Class JComponent
- java.lang.Object
-
- java.awt.Component
-
- java.awt.Container
-
- javax.swing.JComponent
- 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
@JavaBean(defaultProperty="UIClassID") public abstract class JComponent extends Container implements Serializable
The base class for all Swing components except top-level containers. To use a component that inherits from 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.
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:
-
KeyStroke
,Action
,setBorder(javax.swing.border.Border)
,registerKeyboardAction(java.awt.event.ActionListener, java.lang.String, javax.swing.KeyStroke, int)
,JOptionPane
,setDebugGraphicsOptions(int)
,setToolTipText(java.lang.String)
,setAutoscrolls(boolean)
, Serialized Form
Nested Classes
Modifier and Type | Class | Description |
---|---|---|
class | JComponent.AccessibleJComponent | 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
Fields
Modifier and Type | Field | Description |
---|---|---|
protected EventListenerList | listenerList | A list of event listeners for this component. |
static String | 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". |
protected ComponentUI | ui | The look and feel delegate for this component. |
static int | UNDEFINED_CONDITION | Constant used by some of the APIs to mean that no condition is defined. |
static int | WHEN_ANCESTOR_OF_FOCUSED_COMPONENT | Constant used for |
static int | WHEN_FOCUSED | Constant used for |
static int | WHEN_IN_FOCUSED_WINDOW | Constant used for |
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
Constructors
Constructor | Description |
---|---|
JComponent() | Default |
Methods
Modifier and Type | Method | Description |
---|---|---|
void | addAncestorListener(AncestorListener listener) | Registers |
void | addNotify() | Notifies this component that it now has a parent component. |
void | addVetoableChangeListener(VetoableChangeListener listener) | Adds a |
void | computeVisibleRect(Rectangle visibleRect) | Returns the |
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. |
JToolTip | createToolTip() | Returns the instance of |
void | disable() | Deprecated. As of JDK version 1.1, replaced by java.awt.Component.setEnabled(boolean) . |
void | enable() | Deprecated. As of JDK version 1.1, replaced by java.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. |
ActionListener | getActionForKeyStroke(KeyStroke aKeyStroke) | Returns the object that will perform the action registered for a given keystroke. |
ActionMap | getActionMap() | Returns the |
float | getAlignmentX() | Overrides |
float | getAlignmentY() | Overrides |
AncestorListener[] | getAncestorListeners() | Returns an array of all the ancestor listeners registered on this component. |
boolean | getAutoscrolls() | Gets the |
int | getBaseline(int width,
int height) | Returns the baseline. |
Component.BaselineResizeBehavior | getBaselineResizeBehavior() | Returns an enum indicating how the baseline of the component changes as the size changes. |
Border | getBorder() | Returns the border of this component or |
Rectangle | getBounds(Rectangle rv) | Stores the bounds of this component into "return value" |
Object | getClientProperty(Object key) | Returns the value of the property with the specified key. |
protected Graphics | getComponentGraphics(Graphics g) | Returns the graphics object used to paint this component. |
JPopupMenu | getComponentPopupMenu() | Returns |
int | getConditionForKeyStroke(KeyStroke aKeyStroke) | Returns the condition that determines whether a registered action occurs in response to the specified keystroke. |
int | getDebugGraphicsOptions() | Returns the state of graphics debugging. |
static Locale | getDefaultLocale() | Returns the default locale used to initialize each JComponent's locale property upon creation. |
FontMetrics | getFontMetrics(Font font) | Gets the |
Graphics | getGraphics() | Returns this component's graphics context, which lets you draw on a component. |
int | getHeight() | Returns the current height of this component. |
boolean | getInheritsPopupMenu() | Returns true if the JPopupMenu should be inherited from the parent. |
InputMap | getInputMap() | Returns the |
InputMap | getInputMap(int condition) | Returns the |
InputVerifier | getInputVerifier() | Returns the input verifier for this component. |
Insets | getInsets() | If a border has been set on this component, returns the border's insets; otherwise calls |
Insets | getInsets(Insets insets) | Returns an |
<T extends EventListener> | getListeners(Class<T> listenerType) | Returns an array of all the objects currently registered as |
Point | getLocation(Point rv) | Stores the x,y origin of this component into "return value" |
Dimension | getMaximumSize() | If the maximum size has been set to a non- |
Dimension | getMinimumSize() | If the minimum size has been set to a non- |
Component | getNextFocusableComponent() | Deprecated. As of 1.4, replaced by FocusTraversalPolicy . |
Point | getPopupLocation(MouseEvent event) | Returns the preferred location to display the popup menu in this component's coordinate system. |
Dimension | getPreferredSize() | If the |
KeyStroke[] | getRegisteredKeyStrokes() | Returns the |
JRootPane | getRootPane() | Returns the |
Dimension | getSize(Dimension rv) | Stores the width/height of this component into "return value" |
Point | getToolTipLocation(MouseEvent event) | Returns the tooltip location in this component's coordinate system. |
String | getToolTipText() | Returns the tooltip string that has been set with |
String | getToolTipText(MouseEvent event) | Returns the string to be used as the tooltip for event. |
Container | getTopLevelAncestor() | Returns the top-level ancestor of this component (either the containing |
TransferHandler | getTransferHandler() | Gets the |
ComponentUI | getUI() | Returns the look and feel delegate that renders this component. |
String | getUIClassID() | Returns the |
boolean | getVerifyInputWhenFocusTarget() | Returns the value that indicates whether the input verifier for the current focus owner will be called before this component requests focus. |
VetoableChangeListener[] | getVetoableChangeListeners() | Returns an array of all the vetoable change listeners registered on this component. |
Rectangle | getVisibleRect() | Returns the |
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 | grabFocus() | Requests that this Component get the input focus, and that this Component's top-level ancestor become the focused Window. |
boolean | isDoubleBuffered() | Returns whether this component should use a buffer to paint. |
static boolean | isLightweightComponent(Component c) | Returns true if this component is lightweight, that is, if it doesn't have a native window system peer. |
boolean | isManagingFocus() | Deprecated. As of 1.4, replaced by Component.setFocusTraversalKeys(int, Set) and Container.setFocusCycleRoot(boolean) . |
boolean | isOpaque() | Returns true if this component is completely opaque. |
boolean | isOptimizedDrawingEnabled() | Returns true if this component tiles its children -- that is, if it can guarantee that the children will not overlap. |
boolean | isPaintingForPrint() | Returns |
protected boolean | isPaintingOrigin() | Returns |
boolean | isPaintingTile() | Returns true if the component is currently painting a tile. |
boolean | isRequestFocusEnabled() | Returns |
boolean | isValidateRoot() | If this method returns true, |
void | paint(Graphics g) | Invoked by Swing to draw components. |
protected void | paintBorder(Graphics g) | Paints the component's border. |
protected void | paintChildren(Graphics g) | Paints this component's children. |
protected void | paintComponent(Graphics g) | Calls the UI delegate's paint method, if the UI delegate is non- |
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 | paintImmediately(Rectangle r) | Paints the specified region now. |
protected String | paramString() | Returns a string representation of this |
void | print(Graphics g) | Invoke this method to print the component to the specified |
void | printAll(Graphics g) | Invoke this method to print the component. |
protected void | printBorder(Graphics g) | Prints the component's border. |
protected void | printChildren(Graphics g) | Prints this component's children. |
protected void | printComponent(Graphics g) | This is invoked during a printing operation. |
protected void | processComponentKeyEvent(KeyEvent e) | 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 for |
protected void | processKeyEvent(KeyEvent e) | Overrides |
protected void | processMouseEvent(MouseEvent e) | Processes mouse events occurring on this component by dispatching them to any registered |
protected void | processMouseMotionEvent(MouseEvent e) | Processes mouse motion events, such as MouseEvent.MOUSE_DRAGGED. |
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 of |
void | registerKeyboardAction(ActionListener anAction,
KeyStroke aKeyStroke,
int aCondition) | This method is now obsolete, please use a combination of |
void | removeAncestorListener(AncestorListener listener) | Unregisters |
void | removeNotify() | Notifies this component that it no longer has a parent component. |
void | removeVetoableChangeListener(VetoableChangeListener listener) | Removes a |
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 | repaint(Rectangle r) | Adds the specified region to the dirty region list if the component is showing. |
boolean | requestDefaultFocus() | Deprecated. As of 1.4, replaced by FocusTraversalPolicy.getDefaultComponent(Container).requestFocus()
|
void | requestFocus() | Requests that this |
boolean | requestFocus(boolean temporary) | Requests that this |
boolean | requestFocusInWindow() | Requests that this |
protected boolean | requestFocusInWindow(boolean temporary) | Requests that this |
void | resetKeyboardActions() | Unregisters all the bindings in the first tier |
void | reshape(int x,
int y,
int w,
int h) | Deprecated. As of JDK 5, replaced by Component.setBounds(int, int, int, int) . |
void | revalidate() | Supports deferred automatic layout. |
void | scrollRectToVisible(Rectangle aRect) | Forwards the |
void | setActionMap(ActionMap am) | Sets the |
void | setAlignmentX(float alignmentX) | Sets the horizontal alignment. |
void | setAlignmentY(float alignmentY) | Sets the vertical alignment. |
void | setAutoscrolls(boolean autoscrolls) | Sets the |
void | setBackground(Color bg) | Sets the background color of this component. |
void | setBorder(Border border) | Sets the border of this component. |
void | setComponentPopupMenu(JPopupMenu popup) | Sets the |
void | setDebugGraphicsOptions(int debugOptions) | Enables or disables diagnostic information about every graphics operation performed within the component or one of its children. |
static void | setDefaultLocale(Locale l) | 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 | setFont(Font font) | Sets the font for this component. |
void | setForeground(Color fg) | Sets the foreground color of this component. |
void | setInheritsPopupMenu(boolean value) | Sets whether or not |
void | setInputMap(int condition,
InputMap map) | Sets the |
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 by FocusTraversalPolicy
|
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 this |
void | setToolTipText(String text) | Registers the text to display in a tool tip. |
void | setTransferHandler(TransferHandler newHandler) | Sets the |
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 | update(Graphics g) | Calls |
void | updateUI() | Resets 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, hide, 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
Methods declared in class java.lang.Object
clone, equals, finalize, getClass, hashCode, notify, notifyAll, wait, wait, wait
Fields
ui
protected transient ComponentUI ui
The look and feel delegate for this component.
listenerList
protected EventListenerList listenerList
A list of event listeners for this component.
WHEN_FOCUSED
public static final int WHEN_FOCUSED
Constant used for registerKeyboardAction
that means that the command should be invoked when the component has the focus.
- See Also:
- Constant Field Values
WHEN_ANCESTOR_OF_FOCUSED_COMPONENT
public static final int WHEN_ANCESTOR_OF_FOCUSED_COMPONENT
Constant used for registerKeyboardAction
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:
- Constant Field Values
WHEN_IN_FOCUSED_WINDOW
public static final int WHEN_IN_FOCUSED_WINDOW
Constant used for registerKeyboardAction
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:
- Constant Field Values
UNDEFINED_CONDITION
public static final int UNDEFINED_CONDITION
Constant used by some of the APIs to mean that no condition is defined.
- See Also:
- Constant Field Values
TOOL_TIP_TEXT_KEY
public static final String 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:
- Constant Field Values
Constructors
JComponent
public JComponent()
Default JComponent
constructor. This constructor does very little initialization beyond calling the Container
constructor. For example, the initial layout manager is null
. It does, however, set the component's locale property to the value returned by JComponent.getDefaultLocale
.
- See Also:
getDefaultLocale()
Methods
setInheritsPopupMenu
@BeanProperty(description="Whether or not the JPopupMenu is inherited") public void setInheritsPopupMenu(boolean value)
Sets whether or not getComponentPopupMenu
should delegate to the parent if this component does not have a JPopupMenu
assigned to it.
The default value for this is false, but some JComponent
subclasses that are implemented as a number of JComponent
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:
setComponentPopupMenu(javax.swing.JPopupMenu)
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(javax.swing.JPopupMenu)
setComponentPopupMenu
@BeanProperty(preferred=true, description="Popup to show") public void setComponentPopupMenu(JPopupMenu popup)
Sets the JPopupMenu
for this JComponent
. The UI is responsible for registering bindings and adding the necessary listeners such that the JPopupMenu
will be shown at the appropriate time. When the JPopupMenu
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, and getInheritsPopupMenu
returns true, then getComponentPopupMenu
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()
getComponentPopupMenu
public JPopupMenu getComponentPopupMenu()
Returns JPopupMenu
that assigned for this component. If this component does not have a JPopupMenu
assigned to it and getInheritsPopupMenu
is true, this will return getParent().getComponentPopupMenu()
(assuming the parent is valid.)
- Returns:
-
JPopupMenu
assigned for this component ornull
if no popup assigned - Since:
- 1.5
- See Also:
setComponentPopupMenu(javax.swing.JPopupMenu)
updateUI
public void updateUI()
Resets 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); }
- See Also:
-
setUI(javax.swing.plaf.ComponentUI)
,UIManager.getLookAndFeel()
,UIManager.getUI(javax.swing.JComponent)
getUI
public ComponentUI 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, in JSlider
:
public void setUI(SliderUI newUI) { super.setUI(newUI); }
Additionally JComponent
subclasses must provide a getUI
method that returns the correct type. For example:
public SliderUI getUI() { return (SliderUI)ui; }
- Parameters:
-
newUI
- the new UI delegate - See Also:
-
updateUI()
,UIManager.getLookAndFeel()
,UIManager.getUI(javax.swing.JComponent)
getUIClassID
@BeanProperty(bound=false, expert=true, description="UIClassID") public String getUIClassID()
Returns the UIDefaults
key used to look up the name of the swing.plaf.ComponentUI
class that defines the look and feel for this component. Most applications will never need to call this method. Subclasses of JComponent
that support pluggable look and feel should override this method to return a UIDefaults
key that maps to the ComponentUI
subclass that defines their look and feel.
- Returns:
- the
UIDefaults
key for aComponentUI
subclass - See Also:
UIDefaults.getUI(javax.swing.JComponent)
getComponentGraphics
protected Graphics getComponentGraphics(Graphics g)
Returns the graphics object used to paint this component. If DebugGraphics
is turned on we create a new DebugGraphics
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
protected void paintComponent(Graphics g)
Calls the UI delegate's paint method, if the UI delegate is non-null
. We pass the delegate a copy of the Graphics
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 clip Rectangle
or modify the transform. If you need to do these operations you may find it easier to create a new Graphics
from the passed in Graphics
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:
-
paint(java.awt.Graphics)
,ComponentUI
paintChildren
protected void paintChildren(Graphics g)
Paints this component's children. If shouldUseBuffer
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:
-
paint(java.awt.Graphics)
,Container.paint(java.awt.Graphics)
paintBorder
protected void paintBorder(Graphics g)
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 clip Rectangle
or modify the transform. If you need to do these operations you may find it easier to create a new Graphics
from the passed in Graphics
and manipulate it.
- Parameters:
-
g
- theGraphics
context in which to paint - See Also:
-
paint(java.awt.Graphics)
,setBorder(javax.swing.border.Border)
update
public void update(Graphics g)
Calls paint
. Doesn't clear the background but see ComponentUI.update
, which is called by paintComponent
.
- Overrides:
-
update
in classContainer
- Parameters:
-
g
- theGraphics
context in which to paint - See Also:
-
paint(java.awt.Graphics)
,paintComponent(java.awt.Graphics)
,ComponentUI
paint
public void paint(Graphics g)
Invoked by Swing to draw components. Applications should not invoke paint
directly, but should instead use the repaint
method to schedule the component for redrawing.
This method actually delegates the work of painting to three protected methods: paintComponent
, paintBorder
, and paintChildren
. 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's paint
method should just override paintComponent
.
- Overrides:
-
paint
in classContainer
- Parameters:
-
g
- theGraphics
context in which to paint - See Also:
-
paintComponent(java.awt.Graphics)
,paintBorder(java.awt.Graphics)
,paintChildren(java.awt.Graphics)
,getComponentGraphics(java.awt.Graphics)
,repaint(long, int, int, int, int)
printAll
public void printAll(Graphics g)
Invoke this method to print the component. This method invokes print
on the component.
- Overrides:
-
printAll
in classComponent
- Parameters:
-
g
- theGraphics
context in which to paint - See Also:
-
print(java.awt.Graphics)
,printComponent(java.awt.Graphics)
,printBorder(java.awt.Graphics)
,printChildren(java.awt.Graphics)
public void print(Graphics g)
Invoke this method to print the component to the specified Graphics
. This method will result in invocations of printComponent
, printBorder
and printChildren
. 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: to true
immediately before rendering and to false
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
.
- Overrides:
-
print
in classContainer
- Parameters:
-
g
- theGraphics
context in which to paint - See Also:
-
printComponent(java.awt.Graphics)
,printBorder(java.awt.Graphics)
,printChildren(java.awt.Graphics)
,isPaintingForPrint()
printComponent
protected void printComponent(Graphics g)
This is invoked during a printing operation. This is implemented to invoke paintComponent
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:
print(java.awt.Graphics)
printChildren
protected void printChildren(Graphics g)
Prints this component's children. This is implemented to invoke paintChildren
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:
print(java.awt.Graphics)
printBorder
protected void printBorder(Graphics g)
Prints the component's border. This is implemented to invoke paintBorder
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:
print(java.awt.Graphics)
isPaintingTile
@BeanProperty(bound=false) public boolean 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
@BeanProperty(bound=false) public final boolean isPaintingForPrint()
Returns true
if the current painting operation on this component is part of a print
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 is true
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:
print(java.awt.Graphics)
isManagingFocus
@Deprecated @BeanProperty(bound=false) public boolean isManagingFocus()
Component.setFocusTraversalKeys(int, Set)
and Container.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 prevents SortingFocusTraversalPolicy
from considering descendants of this JComponent when computing a focus traversal cycle.
- Returns:
- false
- See Also:
-
Component.setFocusTraversalKeys(int, java.util.Set<? extends java.awt.AWTKeyStroke>)
,SortingFocusTraversalPolicy
setNextFocusableComponent
@Deprecated public void setNextFocusableComponent(Component aComponent)
FocusTraversalPolicy
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 this JComponent
's focus traversal cycle by unconditionally setting the specified Component
as the next Component
in the cycle, and this JComponent
as the specified Component
's previous Component
in the cycle.
- Parameters:
-
aComponent
- theComponent
that should follow thisJComponent
in the focus traversal cycle - See Also:
-
getNextFocusableComponent()
,FocusTraversalPolicy
getNextFocusableComponent
@Deprecated public Component getNextFocusableComponent()
FocusTraversalPolicy
.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 to setNextFocusableComponent(Component)
on this JComponent
.
- Returns:
- the
Component
that will follow thisJComponent
in the focus traversal cycle, ornull
if none has been explicitly specified - See Also:
setNextFocusableComponent(java.awt.Component)
setRequestFocusEnabled
public void setRequestFocusEnabled(boolean requestFocusEnabled)
Provides a hint as to whether or not this JComponent
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 a JComponent
to steal focus, but did want the JComponent
to be traversable via the keyboard. If you do not want this JComponent
focusable at all, use the setFocusable
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:
-
Focus Specification,
Component.setFocusable(boolean)
isRequestFocusEnabled
public boolean isRequestFocusEnabled()
Returns true
if this JComponent
should get focus; otherwise returns false
.
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:
-
setRequestFocusEnabled(boolean)
, Focus Specification,Component.isFocusable()
requestFocus
public void requestFocus()
Requests that this Component
gets the input focus. Refer to Component.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:
-
Component.requestFocusInWindow()
,Component.requestFocusInWindow(boolean)
requestFocus
public boolean requestFocus(boolean temporary)
Requests that this Component
gets the input focus. Refer to Component.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:
-
Component.requestFocusInWindow()
,Component.requestFocusInWindow(boolean)
requestFocusInWindow
public boolean requestFocusInWindow()
Requests that this Component
gets the input focus. Refer to Component.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:
-
Component.requestFocusInWindow()
,Component.requestFocusInWindow(boolean)
requestFocusInWindow
protected boolean requestFocusInWindow(boolean temporary)
Requests that this Component
gets the input focus. Refer to Component.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:
-
Component.requestFocusInWindow()
,Component.requestFocusInWindow(boolean)
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:
requestFocusInWindow()
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:
-
InputVerifier
,setInputVerifier(javax.swing.InputVerifier)
,getInputVerifier()
,getVerifyInputWhenFocusTarget()
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:
-
InputVerifier
,setInputVerifier(javax.swing.InputVerifier)
,getInputVerifier()
,setVerifyInputWhenFocusTarget(boolean)
getFontMetrics
public FontMetrics getFontMetrics(Font font)
Gets the FontMetrics
for the specified Font
.
- 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:
-
Component.getFont()
,ComponentPeer.getFontMetrics(Font)
,Toolkit.getFontMetrics(Font)
setPreferredSize
@BeanProperty(preferred=true, description="The preferred size of the component.") public void setPreferredSize(Dimension preferredSize)
Sets the preferred size of this component. If preferredSize
is null
, the UI will be asked for the preferred size.
- Overrides:
-
setPreferredSize
in classComponent
- Parameters:
-
preferredSize
- The new preferred size, or null - See Also:
-
Component.getPreferredSize()
,Component.isPreferredSizeSet()
getPreferredSize
public Dimension getPreferredSize()
If the preferredSize
has been set to a non-null
value just returns it. If the UI delegate's getPreferredSize
method returns a non null
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:
-
setPreferredSize(java.awt.Dimension)
,ComponentUI
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 to getMaximumSize
will always return this value; the component's UI will not be asked to compute it. Setting the maximum size to null
restores the default behavior.
- Overrides:
-
setMaximumSize
in classComponent
- Parameters:
-
maximumSize
- aDimension
containing the desired maximum allowable size - See Also:
getMaximumSize()
getMaximumSize
public Dimension getMaximumSize()
If the maximum size has been set to a non-null
value just returns it. If the UI delegate's getMaximumSize
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:
-
setMaximumSize(java.awt.Dimension)
,ComponentUI
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 to getMinimumSize
will always return this value; the component's UI will not be asked to compute it. Setting the minimum size to null
restores the default behavior.
- Overrides:
-
setMinimumSize
in classComponent
- Parameters:
-
minimumSize
- the new minimum size of this component - See Also:
getMinimumSize()
getMinimumSize
public Dimension getMinimumSize()
If the minimum size has been set to a non-null
value just returns it. If the UI delegate's getMinimumSize
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:
-
setMinimumSize(java.awt.Dimension)
,ComponentUI
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.
- Overrides:
-
contains
in classComponent
- Parameters:
-
x
- the x coordinate of the point -
y
- the y coordinate of the point - Returns:
- true if this component logically contains x,y
- See Also:
-
Component.contains(int, int)
,ComponentUI
setBorder
@BeanProperty(preferred=true, visualUpdate=true, description="The component\'s border.") public void setBorder(Border border)
Sets the border of this component. The Border
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 than JPanel
or JLabel
, we recommend that you put the component in a JPanel
and set the border on the JPanel
.
This is a bound property.
- Parameters:
-
border
- the border to be rendered for this component - See Also:
-
Border
,CompoundBorder
getBorder
public Border getBorder()
Returns the border of this component or null
if no border is currently set.
- Returns:
- the border object for this component
- See Also:
setBorder(javax.swing.border.Border)
getInsets
@BeanProperty(expert=true) public Insets getInsets()
If a border has been set on this component, returns the border's insets; otherwise calls super.getInsets
.
- Overrides:
-
getInsets
in classContainer
- Returns:
- the value of the insets property
- See Also:
setBorder(javax.swing.border.Border)
getInsets
public Insets getInsets(Insets insets)
Returns an Insets
object containing this component's inset values. The passed-in Insets
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. If insets
is null, this will allocate a new one.
- Parameters:
-
insets
- theInsets
object, which can be reused - Returns:
- the
Insets
object - See Also:
getInsets()
getAlignmentY
public float getAlignmentY()
Overrides Container.getAlignmentY
to return the vertical alignment.
- Overrides:
-
getAlignmentY
in classContainer
- Returns:
- the value of the
alignmentY
property - See Also:
-
setAlignmentY(float)
,Component.getAlignmentY()
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:
getAlignmentY()
getAlignmentX
public float getAlignmentX()
Overrides Container.getAlignmentX
to return the horizontal alignment.
- Overrides:
-
getAlignmentX
in classContainer
- Returns:
- the value of the
alignmentX
property - See Also:
-
setAlignmentX(float)
,Component.getAlignmentX()
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:
getAlignmentX()
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:
InputVerifier
getInputVerifier
public InputVerifier getInputVerifier()
Returns the input verifier for this component.
- Returns:
- the
inputVerifier
property - Since:
- 1.3
- See Also:
InputVerifier
getGraphics
@BeanProperty(bound=false) public Graphics getGraphics()
Returns this component's graphics context, which lets you draw on a component. Use this method to get a Graphics
object and then invoke operations on that object to draw on the component.
- Overrides:
-
getGraphics
in classComponent
- Returns:
- this components graphics context
- See Also:
Component.paint(java.awt.Graphics)
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:
setDebugGraphicsOptions(int)
registerKeyboardAction
public void registerKeyboardAction(ActionListener anAction, String aCommand, KeyStroke aKeyStroke, int aCondition)
This method is now obsolete, please use a combination of getActionMap()
and getInputMap()
for similar behavior. For example, to bind the KeyStroke
aKeyStroke
to the Action
anAction
now use:
component.getInputMap().put(aKeyStroke, aCommand); component.getActionMap().put(aCommmand, anAction);The above assumes you want the binding to be applicable for
WHEN_FOCUSED
. To register bindings for other focus states use the getInputMap
method that takes an integer.
Register a new keyboard action. anAction
will be invoked if a key event matching aKeyStroke
occurs and aCondition
is verified. The KeyStroke
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 registered -
aCommand
- the command to be set in the delivered event -
aKeyStroke
- theKeyStroke
to bind to the action -
aCondition
- the condition that needs to be met, see above - See Also:
KeyStroke
registerKeyboardAction
public void registerKeyboardAction(ActionListener anAction, KeyStroke aKeyStroke, int aCondition)
This method is now obsolete, please use a combination of getActionMap()
and getInputMap()
for similar behavior.
- Parameters:
-
anAction
- action to be registered to given keystroke and condition -
aKeyStroke
- aKeyStroke
-
aCondition
- the condition to be associated with given keystroke and action - See Also:
-
getActionMap()
,getInputMap(int)
unregisterKeyboardAction
public void unregisterKeyboardAction(KeyStroke aKeyStroke)
This method is now obsolete. To unregister an existing binding you can either remove the binding from the ActionMap/InputMap
, or place a dummy binding the InputMap
. Removing the binding from the InputMap
allows bindings in parent InputMap
s to be active, whereas putting a dummy binding in the InputMap
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 the InputMap
s.
- Parameters:
-
aKeyStroke
- the keystroke for which to unregister its keyboard action
getRegisteredKeyStrokes
@BeanProperty(bound=false) public KeyStroke[] getRegisteredKeyStrokes()
Returns the KeyStrokes
that will initiate registered actions.
- Returns:
- an array of
KeyStroke
objects - See Also:
registerKeyboardAction(java.awt.event.ActionListener, java.lang.String, javax.swing.KeyStroke, int)
getConditionForKeyStroke
public int getConditionForKeyStroke(KeyStroke aKeyStroke)
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 conditions WHEN_FOCUSED
and WHEN_IN_FOCUSED_WINDOW
condition.
- Parameters:
-
aKeyStroke
- the keystroke for which to request an action-keystroke condition - Returns:
- the action-keystroke condition
getActionForKeyStroke
public ActionListener getActionForKeyStroke(KeyStroke aKeyStroke)
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 tier InputMaps
and ActionMap
. This has the effect of removing any local bindings, and allowing the bindings defined in parent InputMap/ActionMaps
(the UI is usually defined in the second tier) to persist.
setInputMap
public final void setInputMap(int condition, InputMap map)
Sets the InputMap
to use under the condition condition
to map
. A null
value implies you do not want any bindings to be used, even from the UI. This will not reinstall the UI InputMap
(if there was one). condition
has one of the following values:
-
WHEN_IN_FOCUSED_WINDOW
-
WHEN_FOCUSED
-
WHEN_ANCESTOR_OF_FOCUSED_COMPONENT
condition
is WHEN_IN_FOCUSED_WINDOW
and map
is not a ComponentInputMap
, an IllegalArgumentException
will be thrown. Similarly, if condition
is not one of the values listed, an IllegalArgumentException
will be thrown. - Parameters:
-
condition
- one of the values listed above -
map
- 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
public final InputMap getInputMap(int condition)
Returns the InputMap
that is used during condition
.
- 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
public final InputMap getInputMap()
Returns the InputMap
that is used when the component has focus. This is convenience method for getInputMap(WHEN_FOCUSED)
.
- Returns:
- the
InputMap
used when the component has focus - Since:
- 1.3
setActionMap
public final void setActionMap(ActionMap am)
Sets the ActionMap
to am
. This does not set the parent of the am
to be the ActionMap
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
public final ActionMap getActionMap()
Returns the ActionMap
used to determine what Action
to fire for particular KeyStroke
binding. The returned ActionMap
, unless otherwise set, will have the ActionMap
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 for LayoutManager
s to align components along their baseline. A return value less than 0 indicates this component does not have a reasonable baseline and that LayoutManager
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 a ComponentUI
-1 will be returned. 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.
- Overrides:
-
getBaseline
in classComponent
- Parameters:
-
width
- the width to get the baseline for -
height
- 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()
,FontMetrics
getBaselineResizeBehavior
@BeanProperty(bound=false) public Component.BaselineResizeBehavior 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 a ComponentUI
BaselineResizeBehavior.OTHER
will be returned. 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.
- Overrides:
-
getBaselineResizeBehavior
in classComponent
- Returns:
- an enum indicating how the baseline changes as the component size changes
- Since:
- 1.6
- See Also:
getBaseline(int, int)
requestDefaultFocus
@Deprecated public boolean requestDefaultFocus()
FocusTraversalPolicy.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
's FocusTraversalPolicy
's default Component
. If this JComponent
is a focus cycle root, then its FocusTraversalPolicy
is used. Otherwise, the FocusTraversalPolicy
of this JComponent
'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:
FocusTraversalPolicy.getDefaultComponent(java.awt.Container)
setVisible
@BeanProperty(hidden=true, visualUpdate=true) public void setVisible(boolean aFlag)
Makes the component visible or invisible. Overrides Component.setVisible
.
- Overrides:
-
setVisible
in classComponent
- Parameters:
-
aFlag
- true to make the component visible; false to make it invisible - See Also:
-
Component.isVisible()
,Component.invalidate()
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:
-
Component.isEnabled()
,Component.isLightweight()
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:
Component.getForeground()
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 of JComponent
or ComponentUI
implementations. Direct subclasses of JComponent
must override paintComponent
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:
-
Component.getBackground()
,setOpaque(boolean)
setFont
@BeanProperty(preferred=true, visualUpdate=true, description="The font for the component.") public void setFont(Font font)
Sets the font for this component.
- Overrides:
-
setFont
in classContainer
- Parameters:
-
font
- the desiredFont
for this component - See Also:
Component.getFont()
getDefaultLocale
public static Locale 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(java.util.Locale)
,Component.getLocale()
,Component.setLocale(java.util.Locale)
setDefaultLocale
public static void setDefaultLocale(Locale l)
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).
- Parameters:
-
l
- the desired defaultLocale
for new components. - Since:
- 1.4
- See Also:
-
getDefaultLocale()
,Component.getLocale()
,Component.setLocale(java.util.Locale)
processComponentKeyEvent
protected void processComponentKeyEvent(KeyEvent e)
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
protected void processKeyEvent(KeyEvent e)
Overrides processKeyEvent
to process events.
- Overrides:
-
processKeyEvent
in classComponent
- Parameters:
-
e
- the key event - See Also:
-
KeyEvent
,KeyListener
,KeyboardFocusManager
,DefaultKeyboardFocusManager
,Component.processEvent(java.awt.AWTEvent)
,Component.dispatchEvent(java.awt.AWTEvent)
,Component.addKeyListener(java.awt.event.KeyListener)
,Component.enableEvents(long)
,Component.isShowing()
processKeyBinding
protected boolean processKeyBinding(KeyStroke ks, KeyEvent e, int condition, boolean pressed)
Invoked to process the key bindings for ks
as the result of the KeyEvent
e
. This obtains the appropriate InputMap
, gets the binding, gets the action from the ActionMap
, and then (if the action is found and the component is enabled) invokes notifyAction
to notify the action.
- Parameters:
-
ks
- theKeyStroke
queried -
e
- 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:
TOOL_TIP_TEXT_KEY
getToolTipText
public String getToolTipText()
Returns the tooltip string that has been set with setToolTipText
.
- Returns:
- the text of the tool tip
- See Also:
TOOL_TIP_TEXT_KEY
getToolTipText
public String getToolTipText(MouseEvent event)
Returns the string to be used as the tooltip for event. By default this returns any string set using setToolTipText
. 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
public Point getToolTipLocation(MouseEvent event)
Returns the tooltip location in this component's coordinate system. If null
is returned, Swing will choose a location. The default implementation returns null
.
- Parameters:
-
event
- theMouseEvent
that caused theToolTipManager
to show the tooltip - Returns:
- always returns
null
getPopupLocation
public Point getPopupLocation(MouseEvent event)
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. If null
, 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
public JToolTip createToolTip()
Returns the instance of JToolTip
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
public void scrollRectToVisible(Rectangle aRect)
Forwards the scrollRectToVisible()
message to the JComponent
's parent. Components that can service the request, such as JViewport
, override this method and perform the scrolling.
- Parameters:
-
aRect
- the visibleRectangle
- See Also:
JViewport
setAutoscrolls
@BeanProperty(bound=false, expert=true, description="Determines if this component automatically scrolls its contents when dragged.") public void setAutoscrolls(boolean autoscrolls)
Sets the autoscrolls
property. If true
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 handle mouseDragged
events by calling scrollRectToVisible
with a rectangle that contains the mouse event's location. All of the Swing components that support item selection and are typically displayed in a JScrollPane
(JTable
, JList
, JTree
, JTextArea
, and JEditorPane
) already handle mouse dragged events in this way. To enable autoscrolling in any other component, add a mouse motion listener that calls scrollRectToVisible
. For example, given a JPanel
, 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 the
autoScrolls
property is false
. - 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()
,JViewport
,JScrollPane
getAutoscrolls
public boolean getAutoscrolls()
Gets the autoscrolls
property.
- Returns:
- the value of the
autoscrolls
property - See Also:
-
JViewport
,setAutoscrolls(boolean)
setTransferHandler
@BeanProperty(hidden=true, description="Mechanism for transfer of data to and from the component") public void setTransferHandler(TransferHandler newHandler)
Sets the TransferHandler
, which provides support for transfer of data into and out of this component via cut/copy/paste and drag and drop. This may be null
if the component does not support data transfer operations.
If the new TransferHandler
is not null
, this method also installs a new DropTarget
on the component to activate drop handling through the TransferHandler
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
is null
, 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 property suppressSwingDropSupport
is true
. The default value for the system property is false
.
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:
-
TransferHandler
,getTransferHandler()
getTransferHandler
public TransferHandler getTransferHandler()
Gets the transferHandler
property.
- Returns:
- the value of the
transferHandler
property - Since:
- 1.4
- See Also:
-
TransferHandler
,setTransferHandler(javax.swing.TransferHandler)
processMouseEvent
protected void processMouseEvent(MouseEvent e)
Processes mouse events occurring on this component by dispatching them to any registered MouseListener
objects, refer to Component.processMouseEvent(MouseEvent)
for a complete description of this method.
- Overrides:
-
processMouseEvent
in classComponent
- Parameters:
-
e
- the mouse event - Since:
- 1.5
- See Also:
Component.processMouseEvent(java.awt.event.MouseEvent)
processMouseMotionEvent
protected void processMouseMotionEvent(MouseEvent e)
Processes mouse motion events, such as MouseEvent.MOUSE_DRAGGED.
- Overrides:
-
processMouseMotionEvent
in classComponent
- Parameters:
-
e
- theMouseEvent
- See Also:
MouseEvent
enable
@Deprecated public void enable()
java.awt.Component.setEnabled(boolean)
.disable
@Deprecated public void disable()
java.awt.Component.setEnabled(boolean)
.getClientProperty
public final Object getClientProperty(Object key)
Returns the value of the property with the specified key. Only properties added with putClientProperty
will return a non-null
value.
- Parameters:
-
key
- the being queried - Returns:
- the value of this property or
null
- See Also:
putClientProperty(java.lang.Object, java.lang.Object)
putClientProperty
public final void putClientProperty(Object key, Object value)
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 is
null
this method will remove the property. Changes to client properties are reported with PropertyChange
events. The name of the property (for the sake of PropertyChange events) is key.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 key -
value
- the new client property value; ifnull
this method will remove the property - See Also:
-
getClientProperty(java.lang.Object)
,Container.addPropertyChangeListener(java.beans.PropertyChangeListener)
setFocusTraversalKeys
public void setFocusTraversalKeys(int id, Set<? extends AWTKeyStroke> keystrokes)
Sets the focus traversal keys for a given traversal operation for this Component. Refer to Component.setFocusTraversalKeys(int, java.util.Set<? extends java.awt.AWTKeyStroke>)
for a complete description of this method.
This method may throw a ClassCastException
if any Object
in keystrokes
is not an AWTKeyStroke
.
- Overrides:
-
setFocusTraversalKeys
in classContainer
- Parameters:
-
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 - 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:
-
KeyboardFocusManager.FORWARD_TRAVERSAL_KEYS
,KeyboardFocusManager.BACKWARD_TRAVERSAL_KEYS
,KeyboardFocusManager.UP_CYCLE_TRAVERSAL_KEYS
isLightweightComponent
public static boolean isLightweightComponent(Component c)
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 public void reshape(int x, int y, int w, int h)
As of JDK 5, replaced by Component.setBounds(int, int, int, int)
.
Moves and resizes this component.
Description copied from class: Component
Reshapes the bounding rectangle for this component.
- Overrides:
-
reshape
in classComponent
- Parameters:
-
x
- the new horizontal location -
y
- the new vertical location -
w
- the new width -
h
- the new height - See Also:
Component.setBounds(int, int, int, int)
getBounds
public Rectangle getBounds(Rectangle rv)
Stores the bounds of this component into "return value" rv
and returns rv
. If rv
is null
a new Rectangle
is allocated. This version of getBounds
is useful if the caller wants to avoid allocating a new Rectangle
object on the heap.
- Overrides:
-
getBounds
in classComponent
- Parameters:
-
rv
- the return value, modified to the component's bounds - Returns:
-
rv
; ifrv
isnull
return a newly createdRectangle
with this component's bounds
getSize
public Dimension getSize(Dimension rv)
Stores the width/height of this component into "return value" rv
and returns rv
. If rv
is null
a new Dimension
object is allocated. This version of getSize
is useful if the caller wants to avoid allocating a new Dimension
object on the heap.
- Overrides:
-
getSize
in classComponent
- Parameters:
-
rv
- the return value, modified to the component's size - Returns:
rv
getLocation
public Point getLocation(Point rv)
Stores the x,y origin of this component into "return value" rv
and returns rv
. If rv
is null
a new Point
is allocated. This version of getLocation
is useful if the caller wants to avoid allocating a new Point
object on the heap.
- Overrides:
-
getLocation
in classComponent
- Parameters:
-
rv
- the return value, modified to the component's location - Returns:
rv
getX
@BeanProperty(bound=false) public int getX()
Returns the current x coordinate of the component's origin. This method is preferable to writing component.getBounds().x
, or component.getLocation().x
because it doesn't cause any heap allocations.
getY
@BeanProperty(bound=false) public int getY()
Returns the current y coordinate of the component's origin. This method is preferable to writing component.getBounds().y
, or component.getLocation().y
because it doesn't cause any heap allocations.
getWidth
@BeanProperty(bound=false) public int getWidth()
Returns the current width of this component. This method is preferable to writing component.getBounds().width
, or component.getSize().width
because it doesn't cause any heap allocations.
getHeight
@BeanProperty(bound=false) public int getHeight()
Returns the current height of this component. This method is preferable to writing component.getBounds().height
, or component.getSize().height
because it doesn't cause any heap allocations.
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.
- Overrides:
-
isOpaque
in classComponent
- Returns:
- true if this component is completely opaque
- See Also:
setOpaque(boolean)
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 standard JComponent
subclasses (such as JButton
and JTree
) is look-and-feel dependent.
- Parameters:
-
isOpaque
- true if this component should be opaque - See Also:
isOpaque()
computeVisibleRect
public void computeVisibleRect(Rectangle visibleRect)
Returns the Component
's "visible rect rectangle" - the intersection of the visible rectangles for this component and all of its ancestors. The return value is stored in visibleRect
.
- 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()
getVisibleRect
@BeanProperty(bound=false) public Rectangle getVisibleRect()
Returns the Component
'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
public void firePropertyChange(String propertyName, boolean oldValue, boolean newValue)
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 changed -
oldValue
- the property's previous value -
newValue
- the property's new value
firePropertyChange
public void firePropertyChange(String propertyName, int oldValue, int newValue)
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 changed -
oldValue
- the property's previous value -
newValue
- 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 appropriate PropertyChangeEvent
to any registered VetoableChangeListeners
.
- Parameters:
-
propertyName
- the name of the property that was listened on -
oldValue
- the old value of the property -
newValue
- the new value of the property - Throws:
-
PropertyVetoException
- when the attempt to set the property is vetoed by the component
addVetoableChangeListener
public void addVetoableChangeListener(VetoableChangeListener listener)
Adds a VetoableChangeListener
to the listener list. The listener is registered for all properties.
- Parameters:
-
listener
- theVetoableChangeListener
to be added
removeVetoableChangeListener
public void removeVetoableChangeListener(VetoableChangeListener listener)
Removes a VetoableChangeListener
from the listener list. This removes a VetoableChangeListener
that was registered for all properties.
- Parameters:
-
listener
- theVetoableChangeListener
to be removed
getVetoableChangeListeners
@BeanProperty(bound=false) public VetoableChangeListener[] 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:
-
addVetoableChangeListener(java.beans.VetoableChangeListener)
,removeVetoableChangeListener(java.beans.VetoableChangeListener)
getTopLevelAncestor
@BeanProperty(bound=false) public Container getTopLevelAncestor()
Returns the top-level ancestor of this component (either the containing Window
or Applet
), or null
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
public void addAncestorListener(AncestorListener listener)
Registers listener
so that it will receive AncestorEvents
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:
AncestorEvent
removeAncestorListener
public void removeAncestorListener(AncestorListener listener)
Unregisters listener
so that it will no longer receive AncestorEvents
.
- Parameters:
-
listener
- theAncestorListener
to be removed - See Also:
addAncestorListener(javax.swing.event.AncestorListener)
getAncestorListeners
@BeanProperty(bound=false) public AncestorListener[] 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:
-
addAncestorListener(javax.swing.event.AncestorListener)
,removeAncestorListener(javax.swing.event.AncestorListener)
getListeners
public <T extends EventListener> T[] getListeners(Class<T> listenerType)
Returns an array of all the objects currently registered as FooListener
s upon this JComponent
. FooListener
s 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 JComponent
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:
-
getVetoableChangeListeners()
,getAncestorListeners()
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 with KeyboardAction
event listeners. This method is called by the toolkit internally and should not be called directly by programs.
- Overrides:
-
addNotify
in classContainer
- See Also:
registerKeyboardAction(java.awt.event.ActionListener, java.lang.String, javax.swing.KeyStroke, int)
removeNotify
public void removeNotify()
Notifies this component that it no longer has a parent component. When this method is invoked, any KeyboardAction
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:
registerKeyboardAction(java.awt.event.ActionListener, java.lang.String, javax.swing.KeyStroke, int)
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.
- Overrides:
-
repaint
in classComponent
- Parameters:
-
tm
- this parameter is not used -
x
- the x value of the dirty region -
y
- the y value of the dirty region -
width
- the width of the dirty region -
height
- the height of the dirty region - See Also:
-
isPaintingOrigin()
,Component.isShowing()
,RepaintManager.addDirtyRegion(javax.swing.JComponent, int, int, int, int)
repaint
public void repaint(Rectangle r)
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:
-
isPaintingOrigin()
,Component.isShowing()
,RepaintManager.addDirtyRegion(javax.swing.JComponent, int, int, int, int)
revalidate
public void revalidate()
Supports deferred automatic layout.
Calls invalidate
and then adds this component's validateRoot
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
, and JTextField
return true from isValidateRoot
.
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:
-
Component.invalidate()
,Container.validate()
,isValidateRoot()
,RepaintManager.addInvalidComponent(javax.swing.JComponent)
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:
-
revalidate()
,Component.invalidate()
,Container.validate()
,Container.isValidateRoot()
isOptimizedDrawingEnabled
@BeanProperty(bound=false) public boolean 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 as JLayeredPane
, should override this method to return false.
- Returns:
- always returns true
isPaintingOrigin
protected boolean isPaintingOrigin()
Returns true
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)
or paintImmediately(int, int, int, int)
on a Swing component will result in calling the paintImmediately(int, int, int, int)
method of the first ancestor which isPaintingOrigin()
returns true
, if there are any.
JComponent
subclasses that need to be painted when any of their children are repainted should override this method to return true
.
- Returns:
- always returns
false
- See Also:
paintImmediately(int, int, int, int)
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 painted -
y
- the y value of the region to be painted -
w
- the width of the region to be painted -
h
- the height of the region to be painted - See Also:
-
repaint(long, int, int, int, int)
,isPaintingOrigin()
paintImmediately
public void paintImmediately(Rectangle r)
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 a Component
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
@BeanProperty(bound=false) public JRootPane getRootPane()
Returns the JRootPane
ancestor for this component.
- Returns:
- the
JRootPane
that contains this component, ornull
if noJRootPane
is found
paramString
protected String paramString()
Returns a string representation of this JComponent
. 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 be null
.
- Overrides:
-
paramString
in classContainer
- Returns:
- a string representation of this
JComponent
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Licensed under the GNU General Public License, version 2, with the Classpath Exception.
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https://docs.oracle.com/en/java/javase/11/docs/api/java.desktop/javax/swing/JComponent.html