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java.lang.Object | +----java.awt.Component
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.
BOTTOM_ALIGNMENT
getAlignmentY.
CENTER_ALIGNMENT
getAlignmentY and
getAlignmentX.
LEFT_ALIGNMENT
getAlignmentX.
RIGHT_ALIGNMENT
getAlignmentX.
TOP_ALIGNMENT
getAlignmentY().
Component()
action(Event, Object)
add(PopupMenu)
addComponentListener(ComponentListener)
addFocusListener(FocusListener)
addKeyListener(KeyListener)
addMouseListener(MouseListener)
addMouseMotionListener(MouseMotionListener)
addNotify()
bounds()
checkImage(Image, ImageObserver)
checkImage(Image, int, int, ImageObserver)
contains(int, int)
x and y are defined to be
relative to the coordinate system of this component.
contains(Point)
createImage(ImageProducer)
createImage(int, int)
deliverEvent(Event)
disable()
disableEvents(long)
dispatchEvent(AWTEvent)
doLayout()
enable()
enable(boolean)
enableEvents(long)
getAlignmentX()
getAlignmentY()
getBackground()
getBounds()
Rectangle object.
getColorModel()
ColorModel used to display
the component on the output device.
getComponentAt(int, int)
getComponentAt(Point)
getCursor()
getFont()
getFontMetrics(Font)
getForeground()
getGraphics()
getLocale()
getLocation()
getLocationOnScreen()
getMaximumSize()
getMinimumSize()
getName()
getParent()
getPeer()
getPreferredSize()
getSize()
Dimension object.
getToolkit()
getTreeLock()
gotFocus(Event, Object)
handleEvent(Event)
hide()
imageUpdate(Image, int, int, int, int, int)
inside(int, int)
invalidate()
isEnabled()
isFocusTraversable()
isShowing()
isValid()
isVisible()
keyDown(Event, int)
keyUp(Event, int)
layout()
list()
System.out.
list(PrintStream)
list(PrintStream, int)
list(PrintWriter)
list(PrintWriter, int)
locate(int, int)
location()
lostFocus(Event, Object)
minimumSize()
mouseDown(Event, int, int)
mouseDrag(Event, int, int)
mouseEnter(Event, int, int)
mouseExit(Event, int, int)
mouseMove(Event, int, int)
mouseUp(Event, int, int)
move(int, int)
nextFocus()
paint(Graphics)
paintAll(Graphics)
paramString()
postEvent(Event)
preferredSize()
prepareImage(Image, ImageObserver)
prepareImage(Image, int, int, ImageObserver)
print(Graphics)
printAll(Graphics)
processComponentEvent(ComponentEvent)
ComponentListener objects.
processEvent(AWTEvent)
processFocusEvent(FocusEvent)
FocusListener objects.
processKeyEvent(KeyEvent)
processMouseEvent(MouseEvent)
MouseListener objects.
processMouseMotionEvent(MouseEvent)
MouseMotionListener objects.
remove(MenuComponent)
removeComponentListener(ComponentListener)
removeFocusListener(FocusListener)
removeKeyListener(KeyListener)
removeMouseListener(MouseListener)
removeMouseMotionListener(MouseMotionListener)
removeNotify()
repaint()
repaint(int, int, int, int)
repaint(long)
repaint(long, int, int, int, int)
tm milliseconds.
requestFocus()
reshape(int, int, int, int)
resize(Dimension)
resize(int, int)
setBackground(Color)
setBounds(int, int, int, int)
setBounds(Rectangle)
r.
setCursor(Cursor)
setEnabled(boolean)
b.
setFont(Font)
setForeground(Color)
setLocale(Locale)
setLocation(int, int)
setLocation(Point)
setName(String)
setSize(Dimension)
d.width
and height d.height.
setSize(int, int)
width
and height.
setVisible(boolean)
b.
show()
show(boolean)
size()
toString()
transferFocus()
update(Graphics)
validate()
TOP_ALIGNMENT
public static final float TOP_ALIGNMENT
getAlignmentY(). Specifies an
alignment to the top of the component.
CENTER_ALIGNMENT
public static final float CENTER_ALIGNMENT
getAlignmentY and
getAlignmentX. Specifies an alignment to
the center of the component
BOTTOM_ALIGNMENT
public static final float BOTTOM_ALIGNMENT
getAlignmentY. Specifies an
alignment to the bottom of the component.
LEFT_ALIGNMENT
public static final float LEFT_ALIGNMENT
getAlignmentX. Specifies an
alignment to the left side of the component.
RIGHT_ALIGNMENT
public static final float RIGHT_ALIGNMENT
getAlignmentX. Specifies an
alignment to the right side of the component.
Component
protected Component()
Component can be
extended directly to create a lightweight component that does not
utilize an opaque native window. A lightweight component must be
hosted by a native container somewhere higher up in the component
tree (for example, by a Frame object).
getName
public String getName()
setName
public void setName(String name)
name - The string that is to be this
component's name.
getParent
public Container getParent()
getPeer
public ComponentPeer getPeer()
getTreeLock
public final Object getTreeLock()
getToolkit
public Toolkit getToolkit()
isValid
public boolean isValid()
true if the component is valid; false
otherwise.
isVisible
public boolean isVisible()
Frame objects.
true if the component is visible;
false otherwise.
isShowing
public boolean isShowing()
true if the component is showing;
false otherwise.
isEnabled
public boolean isEnabled()
setEnabled method.
true if the component is enabled;
false otherwise.
setEnabled
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.
enable
public void enable()
setEnabled(boolean).
enable
public void enable(boolean b)
setEnabled(boolean).
disable
public void disable()
setEnabled(boolean).
setVisible
public void setVisible(boolean b)
b.
b - If true, shows this component;
otherwise, hides this component.
show
public void show()
setVisible(boolean).
show
public void show(boolean b)
setVisible(boolean).
hide
public void hide()
setVisible(boolean).
getForeground
public Color getForeground()
setForeground
public void setForeground(Color c)
c - The color to become this component's
foreground color.
getBackground
public Color getBackground()
setBackground
public void setBackground(Color c)
c - The color to become this component's
background color.
getFont
public Font getFont()
setFont
public synchronized void setFont(Font f)
f - The font to become this component's font.
getLocale
public Locale getLocale()
setLocale
public void setLocale(Locale l)
l - The locale to become this component's locale.
getColorModel
public ColorModel getColorModel()
ColorModel used to display
the component on the output device.
getLocation
public Point getLocation()
Point representing
the top-left corner of the component's bounds in the coordinate
space of the component's parent.
getLocationOnScreen
public Point getLocationOnScreen()
Point representing
the top-left corner of the component's bounds in the
coordinate space of the screen.
location
public Point location()
getLocation().
setLocation
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.
move
public void move(int x,
int y)
setLocation(int, int).
setLocation
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.
getSize
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.
size
public Dimension size()
getSize().
setSize
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.
resize
public void resize(int width,
int height)
setSize(int, int).
setSize
public void setSize(Dimension d)
d.width
and height d.height.
d - The dimension specifying the new size
of this component.
resize
public void resize(Dimension d)
setSize(Dimension).
getBounds
public Rectangle getBounds()
Rectangle object. The bounds specify this
component's width, height, and location relative to
its parent.
bounds
public Rectangle bounds()
getBounds().
setBounds
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.
reshape
public void reshape(int x,
int y,
int width,
int height)
setBounds(int, int, int, int).
setBounds
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.
getPreferredSize
public Dimension getPreferredSize()
preferredSize
public Dimension preferredSize()
getPreferredSize().
getMinimumSize
public Dimension getMinimumSize()
minimumSize
public Dimension minimumSize()
getMinimumSize().
getMaximumSize
public Dimension getMaximumSize()
getAlignmentX
public float getAlignmentX()
getAlignmentY
public float getAlignmentY()
doLayout
public void doLayout()
layout
public void layout()
doLayout().
validate
public void validate()
Container.
invalidate
public void invalidate()
getGraphics
public Graphics getGraphics()
null if this component is currently not on
the screen.
null
if it has none.
getFontMetrics
public FontMetrics getFontMetrics(Font font)
font - The font for which font metrics is to be
obtained.
font.
setCursor
public synchronized void setCursor(Cursor cursor)
cursor - One of the constants defined
by the Cursor class.
getCursor
public Cursor getCursor()
paint
public void paint(Graphics g)
g - The graphics context to use for painting.
update
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 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
paintmethod 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.
paintAll
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.
repaint
public void repaint()
This method causes a call to this component's update
method as soon as possible.
repaint
public void repaint(long tm)
update within tm milliseconds.
repaint
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.
repaint
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.
print
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.
printAll
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.
imageUpdate
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.
imageUpdate for more information.
true if the flags indicate that the
image is completely loaded;
false otherwise.
createImage
public Image createImage(ImageProducer producer)
createImage
public Image createImage(int width,
int height)
prepareImage
public boolean prepareImage(Image image,
ImageObserver observer)
Image for which to
prepare a screen representation.
ImageObserver object
to be notified as the image is being prepared.
true if the image has already been fully prepared;
false otherwise.
prepareImage
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
for which to prepare a screen representation.
ImageObserver object
to be notified as the image is being prepared.
true if the image has already been fully prepared;
false otherwise.
checkImage
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 object whose status
is being checked.
ImageObserver
object to be notified as the image is being prepared.
ImageObserver flags indicating what
information about the image is currently available.
checkImage
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 object whose status
is being checked.
ImageObserver object
to be notified as the image is being prepared.
ImageObserver flags indicating what
information about the image is currently available.
contains
public boolean contains(int x,
int y)
x and y are defined to be
relative to the coordinate system of this component.
inside
public boolean inside(int x,
int y)
contains
public boolean contains(Point p)
getComponentAt
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.
null if the location
is outside this component.
locate
public Component locate(int x,
int y)
getComponentAt
public Component getComponentAt(Point p)
deliverEvent
public void deliverEvent(Event e)
dispatchEvent(AWTEvent e).
dispatchEvent
public final void dispatchEvent(AWTEvent e)
postEvent
public boolean postEvent(Event e)
addComponentListener
public synchronized void addComponentListener(ComponentListener l)
removeComponentListener
public synchronized void removeComponentListener(ComponentListener l)
addFocusListener
public synchronized void addFocusListener(FocusListener l)
removeFocusListener
public synchronized void removeFocusListener(FocusListener l)
addKeyListener
public synchronized void addKeyListener(KeyListener l)
removeKeyListener
public synchronized void removeKeyListener(KeyListener l)
addMouseListener
public synchronized void addMouseListener(MouseListener l)
removeMouseListener
public synchronized void removeMouseListener(MouseListener l)
addMouseMotionListener
public synchronized void addMouseMotionListener(MouseMotionListener l)
removeMouseMotionListener
public synchronized void removeMouseMotionListener(MouseMotionListener l)
enableEvents
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.
disableEvents
protected final void disableEvents(long eventsToDisable)
processEvent
protected void processEvent(AWTEvent e)
process<event type>Event
method for the given class of event.
processComponentEvent
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.
processFocusEvent
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.
processKeyEvent
protected void processKeyEvent(KeyEvent e)
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.
processMouseEvent
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.
processMouseMotionEvent
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.
handleEvent
public boolean handleEvent(Event evt)
mouseDown
public boolean mouseDown(Event evt,
int x,
int y)
mouseDrag
public boolean mouseDrag(Event evt,
int x,
int y)
mouseUp
public boolean mouseUp(Event evt,
int x,
int y)
mouseMove
public boolean mouseMove(Event evt,
int x,
int y)
mouseEnter
public boolean mouseEnter(Event evt,
int x,
int y)
mouseExit
public boolean mouseExit(Event evt,
int x,
int y)
keyDown
public boolean keyDown(Event evt,
int key)
keyUp
public boolean keyUp(Event evt,
int key)
action
public boolean action(Event evt,
Object what)
addNotify
public void addNotify()
Container.add, and
not by user code directly.
removeNotify
public void removeNotify()
Container.remove,
and not by user code directly.
gotFocus
public boolean gotFocus(Event evt,
Object what)
lostFocus
public boolean lostFocus(Event evt,
Object what)
isFocusTraversable
public boolean isFocusTraversable()
requestFocus(), but it will not automatically
be assigned focus during tab traversal.
true if this component is
focus-traverable; false otherwise.
requestFocus
public void requestFocus()
This component's gotFocus method is called when this
method is successful. The component must be visible
on the screen for this request to be granted
transferFocus
public void transferFocus()
nextFocus
public void nextFocus()
add
public synchronized void add(PopupMenu popup)
remove
public synchronized void remove(MenuComponent popup)
paramString
protected String paramString()
toString
public String toString()
list
public void list()
System.out.
list
public void list(PrintStream out)
list
public void list(PrintStream out,
int indent)
list
public void list(PrintWriter out)
list
public void list(PrintWriter out,
int indent)
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