javax.swing
Class JLabel

java.lang.Object   
  java.awt.Component   
      java.awt.Container   
          javax.swing.JComponent   
              javax.swing.JLabel

All Implemented Interfaces:

ImageObserver , MenuContainer , Serializable , Accessible , SwingConstants

Direct Known Subclasses:

BasicComboBoxRenderer , DefaultListCellRenderer , DefaultTableCellRenderer , DefaultTreeCellRenderer

public class JLabel
extends JComponent   
implements SwingConstants   , Accessible   

A display area for a short text string or an image, or both. A label does not react to input events. As a result, it cannot get the keyboard focus. A label can, however, display a keyboard alternative as a convenience for a nearby component that has a keyboard alternative but can't display it.

A JLabel object can display either text, an image, or both. You can specify where in the label's display area the label's contents are aligned by setting the vertical and horizontal alignment. By default, labels are vertically centered in their display area. Text-only labels are leading edge aligned, by default; image-only labels are horizontally centered, by default.

You can also specify the position of the text relative to the image. By default, text is on the trailing edge of the image, with the text and image vertically aligned.

A label's leading and trailing edge are determined from the value of its ComponentOrientation property. At present, the default ComponentOrientation setting maps the leading edge to left and the trailing edge to right.

Finally, you can use the setIconTextGap method to specify how many pixels should appear between the text and the image. The default is 4 pixels.

See How to Use Labels in The Java Tutorial for further documentation.

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^TM has been added to the java.beans package. Please see XMLEncoder .

See Also:

Serialized Form

Nested Class Summary

protected class

JLabel.AccessibleJLabel The class used to obtain the accessible role for this object.

Nested classes/interfaces inherited from class javax.swing.JComponent

JComponent.AccessibleJComponent

Nested classes/interfaces inherited from class java.awt.Container

Container.AccessibleAWTContainer

Nested classes/interfaces inherited from class java.awt.Component

Component.AccessibleAWTComponent , Component.BltBufferStrategy , Component.FlipBufferStrategy

Field Summary

protected Component

labelFor

Fields inherited from class javax.swing.JComponent

accessibleContext , listenerList , TOOL_TIP_TEXT_KEY , ui , UNDEFINED_CONDITION , WHEN_ANCESTOR_OF_FOCUSED_COMPONENT , WHEN_FOCUSED , WHEN_IN_FOCUSED_WINDOW

Fields inherited from class java.awt.Component

BOTTOM_ALIGNMENT , CENTER_ALIGNMENT , LEFT_ALIGNMENT , RIGHT_ALIGNMENT , TOP_ALIGNMENT

Fields inherited from interface javax.swing.SwingConstants

BOTTOM , CENTER , EAST , HORIZONTAL , LEADING , LEFT , NEXT , NORTH , NORTH_EAST , NORTH_WEST , PREVIOUS , RIGHT , SOUTH , SOUTH_EAST , SOUTH_WEST , TOP , TRAILING , VERTICAL , WEST

Fields inherited from interface java.awt.image.ImageObserver

ABORT , ALLBITS , ERROR , FRAMEBITS , HEIGHT , PROPERTIES , SOMEBITS , WIDTH

Constructor Summary

JLabel ()
Creates a JLabel instance with no image and with an empty string for the title.

JLabel (Icon image)
Creates a JLabel instance with the specified image.

JLabel (Icon image, int horizontalAlignment)
Creates a JLabel instance with the specified image and horizontal alignment.

JLabel (String text)
Creates a JLabel instance with the specified text.

JLabel (String text, Icon icon, int horizontalAlignment)
Creates a JLabel instance with the specified text, image, and horizontal alignment.

JLabel (String text, int horizontalAlignment)
Creates a JLabel instance with the specified text and horizontal alignment.

Method Summary

protected int	checkHorizontalKey (int key, String message) Verify that key is a legal value for the horizontalAlignment properties.
protected int	checkVerticalKey (int key, String message) Verify that key is a legal value for the verticalAlignment or verticalTextPosition properties.
AccessibleContext	getAccessibleContext () Get the AccessibleContext of this object
Icon	getDisabledIcon () Returns the icon used by the label when it's disabled.
int	getDisplayedMnemonic () Return the keycode that indicates a mnemonic key.
int	getDisplayedMnemonicIndex () Returns the character, as an index, that the look and feel should provide decoration for as representing the mnemonic character.
int	getHorizontalAlignment () Returns the alignment of the label's contents along the X axis.
int	getHorizontalTextPosition () Returns the horizontal position of the label's text, relative to its image.
Icon	getIcon () Returns the graphic image (glyph, icon) that the label displays.
int	getIconTextGap () Returns the amount of space between the text and the icon displayed in this label.
Component	getLabelFor () Get the component this is labelling.
String	getText () Returns the text string that the label displays.
LabelUI	getUI () Returns the L&F object that renders this component.
String	getUIClassID () Returns a string that specifies the name of the l&f class that renders this component.
int	getVerticalAlignment () Returns the alignment of the label's contents along the Y axis.
int	getVerticalTextPosition () Returns the vertical position of the label's text, relative to its image.
boolean	imageUpdate (Image img, int infoflags, int x, int y, int w, int h) This is overridden to return false if the current Icon's Image is not equal to the passed in Image img.
protected String	paramString () Returns a string representation of this JLabel.
void	setDisabledIcon (Icon disabledIcon) Set the icon to be displayed if this JLabel is "disabled" (JLabel.setEnabled(false)).
void	setDisplayedMnemonic (char aChar) Specifies the displayedMnemonic as a char value.
void	setDisplayedMnemonic (int key) Specify a keycode that indicates a mnemonic key.
void	setDisplayedMnemonicIndex (int index) Provides a hint to the look and feel as to which character in the text should be decorated to represent the mnemonic.
void	setHorizontalAlignment (int alignment) Sets the alignment of the label's contents along the X axis.
void	setHorizontalTextPosition (int textPosition) Sets the horizontal position of the label's text, relative to its image.
void	setIcon (Icon icon) Defines the icon this component will display.
void	setIconTextGap (int iconTextGap) If both the icon and text properties are set, this property defines the space between them.
void	setLabelFor (Component c) Set the component this is labelling.
void	setText (String text) Defines the single line of text this component will display.
void	setUI (LabelUI ui) Sets the L&F object that renders this component.
void	setVerticalAlignment (int alignment) Sets the alignment of the label's contents along the Y axis.
void	setVerticalTextPosition (int textPosition) Sets the vertical position of the label's text, relative to its image.
void	updateUI () Resets the UI property to a value from the current look and feel.

Methods inherited from class javax.swing.JComponent

addAncestorListener , addNotify , addVetoableChangeListener , computeVisibleRect , contains , createToolTip , disable , enable , firePropertyChange , firePropertyChange , firePropertyChange , fireVetoableChange , getActionForKeyStroke , getActionMap , getAlignmentX , getAlignmentY , getAncestorListeners , getAutoscrolls , getBorder , getBounds , getClientProperty , getComponentGraphics , getComponentPopupMenu , getConditionForKeyStroke , getDebugGraphicsOptions , getDefaultLocale , getFontMetrics , getGraphics , getHeight , getInheritsPopupMenu ,