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JavaTM 2 Platform Standard Edition |
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SUMMARY: INNER | FIELD | CONSTR | METHOD | DETAIL: FIELD | CONSTR | METHOD |
java.lang.Object | +--java.awt.Component
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.
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 (x, y) 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 |
public static final float TOP_ALIGNMENT
getAlignmentY()
. Specifies an
alignment to the top of the component.getAlignmentY()
public static final float CENTER_ALIGNMENT
getAlignmentY
and
getAlignmentX
. Specifies an alignment to
the center of the componentgetAlignmentX()
,
getAlignmentY()
public static final float BOTTOM_ALIGNMENT
getAlignmentY
. Specifies an
alignment to the bottom of the component.getAlignmentY()
public static final float LEFT_ALIGNMENT
getAlignmentX
. Specifies an
alignment to the left side of the component.getAlignmentX()
public static final float RIGHT_ALIGNMENT
getAlignmentX
. Specifies an
alignment to the right side of the component.getAlignmentX()
Constructor Detail |
protected Component()
Component
can be
extended directly to create a lightweight component that does not
utilize an opaque native window. A lightweight component must be
hosted by a native container somewhere higher up in the component
tree (for example, by a Frame
object).Method Detail |
public String getName()
setName(java.lang.String)
public void setName(String name)
name
- The string that is to be this
component's name.getName()
public Container getParent()
public java.awt.peer.ComponentPeer getPeer()
boolean isDisplayable()
.
public void setDropTarget(DropTarget dt)
dt
- The DropTargetpublic DropTarget getDropTarget()
public final Object getTreeLock()
public Toolkit getToolkit()
public boolean isValid()
true
if the component is valid; false
otherwise.validate()
,
invalidate()
public boolean isDisplayable()
A component is made displayable either when it is added to a displayable containment hierarchy or when its containment hierarchy is made displayable. A containment hierarchy is made displayable when its ancestor window is either packed or made visible.
A component is made undisplayable either when it is removed from a displayable containment hierarchy or when its containment hierarchy is made undisplayable. A containment hierarchy is made undisplayable when its ancestor window is disposed.
true
if the component is displayable;
false
otherwise.Container.add(java.awt.Component)
,
Window.pack()
,
Window.show()
,
Container.remove(java.awt.Component)
,
Window.dispose()
public boolean isVisible()
Frame
objects.true
if the component is visible;
false
otherwise.setVisible(boolean)
public boolean isShowing()
true
if the component is showing;
false
otherwise.setVisible(boolean)
public boolean isEnabled()
setEnabled
method.true
if the component is enabled;
false
otherwise.setEnabled(boolean)
public void setEnabled(boolean b)
b
. An enabled component can respond to user
input and generate events. Components are enabled initially by default.b
- If true
, this component is
enabled; otherwise this component is disabled.isEnabled()
public void enable()
setEnabled(boolean)
.
public void enable(boolean b)
setEnabled(boolean)
.
public void disable()
setEnabled(boolean)
.
public boolean isDoubleBuffered()
public void enableInputMethods(boolean enable)
enable
- true to enable, false to disable.processKeyEvent(java.awt.event.KeyEvent)
public void setVisible(boolean b)
b
.b
- If true
, shows this component;
otherwise, hides this component.isVisible()
public void show()
setVisible(boolean)
.
public void show(boolean b)
setVisible(boolean)
.
public void hide()
setVisible(boolean)
.
public Color getForeground()
#java.awt.Component#setForeground(java.awt.Color)
public void setForeground(Color c)
c
- The color to become this component's
foreground color.
If this parameter is null then this component will inherit
the foreground color of its parent.getForeground()
public Color getBackground()
setBackground(java.awt.Color)
public void setBackground(Color c)
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.getBackground()
public Font getFont()
setFont(java.awt.Font)
public void setFont(Font f)
f
- The font to become this component's font.
If this parameter is null then this component will inherit
the font of its parent.getFont()
public Locale getLocale()
setLocale(java.util.Locale)
public void setLocale(Locale l)
l
- The locale to become this component's locale.getLocale()
public ColorModel getColorModel()
ColorModel
used to display
the component on the output device.ColorModel
,
ComponentPeer.getColorModel()
,
Toolkit.getColorModel()
public Point getLocation()
Point
representing
the top-left corner of the component's bounds in the coordinate
space of the component's parent.setLocation(int, int)
,
getLocationOnScreen()
public Point getLocationOnScreen()
Point
representing
the top-left corner of the component's bounds in the
coordinate space of the screen.setLocation(int, int)
,
getLocation()
public Point location()
getLocation()
.
public void setLocation(int x, int y)
x
and y
parameters in the coordinate space of this component's parent.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.getLocation()
,
setBounds(int, int, int, int)
public void move(int x, int y)
setLocation(int, int)
.
public void setLocation(Point p)
p
. Point
p
is given in the parent's coordinate space.p
- The point defining the top-left corner
of the new location, given in the coordinate space of this
component's parent.getLocation()
,
setBounds(int, int, int, int)
public Dimension getSize()
Dimension
object. The height
field of the Dimension
object contains
this component's height, and the width
field of the Dimension
object contains
this component's width.Dimension
object that indicates the
size of this component.setSize(int, int)
public Dimension size()
getSize()
.
public void setSize(int width, int height)
width
and height
.width
- The new width of this component in pixels.height
- The new height of this component in pixels.getSize()
,
setBounds(int, int, int, int)
public void resize(int width, int height)
setSize(int, int)
.
public void setSize(Dimension d)
d.width
and height d.height
.d
- The dimension specifying the new size
of this component.setSize(int, int)
,
setBounds(int, int, int, int)
public void resize(Dimension d)
setSize(Dimension)
.
public Rectangle getBounds()
Rectangle
object. The bounds specify this
component's width, height, and location relative to
its parent.setBounds(int, int, int, int)
,
getLocation()
,
getSize()
public Rectangle bounds()
getBounds()
.
public void setBounds(int x, int y, int width, int height)
x
and y
, and the
new size is specified by width
and height
.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.getBounds()
,
setLocation(int, int)
,
setLocation(java.awt.Point)
,
setSize(int, int)
,
setSize(java.awt.Dimension)
public void reshape(int x, int y, int width, int height)
setBounds(int, int, int, int)
.
public void setBounds(Rectangle r)
r
. This component's new
position is specified by r.x
and r.y
,
and its new size is specified by r.width
and
r.height
r
- The new bounding rectangle for this component.getBounds()
,
setLocation(int, int)
,
setLocation(java.awt.Point)
,
setSize(int, int)
,
setSize(java.awt.Dimension)
public int getX()
public int getY()
public int getWidth()
public int getHeight()
public Rectangle getBounds(Rectangle rv)
rv
- the return value, modified to the components boundspublic Dimension getSize(Dimension rv)
rv
- the return value, modified to the components sizepublic Point getLocation(Point rv)
rv
- the return value, modified to the components locationpublic boolean isOpaque()
An opaque component paints every pixel within its rectangular region. A non-opaque component paints only some of its pixels, allowing the pixels underneath it to "show through". A component that does not fully paint its pixels therefore provides a degree of transparency. 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.
isLightweight()
public boolean isLightweight()
public Dimension getPreferredSize()
getMinimumSize()
,
LayoutManager
public Dimension preferredSize()
getPreferredSize()
.
public Dimension getMinimumSize()
getPreferredSize()
,
java.awtLayoutManager
public Dimension minimumSize()
getMinimumSize()
.
public Dimension getMaximumSize()
getMinimumSize()
,
getPreferredSize()
,
LayoutManager
public float getAlignmentX()
public float getAlignmentY()
public void doLayout()
validate()
,
LayoutManager
public void layout()
doLayout()
.
public void validate()
Container
.invalidate()
,
doLayout()
,
LayoutManager
,
Container.validate()
public void invalidate()
validate()
,
doLayout()
,
LayoutManager
public Graphics getGraphics()
null
if this component is currently not on
the screen.null
if it has none.paint(java.awt.Graphics)
public FontMetrics getFontMetrics(Font font)
font
- The font for which font metrics is to be
obtained.font
- the font.font
.getFont()
,
getPeer()
,
ComponentPeer.getFontMetrics(java.awt.Font)
,
Toolkit.getFontMetrics(java.awt.Font)
public void setCursor(Cursor cursor)
contains
method for
this component returns true for the current cursor location.
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.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.getCursor()
,
contains(int, int)
,
Toolkit.createCustomCursor(java.awt.Image, java.awt.Point, java.lang.String)
,
Cursor
public Cursor getCursor()
setCursor(java.awt.Cursor)
public void paint(Graphics g)
g
- The graphics context to use for painting.update(java.awt.Graphics)
public void update(Graphics g)
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 update
method 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.
g
- the specified context to use for updating.paint(java.awt.Graphics)
,
repaint()
public void paintAll(Graphics g)
The origin of the graphics context, its
(0
, 0
) coordinate point, is the
top-left corner of this component. The clipping region of the
graphics context is the bounding rectangle of this component.
g
- the graphics context to use for painting.paint(java.awt.Graphics)
public void repaint()
This method causes a call to this component's update
method as soon as possible.
update(java.awt.Graphics)
public void repaint(long tm)
update
within tm milliseconds.tm
- maximum time in milliseconds before updatepaint(java.awt.Graphics)
,
update(java.awt.Graphics)
public void repaint(int x, int y, int width, int height)
This method causes a call to this component's update
method as soon as possible.
x
- the x coordinate.y
- the y coordinate.width
- the width.height
- the height.update(java.awt.Graphics)
public void repaint(long tm, int x, int y, int width, int height)
tm
milliseconds.
This method causes a call to this component's
update
method.
tm
- maximum time in milliseconds before update.x
- the x coordinate.y
- the y coordinate.width
- the width.height
- the height.update(java.awt.Graphics)
public void print(Graphics g)
The default implementation of this method calls the
paint
method.
The origin of the graphics context, its
(0
, 0
) coordinate point, is the
top-left corner of this component. The clipping region of the
graphics context is the bounding rectangle of this component.
g
- the graphics context to use for printing.paint(java.awt.Graphics)
public void printAll(Graphics g)
The origin of the graphics context, its
(0
, 0
) coordinate point, is the
top-left corner of this component. The clipping region of the
graphics context is the bounding rectangle of this component.
g
- the graphics context to use for printing.print(java.awt.Graphics)
public boolean imageUpdate(Image img, int flags, int x, int y, int w, int h)
imageUpdate
method of an ImageObserver
is called when more information about an
image which had been previously requested using an asynchronous
routine such as the drawImage
method of
Graphics
becomes available.
See the definition of imageUpdate
for
more information on this method and its arguments.
The imageUpdate
method of Component
incrementally draws an image on the component as more of the bits
of the image are available.
If the system property awt.image.incrementalDraw
is missing or has the value true
, the image is
incrementally drawn, If the system property has any other value,
then the image is not drawn until it has been completely loaded.
Also, if incremental drawing is in effect, the value of the
system property awt.image.redrawrate
is interpreted
as an integer to give the maximum redraw rate, in milliseconds. If
the system property is missing or cannot be interpreted as an
integer, the redraw rate is once every 100ms.
The interpretation of the x
, y
,
width
, and height
arguments depends on
the value of the infoflags
argument.
img
- the image being observed.infoflags
- see imageUpdate
for more information.x
- the x coordinate.y
- the y coordinate.width
- the width.height
- the height.true
if the flags indicate that the
image is completely loaded;
false
otherwise.ImageObserver
,
Graphics.drawImage(java.awt.Image, int, int, java.awt.Color, java.awt.image.ImageObserver)
,
Graphics.drawImage(java.awt.Image, int, int, java.awt.image.ImageObserver)
,
Graphics.drawImage(java.awt.Image, int, int, int, int, java.awt.Color, java.awt.image.ImageObserver)
,
Graphics.drawImage(java.awt.Image, int, int, int, int, java.awt.image.ImageObserver)
,
ImageObserver.imageUpdate(java.awt.Image, int, int, int, int, int)
public Image createImage(ImageProducer producer)
producer
- the image producerpublic Image createImage(int width, int height)
width
- the specified width.height
- the specified height.public boolean prepareImage(Image image, ImageObserver observer)
image
- the Image
for which to
prepare a screen representation.observer
- the ImageObserver
object
to be notified as the image is being prepared.true
if the image has already been fully prepared;
false
otherwise.public boolean prepareImage(Image image, int width, int height, ImageObserver observer)
The image data is downloaded asynchronously in another thread, and an appropriately scaled screen representation of the image is generated.
image
- the instance of Image
for which to prepare a screen 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.true
if the image has already been fully prepared;
false
otherwise.ImageObserver
public int checkImage(Image image, ImageObserver observer)
This method does not cause the image to begin loading. An
application must use the prepareImage
method
to force the loading of an image.
Information on the flags returned by this method can be found
with the discussion of the ImageObserver
interface.
image
- the Image
object whose status
is being checked.observer
- the ImageObserver
object to be notified as the image is being prepared.ImageObserver
flags indicating what
information about the image is currently available.prepareImage(java.awt.Image, int, int, java.awt.image.ImageObserver)
,
Toolkit.checkImage(java.awt.Image, int, int, java.awt.image.ImageObserver)
,
ImageObserver
public int checkImage(Image image, int width, int height, ImageObserver observer)
This method does not cause the image to begin loading. An
application must use the prepareImage
method
to force the loading of an image.
The checkImage
method of Component
calls its peer's checkImage
method to calculate
the flags. If this component does not yet have a peer, the
component's toolkit's checkImage
method is called
instead.
Information on the flags returned by this method can be found
with the discussion of the ImageObserver
interface.
image
- the Image
object whose status
is being 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.ImageObserver
flags indicating what
information about the image is currently available.prepareImage(java.awt.Image, int, int, java.awt.image.ImageObserver)
,
Toolkit.checkImage(java.awt.Image, int, int, java.awt.image.ImageObserver)
,
java.awt.image.ImageObserver#_top_
public boolean contains(int x, int y)
x
and y
are defined to be
relative to the coordinate system of this component.x
- the x coordinate of the point.y
- the y coordinate of the point.getComponentAt(int, int)
public boolean inside(int x, int y)
public boolean contains(Point p)
p
- the point.getComponentAt(java.awt.Point)
public Component getComponentAt(int x, int y)
The locate
method of Component
simply
returns the component itself if the (x, y)
coordinate location is inside its bounding box, and null
otherwise.
x
- the x coordinate.y
- the y coordinate.null
if the location
is outside this component.contains(int, int)
public Component locate(int x, int y)
public Component getComponentAt(Point p)
p
- the point.contains(int, int)
public void deliverEvent(Event e)
dispatchEvent(AWTEvent e)
.
public final void dispatchEvent(AWTEvent e)
e
- the eventpublic boolean postEvent(Event e)
public void addComponentListener(ComponentListener l)
l
- the component listener.ComponentEvent
,
ComponentListener
,
removeComponentListener(java.awt.event.ComponentListener)
public void removeComponentListener(ComponentListener l)
l
- the component listener.ComponentEvent
,
ComponentListener
,
addComponentListener(java.awt.event.ComponentListener)
public void addFocusListener(FocusListener l)
l
- the focus listener.FocusEvent
,
FocusListener
,
removeFocusListener(java.awt.event.FocusListener)
public void removeFocusListener(FocusListener l)
l
- the focus listener.FocusEvent
,
FocusListener
,
addFocusListener(java.awt.event.FocusListener)
public void addKeyListener(KeyListener l)
l
- the key listener.KeyEvent
,
KeyListener
,
removeKeyListener(java.awt.event.KeyListener)
public void removeKeyListener(KeyListener l)
l
- the key listener.KeyEvent
,
KeyListener
,
addKeyListener(java.awt.event.KeyListener)
public void addMouseListener(MouseListener l)
l
- the mouse listener.MouseEvent
,
MouseListener
,
removeMouseListener(java.awt.event.MouseListener)
public void removeMouseListener(MouseListener l)
l
- the mouse listener.MouseEvent
,
MouseListener
,
addMouseListener(java.awt.event.MouseListener)
public void addMouseMotionListener(MouseMotionListener l)
l
- the mouse motion listener.java.awt.event.MouseMotionEvent
,
MouseMotionListener
,
removeMouseMotionListener(java.awt.event.MouseMotionListener)
public void removeMouseMotionListener(MouseMotionListener l)
l
- the mouse motion listener.java.awt.event.MouseMotionEvent
,
MouseMotionListener
,
addMouseMotionListener(java.awt.event.MouseMotionListener)
public void addInputMethodListener(InputMethodListener l)
l
- the input method listener.InputMethodEvent
,
InputMethodListener
,
removeInputMethodListener(java.awt.event.InputMethodListener)
,
getInputMethodRequests()
public void removeInputMethodListener(InputMethodListener l)
l
- the input method listener.InputMethodEvent
,
InputMethodListener
,
addInputMethodListener(java.awt.event.InputMethodListener)
public InputMethodRequests getInputMethodRequests()
addInputMethodListener(java.awt.event.InputMethodListener)
public InputContext getInputContext()
protected final void enableEvents(long eventsToEnable)
Event types are automatically enabled when a listener for that event type is added to the component.
This method only needs to be invoked by subclasses of
Component
which desire to have the specified event
types delivered to processEvent
regardless of whether
or not a listener is registered.
eventsToEnable
- the event mask defining the event types.processEvent(java.awt.AWTEvent)
,
disableEvents(long)
protected final void disableEvents(long eventsToDisable)
eventsToDisable
- the event mask defining the event typesenableEvents(long)
protected AWTEvent coalesceEvents(AWTEvent existingEvent, AWTEvent newEvent)
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 where the update rectangle of one paint event is completely contained within the update rectangle of the other paint event, the event with the smaller rectangle is discarded.
existingEvent
- the event already on the EventQueue.newEvent
- the event being posted to the EventQueue.protected void processEvent(AWTEvent e)
process<event type>Event
method for the given class of event.e
- the event.processComponentEvent(java.awt.event.ComponentEvent)
,
processFocusEvent(java.awt.event.FocusEvent)
,
processKeyEvent(java.awt.event.KeyEvent)
,
processMouseEvent(java.awt.event.MouseEvent)
,
processMouseMotionEvent(java.awt.event.MouseEvent)
,
processInputMethodEvent(java.awt.event.InputMethodEvent)
protected void processComponentEvent(ComponentEvent e)
ComponentListener
objects.
This method is not called unless component events are enabled for this component. Component events are enabled when one of the following occurs:
ComponentListener
object is registered
via addComponentListener
.
enableEvents
.
e
- the component event.ComponentEvent
,
ComponentListener
,
addComponentListener(java.awt.event.ComponentListener)
,
enableEvents(long)
protected void processFocusEvent(FocusEvent e)
FocusListener
objects.
This method is not called unless focus events are enabled for this component. Focus events are enabled when one of the following occurs:
FocusListener
object is registered
via addFocusListener
.
enableEvents
.
e
- the focus event.FocusEvent
,
FocusListener
,
addFocusListener(java.awt.event.FocusListener)
,
enableEvents(long)
protected void processKeyEvent(KeyEvent e)
KeyListener
objects.
This method is not called unless key events are enabled for this component. Key events are enabled when one of the following occurs:
KeyListener
object is registered
via addKeyListener
.
enableEvents
.
e
- the key event.KeyEvent
,
KeyListener
,
addKeyListener(java.awt.event.KeyListener)
,
enableEvents(long)
protected void processMouseEvent(MouseEvent e)
MouseListener
objects.
This method is not called unless mouse events are enabled for this component. Mouse events are enabled when one of the following occurs:
MouseListener
object is registered
via addMouseListener
.
enableEvents
.
e
- the mouse event.MouseEvent
,
MouseListener
,
addMouseListener(java.awt.event.MouseListener)
,
enableEvents(long)
protected void processMouseMotionEvent(MouseEvent e)
MouseMotionListener
objects.
This method is not called unless mouse motion events are enabled for this component. Mouse motion events are enabled when one of the following occurs:
MouseMotionListener
object is registered
via addMouseMotionListener
.
enableEvents
.
e
- the mouse motion event.java.awt.event.MouseMotionEvent
,
MouseMotionListener
,
addMouseMotionListener(java.awt.event.MouseMotionListener)
,
enableEvents(long)
protected void processInputMethodEvent(InputMethodEvent e)
InputMethodListener
objects.
This method is not called unless input method events are enabled for this component. Input method events are enabled when one of the following occurs:
InputMethodListener
object is registered
via addInputMethodListener
.
enableEvents
.
e
- the input method eventInputMethodEvent
,
InputMethodListener
,
addInputMethodListener(java.awt.event.InputMethodListener)
,
enableEvents(long)
public boolean handleEvent(Event evt)
public boolean mouseDown(Event evt, int x, int y)
public boolean mouseDrag(Event evt, int x, int y)
public boolean mouseUp(Event evt, int x, int y)
public boolean mouseMove(Event evt, int x, int y)
public boolean mouseEnter(Event evt, int x, int y)
public boolean mouseExit(Event evt, int x, int y)
public boolean keyDown(Event evt, int key)
public boolean keyUp(Event evt, int key)
public boolean action(Event evt, Object what)
public void addNotify()
isDisplayable()
,
removeNotify()
public void removeNotify()
isDisplayable()
,
addNotify()
public boolean gotFocus(Event evt, Object what)
public boolean lostFocus(Event evt, Object what)
public boolean isFocusTraversable()
requestFocus()
, but it will not automatically
be assigned focus during tab traversal.true
if this component is
focus-traverable; false
otherwise.public void requestFocus()
FocusEvent
,
addFocusListener(java.awt.event.FocusListener)
,
processFocusEvent(java.awt.event.FocusEvent)
,
isFocusTraversable()
public void transferFocus()
requestFocus()
public void nextFocus()
public boolean hasFocus()
public void add(PopupMenu popup)
popup
- the popup menu to be added to the component.remove(java.awt.MenuComponent)
public void remove(MenuComponent popup)
popup
- the popup menu to be removed.add(java.awt.PopupMenu)
protected String paramString()
null
.public String toString()
public void list()
System.out
.System.out
public void list(PrintStream out)
out
- a print stream.public void list(PrintStream out, int indent)
out
- a print stream.indent
- number of spaces to indent.PrintStream.println(java.lang.Object)
public void list(PrintWriter out)
out
- The print writer to print to.public void list(PrintWriter out, int indent)
out
- The print writer to print to.indent
- The number of spaces to indent.PrintStream.println(java.lang.Object)
public void addPropertyChangeListener(PropertyChangeListener listener)
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.
listener
- The PropertyChangeListener to be addedpublic void removePropertyChangeListener(PropertyChangeListener listener)
listener
- The PropertyChangeListener to be removedpublic void addPropertyChangeListener(String propertyName, PropertyChangeListener listener)
propertyName
- The name of the property to listen on.listener
- The PropertyChangeListener to be addedpublic void removePropertyChangeListener(String propertyName, PropertyChangeListener listener)
propertyName
- The name of the property that was listened on.listener
- The PropertyChangeListener to be removedprotected void firePropertyChange(String propertyName, Object oldValue, Object newValue)
public void setComponentOrientation(ComponentOrientation o)
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.
ComponentOrientation
,
java.awt.Window#ApplyResourceBundle(java.util.ResourceBundle)
public ComponentOrientation getComponentOrientation()
ComponentOrientation
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