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