Class java.awt.Component
java.lang.Object
java.awt.Component
public abstract class Component
implements ImageObserver, MenuContainer, Serializable
extends Object
A component is an object having a graphical representation
that can be displayed on the screen and that can interact with the
user. Examples of components are the buttons, checkboxes, and scrollbars
of a typical graphical user interface.
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 opaque window.
Constructor Index
| Constructor |
Description |
| Component() |
Constructs a new component. |
Method Index
| Method |
Description |
| boolean action(Event, Object) |
Deprecated.
As of JDK version 1.1,
should register this component as ActionListener on component
which fires action events.
|
| void add(PopupMenu) |
Adds the specified popup menu to the component. |
| void addComponentListener(ComponentListener) |
Adds the specified component listener to receive component events from
this component. |
| void addFocusListener(FocusListener) |
Adds the specified focus listener to receive focus events from
this component when this component gains input focus. |
| void addHierarchyBoundsListener(HierarchyBoundsListener) |
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) |
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) |
Adds the specified input method listener to receive
input method events from this component. |
| void addKeyListener(KeyListener) |
Adds the specified key listener to receive key events from
this component. |
| void addMouseListener(MouseListener) |
Adds the specified mouse listener to receive mouse events from
this component. |
| void addMouseMotionListener(MouseMotionListener) |
Adds the specified mouse motion listener to receive mouse motion events from
this component. |
| void addNotify() |
Makes this Component displayable by connecting it to a
native screen resource. |
| void addPropertyChangeListener(PropertyChangeListener) |
Add a PropertyChangeListener to the listener list. |
| void addPropertyChangeListener(String, PropertyChangeListener) |
Add a PropertyChangeListener for a specific property. |
| Rectangle bounds() |
Deprecated.
As of JDK version 1.1,
replaced by getBounds().
|
| int checkImage(Image, ImageObserver) |
Returns the status of the construction of a screen representation
of the specified image. |
| int checkImage(Image, int, int, ImageObserver) |
Returns the status of the construction of a screen representation
of the specified image. |
| AWTEvent coalesceEvents(AWTEvent, AWTEvent) |
Potentially coalesce an event being posted with an existing
event. |
| boolean contains(int, int) |
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) |
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) |
Creates an image from the specified image producer. |
| Image createImage(int, int) |
Creates an off-screen drawable image
to be used for double buffering. |
| void deliverEvent(Event) |
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).
|
| void disableEvents(long) |
Disables the events defined by the specified event mask parameter
from being delivered to this component. |
| void dispatchEvent(AWTEvent) |
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) |
Deprecated.
As of JDK version 1.1,
replaced by setEnabled(boolean).
|
| void enableEvents(long) |
Enables the events defined by the specified event mask parameter
to be delivered to this component. |
| void enableInputMethods(boolean) |
Enables or disables input method support for this component. |
| void firePropertyChange(String, Object, Object) |
Support for reporting bound property changes. |
| AccessibleContext getAccessibleContext() |
Get 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. |
| Rectangle getBounds() |
Gets the bounds of this component in the form of a
Rectangle object. |
| Rectangle getBounds(Rectangle) |
Store 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, int) |
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) |
Returns the component or subcomponent that contains the
specified point. |
| ComponentOrientation getComponentOrientation() |
Retrieve 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() |
Get the DropTarget associated with this Component |
| Font getFont() |
Gets the font of this component. |
| FontMetrics getFontMetrics(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() |
Get the GraphicsConfiguration associated with this
Component. |
| int getHeight() |
Return the current height of this component. |
| InputContext getInputContext() |
Gets the input context used by this component for handling the communication
with input methods when text is entered in this component. |
| InputMethodRequests getInputMethodRequests() |
Gets the input method request handler which supports
requests from input methods for this component. |
| EventListener[] getListeners(Class) |
Return an array of all the listeners that were added to the Component
with addXXXListener(), where XXX is the name of the listenerType
argument. |
| 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) |
Store 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 mininimum size of this component. |
| String getName() |
Gets the name of the component. |
| Container getParent() |
Gets the parent of this component. |
| ComponentPeer getPeer() |
Deprecated.
As of JDK version 1.1,
programs should not directly manipulate peers.
|
| Dimension getPreferredSize() |
Gets the preferred size of this component. |
| Dimension getSize() |
Returns the size of this component in the form of a
Dimension object. |
| Dimension getSize(Dimension) |
Store the width/height of this component into "return value" rv
and return rv. |
| Toolkit getToolkit() |
Gets the toolkit of this component. |
| Object getTreeLock() |
Gets the locking object for AWT component-tree and layout
Gets this component's locking object (the object that owns the thread
sychronization monitor) for AWT component-tree and layout
operations. |
| int getWidth() |
Return the current width of this component. |
| int getX() |
Return the current x coordinate of the components origin. |
| int getY() |
Return the current y coordinate of the components origin. |
| boolean gotFocus(Event, Object) |
Deprecated.
As of JDK version 1.1,
replaced by processFocusEvent(FocusEvent).
|
| boolean handleEvent(Event) |
Deprecated.
As of JDK version 1.1
replaced by processEvent(AWTEvent).
|
| boolean hasFocus() |
Returns true if this Component has the keyboard focus. |
| void hide() |
Deprecated.
As of JDK version 1.1,
replaced by setVisible(boolean).
|
| boolean imageUpdate(Image, int, int, int, int, int) |
Repaints the component when the image has changed. |
| boolean inside(int, int) |
Deprecated.
As of JDK version 1.1,
replaced by contains(int, int).
|
| void invalidate() |
Invalidates 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 isFocusTraversable() |
Returns the value of a flag that indicates whether
this component can be traversed using
Tab or Shift-Tab keyboard focus traversal. |
| boolean isLightweight() |
A lightweight component doesn't have a native toolkit peer. |
| boolean isOpaque() |
Returns true if this component is completely opaque, returns
false by default. |
| 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, int) |
Deprecated.
As of JDK version 1.1,
replaced by processKeyEvent(KeyEvent).
|
| boolean keyUp(Event, int) |
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) |
Prints a listing of this component to the specified output
stream. |
| void list(PrintStream, int) |
Prints out a list, starting at the specified indention, to the
specified print stream. |
| void list(PrintWriter) |
Prints a listing to the specified print writer. |
| void list(PrintWriter, int) |
Prints out a list, starting at the specified indention, to
the specified print writer. |
| Component locate(int, int) |
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, Object) |
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, int, int) |
Deprecated.
As of JDK version 1.1,
replaced by processMouseEvent(MouseEvent).
|
| boolean mouseDrag(Event, int, int) |
Deprecated.
As of JDK version 1.1,
replaced by processMouseMotionEvent(MouseEvent).
|
| boolean mouseEnter(Event, int, int) |
Deprecated.
As of JDK version 1.1,
replaced by processMouseEvent(MouseEvent).
|
| boolean mouseExit(Event, int, int) |
Deprecated.
As of JDK version 1.1,
replaced by processMouseEvent(MouseEvent).
|
| boolean mouseMove(Event, int, int) |
Deprecated.
As of JDK version 1.1,
replaced by processMouseMotionEvent(MouseEvent).
|
| boolean mouseUp(Event, int, int) |
Deprecated.
As of JDK version 1.1,
replaced by processMouseEvent(MouseEvent).
|
| void move(int, int) |
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) |
Paints this component. |
| void paintAll(Graphics) |
Paints this component and all of its subcomponents. |
| String paramString() |
Returns a string representing the state of this component. |
| boolean postEvent(Event) |
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, ImageObserver) |
Prepares an image for rendering on this component. |
| boolean prepareImage(Image, int, int, ImageObserver) |
Prepares an image for rendering on this component at the
specified width and height. |
| void print(Graphics) |
Prints this component. |
| void printAll(Graphics) |
Prints this component and all of its subcomponents. |
| void processComponentEvent(ComponentEvent) |
Processes component events occurring on this component by
dispatching them to any registered
ComponentListener objects. |
| void processEvent(AWTEvent) |
Processes events occurring on this component. |
| void processFocusEvent(FocusEvent) |
Processes focus events occurring on this component by
dispatching them to any registered
FocusListener objects. |
| void processHierarchyBoundsEvent(HierarchyEvent) |
Processes hierarchy bounds events occurring on this component by
dispatching them to any registered
HierarchyBoundsListener objects. |
| void processHierarchyEvent(HierarchyEvent) |
Processes hierarchy events occurring on this component by
dispatching them to any registered
HierarchyListener objects. |
| void processInputMethodEvent(InputMethodEvent) |
Processes input method events occurring on this component by
dispatching them to any registered
InputMethodListener objects. |
| void processKeyEvent(KeyEvent) |
Processes key events occurring on this component by
dispatching them to any registered
KeyListener objects. |
| void processMouseEvent(MouseEvent) |
Processes mouse events occurring on this component by
dispatching them to any registered
MouseListener objects. |
| void processMouseMotionEvent(MouseEvent) |
Processes mouse motion events occurring on this component by
dispatching them to any registered
MouseMotionListener objects. |
| void remove(MenuComponent) |
Removes the specified popup menu from the component. |
| void removeComponentListener(ComponentListener) |
Removes the specified component listener so that it no longer
receives component events from this component. |
| void removeFocusListener(FocusListener) |
Removes the specified focus listener so that it no longer
receives focus events from this component. |
| void removeHierarchyBoundsListener(HierarchyBoundsListener) |
Removes the specified hierarchy bounds listener so that it no longer
receives hierarchy bounds events from this component. |
| void removeHierarchyListener(HierarchyListener) |
Removes the specified hierarchy listener so that it no longer
receives hierarchy changed events from this component. |
| void removeInputMethodListener(InputMethodListener) |
Removes the specified input method listener so that it no longer receives
input method events from this component. |
| void removeKeyListener(KeyListener) |
Removes the specified key listener so that it no longer
receives key events from this component. |
| void removeMouseListener(MouseListener) |
Removes the specified mouse listener so that it no longer
receives mouse events from this component. |
| void removeMouseMotionListener(MouseMotionListener) |
Removes the specified mouse motion listener so that it no longer
receives mouse motion events from this component. |
| void removeNotify() |
Makes this Component undisplayable by destroying it native
screen resource. |
| void removePropertyChangeListener(PropertyChangeListener) |
Remove a PropertyChangeListener from the listener list. |
| void removePropertyChangeListener(String, PropertyChangeListener) |
Remove a PropertyChangeListener for a specific property. |
| void repaint() |
Repaints this component. |
| void repaint(int, int, int, int) |
Repaints the specified rectangle of this component. |
| void repaint(long) |
Repaints the component. |
| void repaint(long, int, int, int, int) |
Repaints the specified rectangle of this component within
tm milliseconds. |
| void requestFocus() |
Requests that this component get the input focus. |
| void reshape(int, int, int, int) |
Deprecated.
As of JDK version 1.1,
replaced by setBounds(int, int, int, int).
|
| void resize(Dimension) |
Deprecated.
As of JDK version 1.1,
replaced by setSize(Dimension).
|
| void resize(int, int) |
Deprecated.
As of JDK version 1.1,
replaced by setSize(int, int).
|
| void setBackground(Color) |
Sets the background color of this component. |
| void setBounds(int, int, int, int) |
Moves and resizes this component. |
| void setBounds(Rectangle) |
Moves and resizes this component to conform to the new
bounding rectangle r. |
| void setComponentOrientation(ComponentOrientation) |
Set the language-sensitive orientation that is to be used to order
the elements or text within this component. |
| void setCursor(Cursor) |
Sets the cursor image to the specified cursor. |
| void setDropTarget(DropTarget) |
Associate a DropTarget with this Component. |
| void setEnabled(boolean) |
Enables or disables this component, depending on the value of the
parameter b. |
| void setFont(Font) |
Sets the font of this component. |
| void setForeground(Color) |
Sets the foreground color of this component. |
| void setLocale(Locale) |
Sets the locale of this component. |
| void setLocation(int, int) |
Moves this component to a new location. |
| void setLocation(Point) |
Moves this component to a new location. |
| void setName(String) |
Sets the name of the component to the specified string. |
| void setSize(Dimension) |
Resizes this component so that it has width d.width
and height d.height. |
| void setSize(int, int) |
Resizes this component so that it has width width
and height. |
| void setVisible(boolean) |
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) |
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. |
| void update(Graphics) |
Updates this component. |
| void validate() |
Ensures that this component has a valid layout. |
Fields
public static final float BOTTOM_ALIGNMENT
Ease-of-use constant for getAlignmentY. Specifies an
alignment to the bottom of the component.
public static final float CENTER_ALIGNMENT
Ease-of-use constant for getAlignmentY and
getAlignmentX. Specifies an alignment to
the center of the component
public static final float LEFT_ALIGNMENT
Ease-of-use constant for getAlignmentX. Specifies an
alignment to the left side of the component.
public static final float RIGHT_ALIGNMENT
Ease-of-use constant for getAlignmentX. Specifies an
alignment to the right side of the component.
public static final float TOP_ALIGNMENT
Ease-of-use constant for getAlignmentY(). Specifies an
alignment to the top of the component.
Constructors
protected Component()
Constructs a new component. Class 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).
Methods
Deprecated.
As of JDK version 1.1,
should register this component as ActionListener on component
which fires action events.
public boolean action(Event evt,
Object what)
public synchronized void add(PopupMenu popup)
Adds the specified popup menu to the component.
- Parameters
- popup - the popup menu to be added to the component.
public synchronized void addComponentListener(ComponentListener l)
Adds the specified component listener to receive component events from
this component.
If l is null, no exception is thrown and no action is performed.
- Parameters
- l - the component listener.
public synchronized void addFocusListener(FocusListener l)
Adds the specified focus listener to receive focus events from
this component when this component gains input focus.
If l is null, no exception is thrown and no action is performed.
public 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.
If l is null, no exception is thrown and no action is performed.
- Parameters
- l - the hierarchy bounds listener.
public 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.
If l is null, no exception is thrown and no action is performed.
- Parameters
- l - the hierarchy listener.
public synchronized void addInputMethodListener(InputMethodListener l)
Adds the specified input method listener to receive
input method events from this component. A component will
only receive input method events from input methods
if it also overrides getInputMethodRequests to return an
InputMethodRequests instance.
If l is null, no exception is thrown and no action is performed.
- Parameters
- l - the input method listener.
public synchronized void addKeyListener(KeyListener l)
Adds the specified key listener to receive key events from
this component.
If l is null, no exception is thrown and no action is performed.
public synchronized void addMouseListener(MouseListener l)
Adds the specified mouse listener to receive mouse events from
this component.
If l is null, no exception is thrown and no action is performed.
public synchronized void addMouseMotionListener(MouseMotionListener l)
Adds the specified mouse motion listener to receive mouse motion events from
this component.
If l is null, no exception is thrown and no action is performed.
- Parameters
- l - the mouse motion listener.
public void addNotify()
Makes this 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.
public synchronized void addPropertyChangeListener(PropertyChangeListener listener)
Add a PropertyChangeListener to the listener list.
The listener is registered for all properties.
A PropertyChangeEvent will get fired in response to an
explicit setFont, setBackground, or SetForeground on the
current component. Note that if the current component is
inheriting its foreground, background, or font from its
container, 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.
- Parameters
- listener - The PropertyChangeListener to be added
public synchronized void addPropertyChangeListener(String propertyName,
PropertyChangeListener listener)
Add a PropertyChangeListener for a specific property. The listener
will be invoked only when a call on firePropertyChange names that
specific property.
If listener is null, no exception is thrown and no action is performed.
- Parameters
- propertyName - The name of the property to listen on.
- listener - The PropertyChangeListener to be added
Deprecated.
As of JDK version 1.1,
replaced by getBounds().
public Rectangle bounds()
public int checkImage(Image image,
ImageObserver observer)
Returns the status of the construction of a screen representation
of the specified image.
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.
- Parameters
- image - the
Image object whose status
is being checked. - observer - the
ImageObserver
object to be notified as the image is being prepared.
- Returns
- the bitwise inclusive OR of
ImageObserver flags indicating what
information about the image is currently available.
public int checkImage(Image image,
int width,
int height,
ImageObserver observer)
Returns the status of the construction of a screen representation
of the specified image.
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.
- Parameters
- image - the
Image object whose status
is being checked. - width - the width of the scaled version
whose status is to be checked.
- height - the height of the scaled version
whose status is to be checked.
- observer - the
ImageObserver object
to be notified as the image is being prepared.
- Returns
- the bitwise inclusive OR of
ImageObserver flags indicating what
information about the image is currently available.
protected AWTEvent coalesceEvents(AWTEvent existingEvent,
AWTEvent newEvent)
Potentially coalesce an event being posted with an existing
event. This method is called by 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 Event is always returned.
- Parameters
- existingEvent - the event already on the EventQueue.
- newEvent - the event being posted to the EventQueue.
- Returns
- a coalesced event, or null indicating that no coalescing
was done.
public 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.
- Parameters
- x - the x coordinate of the point.
- y - the y coordinate of the point.
public 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.
public Image createImage(ImageProducer producer)
Creates an image from the specified image producer.
- Parameters
- producer - the image producer
- Returns
public Image createImage(int width,
int height)
Creates an off-screen drawable image
to be used for double buffering.
- Parameters
- width - the specified width.
- height - the specified height.
- Returns
- an off-screen drawable image,
which can be used for double buffering.
Deprecated.
As of JDK version 1.1,
replaced by dispatchEvent(AWTEvent e).
public void deliverEvent(Event e)
Deprecated.
As of JDK version 1.1,
replaced by setEnabled(boolean).
public void disable()
protected final void disableEvents(long eventsToDisable)
Disables the events defined by the specified event mask parameter
from being delivered to this component.
- Parameters
- eventsToDisable - the event mask defining the event types
public final void dispatchEvent(AWTEvent e)
Dispatches an event to this component or one of its sub components.
Calls processEvent() before returning for 1.1-style events which
have been enabled for the Component.
public void doLayout()
Prompts the layout manager to lay out this component. This is
usually called when the component (more specifically, container)
is validated.
Deprecated.
As of JDK version 1.1,
replaced by setEnabled(boolean).
public void enable()
Deprecated.
As of JDK version 1.1,
replaced by setEnabled(boolean).
public void enable(boolean b)
protected final void enableEvents(long eventsToEnable)
Enables the events defined by the specified event mask parameter
to be delivered to this component.
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.
- Parameters
- eventsToEnable - the event mask defining the event types.
public void enableInputMethods(boolean enable)
Enables or disables input method support for this component. If input
method support is enabled and the component also processes key events,
incoming events are offered to
the current input method and will only be processed by the component or
dispatched to its listeners if the input method does not consume them.
By default, input method support is enabled.
- Parameters
- enable - true to enable, false to disable.
protected void firePropertyChange(String propertyName,
Object oldValue,
Object newValue)
Support for reporting bound property changes. This method can be called
when a bound property has changed and it will send the appropriate
PropertyChangeEvent to any registered PropertyChangeListeners.
public AccessibleContext getAccessibleContext()
Get the AccessibleContext associated with this Component
- Returns
- the AccessibleContext of this Component
public float getAlignmentX()
Returns the alignment along the x axis. This specifies how
the component would like to be aligned relative to other
components. The value should be a number between 0 and 1
where 0 represents alignment along the origin, 1 is aligned
the furthest away from the origin, 0.5 is centered, etc.
public float getAlignmentY()
Returns the alignment along the y axis. This specifies how
the component would like to be aligned relative to other
components. The value should be a number between 0 and 1
where 0 represents alignment along the origin, 1 is aligned
the furthest away from the origin, 0.5 is centered, etc.
public Color getBackground()
Gets the background color of this component.
- Returns
- This component's background color. If this component does
not have a background color, the background color of its parent
is returned.
public Rectangle getBounds()
Gets the bounds of this component in the form of a
Rectangle object. The bounds specify this
component's width, height, and location relative to
its parent.
- Returns
- A rectangle indicating this component's bounds.
public Rectangle getBounds(Rectangle rv)
Store the bounds of this component into "return value" rv and
return rv. If rv is 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.
- Parameters
- rv - the return value, modified to the components bounds
- Returns
public ColorModel getColorModel()
Gets the instance of ColorModel used to display
the component on the output device.
- Returns
- The color model used by this component.
public 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. This method only
looks one level deep. If the point (x, y) is
inside a subcomponent that itself has subcomponents, it does not
go looking down the subcomponent tree.
The locate method of Component simply
returns the component itself if the (x, y)
coordinate location is inside its bounding box, and null
otherwise.
- Parameters
- x - the x coordinate.
- y - the y coordinate.
- Returns
- the component or subcomponent that contains the
(x, y) location;
null if the location
is outside this component.
public Component getComponentAt(Point p)
Returns the component or subcomponent that contains the
specified point.
public ComponentOrientation getComponentOrientation()
Retrieve the language-sensitive orientation that is to be used to order
the elements or text within this component. LayoutManager and Component
subclasses that wish to respect orientation should call this method to
get the component's orientation before performing layout or drawing.
public Cursor getCursor()
Gets the cursor set in the component. If the component does
not have a cursor set, the cursor of its parent is returned.
If no Cursor is set in the entire hierarchy, Cursor.DEFAULT_CURSOR is
returned.
public synchronized DropTarget getDropTarget()
Get the DropTarget associated with this Component
public Font getFont()
Gets the font of this component.
- Returns
- This component's font. If a font has not been set
for this component, the font of its parent is returned.
public FontMetrics getFontMetrics(Font font)
Gets the font metrics for the specified font.
- Parameters
- font - The font for which font metrics is to be
obtained.
- font - the font.
- Returns
- The font metrics for
font. - the font metrics for the specified font.
public Color getForeground()
Gets the foreground color of this component.
- Returns
- This component's foreground color. If this component does
not have a foreground color, the foreground color of its parent
is returned.
public Graphics getGraphics()
Creates a graphics context for this component. This method will
return null if this component is currently not
displayable.
- Returns
- A graphics context for this component, or
null
if it has none.
public GraphicsConfiguration getGraphicsConfiguration()
Get the 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.
- Returns
- the
GraphicsConfiguration used by this
Component or null
public int getHeight()
Return the current height of this component.
This method is preferable to writing component.getBounds().height,
or component.getSize().height because it doesn't cause any
heap allocations.
- Returns
- the current height of this component.
public InputContext getInputContext()
Gets the input context used by this component for handling the communication
with input methods when text is entered in this component. By default, the
input context used for the parent component is returned. Components may
override this to return a private input context.
- Returns
- The input context used by this component. Null if no context can
be determined.
public InputMethodRequests getInputMethodRequests()
Gets the input method request handler which supports
requests from input methods for this component. A component
that supports on-the-spot text input must override this
method to return an InputMethodRequests instance. At the same
time, it also has to handle input method events.
- Returns
- the input method request handler for this component,
null by default.
public EventListener[] getListeners(Class listenerType)
Return an array of all the listeners that were added to the Component
with addXXXListener(), where XXX is the name of the listenerType
argument. For example, to get all of the MouseListeners for the
given Component c, one would write:
MouseListener[] mls = (MouseListener[])(c.getListeners(MouseListener.class))
If no such listener list exists, then an empty array is returned.
- Parameters
- listenerType - Type of listeners requested. This parameter must be
a java.util.EventListener or subclass.
- Throws
ClassCastException if the listenerType
parameter is not a java.util.EventListener or subclass.
public Locale getLocale()
Gets the locale of this component.
- Returns
- This component's locale. If this component does not
have a locale, the locale of its parent is returned.
- Throws
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 parent.
public Point getLocation()
Gets the location of this component in the form of a
point specifying the component's top-left corner.
The location will be relative to the parent's coordinate space.
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.
- Returns
- An instance of
Point representing
the top-left corner of the component's bounds in the coordinate
space of the component's parent.
public Point getLocation(Point rv)
Store the x,y origin of this component into "return value" rv
and return rv. If rv is 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.
- Parameters
- rv - the return value, modified to the components location
- Returns
public 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.
- Returns
- An instance of
Point representing
the top-left corner of the component's bounds in the
coordinate space of the screen.
public Dimension getMaximumSize()
Gets the maximum size of this component.
- Returns
- A dimension object indicating this component's maximum size.
public Dimension getMinimumSize()
Gets the mininimum size of this component.
- Returns
- A dimension object indicating this component's minimum size.
public String getName()
Gets the name of the component.
public Container getParent()
Gets the parent of this component.
- Returns
- The parent container of this component.
Deprecated.
As of JDK version 1.1,
programs should not directly manipulate peers.
replaced by boolean isDisplayable().
public ComponentPeer getPeer()
public Dimension getPreferredSize()
Gets the preferred size of this component.
- Returns
- A dimension object indicating this component's preferred size.
public Dimension getSize()
Returns the size of this component in the form of a
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.
- Returns
- A
Dimension object that indicates the
size of this component.
public Dimension getSize(Dimension rv)
Store the width/height of this component into "return value" rv
and return rv. If rv is 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.
- Parameters
- rv - the return value, modified to the components size
- Returns
public Toolkit getToolkit()
Gets the toolkit of this component. Note that
the frame that contains a component controls which
toolkit is used by that component. Therefore if the component
is moved from one frame to another, the toolkit it uses may change.
- Returns
- The toolkit of this component.
public final Object getTreeLock()
Gets the locking object for AWT component-tree and layout
Gets this component's locking object (the object that owns the thread
sychronization monitor) for AWT component-tree and layout
operations.
- Returns
- This component's locking object.
public int getWidth()
Return the current width of this component.
This method is preferable to writing component.getBounds().width,
or component.getSize().width because it doesn't cause any
heap allocations.
- Returns
- the current width of this component.
public int getX()
Return the current x coordinate of the components origin.
This method is preferable to writing component.getBounds().x,
or component.getLocation().x because it doesn't cause any
heap allocations.
- Returns
- the current x coordinate of the components origin.
public int getY()
Return the current y coordinate of the components origin.
This method is preferable to writing component.getBounds().y,
or component.getLocation().y because it doesn't cause any
heap allocations.
- Returns
- the current y coordinate of the components origin.
Deprecated.
As of JDK version 1.1,
replaced by processFocusEvent(FocusEvent).
public boolean gotFocus(Event evt,
Object what)
Deprecated.
As of JDK version 1.1
replaced by processEvent(AWTEvent).
public boolean handleEvent(Event evt)
public boolean hasFocus()
Returns true if this Component has the keyboard focus.
- Returns
- true if this Component has the keyboard focus.
Deprecated.
As of JDK version 1.1,
replaced by setVisible(boolean).
public void hide()
public boolean imageUpdate(Image img,
int infoflags,
int x,
int y,
int w,
int h)
Repaints the component when the image has changed.
This 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.
- Parameters
- img - the image being observed.
- infoflags - see
imageUpdate for more information. - x - the x coordinate.
- y - the y coordinate.
- w - the width.
- h - the height.
- Returns
false if the infoflags indicate that the
image is completely loaded; true otherwise.
Deprecated.
As of JDK version 1.1,
replaced by contains(int, int).
public boolean inside(int x,
int y)
public void invalidate()
Invalidates this component. This component and all parents
above it are marked as needing to be laid out. This method can
be called often, so it needs to execute quickly.
public boolean isDisplayable()
Determines whether this component is displayable. A component is
displayable when it is connected to a native screen resource.
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.
- Returns
true if the component is displayable;
false otherwise.
public boolean isDoubleBuffered()
Returns true if this component is painted to an offscreen image
("buffer") that's copied to the screen later. Component
subclasses that support double buffering should override this
method to return true if double buffering is enabled.
public boolean isEnabled()
Determines whether this component is enabled. An enabled component
can respond to user input and generate events. Components are
enabled initially by default. A component may be enabled or disabled by
calling its setEnabled method.
- Returns
true if the component is enabled;
false otherwise.
public boolean isFocusTraversable()
Returns the value of a flag that indicates whether
this component can be traversed using
Tab or Shift-Tab keyboard focus traversal. If this method
returns "false", this component may still request the keyboard
focus using requestFocus(), but it will not automatically
be assigned focus during tab traversal.
- Returns
true if this component is
focus-traverable; false otherwise.
public boolean isLightweight()
A lightweight component doesn't have a native toolkit peer.
Subclasses of 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.
- Returns
- true if this component has a lightweight peer; false if
it has a native peer or no peer.
public boolean isOpaque()
Returns true if this component is completely opaque, returns
false by default.
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. Only lightweight
components can be transparent.
Subclasses that guarantee to always completely paint their
contents should override this method and return true. All
of the "heavyweight" AWT components are opaque.
- Returns
- true if this component is completely opaque.
public boolean isShowing()
Determines whether this component is showing on screen. This means
that the component must be visible, and it must be in a container
that is visible and showing.
- Returns
true if the component is showing;
false otherwise.
public boolean isValid()
Determines whether this component is valid. A component is valid
when it is correctly sized and positioned within its parent
container and all its children are also valid. Components are
invalidated when they are first shown on the screen.
- Returns
true if the component is valid; false
otherwise.
public boolean isVisible()
Determines whether this component should be visible when its
parent is visible. Components are
initially visible, with the exception of top level components such
as Frame objects.
- Returns
true if the component is visible;
false otherwise.
Deprecated.
As of JDK version 1.1,
replaced by processKeyEvent(KeyEvent).
public boolean keyDown(Event evt,
int key)
Deprecated.
As of JDK version 1.1,
replaced by processKeyEvent(KeyEvent).
public boolean keyUp(Event evt,
int key)
Deprecated.
As of JDK version 1.1,
replaced by doLayout().
public void layout()
public void list()
Prints a listing of this component to the standard system output
stream System.out.
public void list(PrintStream out)
Prints a listing of this component to the specified output
stream.
public void list(PrintStream out,
int indent)
Prints out a list, starting at the specified indention, to the
specified print stream.
- Parameters
- out - a print stream.
- indent - number of spaces to indent.
public void list(PrintWriter out)
Prints a listing to the specified print writer.
- Parameters
- out - The print writer to print to.
public void list(PrintWriter out,
int indent)
Prints out a list, starting at the specified indention, to
the specified print writer.
- Parameters
- out - The print writer to print to.
- indent - The number of spaces to indent.
Deprecated.
As of JDK version 1.1,
replaced by getComponentAt(int, int).
public Component locate(int x,
int y)
Deprecated.
As of JDK version 1.1,
replaced by getLocation().
public Point location()
Deprecated.
As of JDK version 1.1,
replaced by processFocusEvent(FocusEvent).
public boolean lostFocus(Event evt,
Object what)
Deprecated.
As of JDK version 1.1,
replaced by getMinimumSize().
public Dimension minimumSize()
Deprecated.
As of JDK version 1.1,
replaced by processMouseEvent(MouseEvent).
public boolean mouseDown(Event evt,
int x,
int y)
Deprecated.
As of JDK version 1.1,
replaced by processMouseMotionEvent(MouseEvent).
public boolean mouseDrag(Event evt,
int x,
int y)
Deprecated.
As of JDK version 1.1,
replaced by processMouseEvent(MouseEvent).
public boolean mouseEnter(Event evt,
int x,
int y)
Deprecated.
As of JDK version 1.1,
replaced by processMouseEvent(MouseEvent).
public boolean mouseExit(Event evt,
int x,
int y)
Deprecated.
As of JDK version 1.1,
replaced by processMouseMotionEvent(MouseEvent).
public boolean mouseMove(Event evt,
int x,
int y)
Deprecated.
As of JDK version 1.1,
replaced by processMouseEvent(MouseEvent).
public boolean mouseUp(Event evt,
int x,
int y)
Deprecated.
As of JDK version 1.1,
replaced by setLocation(int, int).
public void move(int x,
int y)
Deprecated.
As of JDK version 1.1,
replaced by transferFocus().
public void nextFocus()
public void paint(Graphics g)
Paints this component. This method is called when the contents
of the component should be painted in response to the component
first being shown or damage needing repair. The clip rectangle
in the Graphics parameter will be set to the area which needs
to be painted.
For performance reasons, Components with zero width or height
aren't considered to need painting when they are first shown,
and also aren't considered to need repair.
- Parameters
- g - The graphics context to use for painting.
public void paintAll(Graphics g)
Paints this component and all of its subcomponents.
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.
- Parameters
- g - the graphics context to use for painting.
protected String paramString()
Returns a string representing the state of this component. This
method is intended to be used only for debugging purposes, and the
content and format of the returned string may vary between
implementations. The returned string may be empty but may not be
null.
- Returns
- a string representation of this component's state.
Deprecated.
As of JDK version 1.1,
replaced by dispatchEvent(AWTEvent).
public boolean postEvent(Event e)
Deprecated.
As of JDK version 1.1,
replaced by getPreferredSize().
public Dimension preferredSize()
public boolean prepareImage(Image image,
ImageObserver observer)
Prepares an image for rendering on this component. The image
data is downloaded asynchronously in another thread and the
appropriate screen representation of the image is generated.
- Parameters
- image - the
Image for which to
prepare a screen representation. - observer - the
ImageObserver object
to be notified as the image is being prepared.
- Returns
true if the image has already been fully prepared;
false otherwise.
public boolean prepareImage(Image image,
int width,
int height,
ImageObserver observer)
Prepares an image for rendering on this component at the
specified width and height.
The image data is downloaded asynchronously in another thread,
and an appropriately scaled screen representation of the image is
generated.
- Parameters
- image - the instance of
Image
for which to prepare a screen representation. - width - the width of the desired screen representation.
- height - the height of the desired screen representation.
- observer - the
ImageObserver object
to be notified as the image is being prepared.
- Returns
true if the image has already been fully prepared;
false otherwise.
public void print(Graphics g)
Prints this component. Applications should override this method
for components that must do special processing before being
printed or should be printed differently than they are painted.
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.
- Parameters
- g - the graphics context to use for printing.
public void printAll(Graphics g)
Prints this component and all of its subcomponents.
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.
- Parameters
- g - the graphics context to use for printing.
protected void processComponentEvent(ComponentEvent e)
Processes component events occurring on this component by
dispatching them to any registered
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:
- A
ComponentListener object is registered
via addComponentListener.
- Component events are enabled via
enableEvents.
protected void processEvent(AWTEvent e)
Processes events occurring on this component. By default this
method calls the appropriate
process<event type>Event
method for the given class of event.
protected void processFocusEvent(FocusEvent e)
Processes focus events occurring on this component by
dispatching them to any registered
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:
- A
FocusListener object is registered
via addFocusListener.
- Focus events are enabled via
enableEvents.
protected void processHierarchyBoundsEvent(HierarchyEvent e)
Processes hierarchy bounds events occurring on this component by
dispatching them to any registered
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:
- An
HierarchyBoundsListener object is registered
via addHierarchyBoundsListener.
- Hierarchy bounds events are enabled via
enableEvents.
protected void processHierarchyEvent(HierarchyEvent e)
Processes hierarchy events occurring on this component by
dispatching them to any registered
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:
- An
HierarchyListener object is registered
via addHierarchyListener.
- Hierarchy events are enabled via
enableEvents.
protected void processInputMethodEvent(InputMethodEvent e)
Processes input method events occurring on this component by
dispatching them to any registered
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:
- An
InputMethodListener object is registered
via addInputMethodListener.
- Input method events are enabled via
enableEvents.
- Parameters
- e - the input method event
protected void processKeyEvent(KeyEvent e)
Processes key events occurring on this component by
dispatching them to any registered
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:
- A
KeyListener object is registered
via addKeyListener.
- Key events are enabled via
enableEvents.
protected void processMouseEvent(MouseEvent e)
Processes mouse events occurring on this component by
dispatching them to any registered
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:
- A
MouseListener object is registered
via addMouseListener.
- Mouse events are enabled via
enableEvents.
protected void processMouseMotionEvent(MouseEvent e)
Processes mouse motion events occurring on this component by
dispatching them to any registered
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:
- A
MouseMotionListener object is registered
via addMouseMotionListener.
- Mouse motion events are enabled via
enableEvents.
- Parameters
- e - the mouse motion event.
public synchronized void remove(MenuComponent popup)
Removes the specified popup menu from the component.
- Parameters
- popup - the popup menu to be removed.
public synchronized void removeComponentListener(ComponentListener l)
Removes the specified component listener so that it no longer
receives component events from this component. This method performs
no function, nor does it throw an exception, if the listener
specified by the argument was not previously added to this component.
If l is null, no exception is thrown and no action is performed.
- Parameters
- l - the component listener.
public synchronized void removeFocusListener(FocusListener l)
Removes the specified focus listener so that it no longer
receives focus events from this component. This method performs
no function, nor does it throw an exception, if the listener
specified by the argument was not previously added to this component.
If l is null, no exception is thrown and no action is performed.
public void removeHierarchyBoundsListener(HierarchyBoundsListener l)
Removes the specified hierarchy bounds listener so that it no longer
receives hierarchy bounds events from this component. This method
performs no function, nor does it throw an exception, if the listener
specified by the argument was not previously added to this component.
If l is null, no exception is thrown and no action is performed.
- Parameters
- l - the hierarchy bounds listener.
public void removeHierarchyListener(HierarchyListener l)
Removes the specified hierarchy listener so that it no longer
receives hierarchy changed events from this component. This method
performs no function, nor does it throw an exception, if the listener
specified by the argument was not previously added to this component.
If l is null, no exception is thrown and no action is performed.
- Parameters
- l - the hierarchy listener.
public synchronized void removeInputMethodListener(InputMethodListener l)
Removes the specified input method listener so that it no longer receives
input method events from this component. This method performs
no function, nor does it throw an exception, if the listener
specified by the argument was not previously added to this component.
If l is null, no exception is thrown and no action is performed.
- Parameters
- l - the input method listener.
public synchronized void removeKeyListener(KeyListener l)
Removes the specified key listener so that it no longer
receives key events from this component. This method performs
no function, nor does it throw an exception, if the listener
specified by the argument was not previously added to this component.
If l is null, no exception is thrown and no action is performed.
public synchronized void removeMouseListener(MouseListener l)
Removes the specified mouse listener so that it no longer
receives mouse events from this component. This method performs
no function, nor does it throw an exception, if the listener
specified by the argument was not previously added to this component.
If l is null, no exception is thrown and no action is performed.
public synchronized void removeMouseMotionListener(MouseMotionListener l)
Removes the specified mouse motion listener so that it no longer
receives mouse motion events from this component. This method performs
no function, nor does it throw an exception, if the listener
specified by the argument was not previously added to this component.
If l is null, no exception is thrown and no action is performed.
- Parameters
- l - the mouse motion listener.
public void removeNotify()
Makes this Component undisplayable by destroying it native
screen resource.
This method is called by the toolkit internally and should
not be called directly by programs.
public synchronized void removePropertyChangeListener(PropertyChangeListener listener)
Remove a PropertyChangeListener from the listener list.
This removes a PropertyChangeListener that was registered
for all properties.
If listener is null, no exception is thrown and no action is performed.
- Parameters
- listener - The PropertyChangeListener to be removed
public synchronized void removePropertyChangeListener(String propertyName,
PropertyChangeListener listener)
Remove a PropertyChangeListener for a specific property.
If listener is null, no exception is thrown and no action is performed.
- Parameters
- propertyName - The name of the property that was listened on.
- listener - The PropertyChangeListener to be removed
public void repaint()
Repaints this component.
This method causes a call to this component's update
method as soon as possible.
public void repaint(int x,
int y,
int width,
int height)
Repaints the specified rectangle of this component.
This method causes a call to this component's update
method as soon as possible.
- Parameters
- x - the x coordinate.
- y - the y coordinate.
- width - the width.
- height - the height.
public void repaint(long tm)
Repaints the component. This will result in a
call to update within tm milliseconds.
- Parameters
- tm - maximum time in milliseconds before update
public void repaint(long tm,
int x,
int y,
int width,
int height)
Repaints the specified rectangle of this component within
tm milliseconds.
This method causes a call to this component's
update method.
- Parameters
- tm - maximum time in milliseconds before update.
- x - the x coordinate.
- y - the y coordinate.
- width - the width.
- height - the height.
public void requestFocus()
Requests that this component get the input focus.
The component must be visible
on the screen for this request to be granted
Deprecated.
As of JDK version 1.1,
replaced by setBounds(int, int, int, int).
public void reshape(int x,
int y,
int width,
int height)
Deprecated.
As of JDK version 1.1,
replaced by setSize(Dimension).
public void resize(Dimension d)
Deprecated.
As of JDK version 1.1,
replaced by setSize(int, int).
public void resize(int width,
int height)
public void setBackground(Color c)
Sets the background color of this component.
- Parameters
- c - The color to become this component's color.
If this parameter is null then this component will inherit
the background color of its parent.
background color.
public void setBounds(int x,
int y,
int width,
int height)
Moves and resizes this component. The new location of the top-left
corner is specified by x and y, and the
new size is specified by width and height.
- Parameters
- x - The new x-coordinate of this component.
- y - The new y-coordinate of this component.
- width - The new
width of this component. - height - The new
height of this
component.
public void setBounds(Rectangle r)
Moves and resizes this component to conform to the new
bounding rectangle 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
- Parameters
- r - The new bounding rectangle for this component.
public void setComponentOrientation(ComponentOrientation o)
Set the language-sensitive orientation that is to be used to order
the elements or text within this component. Language-sensitive
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 apply a ResourceBundle's orientation to an entire component
hierarchy, use java.awt.Window.applyResourceBundle.
public void setCursor(Cursor cursor)
Sets the cursor image to the specified cursor. This cursor
image is displayed when the 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.
- Parameters
- cursor - One of the constants defined
by the
Cursor class.
If this parameter is null then this component will inherit
the cursor of its parent.
public synchronized void setDropTarget(DropTarget dt)
Associate a DropTarget with this Component. The Component will
receive drops only if it is enabled.
public void setEnabled(boolean b)
Enables or disables this component, depending on the value of the
parameter b. An enabled component can respond to user
input and generate events. Components are enabled initially by default.
- Parameters
- b - If
true, this component is
enabled; otherwise this component is disabled.
public void setFont(Font f)
Sets the font of this component.
- Parameters
- f - The font to become this component's font.
If this parameter is null then this component will inherit
the font of its parent.
public void setForeground(Color c)
Sets the foreground color of this component.
- Parameters
- 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 parent.
public void setLocale(Locale l)
Sets the locale of this component.
- Parameters
- l - The locale to become this component's locale.
public void setLocation(int x,
int y)
Moves this component to a new location. The top-left corner of
the new location is specified by the x and y
parameters in the coordinate space of this component's parent.
- Parameters
- x - The x-coordinate of the new location's
top-left corner in the parent's coordinate space.
- y - The y-coordinate of the new location's
top-left corner in the parent's coordinate space.
public void setLocation(Point p)
Moves this component to a new location. The top-left corner of
the new location is specified by point p. Point
p is given in the parent's coordinate space.
- Parameters
- p - The point defining the top-left corner
of the new location, given in the coordinate space of this
component's parent.
public void setName(String name)
Sets the name of the component to the specified string.
- Parameters
- name - The string that is to be this
component's name.
public void setSize(Dimension d)
Resizes this component so that it has width d.width
and height d.height.
- Parameters
- d - The dimension specifying the new size
of this component.
public void setSize(int width,
int height)
Resizes this component so that it has width width
and height.
- Parameters
- width - The new width of this component in pixels.
- height - The new height of this component in pixels.
public void setVisible(boolean b)
Shows or hides this component depending on the value of parameter
b.
- Parameters
- b - If
true, shows this component;
otherwise, hides this component.
Deprecated.
As of JDK version 1.1,
replaced by setVisible(boolean).
public void show()
Deprecated.
As of JDK version 1.1,
replaced by setVisible(boolean).
public void show(boolean b)
Deprecated.
As of JDK version 1.1,
replaced by getSize().
public Dimension size()
public String toString()
Returns a string representation of this component and its values.
- Returns
- a string representation of this component.
- Overrides
public void transferFocus()
Transfers the focus to the next component.
public void update(Graphics g)
Updates this component.
The AWT calls the update method in response to a
call to repaintupdate or paint. You can assume that
the background is not cleared.
The updatemethod of Component
does the following:
- Clears this component by filling it
with the background color.
- Sets the color of the graphics context to be
the foreground color of this component.
- Calls this component's
paint
method to completely redraw this component.
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.
- Parameters
- g - the specified context to use for updating.
public void validate()
Ensures that this component has a valid layout. This method is
primarily intended to operate on instances of Container.
See Also
