- All Implemented Interfaces:
ImageObserver
,MenuContainer
,Serializable
- Direct Known Subclasses:
AbstractButton
,BasicInternalFrameTitlePane
,Box
,Box.Filler
,JColorChooser
,JComboBox
,JFileChooser
,JInternalFrame
,JInternalFrame.JDesktopIcon
,JLabel
,JLayer
,JLayeredPane
,JList
,JMenuBar
,JOptionPane
,JPanel
,JPopupMenu
,JProgressBar
,JRootPane
,JScrollBar
,JScrollPane
,JSeparator
,JSlider
,JSpinner
,JSplitPane
,JTabbedPane
,JTable
,JTableHeader
,JTextComponent
,JToolBar
,JToolTip
,JTree
,JViewport
JComponent
,
you must place the component in a containment hierarchy
whose root is a top-level Swing container.
Top-level Swing containers --
such as JFrame
, JDialog
,
and JApplet
--
are specialized components
that provide a place for other Swing components to paint themselves.
For an explanation of containment hierarchies, see
Swing Components and the Containment Hierarchy,
a section in The Java Tutorial.
The JComponent
class provides:
- The base class for both standard and custom components that use the Swing architecture.
- A "pluggable look and feel" (L&F) that can be specified by the
programmer or (optionally) selected by the user at runtime.
The look and feel for each component is provided by a
UI delegate -- an object that descends from
ComponentUI
. See How to Set the Look and Feel in The Java Tutorial for more information. - Comprehensive keystroke handling. See the document How to Use Key Bindings, an article in The Java Tutorial, for more information.
- Support for tool tips -- short descriptions that pop up when the cursor lingers over a component. See How to Use Tool Tips in The Java Tutorial for more information.
- Support for accessibility.
JComponent
contains all of the methods in theAccessible
interface, but it doesn't actually implement the interface. That is the responsibility of the individual classes that extendJComponent
. - Support for component-specific properties.
With the
putClientProperty(java.lang.Object, java.lang.Object)
andgetClientProperty(java.lang.Object)
methods, you can associate name-object pairs with any object that descends fromJComponent
. - An infrastructure for painting that includes double buffering and support for borders. For more information see Painting and How to Use Borders, both of which are sections in The Java Tutorial.
Swing package description
and The Java Tutorial section
The JComponent Class.
JComponent
and its subclasses document default values
for certain properties. For example, JTable
documents the
default row height as 16. Each JComponent
subclass
that has a ComponentUI
will create the
ComponentUI
as part of its constructor. In order
to provide a particular look and feel each
ComponentUI
may set properties back on the
JComponent
that created it. For example, a custom
look and feel may require JTable
s to have a row
height of 24. The documented defaults are the value of a property
BEFORE the ComponentUI
has been installed. If you
need a specific value for a particular property you should
explicitly set it.
A JComponent
may contain any number of default or initial
components as children. This behaviour may change according to look and
feel, therefore a JComponent
may contain some default or
initial components as children for a particular Look and Feel, whereas it
may not do so for some other Look and Feel. Within a particular Look and
Feel also, this behaviour may change depending upon the configuration
properties of the JComponent
. In summary, it is not valid
to assume a JComponent has no children just because the application
did not directly add them.
In release 1.4, the focus subsystem was rearchitected. For more information, see How to Use the Focus Subsystem, a section in The Java Tutorial.
Warning: Swing is not thread safe. For more information see Swing's Threading Policy.
Warning:
Serialized objects of this class will not be compatible with
future Swing releases. The current serialization support is
appropriate for short term storage or RMI between applications running
the same version of Swing. As of 1.4, support for long term storage
of all JavaBeans
has been added to the java.beans
package.
Please see XMLEncoder
.
- Since:
- 1.2
- See Also:
-
Nested Class Summary
Modifier and TypeClassDescriptionclass
Inner class of JComponent used to provide default support for accessibility.Nested classes/interfaces declared in class java.awt.Container
Container.AccessibleAWTContainer
Nested classes/interfaces declared in class java.awt.Component
Component.AccessibleAWTComponent, Component.BaselineResizeBehavior, Component.BltBufferStrategy, Component.FlipBufferStrategy
-
Field Summary
Modifier and TypeFieldDescriptionprotected EventListenerList
A list of event listeners for this component.static final String
The comment to display when the cursor is over the component, also known as a "value tip", "flyover help", or "flyover label".protected ComponentUI
The look and feel delegate for this component.static final int
Constant used by some of the APIs to mean that no condition is defined.static final int
Constant used forregisterKeyboardAction
that means that the command should be invoked when the receiving component is an ancestor of the focused component or is itself the focused component.static final int
Constant used forregisterKeyboardAction
that means that the command should be invoked when the component has the focus.static final int
Constant used forregisterKeyboardAction
that means that the command should be invoked when the receiving component is in the window that has the focus or is itself the focused component.Fields declared in class java.awt.Component
accessibleContext, BOTTOM_ALIGNMENT, CENTER_ALIGNMENT, LEFT_ALIGNMENT, RIGHT_ALIGNMENT, TOP_ALIGNMENT
Fields declared in interface java.awt.image.ImageObserver
ABORT, ALLBITS, ERROR, FRAMEBITS, HEIGHT, PROPERTIES, SOMEBITS, WIDTH
-
Constructor Summary
-
Method Summary
Modifier and TypeMethodDescriptionvoid
addAncestorListener
(AncestorListener listener) Registerslistener
so that it will receiveAncestorEvents
when it or any of its ancestors move or are made visible or invisible.void
Notifies this component that it now has a parent component.void
Adds aVetoableChangeListener
to the listener list.void
computeVisibleRect
(Rectangle visibleRect) Returns theComponent
's "visible rect rectangle" - the intersection of the visible rectangles for this component and all of its ancestors.boolean
contains
(int x, int y) Gives the UI delegate an opportunity to define the precise shape of this component for the sake of mouse processing.Returns the instance ofJToolTip
that should be used to display the tooltip.void
disable()
Deprecated.void
enable()
Deprecated.As of JDK version 1.1, replaced byjava.awt.Component.setEnabled(boolean)
.void
firePropertyChange
(String propertyName, boolean oldValue, boolean newValue) Support for reporting bound property changes for boolean properties.void
firePropertyChange
(String propertyName, int oldValue, int newValue) Support for reporting bound property changes for integer properties.protected void
fireVetoableChange
(String propertyName, Object oldValue, Object newValue) Supports reporting constrained property changes.getActionForKeyStroke
(KeyStroke aKeyStroke) Returns the object that will perform the action registered for a given keystroke.final ActionMap
Returns theActionMap
used to determine whatAction
to fire for particularKeyStroke
binding.float
OverridesContainer.getAlignmentX
to return the horizontal alignment.float
OverridesContainer.getAlignmentY
to return the vertical alignment.Returns an array of all the ancestor listeners registered on this component.boolean
Gets theautoscrolls
property.int
getBaseline
(int width, int height) Returns the baseline.Returns an enum indicating how the baseline of the component changes as the size changes.Returns the border of this component ornull
if no border is currently set.Stores the bounds of this component into "return value"rv
and returnsrv
.final Object
getClientProperty
(Object key) Returns the value of the property with the specified key.protected Graphics
Returns the graphics object used to paint this component.ReturnsJPopupMenu
that assigned for this component.int
getConditionForKeyStroke
(KeyStroke aKeyStroke) Returns the condition that determines whether a registered action occurs in response to the specified keystroke.int
Returns the state of graphics debugging.static Locale
Returns the default locale used to initialize each JComponent's locale property upon creation.getFontMetrics
(Font font) Gets theFontMetrics
for the specifiedFont
.Returns this component's graphics context, which lets you draw on a component.int
Returns the current height of this component.boolean
Returns true if the JPopupMenu should be inherited from the parent.final InputMap
Returns theInputMap
that is used when the component has focus.final InputMap
getInputMap
(int condition) Returns theInputMap
that is used duringcondition
.Returns the input verifier for this component.If a border has been set on this component, returns the border's insets; otherwise callssuper.getInsets
.Returns anInsets
object containing this component's inset values.<T extends EventListener>
T[]getListeners
(Class<T> listenerType) Returns an array of all the objects currently registered asFooListener
s upon thisJComponent
.getLocation
(Point rv) Stores the x,y origin of this component into "return value"rv
and returnsrv
.If the maximum size has been set to a non-null
value just returns it.If the minimum size has been set to a non-null
value just returns it.Deprecated.As of 1.4, replaced byFocusTraversalPolicy
.getPopupLocation
(MouseEvent event) Returns the preferred location to display the popup menu in this component's coordinate system.If thepreferredSize
has been set to a non-null
value just returns it.Returns theKeyStrokes
that will initiate registered actions.Returns theJRootPane
ancestor for this component.Stores the width/height of this component into "return value"rv
and returnsrv
.getToolTipLocation
(MouseEvent event) Returns the tooltip location in this component's coordinate system.Returns the tooltip string that has been set withsetToolTipText
.getToolTipText
(MouseEvent event) Returns the string to be used as the tooltip for event.Returns the top-level ancestor of this component (either the containingWindow
orApplet
), ornull
if this component has not been added to any container.Gets thetransferHandler
property.getUI()
Returns the look and feel delegate that renders this component.Returns theUIDefaults
key used to look up the name of theswing.plaf.ComponentUI
class that defines the look and feel for this component.boolean
Returns the value that indicates whether the input verifier for the current focus owner will be called before this component requests focus.Returns an array of all the vetoable change listeners registered on this component.Returns theComponent
's "visible rectangle" - the intersection of this component's visible rectangle,new Rectangle(0, 0, getWidth(), getHeight())
, and all of its ancestors' visible rectangles.int
getWidth()
Returns the current width of this component.int
getX()
Returns the current x coordinate of the component's origin.int
getY()
Returns the current y coordinate of the component's origin.void
Requests that this Component get the input focus, and that this Component's top-level ancestor become the focused Window.void
hide()
Deprecated.boolean
Returns whether this component should use a buffer to paint.static boolean
Returns true if this component is lightweight, that is, if it doesn't have a native window system peer.boolean
Deprecated.As of 1.4, replaced byComponent.setFocusTraversalKeys(int, Set)
andContainer.setFocusCycleRoot(boolean)
.boolean
isOpaque()
Returns true if this component is completely opaque.boolean
Returns true if this component tiles its children -- that is, if it can guarantee that the children will not overlap.final boolean
Returnstrue
if the current painting operation on this component is part of aprint
operation.protected boolean
Returnstrue
if a paint triggered on a child component should cause painting to originate from this Component, or one of its ancestors.boolean
Returns true if the component is currently painting a tile.boolean
Returnstrue
if thisJComponent
should get focus; otherwise returnsfalse
.boolean
If this method returns true,revalidate
calls by descendants of this component will cause the entire tree beginning with this root to be validated.void
Invoked by Swing to draw components.protected void
Paints the component's border.protected void
Paints this component's children.protected void
Calls the UI delegate's paint method, if the UI delegate is non-null
.void
paintImmediately
(int x, int y, int w, int h) Paints the specified region in this component and all of its descendants that overlap the region, immediately.void
Paints the specified region now.protected String
Returns a string representation of thisJComponent
.void
Invoke this method to print the component to the specifiedGraphics
.void
Invoke this method to print the component.protected void
Prints the component's border.protected void
Prints this component's children.protected void
This is invoked during a printing operation.protected void
Processes any key events that the component itself recognizes.protected boolean
processKeyBinding
(KeyStroke ks, KeyEvent e, int condition, boolean pressed) Invoked to process the key bindings forks
as the result of theKeyEvent
e
.protected void
OverridesprocessKeyEvent
to process events.protected void
Processes mouse events occurring on this component by dispatching them to any registeredMouseListener
objects, refer toComponent.processMouseEvent(MouseEvent)
for a complete description of this method.protected void
Processes mouse motion events, such as MouseEvent.MOUSE_DRAGGED.final void
putClientProperty
(Object key, Object value) Adds an arbitrary key/value "client property" to this component.void
registerKeyboardAction
(ActionListener anAction, String aCommand, KeyStroke aKeyStroke, int aCondition) This method is now obsolete, please use a combination ofgetActionMap()
andgetInputMap()
for similar behavior.void
registerKeyboardAction
(ActionListener anAction, KeyStroke aKeyStroke, int aCondition) This method is now obsolete, please use a combination ofgetActionMap()
andgetInputMap()
for similar behavior.void
removeAncestorListener
(AncestorListener listener) Unregisterslistener
so that it will no longer receiveAncestorEvents
.void
Notifies this component that it no longer has a parent component.void
Removes aVetoableChangeListener
from the listener list.void
repaint
(long tm, int x, int y, int width, int height) Adds the specified region to the dirty region list if the component is showing.void
Adds the specified region to the dirty region list if the component is showing.boolean
Deprecated.As of 1.4, replaced byFocusTraversalPolicy.getDefaultComponent(Container).requestFocus()
void
Requests that thisComponent
gets the input focus.boolean
requestFocus
(boolean temporary) Requests that thisComponent
gets the input focus.boolean
Requests that thisComponent
gets the input focus.protected boolean
requestFocusInWindow
(boolean temporary) Requests that thisComponent
gets the input focus.void
Unregisters all the bindings in the first tierInputMaps
andActionMap
.void
reshape
(int x, int y, int w, int h) Deprecated.As of JDK 5, replaced byComponent.setBounds(int, int, int, int)
.void
Supports deferred automatic layout.void
scrollRectToVisible
(Rectangle aRect) Forwards thescrollRectToVisible()
message to theJComponent
's parent.final void
Sets theActionMap
toam
.void
setAlignmentX
(float alignmentX) Sets the horizontal alignment.void
setAlignmentY
(float alignmentY) Sets the vertical alignment.void
setAutoscrolls
(boolean autoscrolls) Sets theautoscrolls
property.void
setBackground
(Color bg) Sets the background color of this component.void
Sets the border of this component.void
setComponentPopupMenu
(JPopupMenu popup) Sets theJPopupMenu
for thisJComponent
.void
setDebugGraphicsOptions
(int debugOptions) Enables or disables diagnostic information about every graphics operation performed within the component or one of its children.static void
Sets the default locale used to initialize each JComponent's locale property upon creation.void
setDoubleBuffered
(boolean aFlag) Sets whether this component should use a buffer to paint.void
setEnabled
(boolean enabled) Sets whether or not this component is enabled.void
setFocusTraversalKeys
(int id, Set<? extends AWTKeyStroke> keystrokes) Sets the focus traversal keys for a given traversal operation for this Component.void
Sets the font for this component.void
setForeground
(Color fg) Sets the foreground color of this component.void
setInheritsPopupMenu
(boolean value) Sets whether or notgetComponentPopupMenu
should delegate to the parent if this component does not have aJPopupMenu
assigned to it.final void
setInputMap
(int condition, InputMap map) Sets theInputMap
to use under the conditioncondition
tomap
.void
setInputVerifier
(InputVerifier inputVerifier) Sets the input verifier for this component.void
setMaximumSize
(Dimension maximumSize) Sets the maximum size of this component to a constant value.void
setMinimumSize
(Dimension minimumSize) Sets the minimum size of this component to a constant value.void
setNextFocusableComponent
(Component aComponent) Deprecated.As of 1.4, replaced byFocusTraversalPolicy
void
setOpaque
(boolean isOpaque) If true the component paints every pixel within its bounds.void
setPreferredSize
(Dimension preferredSize) Sets the preferred size of this component.void
setRequestFocusEnabled
(boolean requestFocusEnabled) Provides a hint as to whether or not thisJComponent
should get focus.void
setToolTipText
(String text) Registers the text to display in a tool tip.void
setTransferHandler
(TransferHandler newHandler) Sets theTransferHandler
, which provides support for transfer of data into and out of this component via cut/copy/paste and drag and drop.protected void
setUI
(ComponentUI newUI) Sets the look and feel delegate for this component.void
setVerifyInputWhenFocusTarget
(boolean verifyInputWhenFocusTarget) Sets the value to indicate whether input verifier for the current focus owner will be called before this component requests focus.void
setVisible
(boolean aFlag) Makes the component visible or invisible.void
unregisterKeyboardAction
(KeyStroke aKeyStroke) This method is now obsolete.void
Callspaint
.void
updateUI()
This method is called to update the UI property to a value from the current look and feel.Methods declared in class java.awt.Container
add, add, add, add, add, addContainerListener, addImpl, addPropertyChangeListener, addPropertyChangeListener, applyComponentOrientation, areFocusTraversalKeysSet, countComponents, deliverEvent, doLayout, findComponentAt, findComponentAt, getComponent, getComponentAt, getComponentAt, getComponentCount, getComponents, getComponentZOrder, getContainerListeners, getFocusTraversalKeys, getFocusTraversalPolicy, getLayout, getMousePosition, insets, invalidate, isAncestorOf, isFocusCycleRoot, isFocusCycleRoot, isFocusTraversalPolicyProvider, isFocusTraversalPolicySet, layout, list, list, locate, minimumSize, paintComponents, preferredSize, printComponents, processContainerEvent, processEvent, remove, remove, removeAll, removeContainerListener, setComponentZOrder, setFocusCycleRoot, setFocusTraversalPolicy, setFocusTraversalPolicyProvider, setLayout, transferFocusDownCycle, validate, validateTree
Methods declared in class java.awt.Component
action, add, addComponentListener, addFocusListener, addHierarchyBoundsListener, addHierarchyListener, addInputMethodListener, addKeyListener, addMouseListener, addMouseMotionListener, addMouseWheelListener, bounds, checkImage, checkImage, coalesceEvents, contains, createImage, createImage, createVolatileImage, createVolatileImage, disableEvents, dispatchEvent, enable, enableEvents, enableInputMethods, firePropertyChange, firePropertyChange, firePropertyChange, firePropertyChange, firePropertyChange, firePropertyChange, firePropertyChange, getAccessibleContext, getBackground, getBounds, getColorModel, getComponentListeners, getComponentOrientation, getCursor, getDropTarget, getFocusCycleRootAncestor, getFocusListeners, getFocusTraversalKeysEnabled, getFont, getForeground, getGraphicsConfiguration, getHierarchyBoundsListeners, getHierarchyListeners, getIgnoreRepaint, getInputContext, getInputMethodListeners, getInputMethodRequests, getKeyListeners, getLocale, getLocation, getLocationOnScreen, getMouseListeners, getMouseMotionListeners, getMousePosition, getMouseWheelListeners, getName, getParent, getPropertyChangeListeners, getPropertyChangeListeners, getSize, getToolkit, getTreeLock, gotFocus, handleEvent, hasFocus, imageUpdate, inside, isBackgroundSet, isCursorSet, isDisplayable, isEnabled, isFocusable, isFocusOwner, isFocusTraversable, isFontSet, isForegroundSet, isLightweight, isMaximumSizeSet, isMinimumSizeSet, isPreferredSizeSet, isShowing, isValid, isVisible, keyDown, keyUp, list, list, list, location, lostFocus, mouseDown, mouseDrag, mouseEnter, mouseExit, mouseMove, mouseUp, move, nextFocus, paintAll, postEvent, prepareImage, prepareImage, processComponentEvent, processFocusEvent, processHierarchyBoundsEvent, processHierarchyEvent, processInputMethodEvent, processMouseWheelEvent, remove, removeComponentListener, removeFocusListener, removeHierarchyBoundsListener, removeHierarchyListener, removeInputMethodListener, removeKeyListener, removeMouseListener, removeMouseMotionListener, removeMouseWheelListener, removePropertyChangeListener, removePropertyChangeListener, repaint, repaint, repaint, requestFocus, requestFocus, requestFocusInWindow, resize, resize, setBounds, setBounds, setComponentOrientation, setCursor, setDropTarget, setFocusable, setFocusTraversalKeysEnabled, setIgnoreRepaint, setLocale, setLocation, setLocation, setMixingCutoutShape, setName, setSize, setSize, show, show, size, toString, transferFocus, transferFocusBackward, transferFocusUpCycle
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Field Details
-
ui
The look and feel delegate for this component. -
listenerList
A list of event listeners for this component. -
WHEN_FOCUSED
public static final int WHEN_FOCUSEDConstant used forregisterKeyboardAction
that means that the command should be invoked when the component has the focus.- See Also:
-
WHEN_ANCESTOR_OF_FOCUSED_COMPONENT
public static final int WHEN_ANCESTOR_OF_FOCUSED_COMPONENTConstant used forregisterKeyboardAction
that means that the command should be invoked when the receiving component is an ancestor of the focused component or is itself the focused component.- See Also:
-
WHEN_IN_FOCUSED_WINDOW
public static final int WHEN_IN_FOCUSED_WINDOWConstant used forregisterKeyboardAction
that means that the command should be invoked when the receiving component is in the window that has the focus or is itself the focused component.- See Also:
-
UNDEFINED_CONDITION
public static final int UNDEFINED_CONDITIONConstant used by some of the APIs to mean that no condition is defined.- See Also:
-
TOOL_TIP_TEXT_KEY
The comment to display when the cursor is over the component, also known as a "value tip", "flyover help", or "flyover label".- See Also:
-
-
Constructor Details
-
JComponent
public JComponent()DefaultJComponent
constructor. This constructor does very little initialization beyond calling theContainer
constructor. For example, the initial layout manager isnull
. It does, however, set the component's locale property to the value returned byJComponent.getDefaultLocale
.- See Also:
-
-
Method Details
-
setInheritsPopupMenu
@BeanProperty(description="Whether or not the JPopupMenu is inherited") public void setInheritsPopupMenu(boolean value) Sets whether or notgetComponentPopupMenu
should delegate to the parent if this component does not have aJPopupMenu
assigned to it.The default value for this is false, but some
JComponent
subclasses that are implemented as a number ofJComponent
s may set this to true.This is a bound property.
- Parameters:
value
- whether or not the JPopupMenu is inherited- Since:
- 1.5
- See Also:
-
getInheritsPopupMenu
public boolean getInheritsPopupMenu()Returns true if the JPopupMenu should be inherited from the parent.- Returns:
- true if the JPopupMenu should be inherited from the parent
- Since:
- 1.5
- See Also:
-
setComponentPopupMenu
@BeanProperty(preferred=true, description="Popup to show") public void setComponentPopupMenu(JPopupMenu popup) Sets theJPopupMenu
for thisJComponent
. The UI is responsible for registering bindings and adding the necessary listeners such that theJPopupMenu
will be shown at the appropriate time. When theJPopupMenu
is shown depends upon the look and feel: some may show it on a mouse event, some may enable a key binding.If
popup
is null, andgetInheritsPopupMenu
returns true, thengetComponentPopupMenu
will be delegated to the parent. This provides for a way to make all child components inherit the popupmenu of the parent.This is a bound property.
- Parameters:
popup
- the popup that will be assigned to this component may be null- Since:
- 1.5
- See Also:
-
getComponentPopupMenu
ReturnsJPopupMenu
that assigned for this component. If this component does not have aJPopupMenu
assigned to it andgetInheritsPopupMenu
is true, this will returngetParent().getComponentPopupMenu()
(assuming the parent is valid.)- Returns:
JPopupMenu
assigned for this component ornull
if no popup assigned- Since:
- 1.5
- See Also:
-
updateUI
public void updateUI()This method is called to update the UI property to a value from the current look and feel.JComponent
subclasses must override this method like this:public void updateUI() { setUI((SliderUI)UIManager.getUI(this); }
- Implementation Requirements:
- The default implementation of this method does nothing.
- See Also:
-
getUI
Returns the look and feel delegate that renders this component.- Returns:
- the
ComponentUI
object that renders this component - Since:
- 9
-
setUI
@BeanProperty(hidden=true, visualUpdate=true, description="The component\'s look and feel delegate.") protected void setUI(ComponentUI newUI) Sets the look and feel delegate for this component.JComponent
subclasses generally override this method to narrow the argument type. For example, inJSlider
:public void setUI(SliderUI newUI) { super.setUI(newUI); }
Additionally
JComponent
subclasses must provide agetUI
method that returns the correct type. For example:public SliderUI getUI() { return (SliderUI)ui; }
- Parameters:
newUI
- the new UI delegate- See Also:
-
getUIClassID
Returns theUIDefaults
key used to look up the name of theswing.plaf.ComponentUI
class that defines the look and feel for this component. Most applications will never need to call this method. Subclasses ofJComponent
that support pluggable look and feel should override this method to return aUIDefaults
key that maps to theComponentUI
subclass that defines their look and feel.- Returns:
- the
UIDefaults
key for aComponentUI
subclass - See Also:
-
getComponentGraphics
Returns the graphics object used to paint this component. IfDebugGraphics
is turned on we create a newDebugGraphics
object if necessary. Otherwise we just configure the specified graphics object's foreground and font.- Parameters:
g
- the originalGraphics
object- Returns:
- a
Graphics
object configured for this component
-
paintComponent
Calls the UI delegate's paint method, if the UI delegate is non-null
. We pass the delegate a copy of theGraphics
object to protect the rest of the paint code from irrevocable changes (for example,Graphics.translate
).If you override this in a subclass you should not make permanent changes to the passed in
Graphics
. For example, you should not alter the clipRectangle
or modify the transform. If you need to do these operations you may find it easier to create a newGraphics
from the passed inGraphics
and manipulate it. Further, if you do not invoke super's implementation you must honor the opaque property, that is if this component is opaque, you must completely fill in the background in an opaque color. If you do not honor the opaque property you will likely see visual artifacts.The passed in
Graphics
object might have a transform other than the identify transform installed on it. In this case, you might get unexpected results if you cumulatively apply another transform.- Parameters:
g
- theGraphics
object to protect- See Also:
-
paintChildren
Paints this component's children. IfshouldUseBuffer
is true, no component ancestor has a buffer and the component children can use a buffer if they have one. Otherwise, one ancestor has a buffer currently in use and children should not use a buffer to paint.- Parameters:
g
- theGraphics
context in which to paint- See Also:
-
paintBorder
Paints the component's border.If you override this in a subclass you should not make permanent changes to the passed in
Graphics
. For example, you should not alter the clipRectangle
or modify the transform. If you need to do these operations you may find it easier to create a newGraphics
from the passed inGraphics
and manipulate it.- Parameters:
g
- theGraphics
context in which to paint- See Also:
-
update
Callspaint
. Doesn't clear the background but seeComponentUI.update
, which is called bypaintComponent
. -
paint
Invoked by Swing to draw components. Applications should not invokepaint
directly, but should instead use therepaint
method to schedule the component for redrawing.This method actually delegates the work of painting to three protected methods:
paintComponent
,paintBorder
, andpaintChildren
. They're called in the order listed to ensure that children appear on top of component itself. Generally speaking, the component and its children should not paint in the insets area allocated to the border. Subclasses can just override this method, as always. A subclass that just wants to specialize the UI (look and feel) delegate'spaint
method should just overridepaintComponent
. -
printAll
Invoke this method to print the component. This method invokesprint
on the component. -
print
Invoke this method to print the component to the specifiedGraphics
. This method will result in invocations ofprintComponent
,printBorder
andprintChildren
. It is recommended that you override one of the previously mentioned methods rather than this one if your intention is to customize the way printing looks. However, it can be useful to override this method should you want to prepare state before invoking the superclass behavior. As an example, if you wanted to change the component's background color before printing, you could do the following:public void print(Graphics g) { Color orig = getBackground(); setBackground(Color.WHITE); // wrap in try/finally so that we always restore the state try { super.print(g); } finally { setBackground(orig); } }
Alternatively, or for components that delegate painting to other objects, you can query during painting whether or not the component is in the midst of a print operation. The
isPaintingForPrint
method provides this ability and its return value will be changed by this method: totrue
immediately before rendering and tofalse
immediately after. With each change a property change event is fired on this component with the name"paintingForPrint"
.This method sets the component's state such that the double buffer will not be used: painting will be done directly on the passed in
Graphics
. -
printComponent
This is invoked during a printing operation. This is implemented to invokepaintComponent
on the component. Override this if you wish to add special painting behavior when printing.- Parameters:
g
- theGraphics
context in which to paint- Since:
- 1.3
- See Also:
-
printChildren
Prints this component's children. This is implemented to invokepaintChildren
on the component. Override this if you wish to print the children differently than painting.- Parameters:
g
- theGraphics
context in which to paint- Since:
- 1.3
- See Also:
-
printBorder
Prints the component's border. This is implemented to invokepaintBorder
on the component. Override this if you wish to print the border differently that it is painted.- Parameters:
g
- theGraphics
context in which to paint- Since:
- 1.3
- See Also:
-
isPaintingTile
Returns true if the component is currently painting a tile. If this method returns true, paint will be called again for another tile. This method returns false if you are not painting a tile or if the last tile is painted. Use this method to keep some state you might need between tiles.- Returns:
- true if the component is currently painting a tile, false otherwise
-
isPaintingForPrint
Returnstrue
if the current painting operation on this component is part of aprint
operation. This method is useful when you want to customize what you print versus what you show on the screen.You can detect changes in the value of this property by listening for property change events on this component with name
"paintingForPrint"
.Note: This method provides complimentary functionality to that provided by other high level Swing printing APIs. However, it deals strictly with painting and should not be confused as providing information on higher level print processes. For example, a
JTable.print()
operation doesn't necessarily result in a continuous rendering of the full component, and the return value of this method can change multiple times during that operation. It is even possible for the component to be painted to the screen while the printing process is ongoing. In such a case, the return value of this method istrue
when, and only when, the table is being painted as part of the printing process.- Returns:
- true if the current painting operation on this component is part of a print operation
- Since:
- 1.6
- See Also:
-
isManagingFocus
Deprecated.As of 1.4, replaced byComponent.setFocusTraversalKeys(int, Set)
andContainer.setFocusCycleRoot(boolean)
.In release 1.4, the focus subsystem was rearchitected. For more information, see How to Use the Focus Subsystem, a section in The Java Tutorial.Changes this
JComponent
's focus traversal keys to CTRL+TAB and CTRL+SHIFT+TAB. Also preventsSortingFocusTraversalPolicy
from considering descendants of this JComponent when computing a focus traversal cycle.- Returns:
- false
- See Also:
-
setNextFocusableComponent
Deprecated.As of 1.4, replaced byFocusTraversalPolicy
In release 1.4, the focus subsystem was rearchitected. For more information, see How to Use the Focus Subsystem, a section in The Java Tutorial.Overrides the default
FocusTraversalPolicy
for thisJComponent
's focus traversal cycle by unconditionally setting the specifiedComponent
as the nextComponent
in the cycle, and thisJComponent
as the specifiedComponent
's previousComponent
in the cycle.- Parameters:
aComponent
- theComponent
that should follow thisJComponent
in the focus traversal cycle- See Also:
-
getNextFocusableComponent
Deprecated.As of 1.4, replaced byFocusTraversalPolicy
.In release 1.4, the focus subsystem was rearchitected. For more information, see How to Use the Focus Subsystem, a section in The Java Tutorial.Returns the
Component
set by a prior call tosetNextFocusableComponent(Component)
on thisJComponent
.- Returns:
- the
Component
that will follow thisJComponent
in the focus traversal cycle, ornull
if none has been explicitly specified - See Also:
-
setRequestFocusEnabled
public void setRequestFocusEnabled(boolean requestFocusEnabled) Provides a hint as to whether or not thisJComponent
should get focus. This is only a hint, and it is up to consumers that are requesting focus to honor this property. This is typically honored for mouse operations, but not keyboard operations. For example, look and feels could verify this property is true before requesting focus during a mouse operation. This would often times be used if you did not want a mouse press on aJComponent
to steal focus, but did want theJComponent
to be traversable via the keyboard. If you do not want thisJComponent
focusable at all, use thesetFocusable
method instead.Please see How to Use the Focus Subsystem, a section in The Java Tutorial, for more information.
- Parameters:
requestFocusEnabled
- indicates whether you want thisJComponent
to be focusable or not- See Also:
-
isRequestFocusEnabled
public boolean isRequestFocusEnabled()Returnstrue
if thisJComponent
should get focus; otherwise returnsfalse
.Please see How to Use the Focus Subsystem, a section in The Java Tutorial, for more information.
- Returns:
true
if this component should get focus, otherwise returnsfalse
- See Also:
-
requestFocus
public void requestFocus()Requests that thisComponent
gets the input focus. Refer toComponent.requestFocus()
for a complete description of this method.Note that the use of this method is discouraged because its behavior is platform dependent. Instead we recommend the use of
requestFocusInWindow()
. If you would like more information on focus, see How to Use the Focus Subsystem, a section in The Java Tutorial.- Overrides:
requestFocus
in classComponent
- Since:
- 1.4
- See Also:
-
requestFocus
public boolean requestFocus(boolean temporary) Requests that thisComponent
gets the input focus. Refer toComponent.requestFocus(boolean)
for a complete description of this method.Note that the use of this method is discouraged because its behavior is platform dependent. Instead we recommend the use of
requestFocusInWindow(boolean)
. If you would like more information on focus, see How to Use the Focus Subsystem, a section in The Java Tutorial.- Overrides:
requestFocus
in classComponent
- Parameters:
temporary
- boolean indicating if the focus change is temporary- Returns:
false
if the focus change request is guaranteed to fail;true
if it is likely to succeed- Since:
- 1.4
- See Also:
-
requestFocusInWindow
public boolean requestFocusInWindow()Requests that thisComponent
gets the input focus. Refer toComponent.requestFocusInWindow()
for a complete description of this method.If you would like more information on focus, see How to Use the Focus Subsystem, a section in The Java Tutorial.
- Overrides:
requestFocusInWindow
in classComponent
- Returns:
false
if the focus change request is guaranteed to fail;true
if it is likely to succeed- Since:
- 1.4
- See Also:
-
requestFocusInWindow
protected boolean requestFocusInWindow(boolean temporary) Requests that thisComponent
gets the input focus. Refer toComponent.requestFocusInWindow(boolean)
for a complete description of this method.If you would like more information on focus, see How to Use the Focus Subsystem, a section in The Java Tutorial.
- Overrides:
requestFocusInWindow
in classComponent
- Parameters:
temporary
- boolean indicating if the focus change is temporary- Returns:
false
if the focus change request is guaranteed to fail;true
if it is likely to succeed- Since:
- 1.4
- See Also:
-
grabFocus
public void grabFocus()Requests that this Component get the input focus, and that this Component's top-level ancestor become the focused Window. This component must be displayable, visible, and focusable for the request to be granted.This method is intended for use by focus implementations. Client code should not use this method; instead, it should use
requestFocusInWindow()
.- See Also:
-
setVerifyInputWhenFocusTarget
@BeanProperty(description="Whether the Component verifies input before accepting focus.") public void setVerifyInputWhenFocusTarget(boolean verifyInputWhenFocusTarget) Sets the value to indicate whether input verifier for the current focus owner will be called before this component requests focus. The default is true. Set to false on components such as a Cancel button or a scrollbar, which should activate even if the input in the current focus owner is not "passed" by the input verifier for that component.- Parameters:
verifyInputWhenFocusTarget
- value for theverifyInputWhenFocusTarget
property- Since:
- 1.3
- See Also:
-
getVerifyInputWhenFocusTarget
public boolean getVerifyInputWhenFocusTarget()Returns the value that indicates whether the input verifier for the current focus owner will be called before this component requests focus.- Returns:
- value of the
verifyInputWhenFocusTarget
property - Since:
- 1.3
- See Also:
-
getFontMetrics
Gets theFontMetrics
for the specifiedFont
.- Overrides:
getFontMetrics
in classComponent
- Parameters:
font
- the font for which font metrics is to be obtained- Returns:
- the font metrics for
font
- Throws:
NullPointerException
- iffont
is null- Since:
- 1.5
- See Also:
-
setPreferredSize
@BeanProperty(preferred=true, description="The preferred size of the component.") public void setPreferredSize(Dimension preferredSize) Sets the preferred size of this component. IfpreferredSize
isnull
, the UI will be asked for the preferred size.- Overrides:
setPreferredSize
in classComponent
- Parameters:
preferredSize
- The new preferred size, or null- See Also:
-
getPreferredSize
If thepreferredSize
has been set to a non-null
value just returns it. If the UI delegate'sgetPreferredSize
method returns a nonnull
value then return that; otherwise defer to the component's layout manager.- Overrides:
getPreferredSize
in classContainer
- Returns:
- the value of the
preferredSize
property - See Also:
-
setMaximumSize
@BeanProperty(description="The maximum size of the component.") public void setMaximumSize(Dimension maximumSize) Sets the maximum size of this component to a constant value. Subsequent calls togetMaximumSize
will always return this value; the component's UI will not be asked to compute it. Setting the maximum size tonull
restores the default behavior.- Overrides:
setMaximumSize
in classComponent
- Parameters:
maximumSize
- aDimension
containing the desired maximum allowable size- See Also:
-
getMaximumSize
If the maximum size has been set to a non-null
value just returns it. If the UI delegate'sgetMaximumSize
method returns a non-null
value then return that; otherwise defer to the component's layout manager.- Overrides:
getMaximumSize
in classContainer
- Returns:
- the value of the
maximumSize
property - See Also:
-
setMinimumSize
@BeanProperty(description="The minimum size of the component.") public void setMinimumSize(Dimension minimumSize) Sets the minimum size of this component to a constant value. Subsequent calls togetMinimumSize
will always return this value; the component's UI will not be asked to compute it. Setting the minimum size tonull
restores the default behavior.- Overrides:
setMinimumSize
in classComponent
- Parameters:
minimumSize
- the new minimum size of this component- See Also:
-
getMinimumSize
If the minimum size has been set to a non-null
value just returns it. If the UI delegate'sgetMinimumSize
method returns a non-null
value then return that; otherwise defer to the component's layout manager.- Overrides:
getMinimumSize
in classContainer
- Returns:
- the value of the
minimumSize
property - See Also:
-
contains
public boolean contains(int x, int y) Gives the UI delegate an opportunity to define the precise shape of this component for the sake of mouse processing. -
setBorder
@BeanProperty(preferred=true, visualUpdate=true, description="The component\'s border.") public void setBorder(Border border) Sets the border of this component. TheBorder
object is responsible for defining the insets for the component (overriding any insets set directly on the component) and for optionally rendering any border decorations within the bounds of those insets. Borders should be used (rather than insets) for creating both decorative and non-decorative (such as margins and padding) regions for a swing component. Compound borders can be used to nest multiple borders within a single component.Although technically you can set the border on any object that inherits from
JComponent
, the look and feel implementation of many standard Swing components doesn't work well with user-set borders. In general, when you want to set a border on a standard Swing component other thanJPanel
orJLabel
, we recommend that you put the component in aJPanel
and set the border on theJPanel
.This is a bound property.
- Parameters:
border
- the border to be rendered for this component- See Also:
-
getBorder
Returns the border of this component ornull
if no border is currently set.- Returns:
- the border object for this component
- See Also:
-
getInsets
If a border has been set on this component, returns the border's insets; otherwise callssuper.getInsets
. -
getInsets
Returns anInsets
object containing this component's inset values. The passed-inInsets
object will be reused if possible. Calling methods cannot assume that the same object will be returned, however. All existing values within this object are overwritten. Ifinsets
is null, this will allocate a new one.- Parameters:
insets
- theInsets
object, which can be reused- Returns:
- the
Insets
object - See Also:
-
getAlignmentY
public float getAlignmentY()OverridesContainer.getAlignmentY
to return the vertical alignment.- Overrides:
getAlignmentY
in classContainer
- Returns:
- the value of the
alignmentY
property - See Also:
-
setAlignmentY
@BeanProperty(description="The preferred vertical alignment of the component.") public void setAlignmentY(float alignmentY) Sets the vertical alignment.- Parameters:
alignmentY
- the new vertical alignment- See Also:
-
getAlignmentX
public float getAlignmentX()OverridesContainer.getAlignmentX
to return the horizontal alignment.- Overrides:
getAlignmentX
in classContainer
- Returns:
- the value of the
alignmentX
property - See Also:
-
setAlignmentX
@BeanProperty(description="The preferred horizontal alignment of the component.") public void setAlignmentX(float alignmentX) Sets the horizontal alignment.- Parameters:
alignmentX
- the new horizontal alignment- See Also:
-
setInputVerifier
@BeanProperty(description="The component\'s input verifier.") public void setInputVerifier(InputVerifier inputVerifier) Sets the input verifier for this component.- Parameters:
inputVerifier
- the new input verifier- Since:
- 1.3
- See Also:
-
getInputVerifier
Returns the input verifier for this component.- Returns:
- the
inputVerifier
property - Since:
- 1.3
- See Also:
-
getGraphics
Returns this component's graphics context, which lets you draw on a component. Use this method to get aGraphics
object and then invoke operations on that object to draw on the component.- Overrides:
getGraphics
in classComponent
- Returns:
- this components graphics context
- See Also:
-
setDebugGraphicsOptions
@BeanProperty(bound=false, preferred=true, enumerationValues={"DebugGraphics.NONE_OPTION","DebugGraphics.LOG_OPTION","DebugGraphics.FLASH_OPTION","DebugGraphics.BUFFERED_OPTION"}, description="Diagnostic options for graphics operations.") public void setDebugGraphicsOptions(int debugOptions) Enables or disables diagnostic information about every graphics operation performed within the component or one of its children.- Parameters:
debugOptions
- determines how the component should display the information; one of the following options:- DebugGraphics.LOG_OPTION - causes a text message to be printed.
- DebugGraphics.FLASH_OPTION - causes the drawing to flash several times.
- DebugGraphics.BUFFERED_OPTION - creates an
ExternalWindow
that displays the operations performed on the View's offscreen buffer. - DebugGraphics.NONE_OPTION disables debugging.
- A value of 0 causes no changes to the debugging options.
debugOptions
is bitwise OR'd into the current value
-
getDebugGraphicsOptions
public int getDebugGraphicsOptions()Returns the state of graphics debugging.- Returns:
- a bitwise OR'd flag of zero or more of the following options:
- DebugGraphics.LOG_OPTION - causes a text message to be printed.
- DebugGraphics.FLASH_OPTION - causes the drawing to flash several times.
- DebugGraphics.BUFFERED_OPTION - creates an
ExternalWindow
that displays the operations performed on the View's offscreen buffer. - DebugGraphics.NONE_OPTION disables debugging.
- A value of 0 causes no changes to the debugging options.
- See Also:
-
registerKeyboardAction
public void registerKeyboardAction(ActionListener anAction, String aCommand, KeyStroke aKeyStroke, int aCondition) This method is now obsolete, please use a combination ofgetActionMap()
andgetInputMap()
for similar behavior. For example, to bind theKeyStroke
aKeyStroke
to theAction
anAction
now use:component.getInputMap().put(aKeyStroke, aCommand); component.getActionMap().put(aCommmand, anAction);
The above assumes you want the binding to be applicable forWHEN_FOCUSED
. To register bindings for other focus states use thegetInputMap
method that takes an integer.Register a new keyboard action.
anAction
will be invoked if a key event matchingaKeyStroke
occurs andaCondition
is verified. TheKeyStroke
object defines a particular combination of a keyboard key and one or more modifiers (alt, shift, ctrl, meta).The
aCommand
will be set in the delivered event if specified.The
aCondition
can be one of:- WHEN_FOCUSED
- The action will be invoked only when the keystroke occurs while the component has the focus.
- WHEN_IN_FOCUSED_WINDOW
- The action will be invoked when the keystroke occurs while the component has the focus or if the component is in the window that has the focus. Note that the component need not be an immediate descendent of the window -- it can be anywhere in the window's containment hierarchy. In other words, whenever any component in the window has the focus, the action registered with this component is invoked.
- WHEN_ANCESTOR_OF_FOCUSED_COMPONENT
- The action will be invoked when the keystroke occurs while the component has the focus or if the component is an ancestor of the component that has the focus.
The combination of keystrokes and conditions lets you define high level (semantic) action events for a specified keystroke+modifier combination (using the KeyStroke class) and direct to a parent or child of a component that has the focus, or to the component itself. In other words, in any hierarchical structure of components, an arbitrary key-combination can be immediately directed to the appropriate component in the hierarchy, and cause a specific method to be invoked (usually by way of adapter objects).
If an action has already been registered for the receiving container, with the same charCode and the same modifiers,
anAction
will replace the action.- Parameters:
anAction
- theAction
to be registeredaCommand
- the command to be set in the delivered eventaKeyStroke
- theKeyStroke
to bind to the actionaCondition
- the condition that needs to be met, see above- See Also:
-
registerKeyboardAction
This method is now obsolete, please use a combination ofgetActionMap()
andgetInputMap()
for similar behavior.- Parameters:
anAction
- action to be registered to given keystroke and conditionaKeyStroke
- aKeyStroke
aCondition
- the condition to be associated with given keystroke and action- See Also:
-
unregisterKeyboardAction
This method is now obsolete. To unregister an existing binding you can either remove the binding from theActionMap/InputMap
, or place a dummy binding theInputMap
. Removing the binding from theInputMap
allows bindings in parentInputMap
s to be active, whereas putting a dummy binding in theInputMap
effectively disables the binding from ever happening.Unregisters a keyboard action. This will remove the binding from the
ActionMap
(if it exists) as well as theInputMap
s.- Parameters:
aKeyStroke
- the keystroke for which to unregister its keyboard action
-
getRegisteredKeyStrokes
Returns theKeyStrokes
that will initiate registered actions.- Returns:
- an array of
KeyStroke
objects - See Also:
-
getConditionForKeyStroke
Returns the condition that determines whether a registered action occurs in response to the specified keystroke.For Java 2 platform v1.3, a
KeyStroke
can be associated with more than one condition. For example, 'a' could be bound for the two conditionsWHEN_FOCUSED
andWHEN_IN_FOCUSED_WINDOW
condition.- Parameters:
aKeyStroke
- the keystroke for which to request an action-keystroke condition- Returns:
- the action-keystroke condition
-
getActionForKeyStroke
Returns the object that will perform the action registered for a given keystroke.- Parameters:
aKeyStroke
- the keystroke for which to return a listener- Returns:
- the
ActionListener
object invoked when the keystroke occurs
-
resetKeyboardActions
public void resetKeyboardActions()Unregisters all the bindings in the first tierInputMaps
andActionMap
. This has the effect of removing any local bindings, and allowing the bindings defined in parentInputMap/ActionMaps
(the UI is usually defined in the second tier) to persist. -
setInputMap
Sets theInputMap
to use under the conditioncondition
tomap
. Anull
value implies you do not want any bindings to be used, even from the UI. This will not reinstall the UIInputMap
(if there was one).condition
has one of the following values:WHEN_IN_FOCUSED_WINDOW
WHEN_FOCUSED
WHEN_ANCESTOR_OF_FOCUSED_COMPONENT
condition
isWHEN_IN_FOCUSED_WINDOW
andmap
is not aComponentInputMap
, anIllegalArgumentException
will be thrown. Similarly, ifcondition
is not one of the values listed, anIllegalArgumentException
will be thrown.- Parameters:
condition
- one of the values listed abovemap
- theInputMap
to use for the given condition- Throws:
IllegalArgumentException
- ifcondition
isWHEN_IN_FOCUSED_WINDOW
andmap
is not an instance ofComponentInputMap
; or ifcondition
is not one of the legal values specified above- Since:
- 1.3
-
getInputMap
Returns theInputMap
that is used duringcondition
.- Parameters:
condition
- one of WHEN_IN_FOCUSED_WINDOW, WHEN_FOCUSED, WHEN_ANCESTOR_OF_FOCUSED_COMPONENT- Returns:
- the
InputMap
for the specifiedcondition
- Since:
- 1.3
-
getInputMap
Returns theInputMap
that is used when the component has focus. This is convenience method forgetInputMap(WHEN_FOCUSED)
.- Returns:
- the
InputMap
used when the component has focus - Since:
- 1.3
-
setActionMap
Sets theActionMap
toam
. This does not set the parent of theam
to be theActionMap
from the UI (if there was one), it is up to the caller to have done this.- Parameters:
am
- the newActionMap
- Since:
- 1.3
-
getActionMap
Returns theActionMap
used to determine whatAction
to fire for particularKeyStroke
binding. The returnedActionMap
, unless otherwise set, will have theActionMap
from the UI set as the parent.- Returns:
- the
ActionMap
containing the key/action bindings - Since:
- 1.3
-
getBaseline
public int getBaseline(int width, int height) Returns the baseline. The baseline is measured from the top of the component. This method is primarily meant forLayoutManager
s to align components along their baseline. A return value less than 0 indicates this component does not have a reasonable baseline and thatLayoutManager
s should not align this component on its baseline.This method calls into the
ComponentUI
method of the same name. If this component does not have aComponentUI
-1 will be returned. If a value >= 0 is returned, then the component has a valid baseline for any size >= the minimum size andgetBaselineResizeBehavior
can be used to determine how the baseline changes with size.- Overrides:
getBaseline
in classComponent
- Parameters:
width
- the width to get the baseline forheight
- the height to get the baseline for- Returns:
- the baseline or < 0 indicating there is no reasonable baseline
- Throws:
IllegalArgumentException
- if width or height is < 0- Since:
- 1.6
- See Also:
-
getBaselineResizeBehavior
Returns an enum indicating how the baseline of the component changes as the size changes. This method is primarily meant for layout managers and GUI builders.This method calls into the
ComponentUI
method of the same name. If this component does not have aComponentUI
BaselineResizeBehavior.OTHER
will be returned. Subclasses should never returnnull
; if the baseline can not be calculated returnBaselineResizeBehavior.OTHER
. Callers should first ask for the baseline usinggetBaseline
and if a value >= 0 is returned use this method. It is acceptable for this method to return a value other thanBaselineResizeBehavior.OTHER
even ifgetBaseline
returns a value less than 0.- Overrides:
getBaselineResizeBehavior
in classComponent
- Returns:
- an enum indicating how the baseline changes as the component size changes
- Since:
- 1.6
- See Also:
-
requestDefaultFocus
Deprecated.As of 1.4, replaced byFocusTraversalPolicy.getDefaultComponent(Container).requestFocus()
In release 1.4, the focus subsystem was rearchitected. For more information, see How to Use the Focus Subsystem, a section in The Java Tutorial.Requests focus on this
JComponent
'sFocusTraversalPolicy
's defaultComponent
. If thisJComponent
is a focus cycle root, then itsFocusTraversalPolicy
is used. Otherwise, theFocusTraversalPolicy
of thisJComponent
's focus-cycle-root ancestor is used.- Returns:
- true if this component can request to get the input focus, false if it can not
- See Also:
-
setVisible
Makes the component visible or invisible. OverridesComponent.setVisible
.- Overrides:
setVisible
in classComponent
- Parameters:
aFlag
- true to make the component visible; false to make it invisible- See Also:
-
setEnabled
@BeanProperty(expert=true, preferred=true, visualUpdate=true, description="The enabled state of the component.") public void setEnabled(boolean enabled) Sets whether or not this component is enabled. A component that is enabled may respond to user input, while a component that is not enabled cannot respond to user input. Some components may alter their visual representation when they are disabled in order to provide feedback to the user that they cannot take input.Note: Disabling a component does not disable its children.
Note: Disabling a lightweight component does not prevent it from receiving MouseEvents.
- Overrides:
setEnabled
in classComponent
- Parameters:
enabled
- true if this component should be enabled, false otherwise- See Also:
-
setForeground
@BeanProperty(preferred=true, visualUpdate=true, description="The foreground color of the component.") public void setForeground(Color fg) Sets the foreground color of this component. It is up to the look and feel to honor this property, some may choose to ignore it.- Overrides:
setForeground
in classComponent
- Parameters:
fg
- the desired foregroundColor
- See Also:
-
setBackground
@BeanProperty(preferred=true, visualUpdate=true, description="The background color of the component.") public void setBackground(Color bg) Sets the background color of this component. The background color is used only if the component is opaque, and only by subclasses ofJComponent
orComponentUI
implementations. Direct subclasses ofJComponent
must overridepaintComponent
to honor this property.It is up to the look and feel to honor this property, some may choose to ignore it.
- Overrides:
setBackground
in classComponent
- Parameters:
bg
- the desired backgroundColor
- See Also:
-
setFont
@BeanProperty(preferred=true, visualUpdate=true, description="The font for the component.") public void setFont(Font font) Sets the font for this component. -
getDefaultLocale
Returns the default locale used to initialize each JComponent's locale property upon creation. The default locale has "AppContext" scope so that applets (and potentially multiple lightweight applications running in a single VM) can have their own setting. An applet can safely alter its default locale because it will have no affect on other applets (or the browser).- Returns:
- the default
Locale
. - Since:
- 1.4
- See Also:
-
setDefaultLocale
Sets the default locale used to initialize each JComponent's locale property upon creation. The initial value is the VM's default locale. The default locale has "AppContext" scope so that applets (and potentially multiple lightweight applications running in a single VM) can have their own setting. An applet can safely alter its default locale because it will have no affect on other applets (or the browser). Passingnull
will reset the current locale back to VM's default locale.- Parameters:
l
- the desired defaultLocale
for new components.- Since:
- 1.4
- See Also:
-
processComponentKeyEvent
Processes any key events that the component itself recognizes. This is called after the focus manager and any interested listeners have been given a chance to steal away the event. This method is called only if the event has not yet been consumed. This method is called prior to the keyboard UI logic.This method is implemented to do nothing. Subclasses would normally override this method if they process some key events themselves. If the event is processed, it should be consumed.
- Parameters:
e
- the event to be processed
-
processKeyEvent
OverridesprocessKeyEvent
to process events.- Overrides:
processKeyEvent
in classComponent
- Parameters:
e
- the key event- See Also:
-
processKeyBinding
Invoked to process the key bindings forks
as the result of theKeyEvent
e
. This obtains the appropriateInputMap
, gets the binding, gets the action from theActionMap
, and then (if the action is found and the component is enabled) invokesnotifyAction
to notify the action.- Parameters:
ks
- theKeyStroke
queriede
- theKeyEvent
condition
- one of the following values:- JComponent.WHEN_FOCUSED
- JComponent.WHEN_ANCESTOR_OF_FOCUSED_COMPONENT
- JComponent.WHEN_IN_FOCUSED_WINDOW
pressed
- true if the key is pressed- Returns:
- true if there was a binding to an action, and the action was enabled
- Since:
- 1.3
-
setToolTipText
@BeanProperty(bound=false, preferred=true, description="The text to display in a tool tip.") public void setToolTipText(String text) Registers the text to display in a tool tip. The text displays when the cursor lingers over the component.See How to Use Tool Tips in The Java Tutorial for further documentation.
- Parameters:
text
- the string to display; if the text isnull
, the tool tip is turned off for this component- See Also:
-
getToolTipText
Returns the tooltip string that has been set withsetToolTipText
.- Returns:
- the text of the tool tip
- See Also:
-
getToolTipText
Returns the string to be used as the tooltip for event. By default this returns any string set usingsetToolTipText
. If a component provides more extensive API to support differing tooltips at different locations, this method should be overridden.- Parameters:
event
- theMouseEvent
that initiated theToolTip
display- Returns:
- a string containing the tooltip
-
getToolTipLocation
Returns the tooltip location in this component's coordinate system. Ifnull
is returned, Swing will choose a location. The default implementation returnsnull
.- Parameters:
event
- theMouseEvent
that caused theToolTipManager
to show the tooltip- Returns:
- always returns
null
-
getPopupLocation
Returns the preferred location to display the popup menu in this component's coordinate system. It is up to the look and feel to honor this property, some may choose to ignore it. Ifnull
, the look and feel will choose a suitable location.- Parameters:
event
- theMouseEvent
that triggered the popup to be shown, ornull
if the popup is not being shown as the result of a mouse event- Returns:
- location to display the
JPopupMenu
, ornull
- Since:
- 1.5
-
createToolTip
Returns the instance ofJToolTip
that should be used to display the tooltip. Components typically would not override this method, but it can be used to cause different tooltips to be displayed differently.- Returns:
- the
JToolTip
used to display this toolTip
-
scrollRectToVisible
Forwards thescrollRectToVisible()
message to theJComponent
's parent. Components that can service the request, such asJViewport
, override this method and perform the scrolling.- Parameters:
aRect
- the visibleRectangle
- See Also:
-
setAutoscrolls
@BeanProperty(bound=false, expert=true, description="Determines if this component automatically scrolls its contents when dragged.") public void setAutoscrolls(boolean autoscrolls) Sets theautoscrolls
property. Iftrue
mouse dragged events will be synthetically generated when the mouse is dragged outside of the component's bounds and mouse motion has paused (while the button continues to be held down). The synthetic events make it appear that the drag gesture has resumed in the direction established when the component's boundary was crossed. Components that support autoscrolling must handlemouseDragged
events by callingscrollRectToVisible
with a rectangle that contains the mouse event's location. All of the Swing components that support item selection and are typically displayed in aJScrollPane
(JTable
,JList
,JTree
,JTextArea
, andJEditorPane
) already handle mouse dragged events in this way. To enable autoscrolling in any other component, add a mouse motion listener that callsscrollRectToVisible
. For example, given aJPanel
,myPanel
:MouseMotionListener doScrollRectToVisible = new MouseMotionAdapter() { public void mouseDragged(MouseEvent e) { Rectangle r = new Rectangle(e.getX(), e.getY(), 1, 1); ((JPanel)e.getSource()).scrollRectToVisible(r); } }; myPanel.addMouseMotionListener(doScrollRectToVisible);
The default value of theautoScrolls
property isfalse
.- Parameters:
autoscrolls
- if true, synthetic mouse dragged events are generated when the mouse is dragged outside of a component's bounds and the mouse button continues to be held down; otherwise false- See Also:
-
getAutoscrolls
public boolean getAutoscrolls()Gets theautoscrolls
property.- Returns:
- the value of the
autoscrolls
property - See Also:
-
setTransferHandler
@BeanProperty(hidden=true, description="Mechanism for transfer of data to and from the component") public void setTransferHandler(TransferHandler newHandler) Sets theTransferHandler
, which provides support for transfer of data into and out of this component via cut/copy/paste and drag and drop. This may benull
if the component does not support data transfer operations.If the new
TransferHandler
is notnull
, this method also installs a newDropTarget
on the component to activate drop handling through theTransferHandler
and activate any built-in support (such as calculating and displaying potential drop locations). If you do not wish for this component to respond in any way to drops, you can disable drop support entirely either by removing the drop target (setDropTarget(null)
) or by de-activating it (getDropTaget().setActive(false)
).If the new
TransferHandler
isnull
, this method removes the drop target.Under two circumstances, this method does not modify the drop target: First, if the existing drop target on this component was explicitly set by the developer to a
non-null
value. Second, if the system propertysuppressSwingDropSupport
istrue
. The default value for the system property isfalse
.Please see How to Use Drag and Drop and Data Transfer, a section in The Java Tutorial, for more information.
- Parameters:
newHandler
- the newTransferHandler
- Since:
- 1.4
- See Also:
-
getTransferHandler
Gets thetransferHandler
property.- Returns:
- the value of the
transferHandler
property - Since:
- 1.4
- See Also:
-
processMouseEvent
Processes mouse events occurring on this component by dispatching them to any registeredMouseListener
objects, refer toComponent.processMouseEvent(MouseEvent)
for a complete description of this method.- Overrides:
processMouseEvent
in classComponent
- Parameters:
e
- the mouse event- Since:
- 1.5
- See Also:
-
processMouseMotionEvent
Processes mouse motion events, such as MouseEvent.MOUSE_DRAGGED.- Overrides:
processMouseMotionEvent
in classComponent
- Parameters:
e
- theMouseEvent
- See Also:
-
enable
Deprecated.As of JDK version 1.1, replaced byjava.awt.Component.setEnabled(boolean)
. -
disable
Deprecated.As of JDK version 1.1, replaced byjava.awt.Component.setEnabled(boolean)
. -
getClientProperty
Returns the value of the property with the specified key. Only properties added withputClientProperty
will return a non-null
value.- Parameters:
key
- the being queried- Returns:
- the value of this property or
null
- See Also:
-
putClientProperty
Adds an arbitrary key/value "client property" to this component.The
get/putClientProperty
methods provide access to a small per-instance hashtable. Callers can use get/putClientProperty to annotate components that were created by another module. For example, a layout manager might store per child constraints this way. For example:componentA.putClientProperty("to the left of", componentB);
If value isnull
this method will remove the property. Changes to client properties are reported withPropertyChange
events. The name of the property (for the sake of PropertyChange events) iskey.toString()
.The
clientProperty
dictionary is not intended to support large scale extensions to JComponent nor should be it considered an alternative to subclassing when designing a new component.- Parameters:
key
- the new client property keyvalue
- the new client property value; ifnull
this method will remove the property- See Also:
-
setFocusTraversalKeys
Sets the focus traversal keys for a given traversal operation for this Component. Refer toComponent.setFocusTraversalKeys(int, java.util.Set<? extends java.awt.AWTKeyStroke>)
for a complete description of this method.This method may throw a
ClassCastException
if anyObject
inkeystrokes
is not anAWTKeyStroke
.- Overrides:
setFocusTraversalKeys
in classContainer
- Parameters:
id
- one of KeyboardFocusManager.FORWARD_TRAVERSAL_KEYS, KeyboardFocusManager.BACKWARD_TRAVERSAL_KEYS, or KeyboardFocusManager.UP_CYCLE_TRAVERSAL_KEYSkeystrokes
- the Set of AWTKeyStroke for the specified operation- Throws:
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- Since:
- 1.5
- See Also:
-
isLightweightComponent
Returns true if this component is lightweight, that is, if it doesn't have a native window system peer.- Parameters:
c
- theComponent
to be checked- Returns:
- true if this component is lightweight
-
reshape
Deprecated.As of JDK 5, replaced byComponent.setBounds(int, int, int, int)
.Moves and resizes this component.
Description copied from class:Component
Reshapes the bounding rectangle for this component. -
getBounds
Stores the bounds of this component into "return value"rv
and returnsrv
. Ifrv
isnull
a newRectangle
is allocated. This version ofgetBounds
is useful if the caller wants to avoid allocating a newRectangle
object on the heap. -
getSize
Stores the width/height of this component into "return value"rv
and returnsrv
. Ifrv
isnull
a newDimension
object is allocated. This version ofgetSize
is useful if the caller wants to avoid allocating a newDimension
object on the heap. -
getLocation
Stores the x,y origin of this component into "return value"rv
and returnsrv
. Ifrv
isnull
a newPoint
is allocated. This version ofgetLocation
is useful if the caller wants to avoid allocating a newPoint
object on the heap.- Overrides:
getLocation
in classComponent
- Parameters:
rv
- the return value, modified to the component's location- Returns:
rv
-
getX
Returns the current x coordinate of the component's origin. This method is preferable to writingcomponent.getBounds().x
, orcomponent.getLocation().x
because it doesn't cause any heap allocations. -
getY
Returns the current y coordinate of the component's origin. This method is preferable to writingcomponent.getBounds().y
, orcomponent.getLocation().y
because it doesn't cause any heap allocations. -
getWidth
Returns the current width of this component. This method is preferable to writingcomponent.getBounds().width
, orcomponent.getSize().width
because it doesn't cause any heap allocations. -
getHeight
Returns the current height of this component. This method is preferable to writingcomponent.getBounds().height
, orcomponent.getSize().height
because it doesn't cause any heap allocations. -
isOpaque
public boolean isOpaque()Returns true if this component is completely opaque.An opaque component paints every pixel within its rectangular bounds. A non-opaque component paints only a subset of its pixels or none at all, allowing the pixels underneath it to "show through". Therefore, a component that does not fully paint its pixels provides a degree of transparency.
Subclasses that guarantee to always completely paint their contents should override this method and return true.
-
setOpaque
@BeanProperty(expert=true, description="The component\'s opacity") public void setOpaque(boolean isOpaque) If true the component paints every pixel within its bounds. Otherwise, the component may not paint some or all of its pixels, allowing the underlying pixels to show through.The default value of this property is false for
JComponent
. However, the default value for this property on most standardJComponent
subclasses (such asJButton
andJTree
) is look-and-feel dependent.- Parameters:
isOpaque
- true if this component should be opaque- See Also:
-
computeVisibleRect
Returns theComponent
's "visible rect rectangle" - the intersection of the visible rectangles for this component and all of its ancestors. The return value is stored invisibleRect
.- Parameters:
visibleRect
- aRectangle
computed as the intersection of all visible rectangles for this component and all of its ancestors -- this is the return value for this method- See Also:
-
getVisibleRect
Returns theComponent
's "visible rectangle" - the intersection of this component's visible rectangle,new Rectangle(0, 0, getWidth(), getHeight())
, and all of its ancestors' visible rectangles.- Returns:
- the visible rectangle
-
firePropertyChange
Support for reporting bound property changes for boolean properties. This method can be called when a bound property has changed and it will send the appropriate PropertyChangeEvent to any registered PropertyChangeListeners.- Overrides:
firePropertyChange
in classComponent
- Parameters:
propertyName
- the property whose value has changedoldValue
- the property's previous valuenewValue
- the property's new value
-
firePropertyChange
Support for reporting bound property changes for integer properties. This method can be called when a bound property has changed and it will send the appropriate PropertyChangeEvent to any registered PropertyChangeListeners.- Overrides:
firePropertyChange
in classComponent
- Parameters:
propertyName
- the property whose value has changedoldValue
- the property's previous valuenewValue
- the property's new value
-
fireVetoableChange
protected void fireVetoableChange(String propertyName, Object oldValue, Object newValue) throws PropertyVetoException Supports reporting constrained property changes. This method can be called when a constrained property has changed and it will send the appropriatePropertyChangeEvent
to any registeredVetoableChangeListeners
.- Parameters:
propertyName
- the name of the property that was listened onoldValue
- the old value of the propertynewValue
- the new value of the property- Throws:
PropertyVetoException
- when the attempt to set the property is vetoed by the component
-
addVetoableChangeListener
Adds aVetoableChangeListener
to the listener list. The listener is registered for all properties.- Parameters:
listener
- theVetoableChangeListener
to be added
-
removeVetoableChangeListener
Removes aVetoableChangeListener
from the listener list. This removes aVetoableChangeListener
that was registered for all properties.- Parameters:
listener
- theVetoableChangeListener
to be removed
-
getVetoableChangeListeners
Returns an array of all the vetoable change listeners registered on this component.- Returns:
- all of the component's
VetoableChangeListener
s or an empty array if no vetoable change listeners are currently registered - Since:
- 1.4
- See Also:
-
getTopLevelAncestor
Returns the top-level ancestor of this component (either the containingWindow
orApplet
), ornull
if this component has not been added to any container.- Returns:
- the top-level
Container
that this component is in, ornull
if not in any container
-
addAncestorListener
Registerslistener
so that it will receiveAncestorEvents
when it or any of its ancestors move or are made visible or invisible. Events are also sent when the component or its ancestors are added or removed from the containment hierarchy.- Parameters:
listener
- theAncestorListener
to register- See Also:
-
removeAncestorListener
Unregisterslistener
so that it will no longer receiveAncestorEvents
.- Parameters:
listener
- theAncestorListener
to be removed- See Also:
-
getAncestorListeners
Returns an array of all the ancestor listeners registered on this component.- Returns:
- all of the component's
AncestorListener
s or an empty array if no ancestor listeners are currently registered - Since:
- 1.4
- See Also:
-
getListeners
Returns an array of all the objects currently registered asFooListener
s upon thisJComponent
.FooListener
s are registered using theaddFooListener
method.You can specify the
listenerType
argument with a class literal, such asFooListener.class
. For example, you can query aJComponent
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.- Overrides:
getListeners
in classContainer
- Type Parameters:
T
- the type of the listeners- Parameters:
listenerType
- the type of listeners requested; this parameter should specify an interface that descends fromjava.util.EventListener
- Returns:
- an array of all objects registered as
FooListener
s on this component, or an empty array if no such listeners have been added - Throws:
ClassCastException
- iflistenerType
doesn't specify a class or interface that implementsjava.util.EventListener
- Since:
- 1.3
- See Also:
-
addNotify
public void addNotify()Notifies this component that it now has a parent component. When this method is invoked, the chain of parent components is set up withKeyboardAction
event listeners. This method is called by the toolkit internally and should not be called directly by programs. -
removeNotify
public void removeNotify()Notifies this component that it no longer has a parent component. When this method is invoked, anyKeyboardAction
s set up in the chain of parent components are removed. This method is called by the toolkit internally and should not be called directly by programs.- Overrides:
removeNotify
in classContainer
- See Also:
-
repaint
public void repaint(long tm, int x, int y, int width, int height) Adds the specified region to the dirty region list if the component is showing. The component will be repainted after all of the currently pending events have been dispatched. -
repaint
Adds the specified region to the dirty region list if the component is showing. The component will be repainted after all of the currently pending events have been dispatched.- Parameters:
r
- aRectangle
containing the dirty region- See Also:
-
revalidate
public void revalidate()Supports deferred automatic layout.Calls
invalidate
and then adds this component'svalidateRoot
to a list of components that need to be validated. Validation will occur after all currently pending events have been dispatched. In other words after this method is called, the first validateRoot (if any) found when walking up the containment hierarchy of this component will be validated. By default,JRootPane
,JScrollPane
, andJTextField
return true fromisValidateRoot
.This method will automatically be called on this component when a property value changes such that size, location, or internal layout of this component has been affected. This automatic updating differs from the AWT because programs generally no longer need to invoke
validate
to get the contents of the GUI to update.- Overrides:
revalidate
in classComponent
- See Also:
-
isValidateRoot
public boolean isValidateRoot()If this method returns true,revalidate
calls by descendants of this component will cause the entire tree beginning with this root to be validated. Returns false by default.JScrollPane
overrides this method and returns true.- Overrides:
isValidateRoot
in classContainer
- Returns:
- always returns false
- See Also:
-
isOptimizedDrawingEnabled
Returns true if this component tiles its children -- that is, if it can guarantee that the children will not overlap. The repainting system is substantially more efficient in this common case.JComponent
subclasses that can't make this guarantee, such asJLayeredPane
, should override this method to return false.- Returns:
- always returns true
-
isPaintingOrigin
protected boolean isPaintingOrigin()Returnstrue
if a paint triggered on a child component should cause painting to originate from this Component, or one of its ancestors.Calling
repaint(long, int, int, int, int)
orpaintImmediately(int, int, int, int)
on a Swing component will result in calling thepaintImmediately(int, int, int, int)
method of the first ancestor whichisPaintingOrigin()
returnstrue
, if there are any.JComponent
subclasses that need to be painted when any of their children are repainted should override this method to returntrue
.- Returns:
- always returns
false
- See Also:
-
paintImmediately
public void paintImmediately(int x, int y, int w, int h) Paints the specified region in this component and all of its descendants that overlap the region, immediately.It's rarely necessary to call this method. In most cases it's more efficient to call repaint, which defers the actual painting and can collapse redundant requests into a single paint call. This method is useful if one needs to update the display while the current event is being dispatched.
This method is to be overridden when the dirty region needs to be changed for components that are painting origins.
- Parameters:
x
- the x value of the region to be paintedy
- the y value of the region to be paintedw
- the width of the region to be paintedh
- the height of the region to be painted- See Also:
-
paintImmediately
Paints the specified region now.- Parameters:
r
- aRectangle
containing the region to be painted
-
setDoubleBuffered
public void setDoubleBuffered(boolean aFlag) Sets whether this component should use a buffer to paint. If set to true, all the drawing from this component will be done in an offscreen painting buffer. The offscreen painting buffer will the be copied onto the screen. If aComponent
is buffered and one of its ancestor is also buffered, the ancestor buffer will be used.- Parameters:
aFlag
- if true, set this component to be double buffered
-
isDoubleBuffered
public boolean isDoubleBuffered()Returns whether this component should use a buffer to paint.- Overrides:
isDoubleBuffered
in classComponent
- Returns:
- true if this component is double buffered, otherwise false
-
getRootPane
Returns theJRootPane
ancestor for this component.- Returns:
- the
JRootPane
that contains this component, ornull
if noJRootPane
is found
-
paramString
Returns a string representation of thisJComponent
. This method is intended to be used only for debugging purposes, and the content and format of the returned string may vary between implementations. The returned string may be empty but may not benull
.- Overrides:
paramString
in classContainer
- Returns:
- a string representation of this
JComponent
-
hide
Deprecated.
-
java.awt.Component.setEnabled(boolean)
.