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Java(TM) 2 Platform, Standard Edition, v1.2.2 API Specification: Class Component - JDK 5 Documentation v1.2.2, Java 2 SDK 英文文档

JavaTM 2 Platform
Standard Edition

java.awt
Class Component

java.lang.Object
  |
  +--java.awt.Component
Direct Known Subclasses:
Box.Filler, Button, Canvas, Checkbox, Choice, Container, Label, List, Scrollbar, TextComponent

public abstract class Component
extends Object
implements ImageObserver, MenuContainer, Serializable

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.

See Also:
Serialized Form

Field Summary
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().
 
Fields inherited from interface java.awt.image.ImageObserver
ABORT, ALLBITS, ERROR, FRAMEBITS, HEIGHT, PROPERTIES, SOMEBITS, WIDTH
 
Constructor Summary
protected Component()
          Constructs a new component.
 
Method Summary
 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 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 addNotify()
          Makes this Component displayable by connecting it to a native screen resource.
 void addPropertyChangeListener(PropertyChangeListener listener)
          Add a PropertyChangeListener to the listener list.
 void addPropertyChangeListener(String propertyName, PropertyChangeListener listener)
          Add a PropertyChangeListener for a specific property.
 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.
 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, Object oldValue, Object newValue)
          Support for reporting bound property changes.
 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 rv)
          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 x, int y)
          Determines if this component or one of its immediate subcomponents contains the (xy) location, and if so, returns the containing component.
 Component getComponentAt(Point p)
          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 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.
 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.
 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)
          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.
 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.
 Dimension getSize()
          Returns the size of this component in the form of a Dimension object.
 Dimension getSize(Dimension rv)
          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 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 has the keyboard focus.
 void hide()
          Deprecated. As of JDK version 1.1, replaced by setVisible(boolean).
 boolean imageUpdate(Image img, int flags, 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.
 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 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 indention, 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 indention, 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 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.
 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 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 removeNotify()
          Makes this Component undisplayable by destroying it native screen resource.
 void removePropertyChangeListener(PropertyChangeListener listener)
          Remove a PropertyChangeListener from the listener list.
 void removePropertyChangeListener(String propertyName, PropertyChangeListener listener)
          Remove a PropertyChangeListener 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.
 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 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)
          Set 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 setFont(Font f)
          Sets the font of this component.
 void setForeground(Color c)
          Sets the foreground color of this component.
 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 setName(String name)
          Sets the name of the component to the specified string.
 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.
 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.
 void update(Graphics g)
          Updates this component.
 void validate()
          Ensures that this component has a valid layout.
 
Methods inherited from class java.lang.Object
clone, equals, finalize, getClass, hashCode, notify, notifyAll, wait, wait, wait
 

Field Detail

TOP_ALIGNMENT

public static final float TOP_ALIGNMENT
Ease-of-use constant for getAlignmentY(). Specifies an alignment to the top of the component.
See Also:
getAlignmentY()

CENTER_ALIGNMENT

public static final float CENTER_ALIGNMENT
Ease-of-use constant for getAlignmentY and getAlignmentX. Specifies an alignment to the center of the component
See Also:
getAlignmentX(), getAlignmentY()

BOTTOM_ALIGNMENT

public static final float BOTTOM_ALIGNMENT
Ease-of-use constant for getAlignmentY. Specifies an alignment to the bottom of the component.
See Also:
getAlignmentY()

LEFT_ALIGNMENT

public static final float LEFT_ALIGNMENT
Ease-of-use constant for getAlignmentX. Specifies an alignment to the left side of the component.
See Also:
getAlignmentX()

RIGHT_ALIGNMENT

public static final float RIGHT_ALIGNMENT
Ease-of-use constant for getAlignmentX. Specifies an alignment to the right side of the component.
See Also:
getAlignmentX()
Constructor Detail

Component

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).
Method Detail

getName

public String getName()
Gets the name of the component.
Returns:
This component's name.
Since:
JDK1.1
See Also:
setName(java.lang.String)

setName

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.
Since:
JDK1.1
See Also:
getName()

getParent

public Container getParent()
Gets the parent of this component.
Returns:
The parent container of this component.
Since:
JDK1.0

getPeer

public java.awt.peer.ComponentPeer getPeer()
Deprecated. As of JDK version 1.1, programs should not directly manipulate peers. replaced by boolean isDisplayable().


setDropTarget

public void setDropTarget(DropTarget dt)
Associate a DropTarget with this Component.
Parameters:
dt - The DropTarget

getDropTarget

public DropTarget getDropTarget()
Get the DropTarget associated with this Component

getTreeLock

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.

getToolkit

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.
Since:
JDK1.0

isValid

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.
Since:
JDK1.0
See Also:
validate(), invalidate()

isDisplayable

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.
Since:
JDK1.2
See Also:
Container.add(java.awt.Component), Window.pack(), Window.show(), Container.remove(java.awt.Component), Window.dispose()

isVisible

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.
Since:
JDK1.0
See Also:
setVisible(boolean)

isShowing

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.
Since:
JDK1.0
See Also:
setVisible(boolean)

isEnabled

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.
Since:
JDK1.0
See Also:
setEnabled(boolean)

setEnabled

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.
Since:
JDK1.1
See Also:
isEnabled()

enable

public void enable()
Deprecated. As of JDK version 1.1, replaced by setEnabled(boolean).


enable

public void enable(boolean b)
Deprecated. As of JDK version 1.1, replaced by setEnabled(boolean).


disable

public void disable()
Deprecated. As of JDK version 1.1, replaced by setEnabled(boolean).


isDoubleBuffered

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.
Returns:
false by default

enableInputMethods

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.
Since:
JDK1.2
See Also:
processKeyEvent(java.awt.event.KeyEvent)

setVisible

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.
Since:
JDK1.1
See Also:
isVisible()

show

public void show()
Deprecated. As of JDK version 1.1, replaced by setVisible(boolean).


show

public void show(boolean b)
Deprecated. As of JDK version 1.1, replaced by setVisible(boolean).


hide

public void hide()
Deprecated. As of JDK version 1.1, replaced by setVisible(boolean).


getForeground

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.
Since:
JDK1.0
See Also:
#java.awt.Component#setForeground(java.awt.Color)

setForeground

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.
Since:
JDK1.0
See Also:
getForeground()

getBackground

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.
Since:
JDK1.0
See Also:
setBackground(java.awt.Color)

setBackground

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.
Since:
JDK1.0
See Also:
getBackground()

getFont

public Font getFont()
Gets the font of this component.
Specified by:
getFont in interface MenuContainer
Returns:
This component's font. If a font has not been set for this component, the font of its parent is returned.
Since:
JDK1.0
See Also:
setFont(java.awt.Font)

setFont

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.
Since:
JDK1.0
See Also:
getFont()

getLocale

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.
Since:
JDK1.1
See Also:
setLocale(java.util.Locale)

setLocale

public void setLocale(Locale l)
Sets the locale of this component.
Parameters:
l - The locale to become this component's locale.
Since:
JDK1.1
See Also:
getLocale()

getColorModel

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.
Since:
JDK1.0
See Also:
ColorModel, ComponentPeer.getColorModel(), Toolkit.getColorModel()

getLocation

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.
Returns:
An instance of Point representing the top-left corner of the component's bounds in the coordinate space of the component's parent.
Since:
JDK1.1
See Also:
setLocation(int, int), getLocationOnScreen()

getLocationOnScreen

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.
See Also:
setLocation(int, int), getLocation()

location

public Point location()
Deprecated. As of JDK version 1.1, replaced by getLocation().


setLocation

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.
Since:
JDK1.1
See Also:
getLocation(), setBounds(int, int, int, int)

move

public void move(int x,
                 int y)
Deprecated. As of JDK version 1.1, replaced by setLocation(int, int).


setLocation

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.
Since:
JDK1.1
See Also:
getLocation(), setBounds(int, int, int, int)

getSize

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.
Since:
JDK1.1
See Also:
setSize(int, int)

size

public Dimension size()
Deprecated. As of JDK version 1.1, replaced by getSize().


setSize

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.
Since:
JDK1.1
See Also:
getSize(), setBounds(int, int, int, int)

resize

public void resize(int width,
                   int height)
Deprecated. As of JDK version 1.1, replaced by setSize(int, int).


setSize

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.
Since:
JDK1.1
See Also:
setSize(int, int), setBounds(int, int, int, int)

resize

public void resize(Dimension d)
Deprecated. As of JDK version 1.1, replaced by setSize(Dimension).


getBounds

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.
See Also:
setBounds(int, int, int, int), getLocation(), getSize()

bounds

public Rectangle bounds()
Deprecated. As of JDK version 1.1, replaced by getBounds().


setBounds

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.
See Also:
getBounds(), setLocation(int, int), setLocation(java.awt.Point), setSize(int, int), setSize(java.awt.Dimension)

reshape

public void reshape(int x,
                    int y,
                    int width,
                    int height)
Deprecated. As of JDK version 1.1, replaced by setBounds(int, int, int, int).


setBounds

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.
Since:
JDK1.1
See Also:
getBounds(), setLocation(int, int), setLocation(java.awt.Point), setSize(int, int), setSize(java.awt.Dimension)

getX

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.
Since:
JDK1.2

getY

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.
Since:
JDK1.2

getWidth

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.
Since:
JDK1.2

getHeight

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.
Since:
JDK1.2

getBounds

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:
rv

getSize

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:
rv

getLocation

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:
rv

isOpaque

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.
Since:
JDK1.2
See Also:
isLightweight()

isLightweight

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.
Returns:
true if this component doesn't have a native peer
Since:
JDK1.2

getPreferredSize

public Dimension getPreferredSize()
Gets the preferred size of this component.
Returns:
A dimension object indicating this component's preferred size.
See Also:
getMinimumSize(), LayoutManager

preferredSize

public Dimension preferredSize()
Deprecated. As of JDK version 1.1, replaced by getPreferredSize().


getMinimumSize

public Dimension getMinimumSize()
Gets the mininimum size of this component.
Returns:
A dimension object indicating this component's minimum size.
See Also:
getPreferredSize(), java.awtLayoutManager

minimumSize

public Dimension minimumSize()
Deprecated. As of JDK version 1.1, replaced by getMinimumSize().


getMaximumSize

public Dimension getMaximumSize()
Gets the maximum size of this component.
Returns:
A dimension object indicating this component's maximum size.
See Also:
getMinimumSize(), getPreferredSize(), LayoutManager

getAlignmentX

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.

getAlignmentY

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.

doLayout

public void doLayout()
Prompts the layout manager to lay out this component. This is usually called when the component (more specifically, container) is validated.
See Also:
validate(), LayoutManager

layout

public void layout()
Deprecated. As of JDK version 1.1, replaced by doLayout().


validate

public void validate()
Ensures that this component has a valid layout. This method is primarily intended to operate on instances of Container.
Since:
JDK1.0
See Also:
invalidate(), doLayout(), LayoutManager, Container.validate()

invalidate

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.
Since:
JDK1.0
See Also:
validate(), doLayout(), LayoutManager

getGraphics

public Graphics getGraphics()
Creates a graphics context for this component. This method will return null if this component is currently not on the screen.
Returns:
A graphics context for this component, or null if it has none.
Since:
JDK1.0
See Also:
paint(java.awt.Graphics)

getFontMetrics

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.
Since:
JDK1.0
See Also:
getFont(), getPeer(), ComponentPeer.getFontMetrics(java.awt.Font), Toolkit.getFontMetrics(java.awt.Font)

setCursor

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 tr