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java.lang.Object java.awt.KeyboardFocusManager
The KeyboardFocusManager is responsible for managing the active and focused Windows, and the current focus owner. The focus owner is defined as the Component in an application that will typically receive all KeyEvents generated by the user. The focused Window is the Window that is, or contains, the focus owner. Only a Frame or a Dialog can be the active Window. The native windowing system may denote the active Window or its children with special decorations, such as a highlighted title bar. The active Window is always either the focused Window, or the first Frame or Dialog that is an owner of the focused Window.
The KeyboardFocusManager is both a centralized location for client code to query for the focus owner and initiate focus changes, and an event dispatcher for all FocusEvents, WindowEvents related to focus, and KeyEvents.
Some browsers partition applets in different code bases into separate contexts, and establish walls between these contexts. In such a scenario, there will be one KeyboardFocusManager per context. Other browsers place all applets into the same context, implying that there will be only a single, global KeyboardFocusManager for all applets. This behavior is implementation-dependent. Consult your browser's documentation for more information. No matter how many contexts there may be, however, there can never be more than one focus owner, focused Window, or active Window, per ClassLoader.
Window
,
Frame
,
Dialog
,
FocusEvent
,
WindowEvent
,
KeyEvent
Field Summary | |
static int |
BACKWARD_TRAVERSAL_KEYS
The identifier for the Backward focus traversal keys. |
static int |
DOWN_CYCLE_TRAVERSAL_KEYS
The identifier for the Down Cycle focus traversal keys. |
static int |
FORWARD_TRAVERSAL_KEYS
The identifier for the Forward focus traversal keys. |
static int |
UP_CYCLE_TRAVERSAL_KEYS
The identifier for the Up Cycle focus traversal keys. |
Method Summary | |
void |
addKeyEventDispatcher(KeyEventDispatcher dispatcher)
Adds a KeyEventDispatcher to this KeyboardFocusManager's dispatcher chain. |
void |
addKeyEventPostProcessor(KeyEventPostProcessor processor)
Adds a KeyEventPostProcessor to this KeyboardFocusManager's post- processor chain. |
void |
addPropertyChangeListener(PropertyChangeListener listener)
Adds a PropertyChangeListener to the listener list. |
void |
addVetoableChangeListener(VetoableChangeListener listener)
Adds a VetoableChangeListener to the listener list. |
void |
clearGlobalFocusOwner()
Clears the global focus owner at both the Java and native levels. |
abstract boolean |
dispatchEvent(AWTEvent e)
This method is called by the AWT event dispatcher requesting that the current KeyboardFocusManager dispatch the specified event on its behalf. |
abstract boolean |
dispatchKeyEvent(KeyEvent e)
Typically this method will be called by dispatchEvent if no
other KeyEventDispatcher in the dispatcher chain dispatched the
KeyEvent, or if no other KeyEventDispatchers are registered. |
void |
downFocusCycle()
Moves the focus down one focus traversal cycle from the current focus owner, if and only if the current focus owner is a Container that is a focus cycle root. |
abstract void |
downFocusCycle(Container aContainer)
Moves the focus down one focus traversal cycle. |
void |
focusNextComponent()
Focuses the Component after the current focus owner. |
abstract void |
focusNextComponent(Component aComponent)
Focuses the Component after aComponent, typically based on a FocusTraversalPolicy. |
void |
focusPreviousComponent()
Focuses the Component before the current focus owner. |
abstract void |
focusPreviousComponent(Component aComponent)
Focuses the Component before aComponent, typically based on a FocusTraversalPolicy. |
Window |
getActiveWindow()
Returns the active Window, if the active Window is in the same context as the calling thread. |
Container |
getCurrentFocusCycleRoot()
Returns the current focus cycle root, if the current focus cycle root is in the same context as the calling thread. |
static KeyboardFocusManager |
getCurrentKeyboardFocusManager()
Returns the current KeyboardFocusManager instance for the calling thread's context. |
Set |
getDefaultFocusTraversalKeys(int id)
Returns a Set of default focus traversal keys for a given traversal operation. |
FocusTraversalPolicy |
getDefaultFocusTraversalPolicy()
Returns the default FocusTraversalPolicy. |
Window |
getFocusedWindow()
Returns the focused Window, if the focused Window is in the same context as the calling thread. |
Component |
getFocusOwner()
Returns the focus owner, if the focus owner is in the same context as the calling thread. |
Component |
getPermanentFocusOwner()
Returns the permanent focus owner, if the permanent focus owner is in the same context as the calling thread. |
PropertyChangeListener[] |
getPropertyChangeListeners()
Returns an array of all the property change listeners registered on this keyboard focus manager. |
VetoableChangeListener[] |
getVetoableChangeListeners()
Returns an array of all the vetoable change listeners registered on this keyboard focus manager. |
abstract boolean |
postProcessKeyEvent(KeyEvent e)
This method will be called by dispatchKeyEvent . |
abstract void |
processKeyEvent(Component focusedComponent,
KeyEvent e)
This method initiates a focus traversal operation if and only if the KeyEvent represents a focus traversal key for the specified focusedComponent. |
void |
redispatchEvent(Component target,
AWTEvent e)
Redispatches an AWTEvent in such a way that the AWT event dispatcher will not recursively request that the KeyboardFocusManager, or any installed KeyEventDispatchers, dispatch the event again. |
void |
removeKeyEventDispatcher(KeyEventDispatcher dispatcher)
Removes a KeyEventDispatcher which was previously added to this KeyboardFocusManager's dispatcher chain. |
void |
removeKeyEventPostProcessor(KeyEventPostProcessor processor)
Removes a previously added KeyEventPostProcessor from this KeyboardFocusManager's post-processor chain. |
void |
removePropertyChangeListener(PropertyChangeListener listener)
Removes a PropertyChangeListener from the listener list. |
void |
removeVetoableChangeListener(VetoableChangeListener listener)
Removes a VetoableChangeListener from the listener list. |
void |
setDefaultFocusTraversalKeys(int id,
Set keystrokes)
Sets the default focus traversal keys for a given traversal operation. |
void |
setDefaultFocusTraversalPolicy(FocusTraversalPolicy defaultPolicy)
Sets the default FocusTraversalPolicy. |
void |
upFocusCycle()
Moves the focus up one focus traversal cycle from the current focus owner. |
abstract void |
upFocusCycle(Component aComponent)
Moves the focus up one focus traversal cycle. |
Methods inherited from class java.lang.Object |
clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait |
Field Detail |
public static final int FORWARD_TRAVERSAL_KEYS
setDefaultFocusTraversalKeys(int, java.util.Set)
,
getDefaultFocusTraversalKeys(int)
,
Component.setFocusTraversalKeys(int, java.util.Set)
,
Component.getFocusTraversalKeys(int)
,
Constant Field Valuespublic static final int BACKWARD_TRAVERSAL_KEYS
setDefaultFocusTraversalKeys(int, java.util.Set)
,
getDefaultFocusTraversalKeys(int)
,
Component.setFocusTraversalKeys(int, java.util.Set)
,
Component.getFocusTraversalKeys(int)
,
Constant Field Valuespublic static final int UP_CYCLE_TRAVERSAL_KEYS
setDefaultFocusTraversalKeys(int, java.util.Set)
,
getDefaultFocusTraversalKeys(int)
,
Component.setFocusTraversalKeys(int, java.util.Set)
,
Component.getFocusTraversalKeys(int)
,
Constant Field Valuespublic static final int DOWN_CYCLE_TRAVERSAL_KEYS
setDefaultFocusTraversalKeys(int, java.util.Set)
,
getDefaultFocusTraversalKeys(int)
,
Component.setFocusTraversalKeys(int, java.util.Set)
,
Component.getFocusTraversalKeys(int)
,
Constant Field ValuesMethod Detail |
public static KeyboardFocusManager getCurrentKeyboardFocusManager()
public Component getFocusOwner()
public void clearGlobalFocusOwner()
requestFocus()
. This operation
does not change the focused or active Windows.
Component.requestFocus()
,
FocusEvent.FOCUS_LOST
public Component getPermanentFocusOwner()
public Window getFocusedWindow()
public Window getActiveWindow()
public FocusTraversalPolicy getDefaultFocusTraversalPolicy()
setDefaultFocusTraversalPolicy(java.awt.FocusTraversalPolicy)
,
Container.setFocusTraversalPolicy(java.awt.FocusTraversalPolicy)
,
Container.getFocusTraversalPolicy()
public void setDefaultFocusTraversalPolicy(FocusTraversalPolicy defaultPolicy)
defaultPolicy
- the new, default FocusTraversalPolicy
IllegalArgumentException
- if defaultPolicy is nullgetDefaultFocusTraversalPolicy()
,
Container.setFocusTraversalPolicy(java.awt.FocusTraversalPolicy)
,
Container.getFocusTraversalPolicy()
public void setDefaultFocusTraversalKeys(int id, Set keystrokes)
Set
will be in effect on all
Window
s that have no such Set
of
their own explicitly defined. This Set
will also be
inherited, recursively, by any child Component
of
those Windows
that has
no such Set
of its own explicitly defined.
The default values for the default focus traversal keys are implementation-dependent. Sun recommends that all implementations for a particular native platform use the same default values. The recommendations for Windows and Unix are listed below. These recommendations are used in the Sun AWT implementations.
Identifier | Meaning | Default |
---|---|---|
KeyboardFocusManager.FORWARD_TRAVERSAL_KEYS |
Normal forward keyboard traversal | TAB on KEY_PRESSED ,
CTRL-TAB on KEY_PRESSED |
KeyboardFocusManager.BACKWARD_TRAVERSAL_KEYS |
Normal reverse keyboard traversal | SHIFT-TAB on KEY_PRESSED ,
CTRL-SHIFT-TAB on KEY_PRESSED |
KeyboardFocusManager.UP_CYCLE_TRAVERSAL_KEYS |
Go up one focus traversal cycle | none |
KeyboardFocusManager.DOWN_CYCLE_TRAVERSAL_KEYS |
Go down one focus traversal cycle | none |
Set
;
Collections.EMPTY_SET
is recommended.
Using the AWTKeyStroke
API, client code can
specify on which of two
specific KeyEvent
s, KEY_PRESSED
or
KEY_RELEASED
, the focus traversal operation will
occur. Regardless of which KeyEvent
is specified,
however, all KeyEvent
s related to the focus
traversal key, including the associated KEY_TYPED
event, will be consumed, and will not be dispatched
to any Component
. It is a runtime error to
specify a KEY_TYPED
event as
mapping to a focus traversal operation, or to map the same event to
multiple default focus traversal operations.
id
- one of
KeyboardFocusManager.FORWARD_TRAVERSAL_KEYS
,
KeyboardFocusManager.BACKWARD_TRAVERSAL_KEYS
,
KeyboardFocusManager.UP_CYCLE_TRAVERSAL_KEYS
, or
KeyboardFocusManager.DOWN_CYCLE_TRAVERSAL_KEYS
keystrokes
- the Set of AWTKeyStroke
s for the
specified operation
IllegalArgumentException
- if id is not one of
KeyboardFocusManager.FORWARD_TRAVERSAL_KEYS
,
KeyboardFocusManager.BACKWARD_TRAVERSAL_KEYS
,
KeyboardFocusManager.UP_CYCLE_TRAVERSAL_KEYS
, or
KeyboardFocusManager.DOWN_CYCLE_TRAVERSAL_KEYS
,
or if keystrokes is null
,
or if keystrokes contains null
,
or if any Object
in
keystrokes is not an AWTKeyStroke
,
or if any keystroke
represents a KEY_TYPED
event,
or if any keystroke already maps
to another default focus traversal operationgetDefaultFocusTraversalKeys(int)
,
Component.setFocusTraversalKeys(int, java.util.Set)
,
Component.getFocusTraversalKeys(int)
public Set getDefaultFocusTraversalKeys(int id)
setDefaultFocusTraversalKeys
for a full description of each
operation.)
id
- one of KeyboardFocusManager.FORWARD_TRAVERSAL_KEYS,
KeyboardFocusManager.BACKWARD_TRAVERSAL_KEYS,
KeyboardFocusManager.UP_CYCLE_TRAVERSAL_KEYS, or
KeyboardFocusManager.DOWN_CYCLE_TRAVERSAL_KEYS
Set
of AWTKeyStroke
s
for the specified operation; the Set
will be unmodifiable, and may be empty; null
will never be returned
IllegalArgumentException
- if id is not one of
KeyboardFocusManager.FORWARD_TRAVERSAL_KEYS,
KeyboardFocusManager.BACKWARD_TRAVERSAL_KEYS,
KeyboardFocusManager.UP_CYCLE_TRAVERSAL_KEYS, or
KeyboardFocusManager.DOWN_CYCLE_TRAVERSAL_KEYSsetDefaultFocusTraversalKeys(int, java.util.Set)
,
Component.setFocusTraversalKeys(int, java.util.Set)
,
Component.getFocusTraversalKeys(int)
public Container getCurrentFocusCycleRoot()
public void addPropertyChangeListener(PropertyChangeListener listener)
listener
- the PropertyChangeListener to be addedremovePropertyChangeListener(java.beans.PropertyChangeListener)
,
getPropertyChangeListeners()
public void removePropertyChangeListener(PropertyChangeListener listener)
If listener is null, no exception is thrown and no action is performed.
listener
- the PropertyChangeListener to be removedaddPropertyChangeListener(java.beans.PropertyChangeListener)
,
getPropertyChangeListeners()
public PropertyChangeListener[] getPropertyChangeListeners()
PropertyChangeListener
s
or an empty array if no property change
listeners are currently registeredaddPropertyChangeListener(java.beans.PropertyChangeListener)
,
removePropertyChangeListener(java.beans.PropertyChangeListener)
public void addVetoableChangeListener(VetoableChangeListener listener)
listener
- the VetoableChangeListener to be addedremoveVetoableChangeListener(java.beans.VetoableChangeListener)
,
getVetoableChangeListeners()
public void removeVetoableChangeListener(VetoableChangeListener listener)
If listener is null, no exception is thrown and no action is performed.
listener
- the VetoableChangeListener to be removedaddVetoableChangeListener(java.beans.VetoableChangeListener)
,
getVetoableChangeListeners()
public VetoableChangeListener[] getVetoableChangeListeners()
VetoableChangeListener
s
or an empty array if no vetoable change
listeners are currently registeredaddVetoableChangeListener(java.beans.VetoableChangeListener)
,
removeVetoableChangeListener(java.beans.VetoableChangeListener)
public void addKeyEventDispatcher(KeyEventDispatcher dispatcher)
true
from its
dispatchKeyEvent
method. There is no limit to the total
number of KeyEventDispatchers which can be added, nor to the number of
times which a particular KeyEventDispatcher instance can be added.
If a null dispatcher is specified, no action is taken and no exception is thrown.
dispatcher
- the KeyEventDispatcher to add to the dispatcher chainremoveKeyEventDispatcher(java.awt.KeyEventDispatcher)
public void removeKeyEventDispatcher(KeyEventDispatcher dispatcher)
addKeyEventDispatcher
.
If a null dispatcher is specified, if the specified dispatcher is not in the dispatcher chain, or if this KeyboardFocusManager is specified without having been explicitly re-registered, no action is taken and no exception is thrown.
dispatcher
- the KeyEventDispatcher to remove from the dispatcher
chainaddKeyEventDispatcher(java.awt.KeyEventDispatcher)
public void addKeyEventPostProcessor(KeyEventPostProcessor processor)
true
from its
postProcessKeyEvent
method. There is no limit to the the
total number of KeyEventPostProcessors that can be added, nor to the
number of times that a particular KeyEventPostProcessor instance can be
added.
If a null post-processor is specified, no action is taken and no exception is thrown.
processor
- the KeyEventPostProcessor to add to the post-processor
chainremoveKeyEventPostProcessor(java.awt.KeyEventPostProcessor)
public void removeKeyEventPostProcessor(KeyEventPostProcessor processor)
addKeyEventPostProcessor
can be
removed.
If a null post-processor is specified, if the specified post-processor is not in the post-processor chain, or if this KeyboardFocusManager is specified without having been explicitly added, no action is taken and no exception is thrown.
processor
- the KeyEventPostProcessor to remove from the post-
processor chainaddKeyEventPostProcessor(java.awt.KeyEventPostProcessor)
public abstract boolean dispatchEvent(AWTEvent e)
redispatchEvent
to prevent the AWT event
dispatcher from recursively requesting that the KeyboardFocusManager
dispatch the event again. If this method returns false
,
then the AWT event dispatcher will attempt to dispatch the event itself.
e
- the AWTEvent to be dispatched
true
if this method dispatched the event;
false
otherwiseredispatchEvent(java.awt.Component, java.awt.AWTEvent)
,
dispatchKeyEvent(java.awt.event.KeyEvent)
public final void redispatchEvent(Component target, AWTEvent e)
dispatchEvent
and client-defined
KeyEventDispatchers must call redispatchEvent(target, e)
instead of target.dispatchEvent(e)
to dispatch an event.
This method is intended to be used only by KeyboardFocusManagers and KeyEventDispatchers. It is not for general client use.
target
- the Component to which the event should be dispatchede
- the event to dispatchdispatchEvent(java.awt.AWTEvent)
,
KeyEventDispatcher
public abstract boolean dispatchKeyEvent(KeyEvent e)
dispatchEvent
if no
other KeyEventDispatcher in the dispatcher chain dispatched the
KeyEvent, or if no other KeyEventDispatchers are registered. If an
implementation of this method returns false
,
dispatchEvent
may try to dispatch the KeyEvent itself, or
may simply return false
. If true
is returned,
dispatchEvent
should return true
as well.
dispatchKeyEvent
in interface KeyEventDispatcher
e
- the KeyEvent which the current KeyboardFocusManager has
requested that this KeyEventDispatcher dispatch
true
if the KeyEvent was dispatched;
false
otherwisedispatchEvent(java.awt.AWTEvent)
public abstract boolean postProcessKeyEvent(KeyEvent e)
dispatchKeyEvent
.
By default, this method will handle any unconsumed KeyEvents that
map to an AWT MenuShortcut
by consuming the event
and activating the shortcut.
postProcessKeyEvent
in interface KeyEventPostProcessor
e
- the KeyEvent to post-process
true
to indicate that no other
KeyEventPostProcessor will be notified of the KeyEvent.dispatchKeyEvent(java.awt.event.KeyEvent)
,
MenuShortcut
public abstract void processKeyEvent(Component focusedComponent, KeyEvent e)
focusedComponent
- the Component that will be the basis for a focus
traversal operation if the specified event represents a focus
traversal key for the Componente
- the event that may represent a focus traversal keypublic abstract void focusNextComponent(Component aComponent)
aComponent
- the Component that is the basis for the focus
traversal operationFocusTraversalPolicy
public abstract void focusPreviousComponent(Component aComponent)
aComponent
- the Component that is the basis for the focus
traversal operationFocusTraversalPolicy
public abstract void upFocusCycle(Component aComponent)
aComponent
- the Component that is the basis for the focus
traversal operationpublic abstract void downFocusCycle(Container aContainer)
aContainer
- the Container that is the basis for the focus
traversal operationpublic final void focusNextComponent()
public final void focusPreviousComponent()
public final void upFocusCycle()
public final void downFocusCycle()
|
JSR 216 (Maintenance Release) | ||||||||||
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SUMMARY: NESTED | FIELD | CONSTR | METHOD | DETAIL: FIELD | CONSTR | METHOD |