public abstract class Component extends Object implements ImageObserver, MenuContainer, Serializable
The Component
class is the abstract superclass of
the nonmenu-related Abstract Window Toolkit components. Class
Component
can also be extended directly to create a
lightweight component. A lightweight component is a component that is
not associated with a native window. On the contrary, a heavyweight
component is associated with a native window. The isLightweight()
method may be used to distinguish between the two kinds of the components.
Lightweight and heavyweight components may be mixed in a single component
hierarchy. However, for correct operating of such a mixed hierarchy of
components, the whole hierarchy must be valid. When the hierarchy gets
invalidated, like after changing the bounds of components, or
adding/removing components to/from containers, the whole hierarchy must be
validated afterwards by means of the Container.validate()
method
invoked on the top-most invalid container of the hierarchy.
Serializable
protocol will be saved when
the object is stored. If an AWT object has listeners that
aren't marked serializable, they will be dropped at
writeObject
time. Developers will need, as always,
to consider the implications of making an object serializable.
One situation to watch out for is this:
import java.awt.*; import java.awt.event.*; import java.io.Serializable; class MyApp implements ActionListener, Serializable { BigObjectThatShouldNotBeSerializedWithAButton bigOne; Button aButton = new Button(); MyApp() { // Oops, now aButton has a listener with a reference // to bigOne! aButton.addActionListener(this); } public void actionPerformed(ActionEvent e) { System.out.println("Hello There"); } }In this example, serializing
aButton
by itself
will cause MyApp
and everything it refers to
to be serialized as well. The problem is that the listener
is serializable by coincidence, not by design. To separate
the decisions about MyApp
and the
ActionListener
being serializable one can use a
nested class, as in the following example:
import java.awt.*; import java.awt.event.*; import java.io.Serializable; class MyApp implements java.io.Serializable { BigObjectThatShouldNotBeSerializedWithAButton bigOne; Button aButton = new Button(); static class MyActionListener implements ActionListener { public void actionPerformed(ActionEvent e) { System.out.println("Hello There"); } } MyApp() { aButton.addActionListener(new MyActionListener()); } }
Note: For more information on the paint mechanisms utilitized by AWT and Swing, including information on how to write the most efficient painting code, see Painting in AWT and Swing.
For details on the focus subsystem, see How to Use the Focus Subsystem, a section in The Java Tutorial, and the Focus Specification for more information.
Modifier and Type | Class and Description |
---|---|
protected class |
Component.AccessibleAWTComponent
Inner class of Component used to provide default support for
accessibility.
|
static class |
Component.BaselineResizeBehavior
Enumeration of the common ways the baseline of a component can
change as the size changes.
|
protected class |
Component.BltBufferStrategy
Inner class for blitting offscreen surfaces to a component.
|
protected class |
Component.FlipBufferStrategy
Inner class for flipping buffers on a component.
|
Modifier and Type | Field and Description |
---|---|
protected AccessibleContext |
accessibleContext
The
AccessibleContext associated with this Component . |
static float |
BOTTOM_ALIGNMENT
Ease-of-use constant for
getAlignmentY . |
static float |
CENTER_ALIGNMENT
Ease-of-use constant for
getAlignmentY and
getAlignmentX . |
static float |
LEFT_ALIGNMENT
Ease-of-use constant for
getAlignmentX . |
static float |
RIGHT_ALIGNMENT
Ease-of-use constant for
getAlignmentX . |
static float |
TOP_ALIGNMENT
Ease-of-use constant for
getAlignmentY() . |
ABORT, ALLBITS, ERROR, FRAMEBITS, HEIGHT, PROPERTIES, SOMEBITS, WIDTH
Modifier | Constructor and Description |
---|---|
protected |
Component()
Constructs a new component.
|
Modifier and Type | Method and Description |
---|---|
boolean |
action(Event evt,
Object what)
Deprecated.
As of JDK version 1.1,
should register this component as ActionListener on component
which fires action events.
|
void |
add(PopupMenu popup)
Adds the specified popup menu to the component.
|
void |
addComponentListener(ComponentListener l)
Adds the specified component listener to receive component events from
this component.
|
void |
addFocusListener(FocusListener l)
Adds the specified focus listener to receive focus events from
this component when this component gains input focus.
|
void |
addHierarchyBoundsListener(HierarchyBoundsListener l)
Adds the specified hierarchy bounds listener to receive hierarchy
bounds events from this component when the hierarchy to which this
container belongs changes.
|
void |
addHierarchyListener(HierarchyListener l)
Adds the specified hierarchy listener to receive hierarchy changed
events from this component when the hierarchy to which this container
belongs changes.
|
void |
addInputMethodListener(InputMethodListener l)
Adds the specified input method listener to receive
input method events from this component.
|
void |
addKeyListener(KeyListener l)
Adds the specified key listener to receive key events from
this component.
|
void |
addMouseListener(MouseListener l)
Adds the specified mouse listener to receive mouse events from
this component.
|
void |
addMouseMotionListener(MouseMotionListener l)
Adds the specified mouse motion listener to receive mouse motion
events from this component.
|
void |
addMouseWheelListener(MouseWheelListener l)
Adds the specified mouse wheel listener to receive mouse wheel events
from this component.
|
void |
addNotify()
Makes this
Component displayable by connecting it to a
native screen resource. |
void |
addPropertyChangeListener(PropertyChangeListener listener)
Adds a PropertyChangeListener to the listener list.
|
void |
addPropertyChangeListener(String propertyName,
PropertyChangeListener listener)
Adds a PropertyChangeListener to the listener list for a specific
property.
|
void |
applyComponentOrientation(ComponentOrientation orientation)
Sets the
ComponentOrientation property of this component
and all components contained within it. |
boolean |
areFocusTraversalKeysSet(int id)
Returns whether the Set of focus traversal keys for the given focus
traversal operation has been explicitly defined for this Component.
|
Rectangle |
bounds()
Deprecated.
As of JDK version 1.1,
replaced by
getBounds() . |
int |
checkImage(Image image,
ImageObserver observer)
Returns the status of the construction of a screen representation
of the specified image.
|
int |
checkImage(Image image,
int width,
int height,
ImageObserver observer)
Returns the status of the construction of a screen representation
of the specified image.
|
protected AWTEvent |
coalesceEvents(AWTEvent existingEvent,
AWTEvent newEvent)
Potentially coalesce an event being posted with an existing
event.
|
boolean |
contains(int x,
int y)
Checks whether this component "contains" the specified point,
where
x and y are defined to be
relative to the coordinate system of this component. |
boolean |
contains(Point p)
Checks whether this component "contains" the specified point,
where the point's x and y coordinates are defined
to be relative to the coordinate system of this component.
|
Image |
createImage(ImageProducer producer)
Creates an image from the specified image producer.
|
Image |
createImage(int width,
int height)
Creates an off-screen drawable image
to be used for double buffering.
|
VolatileImage |
createVolatileImage(int width,
int height)
Creates a volatile off-screen drawable image
to be used for double buffering.
|
VolatileImage |
createVolatileImage(int width,
int height,
ImageCapabilities caps)
Creates a volatile off-screen drawable image, with the given capabilities.
|
void |
deliverEvent(Event e)
Deprecated.
As of JDK version 1.1,
replaced by
dispatchEvent(AWTEvent e) . |
void |
disable()
Deprecated.
As of JDK version 1.1,
replaced by
setEnabled(boolean) . |
protected void |
disableEvents(long eventsToDisable)
Disables the events defined by the specified event mask parameter
from being delivered to this component.
|
void |
dispatchEvent(AWTEvent e)
Dispatches an event to this component or one of its sub components.
|
void |
doLayout()
Prompts the layout manager to lay out this component.
|
void |
enable()
Deprecated.
As of JDK version 1.1,
replaced by
setEnabled(boolean) . |
void |
enable(boolean b)
Deprecated.
As of JDK version 1.1,
replaced by
setEnabled(boolean) . |
protected void |
enableEvents(long eventsToEnable)
Enables the events defined by the specified event mask parameter
to be delivered to this component.
|
void |
enableInputMethods(boolean enable)
Enables or disables input method support for this component.
|
protected void |
firePropertyChange(String propertyName,
boolean oldValue,
boolean newValue)
Support for reporting bound property changes for boolean properties.
|
void |
firePropertyChange(String propertyName,
byte oldValue,
byte newValue)
Reports a bound property change.
|
void |
firePropertyChange(String propertyName,
char oldValue,
char newValue)
Reports a bound property change.
|
void |
firePropertyChange(String propertyName,
double oldValue,
double newValue)
Reports a bound property change.
|
void |
firePropertyChange(String propertyName,
float oldValue,
float newValue)
Reports a bound property change.
|
protected void |
firePropertyChange(String propertyName,
int oldValue,
int newValue)
Support for reporting bound property changes for integer properties.
|
void |
firePropertyChange(String propertyName,
long oldValue,
long newValue)
Reports a bound property change.
|
protected void |
firePropertyChange(String propertyName,
Object oldValue,
Object newValue)
Support for reporting bound property changes for Object properties.
|
void |
firePropertyChange(String propertyName,
short oldValue,
short newValue)
Reports a bound property change.
|
AccessibleContext |
getAccessibleContext()
Gets the
AccessibleContext associated
with this Component . |
float |
getAlignmentX()
Returns the alignment along the x axis.
|
float |
getAlignmentY()
Returns the alignment along the y axis.
|
Color |
getBackground()
Gets the background color of this component.
|
int |
getBaseline(int width,
int height)
Returns the baseline.
|
Component.BaselineResizeBehavior |
getBaselineResizeBehavior()
Returns an enum indicating how the baseline of the component
changes as the size changes.
|
Rectangle |
getBounds()
Gets the bounds of this component in the form of a
Rectangle object. |
Rectangle |
getBounds(Rectangle rv)
Stores the bounds of this component into "return value" rv and
return rv.
|
ColorModel |
getColorModel()
Gets the instance of
ColorModel used to display
the component on the output device. |
Component |
getComponentAt(int x,
int y)
Determines if this component or one of its immediate
subcomponents contains the (x, y) location,
and if so, returns the containing component.
|
Component |
getComponentAt(Point p)
Returns the component or subcomponent that contains the
specified point.
|
ComponentListener[] |
getComponentListeners()
Returns an array of all the component listeners
registered on this component.
|
ComponentOrientation |
getComponentOrientation()
Retrieves the language-sensitive orientation that is to be used to order
the elements or text within this component.
|
Cursor |
getCursor()
Gets the cursor set in the component.
|
DropTarget |
getDropTarget()
Gets the
DropTarget associated with this
Component . |
Container |
getFocusCycleRootAncestor()
Returns the Container which is the focus cycle root of this Component's
focus traversal cycle.
|
FocusListener[] |
getFocusListeners()
Returns an array of all the focus listeners
registered on this component.
|
Set<AWTKeyStroke> |
getFocusTraversalKeys(int id)
Returns the Set of focus traversal keys for a given traversal operation
for this Component.
|
boolean |
getFocusTraversalKeysEnabled()
Returns whether focus traversal keys are enabled for this Component.
|
Font |
getFont()
Gets the font of this component.
|
FontMetrics |
getFontMetrics(Font font)
Gets the font metrics for the specified font.
|
Color |
getForeground()
Gets the foreground color of this component.
|
Graphics |
getGraphics()
Creates a graphics context for this component.
|
GraphicsConfiguration |
getGraphicsConfiguration()
Gets the
GraphicsConfiguration associated with this
Component . |
int |
getHeight()
Returns the current height of this component.
|
HierarchyBoundsListener[] |
getHierarchyBoundsListeners()
Returns an array of all the hierarchy bounds listeners
registered on this component.
|
HierarchyListener[] |
getHierarchyListeners()
Returns an array of all the hierarchy listeners
registered on this component.
|
boolean |
getIgnoreRepaint() |
InputContext |
getInputContext()
Gets the input context used by this component for handling
the communication with input methods when text is entered
in this component.
|
InputMethodListener[] |
getInputMethodListeners()
Returns an array of all the input method listeners
registered on this component.
|
InputMethodRequests |
getInputMethodRequests()
Gets the input method request handler which supports
requests from input methods for this component.
|
KeyListener[] |
getKeyListeners()
Returns an array of all the key listeners
registered on this component.
|
<T extends EventListener> |
getListeners(Class<T> listenerType)
Returns an array of all the objects currently registered
as
FooListener s
upon this Component . |
Locale |
getLocale()
Gets the locale of this component.
|
Point |
getLocation()
Gets the location of this component in the form of a
point specifying the component's top-left corner.
|
Point |
getLocation(Point rv)
Stores the x,y origin of this component into "return value" rv
and return rv.
|
Point |
getLocationOnScreen()
Gets the location of this component in the form of a point
specifying the component's top-left corner in the screen's
coordinate space.
|
Dimension |
getMaximumSize()
Gets the maximum size of this component.
|
Dimension |
getMinimumSize()
Gets the minimum size of this component.
|
MouseListener[] |
getMouseListeners()
Returns an array of all the mouse listeners
registered on this component.
|
MouseMotionListener[] |
getMouseMotionListeners()
Returns an array of all the mouse motion listeners
registered on this component.
|
Point |
getMousePosition()
Returns the position of the mouse pointer in this
Component 's
coordinate space if the Component is directly under the mouse
pointer, otherwise returns null . |
MouseWheelListener[] |
getMouseWheelListeners()
Returns an array of all the mouse wheel listeners
registered on this component.
|
String |
getName()
Gets the name of the component.
|
Container |
getParent()
Gets the parent of this component.
|
java.awt.peer.ComponentPeer |
getPeer()
Deprecated.
As of JDK version 1.1,
programs should not directly manipulate peers;
replaced by
boolean isDisplayable() . |
Dimension |
getPreferredSize()
Gets the preferred size of this component.
|
PropertyChangeListener[] |
getPropertyChangeListeners()
Returns an array of all the property change listeners
registered on this component.
|
PropertyChangeListener[] |
getPropertyChangeListeners(String propertyName)
Returns an array of all the listeners which have been associated
with the named property.
|
Dimension |
getSize()
Returns the size of this component in the form of a
Dimension object. |
Dimension |
getSize(Dimension rv)
Stores the width/height of this component into "return value" rv
and return rv.
|
Toolkit |
getToolkit()
Gets the toolkit of this component.
|
Object |
getTreeLock()
Gets this component's locking object (the object that owns the thread
synchronization monitor) for AWT component-tree and layout
operations.
|
int |
getWidth()
Returns the current width of this component.
|
int |
getX()
Returns the current x coordinate of the components origin.
|
int |
getY()
Returns the current y coordinate of the components origin.
|
boolean |
gotFocus(Event evt,
Object what)
Deprecated.
As of JDK version 1.1,
replaced by processFocusEvent(FocusEvent).
|
boolean |
handleEvent(Event evt)
Deprecated.
As of JDK version 1.1
replaced by processEvent(AWTEvent).
|
boolean |
hasFocus()
Returns
true if this Component is the
focus owner. |
void |
hide()
Deprecated.
As of JDK version 1.1,
replaced by
setVisible(boolean) . |
boolean |
imageUpdate(Image img,
int infoflags,
int x,
int y,
int w,
int h)
Repaints the component when the image has changed.
|
boolean |
inside(int x,
int y)
Deprecated.
As of JDK version 1.1,
replaced by contains(int, int).
|
void |
invalidate()
Invalidates this component and its ancestors.
|
boolean |
isBackgroundSet()
Returns whether the background color has been explicitly set for this
Component.
|
boolean |
isCursorSet()
Returns whether the cursor has been explicitly set for this Component.
|
boolean |
isDisplayable()
Determines whether this component is displayable.
|
boolean |
isDoubleBuffered()
Returns true if this component is painted to an offscreen image
("buffer") that's copied to the screen later.
|
boolean |
isEnabled()
Determines whether this component is enabled.
|
boolean |
isFocusable()
Returns whether this Component can be focused.
|
boolean |
isFocusCycleRoot(Container container)
Returns whether the specified Container is the focus cycle root of this
Component's focus traversal cycle.
|
boolean |
isFocusOwner()
Returns
true if this Component is the
focus owner. |
boolean |
isFocusTraversable()
Deprecated.
As of 1.4, replaced by
isFocusable() . |
boolean |
isFontSet()
Returns whether the font has been explicitly set for this Component.
|
boolean |
isForegroundSet()
Returns whether the foreground color has been explicitly set for this
Component.
|
boolean |
isLightweight()
A lightweight component doesn't have a native toolkit peer.
|
boolean |
isMaximumSizeSet()
Returns true if the maximum size has been set to a non-
null
value otherwise returns false. |
boolean |
isMinimumSizeSet()
Returns whether or not
setMinimumSize has been
invoked with a non-null value. |
boolean |
isOpaque()
Returns true if this component is completely opaque, returns
false by default.
|
boolean |
isPreferredSizeSet()
Returns true if the preferred size has been set to a
non-
null value otherwise returns false. |
boolean |
isShowing()
Determines whether this component is showing on screen.
|
boolean |
isValid()
Determines whether this component is valid.
|
boolean |
isVisible()
Determines whether this component should be visible when its
parent is visible.
|
boolean |
keyDown(Event evt,
int key)
Deprecated.
As of JDK version 1.1,
replaced by processKeyEvent(KeyEvent).
|
boolean |
keyUp(Event evt,
int key)
Deprecated.
As of JDK version 1.1,
replaced by processKeyEvent(KeyEvent).
|
void |
layout()
Deprecated.
As of JDK version 1.1,
replaced by
doLayout() . |
void |
list()
Prints a listing of this component to the standard system output
stream
System.out . |
void |
list(PrintStream out)
Prints a listing of this component to the specified output
stream.
|
void |
list(PrintStream out,
int indent)
Prints out a list, starting at the specified indentation, to the
specified print stream.
|
void |
list(PrintWriter out)
Prints a listing to the specified print writer.
|
void |
list(PrintWriter out,
int indent)
Prints out a list, starting at the specified indentation, to
the specified print writer.
|
Component |
locate(int x,
int y)
Deprecated.
As of JDK version 1.1,
replaced by getComponentAt(int, int).
|
Point |
location()
Deprecated.
As of JDK version 1.1,
replaced by
getLocation() . |
boolean |
lostFocus(Event evt,
Object what)
Deprecated.
As of JDK version 1.1,
replaced by processFocusEvent(FocusEvent).
|
Dimension |
minimumSize()
Deprecated.
As of JDK version 1.1,
replaced by
getMinimumSize() . |
boolean |
mouseDown(Event evt,
int x,
int y)
Deprecated.
As of JDK version 1.1,
replaced by processMouseEvent(MouseEvent).
|
boolean |
mouseDrag(Event evt,
int x,
int y)
Deprecated.
As of JDK version 1.1,
replaced by processMouseMotionEvent(MouseEvent).
|
boolean |
mouseEnter(Event evt,
int x,
int y)
Deprecated.
As of JDK version 1.1,
replaced by processMouseEvent(MouseEvent).
|
boolean |
mouseExit(Event evt,
int x,
int y)
Deprecated.
As of JDK version 1.1,
replaced by processMouseEvent(MouseEvent).
|
boolean |
mouseMove(Event evt,
int x,
int y)
Deprecated.
As of JDK version 1.1,
replaced by processMouseMotionEvent(MouseEvent).
|
boolean |
mouseUp(Event evt,
int x,
int y)
Deprecated.
As of JDK version 1.1,
replaced by processMouseEvent(MouseEvent).
|
void |
move(int x,
int y)
Deprecated.
As of JDK version 1.1,
replaced by
setLocation(int, int) . |
void |
nextFocus()
Deprecated.
As of JDK version 1.1,
replaced by transferFocus().
|
void |
paint(Graphics g)
Paints this component.
|
void |
paintAll(Graphics g)
Paints this component and all of its subcomponents.
|
protected String |
paramString()
Returns a string representing the state of this component.
|
boolean |
postEvent(Event e)
Deprecated.
As of JDK version 1.1,
replaced by dispatchEvent(AWTEvent).
|
Dimension |
preferredSize()
Deprecated.
As of JDK version 1.1,
replaced by
getPreferredSize() . |
boolean |
prepareImage(Image image,
ImageObserver observer)
Prepares an image for rendering on this component.
|
boolean |
prepareImage(Image image,
int width,
int height,
ImageObserver observer)
Prepares an image for rendering on this component at the
specified width and height.
|
void |
print(Graphics g)
Prints this component.
|
void |
printAll(Graphics g)
Prints this component and all of its subcomponents.
|
protected void |
processComponentEvent(ComponentEvent e)
Processes component events occurring on this component by
dispatching them to any registered
ComponentListener objects. |
protected void |
processEvent(AWTEvent e)
Processes events occurring on this component.
|
protected void |
processFocusEvent(FocusEvent e)
Processes focus events occurring on this component by
dispatching them to any registered
FocusListener objects. |
protected void |
processHierarchyBoundsEvent(HierarchyEvent e)
Processes hierarchy bounds events occurring on this component by
dispatching them to any registered
HierarchyBoundsListener objects. |
protected void |
processHierarchyEvent(HierarchyEvent e)
Processes hierarchy events occurring on this component by
dispatching them to any registered
HierarchyListener objects. |
protected void |
processInputMethodEvent(InputMethodEvent e)
Processes input method events occurring on this component by
dispatching them to any registered
InputMethodListener objects. |
protected void |
processKeyEvent(KeyEvent e)
Processes key events occurring on this component by
dispatching them to any registered
KeyListener objects. |
protected void |
processMouseEvent(MouseEvent e)
Processes mouse events occurring on this component by
dispatching them to any registered
MouseListener objects. |
protected void |
processMouseMotionEvent(MouseEvent e)
Processes mouse motion events occurring on this component by
dispatching them to any registered
MouseMotionListener objects. |
protected void |
processMouseWheelEvent(MouseWheelEvent e)
Processes mouse wheel events occurring on this component by
dispatching them to any registered
MouseWheelListener objects. |
void |
remove(MenuComponent popup)
Removes the specified popup menu from the component.
|
void |
removeComponentListener(ComponentListener l)
Removes the specified component listener so that it no longer
receives component events from this component.
|
void |
removeFocusListener(FocusListener l)
Removes the specified focus listener so that it no longer
receives focus events from this component.
|
void |
removeHierarchyBoundsListener(HierarchyBoundsListener l)
Removes the specified hierarchy bounds listener so that it no longer
receives hierarchy bounds events from this component.
|
void |
removeHierarchyListener(HierarchyListener l)
Removes the specified hierarchy listener so that it no longer
receives hierarchy changed events from this component.
|
void |
removeInputMethodListener(InputMethodListener l)
Removes the specified input method listener so that it no longer
receives input method events from this component.
|
void |
removeKeyListener(KeyListener l)
Removes the specified key listener so that it no longer
receives key events from this component.
|
void |
removeMouseListener(MouseListener l)
Removes the specified mouse listener so that it no longer
receives mouse events from this component.
|
void |
removeMouseMotionListener(MouseMotionListener l)
Removes the specified mouse motion listener so that it no longer
receives mouse motion events from this component.
|
void |
removeMouseWheelListener(MouseWheelListener l)
Removes the specified mouse wheel listener so that it no longer
receives mouse wheel events from this component.
|
void |
removeNotify()
Makes this
Component undisplayable by destroying it native
screen resource. |
void |
removePropertyChangeListener(PropertyChangeListener listener)
Removes a PropertyChangeListener from the listener list.
|
void |
removePropertyChangeListener(String propertyName,
PropertyChangeListener listener)
Removes a
PropertyChangeListener from the listener
list for a specific property. |
void |
repaint()
Repaints this component.
|
void |
repaint(int x,
int y,
int width,
int height)
Repaints the specified rectangle of this component.
|
void |
repaint(long tm)
Repaints the component.
|
void |
repaint(long tm,
int x,
int y,
int width,
int height)
Repaints the specified rectangle of this component within
tm milliseconds. |
void |
requestFocus()
Requests that this Component get the input focus, and that this
Component's top-level ancestor become the focused Window.
|
protected boolean |
requestFocus(boolean temporary)
Requests that this
Component get the input focus,
and that this Component 's top-level ancestor
become the focused Window . |
boolean |
requestFocusInWindow()
Requests that this Component get the input focus, if this
Component's top-level ancestor is already the focused
Window.
|
protected boolean |
requestFocusInWindow(boolean temporary)
Requests that this
Component get the input focus,
if this Component 's top-level ancestor is already
the focused Window . |
void |
reshape(int x,
int y,
int width,
int height)
Deprecated.
As of JDK version 1.1,
replaced by
setBounds(int, int, int, int) . |
void |
resize(Dimension d)
Deprecated.
As of JDK version 1.1,
replaced by
setSize(Dimension) . |
void |
resize(int width,
int height)
Deprecated.
As of JDK version 1.1,
replaced by
setSize(int, int) . |
void |
revalidate()
Revalidates the component hierarchy up to the nearest validate root.
|
void |
setBackground(Color c)
Sets the background color of this component.
|
void |
setBounds(int x,
int y,
int width,
int height)
Moves and resizes this component.
|
void |
setBounds(Rectangle r)
Moves and resizes this component to conform to the new
bounding rectangle
r . |
void |
setComponentOrientation(ComponentOrientation o)
Sets the language-sensitive orientation that is to be used to order
the elements or text within this component.
|
void |
setCursor(Cursor cursor)
Sets the cursor image to the specified cursor.
|
void |
setDropTarget(DropTarget dt)
Associate a
DropTarget with this component. |
void |
setEnabled(boolean b)
Enables or disables this component, depending on the value of the
parameter
b . |
void |
setFocusable(boolean focusable)
Sets the focusable state of this Component to the specified value.
|
void |
setFocusTraversalKeys(int id,
Set<? extends AWTKeyStroke> keystrokes)
Sets the focus traversal keys for a given traversal operation for this
Component.
|
void |
setFocusTraversalKeysEnabled(boolean focusTraversalKeysEnabled)
Sets whether focus traversal keys are enabled for this Component.
|
void |
setFont(Font f)
Sets the font of this component.
|
void |
setForeground(Color c)
Sets the foreground color of this component.
|
void |
setIgnoreRepaint(boolean ignoreRepaint)
Sets whether or not paint messages received from the operating system
should be ignored.
|
void |
setLocale(Locale l)
Sets the locale of this component.
|
void |
setLocation(int x,
int y)
Moves this component to a new location.
|
void |
setLocation(Point p)
Moves this component to a new location.
|
void |
setMaximumSize(Dimension maximumSize)
Sets the maximum size of this component to a constant
value.
|
void |
setMinimumSize(Dimension minimumSize)
Sets the minimum size of this component to a constant
value.
|
void |
setName(String name)
Sets the name of the component to the specified string.
|
void |
setPreferredSize(Dimension preferredSize)
Sets the preferred size of this component to a constant
value.
|
void |
setSize(Dimension d)
Resizes this component so that it has width
d.width
and height d.height . |
void |
setSize(int width,
int height)
Resizes this component so that it has width
width
and height height . |
void |
setVisible(boolean b)
Shows or hides this component depending on the value of parameter
b . |
void |
show()
Deprecated.
As of JDK version 1.1,
replaced by
setVisible(boolean) . |
void |
show(boolean b)
Deprecated.
As of JDK version 1.1,
replaced by
setVisible(boolean) . |
Dimension |
size()
Deprecated.
As of JDK version 1.1,
replaced by
getSize() . |
String |
toString()
Returns a string representation of this component and its values.
|
void |
transferFocus()
Transfers the focus to the next component, as though this Component were
the focus owner.
|
void |
transferFocusBackward()
Transfers the focus to the previous component, as though this Component
were the focus owner.
|
void |
transferFocusUpCycle()
Transfers the focus up one focus traversal cycle.
|
void |
update(Graphics g)
Updates this component.
|
void |
validate()
Validates this component.
|
public static final float TOP_ALIGNMENT
getAlignmentY()
.
Specifies an alignment to the top of the component.getAlignmentY()
,
Constant Field Valuespublic static final float CENTER_ALIGNMENT
getAlignmentY
and
getAlignmentX
. Specifies an alignment to
the center of the componentgetAlignmentX()
,
getAlignmentY()
,
Constant Field Valuespublic static final float BOTTOM_ALIGNMENT
getAlignmentY
.
Specifies an alignment to the bottom of the component.getAlignmentY()
,
Constant Field Valuespublic static final float LEFT_ALIGNMENT
getAlignmentX
.
Specifies an alignment to the left side of the component.getAlignmentX()
,
Constant Field Valuespublic static final float RIGHT_ALIGNMENT
getAlignmentX
.
Specifies an alignment to the right side of the component.getAlignmentX()
,
Constant Field Valuesprotected AccessibleContext accessibleContext
AccessibleContext
associated with this Component
.protected Component()
Component
can be
extended directly to create a lightweight component that does not
utilize an opaque native window. A lightweight component must be
hosted by a native container somewhere higher up in the component
tree (for example, by a Frame
object).public String getName()
setName(java.lang.String)
public void setName(String name)
name
- the string that is to be this
component's namegetName()
public Container getParent()
@Deprecated public java.awt.peer.ComponentPeer getPeer()
boolean isDisplayable()
.public void setDropTarget(DropTarget dt)
DropTarget
with this component.
The Component
will receive drops only if it
is enabled.dt
- The DropTargetisEnabled()
public DropTarget getDropTarget()
DropTarget
associated with this
Component
.public GraphicsConfiguration getGraphicsConfiguration()
GraphicsConfiguration
associated with this
Component
.
If the Component
has not been assigned a specific
GraphicsConfiguration
,
the GraphicsConfiguration
of the
Component
object's top-level container is
returned.
If the Component
has been created, but not yet added
to a Container
, this method returns null
.GraphicsConfiguration
used by this
Component
or null
public final Object getTreeLock()
public Toolkit getToolkit()
public boolean isValid()
true
if the component is valid, false
otherwisevalidate()
,
invalidate()
public boolean isDisplayable()
A component is made displayable either when it is added to a displayable containment hierarchy or when its containment hierarchy is made displayable. A containment hierarchy is made displayable when its ancestor window is either packed or made visible.
A component is made undisplayable either when it is removed from a displayable containment hierarchy or when its containment hierarchy is made undisplayable. A containment hierarchy is made undisplayable when its ancestor window is disposed.
true
if the component is displayable,
false
otherwiseContainer.add(Component)
,
Window.pack()
,
Window.show()
,
Container.remove(Component)
,
Window.dispose()
public boolean isVisible()
Frame
objects.true
if the component is visible,
false
otherwisesetVisible(boolean)
public Point getMousePosition() throws HeadlessException
Component
's
coordinate space if the Component
is directly under the mouse
pointer, otherwise returns null
.
If the Component
is not showing on the screen, this method
returns null
even if the mouse pointer is above the area
where the Component
would be displayed.
If the Component
is partially or fully obscured by other
Component
s or native windows, this method returns a non-null
value only if the mouse pointer is located above the unobscured part of the
Component
.
For Container
s it returns a non-null value if the mouse is
above the Container
itself or above any of its descendants.
Use Container.getMousePosition(boolean)
if you need to exclude children.
Sometimes the exact mouse coordinates are not important, and the only thing
that matters is whether a specific Component
is under the mouse
pointer. If the return value of this method is null
, mouse
pointer is not directly above the Component
.
Component
, or nullHeadlessException
- if GraphicsEnvironment.isHeadless() returns trueisShowing()
,
Container.getMousePosition(boolean)
public boolean isShowing()
Note: sometimes there is no way to detect whether the
Component
is actually visible to the user. This can happen when:
ScrollPane
but
the Component
is not currently in the scroll pane's view port.
Component
is obscured by another Component
or
Container
.
true
if the component is showing,
false
otherwisesetVisible(boolean)
public boolean isEnabled()
setEnabled
method.true
if the component is enabled,
false
otherwisesetEnabled(boolean)
public void setEnabled(boolean b)
b
. An enabled component can respond to user
input and generate events. Components are enabled initially by default.
Note: Disabling a lightweight component does not prevent it from receiving MouseEvents.
Note: Disabling a heavyweight container prevents all components in this container from receiving any input events. But disabling a lightweight container affects only this container.
b
- If true
, this component is
enabled; otherwise this component is disabledisEnabled()
,
isLightweight()
@Deprecated public void enable()
setEnabled(boolean)
.@Deprecated public void enable(boolean b)
setEnabled(boolean)
.@Deprecated public void disable()
setEnabled(boolean)
.public boolean isDoubleBuffered()
public void enableInputMethods(boolean enable)
enable
- true to enable, false to disableprocessKeyEvent(java.awt.event.KeyEvent)
public void setVisible(boolean b)
b
.
This method changes layout-related information, and therefore, invalidates the component hierarchy.
b
- if true
, shows this component;
otherwise, hides this componentisVisible()
,
invalidate()
@Deprecated public void show()
setVisible(boolean)
.@Deprecated public void show(boolean b)
setVisible(boolean)
.@Deprecated public void hide()
setVisible(boolean)
.public Color getForeground()
setForeground(java.awt.Color)
public void setForeground(Color c)
c
- the color to become this component's
foreground color; if this parameter is null
then this component will inherit
the foreground color of its parentgetForeground()
public boolean isForegroundSet()
false
, this Component is
inheriting its foreground color from an ancestor.true
if the foreground color has been explicitly
set for this Component; false
otherwise.public Color getBackground()
setBackground(java.awt.Color)
public void setBackground(Color c)
The background color affects each component differently and the parts of the component that are affected by the background color may differ between operating systems.
c
- the color to become this component's color;
if this parameter is null
, then this
component will inherit the background color of its parentgetBackground()
public boolean isBackgroundSet()
false
, this Component is
inheriting its background color from an ancestor.true
if the background color has been explicitly
set for this Component; false
otherwise.public Font getFont()
getFont
in interface MenuContainer
setFont(java.awt.Font)
public void setFont(Font f)
This method changes layout-related information, and therefore, invalidates the component hierarchy.
f
- the font to become this component's font;
if this parameter is null
then this
component will inherit the font of its parentgetFont()
,
invalidate()
public boolean isFontSet()
false
, this Component is inheriting its
font from an ancestor.true
if the font has been explicitly set for this
Component; false
otherwise.public Locale getLocale()
IllegalComponentStateException
- if the Component
does not have its own locale and has not yet been added to
a containment hierarchy such that the locale can be determined
from the containing parentsetLocale(java.util.Locale)
public void setLocale(Locale l)
This method changes layout-related information, and therefore, invalidates the component hierarchy.
l
- the locale to become this component's localegetLocale()
,
invalidate()
public ColorModel getColorModel()
ColorModel
used to display
the component on the output device.ColorModel
,
ComponentPeer.getColorModel()
,
Toolkit.getColorModel()
public Point getLocation()
Due to the asynchronous nature of native event handling, this
method can return outdated values (for instance, after several calls
of setLocation()
in rapid succession). For this
reason, the recommended method of obtaining a component's position is
within java.awt.event.ComponentListener.componentMoved()
,
which is called after the operating system has finished moving the
component.
Point
representing
the top-left corner of the component's bounds in
the coordinate space of the component's parentsetLocation(int, int)
,
getLocationOnScreen()
public Point getLocationOnScreen()
Point
representing
the top-left corner of the component's bounds in the
coordinate space of the screenIllegalComponentStateException
- if the
component is not showing on the screensetLocation(int, int)
,
getLocation()
@Deprecated public Point location()
getLocation()
.public void setLocation(int x, int y)
x
and y
parameters in the coordinate space of this component's parent.
This method changes layout-related information, and therefore, invalidates the component hierarchy.
x
- the x-coordinate of the new location's
top-left corner in the parent's coordinate spacey
- the y-coordinate of the new location's
top-left corner in the parent's coordinate spacegetLocation()
,
setBounds(int, int, int, int)
,
invalidate()
@Deprecated public void move(int x, int y)
setLocation(int, int)
.public void setLocation(Point p)
p
. Point
p
is given in the parent's coordinate space.
This method changes layout-related information, and therefore, invalidates the component hierarchy.
p
- the point defining the top-left corner
of the new location, given in the coordinate space of this
component's parentgetLocation()
,
setBounds(int, int, int, int)
,
invalidate()
public Dimension getSize()
Dimension
object. The height
field of the Dimension
object contains
this component's height, and the width
field of the Dimension
object contains
this component's width.Dimension
object that indicates the
size of this componentsetSize(int, int)
@Deprecated public Dimension size()
getSize()
.public void setSize(int width, int height)
width
and height height
.
This method changes layout-related information, and therefore, invalidates the component hierarchy.
width
- the new width of this component in pixelsheight
- the new height of this component in pixelsgetSize()
,
setBounds(int, int, int, int)
,
invalidate()
@Deprecated public void resize(int width, int height)
setSize(int, int)
.public void setSize(Dimension d)
d.width
and height d.height
.
This method changes layout-related information, and therefore, invalidates the component hierarchy.
d
- the dimension specifying the new size
of this componentNullPointerException
- if d
is null
setSize(int, int)
,
setBounds(int, int, int, int)
,
invalidate()
@Deprecated public void resize(Dimension d)
setSize(Dimension)
.public Rectangle getBounds()
Rectangle
object. The bounds specify this
component's width, height, and location relative to
its parent.setBounds(int, int, int, int)
,
getLocation()
,
getSize()
@Deprecated public Rectangle bounds()
getBounds()
.public void setBounds(int x, int y, int width, int height)
x
and y
, and the
new size is specified by width
and height
.
This method changes layout-related information, and therefore, invalidates the component hierarchy.
x
- the new x-coordinate of this componenty
- the new y-coordinate of this componentwidth
- the new width
of this componentheight
- the new height
of this
componentgetBounds()
,
setLocation(int, int)
,
setLocation(Point)
,
setSize(int, int)
,
setSize(Dimension)
,
invalidate()
@Deprecated public void reshape(int x, int y, int width, int height)
setBounds(int, int, int, int)
.public void setBounds(Rectangle r)
r
. This component's new
position is specified by r.x
and r.y
,
and its new size is specified by r.width
and
r.height
This method changes layout-related information, and therefore, invalidates the component hierarchy.
r
- the new bounding rectangle for this componentNullPointerException
- if r
is null
getBounds()
,
setLocation(int, int)
,
setLocation(Point)
,
setSize(int, int)
,
setSize(Dimension)
,
invalidate()
public int getX()
component.getBounds().x
,
or component.getLocation().x
because it doesn't
cause any heap allocations.public int getY()
component.getBounds().y
,
or component.getLocation().y
because it
doesn't cause any heap allocations.public int getWidth()
component.getBounds().width
,
or component.getSize().width
because it
doesn't cause any heap allocations.public int getHeight()
component.getBounds().height
,
or component.getSize().height
because it
doesn't cause any heap allocations.public Rectangle getBounds(Rectangle rv)
null
a new
Rectangle
is allocated.
This version of getBounds
is useful if the caller
wants to avoid allocating a new Rectangle
object
on the heap.rv
- the return value, modified to the components boundspublic Dimension getSize(Dimension rv)
null
a new
Dimension
object is allocated. This version of
getSize
is useful if the caller wants to avoid
allocating a new Dimension
object on the heap.rv
- the return value, modified to the components sizepublic Point getLocation(Point rv)
null
a new
Point
is allocated.
This version of getLocation
is useful if the
caller wants to avoid allocating a new Point
object on the heap.rv
- the return value, modified to the components locationpublic boolean isOpaque()
An opaque component paints every pixel within its rectangular region. A non-opaque component paints only some of its pixels, allowing the pixels underneath it to "show through". A component that does not fully paint its pixels therefore provides a degree of transparency.
Subclasses that guarantee to always completely paint their contents should override this method and return true.
isLightweight()
public boolean isLightweight()
Component
and Container
,
other than the ones defined in this package like Button
or Scrollbar
, are lightweight.
All of the Swing components are lightweights.
This method will always return false
if this component
is not displayable because it is impossible to determine the
weight of an undisplayable component.
isDisplayable()
public void setPreferredSize(Dimension preferredSize)
getPreferredSize
will always
return this value. Setting the preferred size to null
restores the default behavior.preferredSize
- The new preferred size, or nullgetPreferredSize()
,
isPreferredSizeSet()
public boolean isPreferredSizeSet()
null
value otherwise returns false.setPreferredSize
has been invoked
with a non-null value.public Dimension getPreferredSize()
getMinimumSize()
,
LayoutManager
@Deprecated public Dimension preferredSize()
getPreferredSize()
.public void setMinimumSize(Dimension minimumSize)
getMinimumSize
will always
return this value. Setting the minimum size to null
restores the default behavior.minimumSize
- the new minimum size of this componentgetMinimumSize()
,
isMinimumSizeSet()
public boolean isMinimumSizeSet()
setMinimumSize
has been
invoked with a non-null value.setMinimumSize
has been invoked with a
non-null value.public Dimension getMinimumSize()
getPreferredSize()
,
LayoutManager
@Deprecated public Dimension minimumSize()
getMinimumSize()
.public void setMaximumSize(Dimension maximumSize)
getMaximumSize
will always
return this value. Setting the maximum size to null
restores the default behavior.maximumSize
- a Dimension
containing the
desired maximum allowable sizegetMaximumSize()
,
isMaximumSizeSet()
public boolean isMaximumSizeSet()
null
value otherwise returns false.maximumSize
is non-null
,
false otherwisepublic Dimension getMaximumSize()
getMinimumSize()
,
getPreferredSize()
,
LayoutManager
public float getAlignmentX()
public float getAlignmentY()
public int getBaseline(int width, int height)
LayoutManager
s to align components along their
baseline. A return value less than 0 indicates this component
does not have a reasonable baseline and that
LayoutManager
s should not align this component on
its baseline.
The default implementation returns -1. Subclasses that support
baseline should override appropriately. If a value >= 0 is
returned, then the component has a valid baseline for any
size >= the minimum size and getBaselineResizeBehavior
can be used to determine how the baseline changes with size.
width
- the width to get the baseline forheight
- the height to get the baseline forIllegalArgumentException
- if width or height is < 0getBaselineResizeBehavior()
,
FontMetrics
public Component.BaselineResizeBehavior getBaselineResizeBehavior()
The default implementation returns
BaselineResizeBehavior.OTHER
. Subclasses that have a
baseline should override appropriately. Subclasses should
never return null
; if the baseline can not be
calculated return BaselineResizeBehavior.OTHER
. Callers
should first ask for the baseline using
getBaseline
and if a value >= 0 is returned use
this method. It is acceptable for this method to return a
value other than BaselineResizeBehavior.OTHER
even if
getBaseline
returns a value less than 0.
getBaseline(int, int)
public void doLayout()
validate()
,
LayoutManager
@Deprecated public void layout()
doLayout()
.public void validate()
The meaning of the term validating is defined by the ancestors of
this class. See Container.validate()
for more details.
invalidate()
,
doLayout()
,
LayoutManager
,
Container.validate()
public void invalidate()
By default, all the ancestors of the component up to the top-most
container of the hierarchy are marked invalid. If the java.awt.smartInvalidate
system property is set to true
,
invalidation stops on the nearest validate root of this component.
Marking a container invalid indicates that the container needs to
be laid out.
This method is called automatically when any layout-related information changes (e.g. setting the bounds of the component, or adding the component to a container).
This method might be called often, so it should work fast.
validate()
,
doLayout()
,
LayoutManager
,
Container.isValidateRoot()
public void revalidate()
This method first invalidates the component hierarchy starting from this component up to the nearest validate root. Afterwards, the component hierarchy is validated starting from the nearest validate root.
This is a convenience method supposed to help application developers
avoid looking for validate roots manually. Basically, it's equivalent to
first calling the invalidate()
method on this component, and
then calling the validate()
method on the nearest validate
root.
Container.isValidateRoot()
public Graphics getGraphics()
null
if this component is currently not
displayable.null
if it has nonepaint(java.awt.Graphics)
public FontMetrics getFontMetrics(Font font)
FontRenderContext
and
this method does not provide one, it can return only metrics for
the default render context which may not match that used when
rendering on the Component if Graphics2D
functionality is being
used. Instead metrics can be obtained at rendering time by calling
Graphics.getFontMetrics()
or text measurement APIs on the
Font
class.font
- the font for which font metrics is to be
obtainedfont
getFont()
,
getPeer()
,
ComponentPeer.getFontMetrics(Font)
,
Toolkit.getFontMetrics(Font)
public void setCursor(Cursor cursor)
contains
method for
this component returns true for the current cursor location, and
this Component is visible, displayable, and enabled. Setting the
cursor of a Container
causes that cursor to be displayed
within all of the container's subcomponents, except for those
that have a non-null
cursor.
The method may have no visual effect if the Java platform implementation and/or the native system do not support changing the mouse cursor shape.
cursor
- One of the constants defined
by the Cursor
class;
if this parameter is null
then this component will inherit
the cursor of its parentisEnabled()
,
isShowing()
,
getCursor()
,
contains(int, int)
,
Toolkit.createCustomCursor(java.awt.Image, java.awt.Point, java.lang.String)
,
Cursor
public Cursor getCursor()
Cursor.DEFAULT_CURSOR
is returned.setCursor(java.awt.Cursor)
public boolean isCursorSet()
false
, this Component is inheriting
its cursor from an ancestor.true
if the cursor has been explicitly set for this
Component; false
otherwise.public void paint(Graphics g)
This method is called when the contents of the component should
be painted; such as when the component is first being shown or
is damaged and in need of repair. The clip rectangle in the
Graphics
parameter is set to the area
which needs to be painted.
Subclasses of Component
that override this
method need not call super.paint(g)
.
For performance reasons, Component
s with zero width
or height aren't considered to need painting when they are first shown,
and also aren't considered to need repair.
Note: For more information on the paint mechanisms utilitized by AWT and Swing, including information on how to write the most efficient painting code, see Painting in AWT and Swing.
g
- the graphics context to use for paintingupdate(java.awt.Graphics)
public void update(Graphics g)
If this component is not a lightweight component, the
AWT calls the update
method in response to
a call to repaint
. You can assume that
the background is not cleared.
The update
method of Component
calls this component's paint
method to redraw
this component. This method is commonly overridden by subclasses
which need to do additional work in response to a call to
repaint
.
Subclasses of Component that override this method should either
call super.update(g)
, or call paint(g)
directly from their update
method.
The origin of the graphics context, its
(0
, 0
) coordinate point, is the
top-left corner of this component. The clipping region of the
graphics context is the bounding rectangle of this component.
Note: For more information on the paint mechanisms utilitized by AWT and Swing, including information on how to write the most efficient painting code, see Painting in AWT and Swing.
g
- the specified context to use for updatingpaint(java.awt.Graphics)
,
repaint()
public void paintAll(Graphics g)
The origin of the graphics context, its
(0
, 0
) coordinate point, is the
top-left corner of this component. The clipping region of the
graphics context is the bounding rectangle of this component.
g
- the graphics context to use for paintingpaint(java.awt.Graphics)
public void repaint()
If this component is a lightweight component, this method
causes a call to this component's paint
method as soon as possible. Otherwise, this method causes
a call to this component's update
method as soon
as possible.
Note: For more information on the paint mechanisms utilitized by AWT and Swing, including information on how to write the most efficient painting code, see Painting in AWT and Swing.
update(Graphics)
public void repaint(long tm)
paint
within tm
milliseconds.
Note: For more information on the paint mechanisms utilitized by AWT and Swing, including information on how to write the most efficient painting code, see Painting in AWT and Swing.
tm
- maximum time in milliseconds before updatepaint(java.awt.Graphics)
,
update(Graphics)
public void repaint(int x, int y, int width, int height)
If this component is a lightweight component, this method
causes a call to this component's paint
method
as soon as possible. Otherwise, this method causes a call to
this component's update
method as soon as possible.
Note: For more information on the paint mechanisms utilitized by AWT and Swing, including information on how to write the most efficient painting code, see Painting in AWT and Swing.
x
- the x coordinatey
- the y coordinatewidth
- the widthheight
- the heightupdate(Graphics)
public void repaint(long tm, int x, int y, int width, int height)
tm
milliseconds.
If this component is a lightweight component, this method causes
a call to this component's paint
method.
Otherwise, this method causes a call to this component's
update
method.
Note: For more information on the paint mechanisms utilitized by AWT and Swing, including information on how to write the most efficient painting code, see Painting in AWT and Swing.
tm
- maximum time in milliseconds before updatex
- the x coordinatey
- the y coordinatewidth
- the widthheight
- the heightupdate(Graphics)
public void print(Graphics g)
The default implementation of this method calls the
paint
method.
The origin of the graphics context, its
(0
, 0
) coordinate point, is the
top-left corner of this component. The clipping region of the
graphics context is the bounding rectangle of this component.
g
- the graphics context to use for printingpaint(Graphics)
public void printAll(Graphics g)
The origin of the graphics context, its
(0
, 0
) coordinate point, is the
top-left corner of this component. The clipping region of the
graphics context is the bounding rectangle of this component.
g
- the graphics context to use for printingprint(Graphics)
public boolean imageUpdate(Image img, int infoflags, int x, int y, int w, int h)
imageUpdate
method of an ImageObserver
is called when more information about an
image which had been previously requested using an asynchronous
routine such as the drawImage
method of
Graphics
becomes available.
See the definition of imageUpdate
for
more information on this method and its arguments.
The imageUpdate
method of Component
incrementally draws an image on the component as more of the bits
of the image are available.
If the system property awt.image.incrementaldraw
is missing or has the value true
, the image is
incrementally drawn. If the system property has any other value,
then the image is not drawn until it has been completely loaded.
Also, if incremental drawing is in effect, the value of the
system property awt.image.redrawrate
is interpreted
as an integer to give the maximum redraw rate, in milliseconds. If
the system property is missing or cannot be interpreted as an
integer, the redraw rate is once every 100ms.
The interpretation of the x
, y
,
width
, and height
arguments depends on
the value of the infoflags
argument.
imageUpdate
in interface ImageObserver
img
- the image being observedinfoflags
- see imageUpdate
for more informationx
- the x coordinatey
- the y coordinatew
- the widthh
- the heightfalse
if the infoflags indicate that the
image is completely loaded; true
otherwise.ImageObserver
,
Graphics.drawImage(Image, int, int, Color, java.awt.image.ImageObserver)
,
Graphics.drawImage(Image, int, int, java.awt.image.ImageObserver)
,
Graphics.drawImage(Image, int, int, int, int, Color, java.awt.image.ImageObserver)
,
Graphics.drawImage(Image, int, int, int, int, java.awt.image.ImageObserver)
,
ImageObserver.imageUpdate(java.awt.Image, int, int, int, int, int)
public Image createImage(ImageProducer producer)
producer
- the image producerpublic Image createImage(int width, int height)
width
- the specified widthheight
- the specified heightnull
if the
component is not displayable. This will always happen if
GraphicsEnvironment.isHeadless()
returns
true
.isDisplayable()
,
GraphicsEnvironment.isHeadless()
public VolatileImage createVolatileImage(int width, int height)
width
- the specified width.height
- the specified height.null
if the
component is not displayable. This will always happen if
GraphicsEnvironment.isHeadless()
returns
true
.VolatileImage
,
isDisplayable()
,
GraphicsEnvironment.isHeadless()
public VolatileImage createVolatileImage(int width, int height, ImageCapabilities caps) throws AWTException
VolatileImage
interface.width
- the specified width.height
- the specified height.caps
- the image capabilitiesAWTException
- if an image with the specified capabilities cannot
be createdVolatileImage
public boolean prepareImage(Image image, ImageObserver observer)
image
- the Image
for which to
prepare a screen representationobserver
- the ImageObserver
object
to be notified as the image is being preparedtrue
if the image has already been fully
prepared; false
otherwisepublic boolean prepareImage(Image image, int width, int height, ImageObserver observer)
The image data is downloaded asynchronously in another thread, and an appropriately scaled screen representation of the image is generated.
image
- the instance of Image
for which to prepare a screen representationwidth
- the width of the desired screen representationheight
- the height of the desired screen representationobserver
- the ImageObserver
object
to be notified as the image is being preparedtrue
if the image has already been fully
prepared; false
otherwiseImageObserver
public int checkImage(Image image, ImageObserver observer)
This method does not cause the image to begin loading. An
application must use the prepareImage
method
to force the loading of an image.
Information on the flags returned by this method can be found
with the discussion of the ImageObserver
interface.
image
- the Image
object whose status
is being checkedobserver
- the ImageObserver
object to be notified as the image is being preparedImageObserver
flags indicating what
information about the image is currently availableprepareImage(Image, int, int, java.awt.image.ImageObserver)
,
Toolkit.checkImage(Image, int, int, java.awt.image.ImageObserver)
,
ImageObserver
public int checkImage(Image image, int width, int height, ImageObserver observer)
This method does not cause the image to begin loading. An
application must use the prepareImage
method
to force the loading of an image.
The checkImage
method of Component
calls its peer's checkImage
method to calculate
the flags. If this component does not yet have a peer, the
component's toolkit's checkImage
method is called
instead.
Information on the flags returned by this method can be found
with the discussion of the ImageObserver
interface.
image
- the Image
object whose status
is being checkedwidth
- the width of the scaled version
whose status is to be checkedheight
- the height of the scaled version
whose status is to be checkedobserver
- the ImageObserver
object
to be notified as the image is being preparedImageObserver
flags indicating what
information about the image is currently availableprepareImage(Image, int, int, java.awt.image.ImageObserver)
,
Toolkit.checkImage(Image, int, int, java.awt.image.ImageObserver)
,
ImageObserver
public void setIgnoreRepaint(boolean ignoreRepaint)
This is useful, for example, if running under full-screen mode and better performance is desired, or if page-flipping is used as the buffer strategy.
public boolean getIgnoreRepaint()
setIgnoreRepaint(boolean)
public boolean contains(int x, int y)
x
and y
are defined to be
relative to the coordinate system of this component.x
- the x coordinate of the pointy
- the y coordinate of the pointgetComponentAt(int, int)
@Deprecated public boolean inside(int x, int y)
public boolean contains(Point p)
p
- the pointNullPointerException
- if p
is null
getComponentAt(Point)
public Component getComponentAt(int x, int y)
The locate
method of Component
simply
returns the component itself if the (x, y)
coordinate location is inside its bounding box, and null
otherwise.
x
- the x coordinatey
- the y coordinatenull
if the location
is outside this componentcontains(int, int)
@Deprecated public Component locate(int x, int y)
public Component getComponentAt(Point p)
p
- the pointcontains(int, int)
@Deprecated public void deliverEvent(Event e)
dispatchEvent(AWTEvent e)
.public final void dispatchEvent(AWTEvent e)
processEvent
before returning for 1.1-style
events which have been enabled for the Component
.e
- the event@Deprecated public boolean postEvent(Event e)
postEvent
in interface MenuContainer
public void addComponentListener(ComponentListener l)
l
is null
,
no exception is thrown and no action is performed.
Refer to AWT Threading Issues for details on AWT's threading model.
l
- the component listenerComponentEvent
,
ComponentListener
,
removeComponentListener(java.awt.event.ComponentListener)
,
getComponentListeners()
public void removeComponentListener(ComponentListener l)
l
is null
,
no exception is thrown and no action is performed.
Refer to AWT Threading Issues for details on AWT's threading model.
l
- the component listenerComponentEvent
,
ComponentListener
,
addComponentListener(java.awt.event.ComponentListener)
,
getComponentListeners()
public ComponentListener[] getComponentListeners()
ComponentListener
s of this component
or an empty array if no component
listeners are currently registeredaddComponentListener(java.awt.event.ComponentListener)
,
removeComponentListener(java.awt.event.ComponentListener)
public void addFocusListener(FocusListener l)
l
is null
,
no exception is thrown and no action is performed.
Refer to AWT Threading Issues for details on AWT's threading model.
l
- the focus listenerFocusEvent
,
FocusListener
,
removeFocusListener(java.awt.event.FocusListener)
,
getFocusListeners()
public void removeFocusListener(FocusListener l)
l
is null
,
no exception is thrown and no action is performed.
Refer to AWT Threading Issues for details on AWT's threading model.
l
- the focus listenerFocusEvent
,
FocusListener
,
addFocusListener(java.awt.event.FocusListener)
,
getFocusListeners()
public FocusListener[] getFocusListeners()
FocusListener
s
or an empty array if no component
listeners are currently registeredaddFocusListener(java.awt.event.FocusListener)
,
removeFocusListener(java.awt.event.FocusListener)
public void addHierarchyListener(HierarchyListener l)
l
is null
,
no exception is thrown and no action is performed.
Refer to AWT Threading Issues for details on AWT's threading model.
l
- the hierarchy listenerHierarchyEvent
,
HierarchyListener
,
removeHierarchyListener(java.awt.event.HierarchyListener)
,
getHierarchyListeners()
public void removeHierarchyListener(HierarchyListener l)
l
is null
,
no exception is thrown and no action is performed.
Refer to AWT Threading Issues for details on AWT's threading model.
l
- the hierarchy listenerHierarchyEvent
,
HierarchyListener
,
addHierarchyListener(java.awt.event.HierarchyListener)
,
getHierarchyListeners()
public HierarchyListener[] getHierarchyListeners()
HierarchyListener
s
or an empty array if no hierarchy
listeners are currently registeredaddHierarchyListener(java.awt.event.HierarchyListener)
,
removeHierarchyListener(java.awt.event.HierarchyListener)
public void addHierarchyBoundsListener(HierarchyBoundsListener l)
l
is null
,
no exception is thrown and no action is performed.
Refer to AWT Threading Issues for details on AWT's threading model.
l
- the hierarchy bounds listenerHierarchyEvent
,
HierarchyBoundsListener
,
removeHierarchyBoundsListener(java.awt.event.HierarchyBoundsListener)
,
getHierarchyBoundsListeners()
public void removeHierarchyBoundsListener(HierarchyBoundsListener l)
l
is null
,
no exception is thrown and no action is performed.
Refer to AWT Threading Issues for details on AWT's threading model.
l
- the hierarchy bounds listenerHierarchyEvent
,
HierarchyBoundsListener
,
addHierarchyBoundsListener(java.awt.event.HierarchyBoundsListener)
,
getHierarchyBoundsListeners()
public HierarchyBoundsListener[] getHierarchyBoundsListeners()
HierarchyBoundsListener
s
or an empty array if no hierarchy bounds
listeners are currently registeredaddHierarchyBoundsListener(java.awt.event.HierarchyBoundsListener)
,
removeHierarchyBoundsListener(java.awt.event.HierarchyBoundsListener)
public void addKeyListener(KeyListener l)
Refer to AWT Threading Issues for details on AWT's threading model.
l
- the key listener.KeyEvent
,
KeyListener
,
removeKeyListener(java.awt.event.KeyListener)
,
getKeyListeners()
public void removeKeyListener(KeyListener l)
l
is null
,
no exception is thrown and no action is performed.
Refer to AWT Threading Issues for details on AWT's threading model.
l
- the key listenerKeyEvent
,
KeyListener
,
addKeyListener(java.awt.event.KeyListener)
,
getKeyListeners()
public KeyListener[] getKeyListeners()
KeyListener
s
or an empty array if no key
listeners are currently registeredaddKeyListener(java.awt.event.KeyListener)
,
removeKeyListener(java.awt.event.KeyListener)
public void addMouseListener(MouseListener l)
l
is null
,
no exception is thrown and no action is performed.
Refer to AWT Threading Issues for details on AWT's threading model.
l
- the mouse listenerMouseEvent
,
MouseListener
,
removeMouseListener(java.awt.event.MouseListener)
,
getMouseListeners()
public void removeMouseListener(MouseListener l)
l
is null
,
no exception is thrown and no action is performed.
Refer to AWT Threading Issues for details on AWT's threading model.
l
- the mouse listenerMouseEvent
,
MouseListener
,
addMouseListener(java.awt.event.MouseListener)
,
getMouseListeners()
public MouseListener[] getMouseListeners()
MouseListener
s
or an empty array if no mouse
listeners are currently registeredaddMouseListener(java.awt.event.MouseListener)
,
removeMouseListener(java.awt.event.MouseListener)
public void addMouseMotionListener(MouseMotionListener l)
l
is null
,
no exception is thrown and no action is performed.
Refer to AWT Threading Issues for details on AWT's threading model.
l
- the mouse motion listenerMouseEvent
,
MouseMotionListener
,
removeMouseMotionListener(java.awt.event.MouseMotionListener)
,
getMouseMotionListeners()
public void removeMouseMotionListener(MouseMotionListener l)
l
is null
,
no exception is thrown and no action is performed.
Refer to AWT Threading Issues for details on AWT's threading model.
l
- the mouse motion listenerMouseEvent
,
MouseMotionListener
,
addMouseMotionListener(java.awt.event.MouseMotionListener)
,
getMouseMotionListeners()
public MouseMotionListener[] getMouseMotionListeners()
MouseMotionListener
s
or an empty array if no mouse motion
listeners are currently registeredaddMouseMotionListener(java.awt.event.MouseMotionListener)
,
removeMouseMotionListener(java.awt.event.MouseMotionListener)
public void addMouseWheelListener(MouseWheelListener l)
For information on how mouse wheel events are dispatched, see
the class description for MouseWheelEvent
.
If l is null
, no exception is thrown and no
action is performed.
Refer to AWT Threading Issues for details on AWT's threading model.
l
- the mouse wheel listenerMouseWheelEvent
,
MouseWheelListener
,
removeMouseWheelListener(java.awt.event.MouseWheelListener)
,
getMouseWheelListeners()
public void removeMouseWheelListener(MouseWheelListener l)
Refer to AWT Threading Issues for details on AWT's threading model.
l
- the mouse wheel listener.MouseWheelEvent
,
MouseWheelListener
,
addMouseWheelListener(java.awt.event.MouseWheelListener)
,
getMouseWheelListeners()
public MouseWheelListener[] getMouseWheelListeners()
MouseWheelListener
s
or an empty array if no mouse wheel
listeners are currently registeredaddMouseWheelListener(java.awt.event.MouseWheelListener)
,
removeMouseWheelListener(java.awt.event.MouseWheelListener)
public void addInputMethodListener(InputMethodListener l)
getInputMethodRequests
to return an
InputMethodRequests
instance.
If listener l
is null
,
no exception is thrown and no action is performed.
Refer to AWT Threading Issues for details on AWT's threading model.
l
- the input method listenerInputMethodEvent
,
InputMethodListener
,
removeInputMethodListener(java.awt.event.InputMethodListener)
,
getInputMethodListeners()
,
getInputMethodRequests()
public void removeInputMethodListener(InputMethodListener l)
l
is null
,
no exception is thrown and no action is performed.
Refer to AWT Threading Issues for details on AWT's threading model.
l
- the input method listenerInputMethodEvent
,
InputMethodListener
,
addInputMethodListener(java.awt.event.InputMethodListener)
,
getInputMethodListeners()
public InputMethodListener[] getInputMethodListeners()
InputMethodListener
s
or an empty array if no input method
listeners are currently registeredaddInputMethodListener(java.awt.event.InputMethodListener)
,
removeInputMethodListener(java.awt.event.InputMethodListener)
public <T extends EventListener> T[] getListeners(Class<T> listenerType)
FooListener
s
upon this Component
.
FooListener
s are registered using the
addFooListener
method.
You can specify the listenerType
argument
with a class literal, such as
FooListener.class
.
For example, you can query a
Component
c
for its mouse listeners with the following code:
MouseListener[] mls = (MouseListener[])(c.getListeners(MouseListener.class));If no such listeners exist, this method returns an empty array.
listenerType
- the type of listeners requested; this parameter
should specify an interface that descends from
java.util.EventListener
FooListener
s on this component,
or an empty array if no such listeners have been addedClassCastException
- if listenerType
doesn't specify a class or interface that implements
java.util.EventListener
NullPointerException
- if listenerType
is null
getComponentListeners()
,
getFocusListeners()
,
getHierarchyListeners()
,
getHierarchyBoundsListeners()
,
getKeyListeners()
,
getMouseListeners()
,
getMouseMotionListeners()
,
getMouseWheelListeners()
,
getInputMethodListeners()
,
getPropertyChangeListeners()
public InputMethodRequests getInputMethodRequests()
InputMethodRequests
instance.
At the same time, it also has to handle input method events.null
by defaultaddInputMethodListener(java.awt.event.InputMethodListener)
public InputContext getInputContext()
null
if no context can be determinedprotected final void enableEvents(long eventsToEnable)
Event types are automatically enabled when a listener for that event type is added to the component.
This method only needs to be invoked by subclasses of
Component
which desire to have the specified event
types delivered to processEvent
regardless of whether
or not a listener is registered.
eventsToEnable
- the event mask defining the event typesprocessEvent(java.awt.AWTEvent)
,
disableEvents(long)
,
AWTEvent
protected final void disableEvents(long eventsToDisable)
eventsToDisable
- the event mask defining the event typesenableEvents(long)
protected AWTEvent coalesceEvents(AWTEvent existingEvent, AWTEvent newEvent)
EventQueue.postEvent
if an event with the same ID as the event to be posted is found in
the queue (both events must have this component as their source).
This method either returns a coalesced event which replaces
the existing event (and the new event is then discarded), or
null
to indicate that no combining should be done
(add the second event to the end of the queue). Either event
parameter may be modified and returned, as the other one is discarded
unless null
is returned.
This implementation of coalesceEvents
coalesces
two event types: mouse move (and drag) events,
and paint (and update) events.
For mouse move events the last event is always returned, causing
intermediate moves to be discarded. For paint events, the new
event is coalesced into a complex RepaintArea
in the peer.
The new AWTEvent
is always returned.
existingEvent
- the event already on the EventQueue
newEvent
- the event being posted to the
EventQueue
null
indicating that no
coalescing was doneprotected void processEvent(AWTEvent e)
process<event type>Event
method for the given class of event.
Note that if the event parameter is null
the behavior is unspecified and may result in an
exception.
e
- the eventprocessComponentEvent(java.awt.event.ComponentEvent)
,
processFocusEvent(java.awt.event.FocusEvent)
,
processKeyEvent(java.awt.event.KeyEvent)
,
processMouseEvent(java.awt.event.MouseEvent)
,
processMouseMotionEvent(java.awt.event.MouseEvent)
,
processInputMethodEvent(java.awt.event.InputMethodEvent)
,
processHierarchyEvent(java.awt.event.HierarchyEvent)
,
processMouseWheelEvent(java.awt.event.MouseWheelEvent)
protected void processComponentEvent(ComponentEvent e)
ComponentListener
objects.
This method is not called unless component events are enabled for this component. Component events are enabled when one of the following occurs:
ComponentListener
object is registered
via addComponentListener
.
enableEvents
.
Note that if the event parameter is null
the behavior is unspecified and may result in an
exception.
e
- the component eventComponentEvent
,
ComponentListener
,
addComponentListener(java.awt.event.ComponentListener)
,
enableEvents(long)
protected void processFocusEvent(FocusEvent e)
FocusListener
objects.
This method is not called unless focus events are enabled for this component. Focus events are enabled when one of the following occurs:
FocusListener
object is registered
via addFocusListener
.
enableEvents
.
If focus events are enabled for a Component
,
the current KeyboardFocusManager
determines
whether or not a focus event should be dispatched to
registered FocusListener
objects. If the
events are to be dispatched, the KeyboardFocusManager
calls the Component
's dispatchEvent
method, which results in a call to the Component
's
processFocusEvent
method.
If focus events are enabled for a Component
, calling
the Component
's dispatchEvent
method
with a FocusEvent
as the argument will result in a
call to the Component
's processFocusEvent
method regardless of the current KeyboardFocusManager
.
Note that if the event parameter is null
the behavior is unspecified and may result in an
exception.
e
- the focus eventFocusEvent
,
FocusListener
,
KeyboardFocusManager
,
addFocusListener(java.awt.event.FocusListener)
,
enableEvents(long)
,
dispatchEvent(java.awt.AWTEvent)
protected void processKeyEvent(KeyEvent e)
KeyListener
objects.
This method is not called unless key events are enabled for this component. Key events are enabled when one of the following occurs:
KeyListener
object is registered
via addKeyListener
.
enableEvents
.
If key events are enabled for a Component
,
the current KeyboardFocusManager
determines
whether or not a key event should be dispatched to
registered KeyListener
objects. The
DefaultKeyboardFocusManager
will not dispatch
key events to a Component
that is not the focus
owner or is not showing.
As of J2SE 1.4, KeyEvent
s are redirected to
the focus owner. Please see the
Focus Specification
for further information.
Calling a Component
's dispatchEvent
method with a KeyEvent
as the argument will
result in a call to the Component
's
processKeyEvent
method regardless of the
current KeyboardFocusManager
as long as the
component is showing, focused, and enabled, and key events
are enabled on it.
If the event parameter is null
the behavior is unspecified and may result in an
exception.
e
- the key eventKeyEvent
,
KeyListener
,
KeyboardFocusManager
,
DefaultKeyboardFocusManager
,
processEvent(java.awt.AWTEvent)
,
dispatchEvent(java.awt.AWTEvent)
,
addKeyListener(java.awt.event.KeyListener)
,
enableEvents(long)
,
isShowing()
protected void processMouseEvent(MouseEvent e)
MouseListener
objects.
This method is not called unless mouse events are enabled for this component. Mouse events are enabled when one of the following occurs:
MouseListener
object is registered
via addMouseListener
.
enableEvents
.
Note that if the event parameter is null
the behavior is unspecified and may result in an
exception.
e
- the mouse eventMouseEvent
,
MouseListener
,
addMouseListener(java.awt.event.MouseListener)
,
enableEvents(long)
protected void processMouseMotionEvent(MouseEvent e)
MouseMotionListener
objects.
This method is not called unless mouse motion events are enabled for this component. Mouse motion events are enabled when one of the following occurs:
MouseMotionListener
object is registered
via addMouseMotionListener
.
enableEvents
.
Note that if the event parameter is null
the behavior is unspecified and may result in an
exception.
e
- the mouse motion eventMouseEvent
,
MouseMotionListener
,
addMouseMotionListener(java.awt.event.MouseMotionListener)
,
enableEvents(long)
protected void processMouseWheelEvent(MouseWheelEvent e)
MouseWheelListener
objects.
This method is not called unless mouse wheel events are enabled for this component. Mouse wheel events are enabled when one of the following occurs:
MouseWheelListener
object is registered
via addMouseWheelListener
.
enableEvents
.
For information on how mouse wheel events are dispatched, see
the class description for MouseWheelEvent
.
Note that if the event parameter is null
the behavior is unspecified and may result in an
exception.
e
- the mouse wheel eventMouseWheelEvent
,
MouseWheelListener
,
addMouseWheelListener(java.awt.event.MouseWheelListener)
,
enableEvents(long)
protected void processInputMethodEvent(InputMethodEvent e)
InputMethodListener
objects.
This method is not called unless input method events are enabled for this component. Input method events are enabled when one of the following occurs:
InputMethodListener
object is registered
via addInputMethodListener
.
enableEvents
.
Note that if the event parameter is null
the behavior is unspecified and may result in an
exception.
e
- the input method eventInputMethodEvent
,
InputMethodListener
,
addInputMethodListener(java.awt.event.InputMethodListener)
,
enableEvents(long)
protected void processHierarchyEvent(HierarchyEvent e)
HierarchyListener
objects.
This method is not called unless hierarchy events are enabled for this component. Hierarchy events are enabled when one of the following occurs:
HierarchyListener
object is registered
via addHierarchyListener
.
enableEvents
.
Note that if the event parameter is null
the behavior is unspecified and may result in an
exception.
e
- the hierarchy eventHierarchyEvent
,
HierarchyListener
,
addHierarchyListener(java.awt.event.HierarchyListener)
,
enableEvents(long)
protected void processHierarchyBoundsEvent(HierarchyEvent e)
HierarchyBoundsListener
objects.
This method is not called unless hierarchy bounds events are enabled for this component. Hierarchy bounds events are enabled when one of the following occurs:
HierarchyBoundsListener
object is registered
via addHierarchyBoundsListener
.
enableEvents
.
Note that if the event parameter is null
the behavior is unspecified and may result in an
exception.
e
- the hierarchy eventHierarchyEvent
,
HierarchyBoundsListener
,
addHierarchyBoundsListener(java.awt.event.HierarchyBoundsListener)
,
enableEvents(long)
@Deprecated public boolean handleEvent(Event evt)
@Deprecated public boolean mouseDown(Event evt, int x, int y)
@Deprecated public boolean mouseDrag(Event evt, int x, int y)
@Deprecated public boolean mouseUp(Event evt, int x, int y)
@Deprecated public boolean mouseMove(Event evt, int x, int y)
@Deprecated public boolean mouseEnter(Event evt, int x, int y)
@Deprecated public boolean mouseExit(Event evt, int x, int y)
@Deprecated public boolean keyDown(Event evt, int key)
@Deprecated public boolean keyUp(Event evt, int key)
@Deprecated public boolean action(Event evt, Object what)
public void addNotify()
Component
displayable by connecting it to a
native screen resource.
This method is called internally by the toolkit and should
not be called directly by programs.
This method changes layout-related information, and therefore, invalidates the component hierarchy.
isDisplayable()
,
removeNotify()
,
invalidate()
public void removeNotify()
Component
undisplayable by destroying it native
screen resource.
This method is called by the toolkit internally and should
not be called directly by programs. Code overriding
this method should call super.removeNotify
as
the first line of the overriding method.
isDisplayable()
,
addNotify()
@Deprecated public boolean gotFocus(Event evt, Object what)
@Deprecated public boolean lostFocus(Event evt, Object what)
@Deprecated public boolean isFocusTraversable()
isFocusable()
.Component
can become the focus
owner.true
if this Component
is
focusable; false
otherwisesetFocusable(boolean)
public boolean isFocusable()
true
if this Component is focusable;
false
otherwise.setFocusable(boolean)
public void setFocusable(boolean focusable)
focusable
- indicates whether this Component is focusableisFocusable()
public void setFocusTraversalKeys(int id, Set<? extends AWTKeyStroke> keystrokes)
The default values for a Component's 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 |
Using the AWTKeyStroke API, client code can specify on which of two specific KeyEvents, KEY_PRESSED or KEY_RELEASED, the focus traversal operation will occur. Regardless of which KeyEvent is specified, however, all KeyEvents 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.
If a value of null is specified for the Set, this Component inherits the Set from its parent. If all ancestors of this Component have null specified for the Set, then the current KeyboardFocusManager's default Set is used.
This method may throw a ClassCastException
if any Object
in keystrokes
is not an AWTKeyStroke
.
id
- one of KeyboardFocusManager.FORWARD_TRAVERSAL_KEYS,
KeyboardFocusManager.BACKWARD_TRAVERSAL_KEYS, or
KeyboardFocusManager.UP_CYCLE_TRAVERSAL_KEYSkeystrokes
- the Set of AWTKeyStroke for the specified operationIllegalArgumentException
- if id is not one of
KeyboardFocusManager.FORWARD_TRAVERSAL_KEYS,
KeyboardFocusManager.BACKWARD_TRAVERSAL_KEYS, or
KeyboardFocusManager.UP_CYCLE_TRAVERSAL_KEYS, or if keystrokes
contains null, or if any keystroke represents a KEY_TYPED event,
or if any keystroke already maps to another focus traversal
operation for this ComponentgetFocusTraversalKeys(int)
,
KeyboardFocusManager.FORWARD_TRAVERSAL_KEYS
,
KeyboardFocusManager.BACKWARD_TRAVERSAL_KEYS
,
KeyboardFocusManager.UP_CYCLE_TRAVERSAL_KEYS
public Set<AWTKeyStroke> getFocusTraversalKeys(int id)
setFocusTraversalKeys
for a full description of each key.)
If a Set of traversal keys has not been explicitly defined for this Component, then this Component's parent's Set is returned. If no Set has been explicitly defined for any of this Component's ancestors, then the current KeyboardFocusManager's default Set is returned.
id
- one of KeyboardFocusManager.FORWARD_TRAVERSAL_KEYS,
KeyboardFocusManager.BACKWARD_TRAVERSAL_KEYS, or
KeyboardFocusManager.UP_CYCLE_TRAVERSAL_KEYSIllegalArgumentException
- if id is not one of
KeyboardFocusManager.FORWARD_TRAVERSAL_KEYS,
KeyboardFocusManager.BACKWARD_TRAVERSAL_KEYS, or
KeyboardFocusManager.UP_CYCLE_TRAVERSAL_KEYSsetFocusTraversalKeys(int, java.util.Set<? extends java.awt.AWTKeyStroke>)
,
KeyboardFocusManager.FORWARD_TRAVERSAL_KEYS
,
KeyboardFocusManager.BACKWARD_TRAVERSAL_KEYS
,
KeyboardFocusManager.UP_CYCLE_TRAVERSAL_KEYS
public boolean areFocusTraversalKeysSet(int id)
false
, this Component is inheriting the
Set from an ancestor, or from the current KeyboardFocusManager.id
- one of KeyboardFocusManager.FORWARD_TRAVERSAL_KEYS,
KeyboardFocusManager.BACKWARD_TRAVERSAL_KEYS, or
KeyboardFocusManager.UP_CYCLE_TRAVERSAL_KEYStrue
if the the Set of focus traversal keys for the
given focus traversal operation has been explicitly defined for
this Component; false
otherwise.IllegalArgumentException
- if id is not one of
KeyboardFocusManager.FORWARD_TRAVERSAL_KEYS,
KeyboardFocusManager.BACKWARD_TRAVERSAL_KEYS, or
KeyboardFocusManager.UP_CYCLE_TRAVERSAL_KEYSpublic void setFocusTraversalKeysEnabled(boolean focusTraversalKeysEnabled)
focusTraversalKeysEnabled
- whether focus traversal keys are
enabled for this ComponentgetFocusTraversalKeysEnabled()
,
setFocusTraversalKeys(int, java.util.Set<? extends java.awt.AWTKeyStroke>)
,
getFocusTraversalKeys(int)
public boolean getFocusTraversalKeysEnabled()
setFocusTraversalKeysEnabled(boolean)
,
setFocusTraversalKeys(int, java.util.Set<? extends java.awt.AWTKeyStroke>)
,
getFocusTraversalKeys(int)
public void requestFocus()
This method cannot be used to set the focus owner to no Component at
all. Use KeyboardFocusManager.clearGlobalFocusOwner()
instead.
Because the focus behavior of this method is platform-dependent,
developers are strongly encouraged to use
requestFocusInWindow
when possible.
Note: Not all focus transfers result from invoking this method. As
such, a component may receive focus without this or any of the other
requestFocus
methods of Component
being invoked.
protected boolean requestFocus(boolean temporary)
Component
get the input focus,
and that this Component
's top-level ancestor
become the focused Window
. This component must be
displayable, focusable, visible and all of its ancestors (with
the exception of the top-level Window) must be visible for the
request to be granted. Every effort will be made to honor the
request; however, in some cases it may be impossible to do
so. Developers must never assume that this component is the
focus owner until this component receives a FOCUS_GAINED
event. If this request is denied because this component's
top-level window cannot become the focused window, the request
will be remembered and will be granted when the window is later
focused by the user.
This method returns a boolean value. If false
is returned,
the request is guaranteed to fail. If true
is
returned, the request will succeed unless it is vetoed, or an
extraordinary event, such as disposal of the component's peer, occurs
before the request can be granted by the native windowing system. Again,
while a return value of true
indicates that the request is
likely to succeed, developers must never assume that this component is
the focus owner until this component receives a FOCUS_GAINED event.
This method cannot be used to set the focus owner to no component at
all. Use KeyboardFocusManager.clearGlobalFocusOwner
instead.
Because the focus behavior of this method is platform-dependent,
developers are strongly encouraged to use
requestFocusInWindow
when possible.
Every effort will be made to ensure that FocusEvent
s
generated as a
result of this request will have the specified temporary value. However,
because specifying an arbitrary temporary state may not be implementable
on all native windowing systems, correct behavior for this method can be
guaranteed only for lightweight Component
s.
This method is not intended
for general use, but exists instead as a hook for lightweight component
libraries, such as Swing.
Note: Not all focus transfers result from invoking this method. As
such, a component may receive focus without this or any of the other
requestFocus
methods of Component
being invoked.
temporary
- true if the focus change is temporary,
such as when the window loses the focus; for
more information on temporary focus changes see the
Focus Specificationfalse
if the focus change request is guaranteed to
fail; true
if it is likely to succeedFocusEvent
,
addFocusListener(java.awt.event.FocusListener)
,
isFocusable()
,
isDisplayable()
,
KeyboardFocusManager.clearGlobalFocusOwner()
public boolean requestFocusInWindow()
This method returns a boolean value. If false
is returned,
the request is guaranteed to fail. If true
is
returned, the request will succeed unless it is vetoed, or an
extraordinary event, such as disposal of the Component's peer, occurs
before the request can be granted by the native windowing system. Again,
while a return value of true
indicates that the request is
likely to succeed, developers must never assume that this Component is
the focus owner until this Component receives a FOCUS_GAINED event.
This method cannot be used to set the focus owner to no Component at
all. Use KeyboardFocusManager.clearGlobalFocusOwner()
instead.
The focus behavior of this method can be implemented uniformly across
platforms, and thus developers are strongly encouraged to use this
method over requestFocus
when possible. Code which relies
on requestFocus
may exhibit different focus behavior on
different platforms.
Note: Not all focus transfers result from invoking this method. As
such, a component may receive focus without this or any of the other
requestFocus
methods of Component
being invoked.
false
if the focus change request is guaranteed to
fail; true
if it is likely to succeedrequestFocus()
,
FocusEvent
,
addFocusListener(java.awt.event.FocusListener)
,
isFocusable()
,
isDisplayable()
,
KeyboardFocusManager.clearGlobalFocusOwner()
protected boolean requestFocusInWindow(boolean temporary)
Component
get the input focus,
if this Component
's top-level ancestor is already
the focused Window
. This component must be
displayable, focusable, visible and all of its ancestors (with
the exception of the top-level Window) must be visible for the
request to be granted. Every effort will be made to honor the
request; however, in some cases it may be impossible to do
so. Developers must never assume that this component is the
focus owner until this component receives a FOCUS_GAINED event.
This method returns a boolean value. If false
is returned,
the request is guaranteed to fail. If true
is
returned, the request will succeed unless it is vetoed, or an
extraordinary event, such as disposal of the component's peer, occurs
before the request can be granted by the native windowing system. Again,
while a return value of true
indicates that the request is
likely to succeed, developers must never assume that this component is
the focus owner until this component receives a FOCUS_GAINED event.
This method cannot be used to set the focus owner to no component at
all. Use KeyboardFocusManager.clearGlobalFocusOwner
instead.
The focus behavior of this method can be implemented uniformly across
platforms, and thus developers are strongly encouraged to use this
method over requestFocus
when possible. Code which relies
on requestFocus
may exhibit different focus behavior on
different platforms.
Every effort will be made to ensure that FocusEvent
s
generated as a
result of this request will have the specified temporary value. However,
because specifying an arbitrary temporary state may not be implementable
on all native windowing systems, correct behavior for this method can be
guaranteed only for lightweight components. This method is not intended
for general use, but exists instead as a hook for lightweight component
libraries, such as Swing.
Note: Not all focus transfers result from invoking this method. As
such, a component may receive focus without this or any of the other
requestFocus
methods of Component
being invoked.
temporary
- true if the focus change is temporary,
such as when the window loses the focus; for
more information on temporary focus changes see the
Focus Specificationfalse
if the focus change request is guaranteed to
fail; true
if it is likely to succeedrequestFocus()
,
FocusEvent
,
addFocusListener(java.awt.event.FocusListener)
,
isFocusable()
,
isDisplayable()
,
KeyboardFocusManager.clearGlobalFocusOwner()
public Container getFocusCycleRootAncestor()
Container.isFocusCycleRoot()
public boolean isFocusCycleRoot(Container container)
container
- the Container to be testedtrue
if the specified Container is a focus-cycle-
root of this Component; false
otherwiseContainer.isFocusCycleRoot()
public void transferFocus()
requestFocus()
@Deprecated public void nextFocus()
public void transferFocusBackward()
requestFocus()
public void transferFocusUpCycle()
requestFocus()
,
Container.isFocusCycleRoot()
,
Container.setFocusCycleRoot(boolean)
public boolean hasFocus()
true
if this Component
is the
focus owner. This method is obsolete, and has been replaced by
isFocusOwner()
.true
if this Component
is the
focus owner; false
otherwisepublic boolean isFocusOwner()
true
if this Component
is the
focus owner.true
if this Component
is the
focus owner; false
otherwisepublic void add(PopupMenu popup)
popup
- the popup menu to be added to the component.NullPointerException
- if popup
is null
remove(MenuComponent)
public void remove(MenuComponent popup)
remove
in interface MenuContainer
popup
- the popup menu to be removedadd(PopupMenu)
protected String paramString()
null
.public String toString()
public void list()
System.out
.System.out
public void list(PrintStream out)
out
- a print streamNullPointerException
- if out
is null
public void list(PrintStream out, int indent)
out
- a print streamindent
- number of spaces to indentNullPointerException
- if out
is null
PrintStream.println(java.lang.Object)
public void list(PrintWriter out)
out
- the print writer to print toNullPointerException
- if out
is null
public void list(PrintWriter out, int indent)
out
- the print writer to print toindent
- the number of spaces to indentNullPointerException
- if out
is null
PrintStream.println(java.lang.Object)
public void addPropertyChangeListener(PropertyChangeListener listener)
Component
is inheriting a bound property, then no
event will be fired in response to a change in the inherited property.
If listener
is null
,
no exception is thrown and no action is performed.
listener
- the property change listener to be addedremovePropertyChangeListener(java.beans.PropertyChangeListener)
,
getPropertyChangeListeners()
,
addPropertyChangeListener(java.lang.String, java.beans.PropertyChangeListener)
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()
,
removePropertyChangeListener(java.lang.String,java.beans.PropertyChangeListener)
public PropertyChangeListener[] getPropertyChangeListeners()
PropertyChangeListener
s
or an empty array if no property change
listeners are currently registeredaddPropertyChangeListener(java.beans.PropertyChangeListener)
,
removePropertyChangeListener(java.beans.PropertyChangeListener)
,
getPropertyChangeListeners(java.lang.String)
,
PropertyChangeSupport.getPropertyChangeListeners()
public void addPropertyChangeListener(String propertyName, PropertyChangeListener listener)
Component
is inheriting a bound property, then no
event will be fired in response to a change in the inherited property.
If propertyName
or listener
is null
,
no exception is thrown and no action is taken.
propertyName
- one of the property names listed abovelistener
- the property change listener to be addedremovePropertyChangeListener(java.lang.String, java.beans.PropertyChangeListener)
,
getPropertyChangeListeners(java.lang.String)
,
addPropertyChangeListener(java.lang.String, java.beans.PropertyChangeListener)
public void removePropertyChangeListener(String propertyName, PropertyChangeListener listener)
PropertyChangeListener
from the listener
list for a specific property. This method should be used to remove
PropertyChangeListener
s
that were registered for a specific bound property.
If propertyName
or listener
is null
,
no exception is thrown and no action is taken.
propertyName
- a valid property namelistener
- the PropertyChangeListener to be removedaddPropertyChangeListener(java.lang.String, java.beans.PropertyChangeListener)
,
getPropertyChangeListeners(java.lang.String)
,
removePropertyChangeListener(java.beans.PropertyChangeListener)
public PropertyChangeListener[] getPropertyChangeListeners(String propertyName)
PropertyChangeListener
s associated with
the named property; if no such listeners have been added or
if propertyName
is null
, an empty
array is returnedaddPropertyChangeListener(java.lang.String, java.beans.PropertyChangeListener)
,
removePropertyChangeListener(java.lang.String, java.beans.PropertyChangeListener)
,
getPropertyChangeListeners()
protected void firePropertyChange(String propertyName, Object oldValue, Object newValue)
propertyName
- the property whose value has changedoldValue
- the property's previous valuenewValue
- the property's new valueprotected void firePropertyChange(String propertyName, boolean oldValue, boolean newValue)
propertyName
- the property whose value has changedoldValue
- the property's previous valuenewValue
- the property's new valueprotected void firePropertyChange(String propertyName, int oldValue, int newValue)
propertyName
- the property whose value has changedoldValue
- the property's previous valuenewValue
- the property's new valuepublic void firePropertyChange(String propertyName, byte oldValue, byte newValue)
propertyName
- the programmatic name of the property
that was changedoldValue
- the old value of the property (as a byte)newValue
- the new value of the property (as a byte)firePropertyChange(java.lang.String, java.lang.Object,
java.lang.Object)
public void firePropertyChange(String propertyName, char oldValue, char newValue)
propertyName
- the programmatic name of the property
that was changedoldValue
- the old value of the property (as a char)newValue
- the new value of the property (as a char)firePropertyChange(java.lang.String, java.lang.Object,
java.lang.Object)
public void firePropertyChange(String propertyName, short oldValue, short newValue)
propertyName
- the programmatic name of the property
that was changedoldValue
- the old value of the property (as a short)newValue
- the old value of the property (as a short)firePropertyChange(java.lang.String, java.lang.Object,
java.lang.Object)
public void firePropertyChange(String propertyName, long oldValue, long newValue)
propertyName
- the programmatic name of the property
that was changedoldValue
- the old value of the property (as a long)newValue
- the new value of the property (as a long)firePropertyChange(java.lang.String, java.lang.Object,
java.lang.Object)
public void firePropertyChange(String propertyName, float oldValue, float newValue)
propertyName
- the programmatic name of the property
that was changedoldValue
- the old value of the property (as a float)newValue
- the new value of the property (as a float)firePropertyChange(java.lang.String, java.lang.Object,
java.lang.Object)
public void firePropertyChange(String propertyName, double oldValue, double newValue)
propertyName
- the programmatic name of the property
that was changedoldValue
- the old value of the property (as a double)newValue
- the new value of the property (as a double)firePropertyChange(java.lang.String, java.lang.Object,
java.lang.Object)
public void setComponentOrientation(ComponentOrientation o)
LayoutManager
and Component
subclasses will use this property to
determine how to lay out and draw components.
At construction time, a component's orientation is set to
ComponentOrientation.UNKNOWN
,
indicating that it has not been specified
explicitly. The UNKNOWN orientation behaves the same as
ComponentOrientation.LEFT_TO_RIGHT
.
To set the orientation of a single component, use this method.
To set the orientation of an entire component
hierarchy, use
applyComponentOrientation
.
This method changes layout-related information, and therefore, invalidates the component hierarchy.
ComponentOrientation
,
invalidate()
public ComponentOrientation getComponentOrientation()
LayoutManager
and Component
subclasses that wish to respect orientation should call this method to
get the component's orientation before performing layout or drawing.ComponentOrientation
public void applyComponentOrientation(ComponentOrientation orientation)
ComponentOrientation
property of this component
and all components contained within it.
This method changes layout-related information, and therefore, invalidates the component hierarchy.
orientation
- the new component orientation of this component and
the components contained within it.NullPointerException
- if orientation
is null.setComponentOrientation(java.awt.ComponentOrientation)
,
getComponentOrientation()
,
invalidate()
public AccessibleContext getAccessibleContext()
AccessibleContext
associated
with this Component
.
The method implemented by this base
class returns null. Classes that extend Component
should implement this method to return the
AccessibleContext
associated with the subclass.AccessibleContext
of this
Component
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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