available window progress states.

Methods

Modifier and Type Method Description
Image getIconImage()

Obtains an image of this application's icon.
PopupMenu getMenu()

Gets PopupMenu used to add items to this application's icon in system task area.
static Taskbar getTaskbar()

Returns the Taskbar instance of the current taskbar context.
boolean isSupported​(Taskbar.Feature feature)

Tests whether a Feature is supported on the current platform.
static boolean isTaskbarSupported()

Tests whether this class is supported on the current platform.
void requestUserAttention​(boolean enabled, boolean critical)

Requests user attention to this application.
void requestWindowUserAttention​(Window w)

Requests user attention to the specified window.
void setIconBadge​(String badge)

Affixes a small system-provided badge to this application's icon.
void setIconImage​(Image image)

Changes this application's icon to the provided image.
void setMenu​(PopupMenu menu)

Attaches the contents of the provided PopupMenu to the application icon in the task area.
void setProgressValue​(int value)

Affixes a small system-provided progress bar to this application's icon.
void setWindowIconBadge​(Window w, Image badge)

Affixes a small badge to this application's icon in the task area for the specified window.
void setWindowProgressState​(Window w, Taskbar.State state)

Sets a progress state for a specified window.
void setWindowProgressValue​(Window w, int value)

Displays a determinate progress bar in the task area for the specified window.

Methods declared in class java.lang.Object

clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait

Methods

isSupported

public boolean isSupported(Taskbar.Feature feature)

Tests whether a Feature is supported on the current platform.

Parameters:
feature - the specified Taskbar.Feature
Returns:
true if the specified feature is supported on the current platform

getTaskbar

public static Taskbar getTaskbar()

Returns the Taskbar instance of the current taskbar context. On some platforms the Taskbar API may not be supported; use the isTaskbarSupported() method to determine if the current taskbar is supported.

Returns:
the Taskbar instance
Throws:
HeadlessException - if GraphicsEnvironment.isHeadless() returns true
UnsupportedOperationException - if this class is not supported on the current platform
See Also:
isTaskbarSupported(), GraphicsEnvironment.isHeadless()

isTaskbarSupported

public static boolean isTaskbarSupported()

Tests whether this class is supported on the current platform. If it's supported, use getTaskbar() to retrieve an instance.

Returns:
true if this class is supported on the current platform; false otherwise
See Also:
getTaskbar()

requestUserAttention

public void requestUserAttention(boolean enabled,
                                 boolean critical)

Requests user attention to this application. Depending on the platform, this may be visually indicated by a bouncing or flashing icon in the task area. It may have no effect on an already active application. On some platforms (e.g. Mac OS) this effect may disappear upon app activation and cannot be dismissed by setting enabled to false. Other platforms may require an additional call requestUserAttention(boolean, boolean) to dismiss this request with enabled parameter set to false.

Parameters:
enabled - disables this request if false
critical - if this is an important request
Throws:
SecurityException - if a security manager exists and it denies the RuntimePermission("canProcessApplicationEvents") permission.
UnsupportedOperationException - if the current platform does not support the Taskbar.Feature.USER_ATTENTION feature

requestWindowUserAttention

public void requestWindowUserAttention(Window w)

Requests user attention to the specified window. Has no effect if a window representation is not displayable in the task area. Whether it is displayable is dependent on all of window type, platform, and implementation.

Parameters:
w - window
Throws:
SecurityException - if a security manager exists and it denies the RuntimePermission("canProcessApplicationEvents") permission.
UnsupportedOperationException - if the current platform does not support the Taskbar.Feature.USER_ATTENTION_WINDOW feature

setMenu

public void setMenu(PopupMenu menu)

Attaches the contents of the provided PopupMenu to the application icon in the task area.

Parameters:
menu - the PopupMenu to attach to this application
Throws:
SecurityException - if a security manager exists and it denies the RuntimePermission("canProcessApplicationEvents") permission.
UnsupportedOperationException - if the current platform does not support the Taskbar.Feature.MENU feature

getMenu

public PopupMenu getMenu()

Gets PopupMenu used to add items to this application's icon in system task area.

Returns:
the PopupMenu
Throws:
SecurityException - if a security manager exists and it denies the RuntimePermission("canProcessApplicationEvents") permission.
UnsupportedOperationException - if the current platform does not support the Taskbar.Feature.MENU feature

setIconImage

public void setIconImage(Image image)

Changes this application's icon to the provided image.

Parameters:
image - to change
Throws:
SecurityException - if a security manager exists and it denies the RuntimePermission("canProcessApplicationEvents") permission.
UnsupportedOperationException - if the current platform does not support the Taskbar.Feature.ICON_IMAGE feature

getIconImage

public Image getIconImage()

Obtains an image of this application's icon.

Returns:
an image of this application's icon
Throws:
SecurityException - if a security manager exists and it denies the RuntimePermission("canProcessApplicationEvents") permission.
UnsupportedOperationException - if the current platform does not support the Taskbar.Feature.ICON_IMAGE feature

setIconBadge

public void setIconBadge(String badge)

Affixes a small system-provided badge to this application's icon. Usually a number. Some platforms do not support string values and accept only integer values. In this case, pass an integer represented as a string as parameter. This can be tested by Feature.ICON_BADGE_TEXT and Feature.ICON_BADGE_NUMBER. Passing null as parameter hides the badge.

Parameters:
badge - label to affix to the icon
Throws:
SecurityException - if a security manager exists and it denies the RuntimePermission("canProcessApplicationEvents") permission.
UnsupportedOperationException - if the current platform does not support the Taskbar.Feature.ICON_BADGE_NUMBER or Taskbar.Feature.ICON_BADGE_TEXT feature

setWindowIconBadge

public void setWindowIconBadge(Window w,
                               Image badge)

Affixes a small badge to this application's icon in the task area for the specified window. It may be disabled by system settings. Has no effect if a window representation is not displayable in the task area. Whether it is displayable is dependent on all of window type, platform, and implementation.

Parameters:
w - window to update
badge - image to affix to the icon
Throws:
SecurityException - if a security manager exists and it denies the RuntimePermission("canProcessApplicationEvents") permission.
UnsupportedOperationException - if the current platform does not support the Taskbar.Feature.ICON_BADGE_IMAGE_WINDOW feature

setProgressValue

public void setProgressValue(int value)

Affixes a small system-provided progress bar to this application's icon.

Parameters:
value - from 0 to 100, other to disable progress indication
Throws:
SecurityException - if a security manager exists and it denies the RuntimePermission("canProcessApplicationEvents") permission.
UnsupportedOperationException - if the current platform does not support the Taskbar.Feature.PROGRESS_VALUE feature

setWindowProgressValue

public void setWindowProgressValue(Window w,
                                   int value)

Displays a determinate progress bar in the task area for the specified window. Has no effect if a window representation is not displayable in the task area. Whether it is displayable is dependent on all of window type, platform, and implementation.
The visual behavior is platform and Taskbar.State dependent.
This call cancels the INDETERMINATE state of the window.
Note that when multiple windows is grouped in the task area the behavior is platform specific.

Parameters:
w - window to update
value - from 0 to 100, other to switch to Taskbar.State.OFF state and disable progress indication
Throws:
SecurityException - if a security manager exists and it denies the RuntimePermission("canProcessApplicationEvents") permission.
UnsupportedOperationException - if the current platform does not support the Taskbar.Feature.PROGRESS_VALUE_WINDOW feature
See Also:
setWindowProgressState(java.awt.Window, State)

setWindowProgressState

public void setWindowProgressState(Window w,
                                   Taskbar.State state)

Sets a progress state for a specified window. Has no effect if a window representation is not displayable in the task area. Whether it is displayable is dependent on all of window type, platform, and implementation.
Each state displays a progress in a platform-dependent way.
Note than switching from INDETERMINATE state to any of determinate states may reset value set by setWindowProgressValue

Parameters:
w - window
state - to change to
Throws:
SecurityException - if a security manager exists and it denies the RuntimePermission("canProcessApplicationEvents") permission.
UnsupportedOperationException - if the current platform does not support the Taskbar.Feature.PROGRESS_STATE_WINDOW feature
See Also:
Taskbar.State.OFF, Taskbar.State.NORMAL, Taskbar.State.PAUSED, Taskbar.State.ERROR, Taskbar.State.INDETERMINATE, setWindowProgressValue(java.awt.Window, int)

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Documentation extracted from Debian's OpenJDK Development Kit package.
Licensed under the GNU General Public License, version 2, with the Classpath Exception.
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https://docs.oracle.com/en/java/javase/11/docs/api/java.desktop/java/awt/Taskbar.html