public class JLabel extends JComponentimplements SwingConstants , Accessible
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: 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.
| Modifier and Type | Class and Description |
|---|---|
protected class |
JLabel
The class used to obtain the accessible role for this object.
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JComponent.AccessibleJComponent Container.AccessibleAWTContainer Component.AccessibleAWTComponent , Component.BaselineResizeBehavior , Component.BltBufferStrategy , Component.FlipBufferStrategy | Modifier and Type | Field and Description |
|---|---|
protected Component |
labelFor
|
listenerList, TOOL_TIP_TEXT_KEY, ui, UNDEFINED_CONDITION, WHEN_ANCESTOR_OF_FOCUSED_COMPONENT, WHEN_FOCUSED, WHEN_IN_FOCUSED_WINDOWaccessibleContext, BOTTOM_ALIGNMENT, CENTER_ALIGNMENT, LEFT_ALIGNMENT, RIGHT_ALIGNMENT, TOP_ALIGNMENTBOTTOM, CENTER, EAST, HORIZONTAL, LEADING, LEFT, NEXT, NORTH, NORTH_EAST, NORTH_WEST, PREVIOUS, RIGHT, SOUTH, SOUTH_EAST, SOUTH_WEST, TOP, TRAILING, VERTICAL, WESTABORT, ALLBITS, ERROR, FRAMEBITS, HEIGHT, PROPERTIES, SOMEBITS, WIDTH| Constructor and Description |
|---|
JLabel()
Creates a
JLabel instance with no image and with an empty string for the title.
|
JLabel(Icon
Creates a
JLabel instance with the specified image.
|
JLabel(Icon
Creates a
JLabel instance with the specified image and horizontal alignment.
|
JLabel(String
Creates a
JLabel instance with the specified text.
|
JLabel(String
Creates a
JLabel instance with the specified text, image, and horizontal alignment.
|
JLabel(String
Creates a
JLabel instance with the specified text and horizontal alignment.
|
| Modifier and Type | Method and Description |
|---|---|
protected int |
checkHorizontalKey(int key, String
Verify that key is a legal value for the horizontalAlignment properties.
|
protected int |
checkVerticalKey(int key, String
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
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
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
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
Set the component this is labelling.
|
void |
setText(String
Defines the single line of text this component will display.
|
void |
setUI(LabelUI
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.
|
addAncestorListener, addNotify, addVetoableChangeListener, computeVisibleRect, contains, createToolTip, disable, enable, firePropertyChange, firePropertyChange, firePropertyChange, fireVetoableChange, getActionForKeyStroke, getActionMap, getAlignmentX, getAlignmentY, getAncestorListeners, getAutoscrolls, getBaseline, getBaselineResizeBehavior, getBorder, getBounds, getClientProperty, getComponentGraphics, getComponentPopupMenu, getConditionForKeyStroke, getDebugGraphicsOptions, getDefaultLocale, getFontMetrics, getGraphics, getHeight, getInheritsPopupMenu, getInputMap, getInputMap, getInputVerifier, getInsets, getInsets, getListeners, getLocation, getMaximumSize, getMinimumSize, getNextFocusableComponent, getPopupLocation, getPreferredSize, getRegisteredKeyStrokes, getRootPane, getSize, getToolTipLocation, getToolTipText, getToolTipText, getTopLevelAncestor, getTransferHandler, getVerifyInputWhenFocusTarget, getVetoableChangeListeners, getVisibleRect, getWidth, getX, getY, grabFocus, hide, isDoubleBuffered, isLightweightComponent, isManagingFocus, isOpaque, isOptimizedDrawingEnabled, isPaintingForPrint, isPaintingOrigin, isPaintingTile, isRequestFocusEnabled, isValidateRoot, paint, paintBorder, paintChildren, paintComponent, paintImmediately, paintImmediately, print, printAll, printBorder, printChildren, printComponent, processComponentKeyEvent, processKeyBinding, processKeyEvent, processMouseEvent, processMouseMotionEvent, putClientProperty, registerKeyboardAction, registerKeyboardAction, removeAncestorListener, removeNotify, removeVetoableChangeListener, repaint, repaint, requestDefaultFocus, requestFocus, requestFocus, requestFocusInWindow, requestFocusInWindow, resetKeyboardActions, reshape, revalidate, scrollRectToVisible, setActionMap, setAlignmentX, setAlignmentY, setAutoscrolls, setBackground, setBorder, setComponentPopupMenu, setDebugGraphicsOptions, setDefaultLocale, setDoubleBuffered, setEnabled, setFocusTraversalKeys, setFont, setForeground, setInheritsPopupMenu, setInputMap, setInputVerifier, setMaximumSize, setMinimumSize, setNextFocusableComponent, setOpaque, setPreferredSize, setRequestFocusEnabled, setToolTipText, setTransferHandler, setUI, setVerifyInputWhenFocusTarget, setVisible, unregisterKeyboardAction, updateadd, 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, validateTreeaction, 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, 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, getPeer, getPropertyChangeListeners, getPropertyChangeListeners, getSize, getToolkit, getTreeLock, gotFocus, handleEvent, hasFocus, 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, resize, resize, setBounds, setBounds, setComponentOrientation, setCursor, setDropTarget, setFocusable, setFocusTraversalKeysEnabled, setIgnoreRepaint, setLocale, setLocation, setLocation, setName, setSize, setSize, show, show, size, toString, transferFocus, transferFocusBackward, transferFocusUpCycleprotected ComponentlabelFor
public JLabel(Stringtext, Icon icon, int horizontalAlignment)
JLabel instance with the specified text, image, and horizontal alignment. The label is centered vertically in its display area. The text is on the trailing edge of the image.
text - The text to be displayed by the label.
icon - The image to be displayed by the label.
horizontalAlignment - One of the following constants defined in
SwingConstants:
LEFT,
CENTER,
RIGHT,
LEADING or
TRAILING.
public JLabel(Stringtext, int horizontalAlignment)
JLabel instance with the specified text and horizontal alignment. The label is centered vertically in its display area.
text - The text to be displayed by the label.
horizontalAlignment - One of the following constants defined in
SwingConstants:
LEFT,
CENTER,
RIGHT,
LEADING or
TRAILING.
public JLabel(Stringtext)
JLabel instance with the specified text. The label is aligned against the leading edge of its display area, and centered vertically.
text - The text to be displayed by the label.
public JLabel(Iconimage, int horizontalAlignment)
JLabel instance with the specified image and horizontal alignment. The label is centered vertically in its display area.
image - The image to be displayed by the label.
horizontalAlignment - One of the following constants defined in
SwingConstants:
LEFT,
CENTER,
RIGHT,
LEADING or
TRAILING.
public JLabel(Iconimage)
JLabel instance with the specified image. The label is centered vertically and horizontally in its display area.
image - The image to be displayed by the label.
public JLabel()
JLabel instance with no image and with an empty string for the title. The label is centered vertically in its display area. The label's contents, once set, will be displayed on the leading edge of the label's display area.
public LabelUIgetUI()
public void setUI(LabelUIui)
ui - the LabelUI L&F object
UIDefaults.getUI(javax.swing.JComponent)
public void updateUI()
updateUI in class
JComponent
JComponent.updateUI()
public StringgetUIClassID()
getUIClassID in class
JComponent
JComponent.getUIClassID() ,
UIDefaults.getUI(javax.swing.JComponent)
public StringgetText()
setText(java.lang.String)
public void setText(Stringtext)
The default value of this property is null.
This is a JavaBeans bound property.
public IcongetIcon()
setIcon(javax.swing.Icon)
public void setIcon(Iconicon)
The default value of this property is null.
This is a JavaBeans bound property.
public IcongetDisabledIcon()
Some look and feels might not render the disabled Icon, in which case they will ignore this.
disabledIcon property
setDisabledIcon(javax.swing.Icon),
LookAndFeel.getDisabledIcon(javax.swing.JComponent, javax.swing.Icon) ,
ImageIcon
public void setDisabledIcon(IcondisabledIcon)
The default value of this property is null.
disabledIcon - the Icon to display when the component is disabled
getDisabledIcon(),
JComponent.setEnabled(boolean)
public void setDisplayedMnemonic(int key)
getLabelFor(),
setLabelFor(java.awt.Component)
public void setDisplayedMnemonic(char aChar)
aChar - a char specifying the mnemonic to display
setDisplayedMnemonic(int)
public int getDisplayedMnemonic()
getLabelFor(),
setLabelFor(java.awt.Component)
public void setDisplayedMnemonicIndex(int index)
throws IllegalArgumentException
The value of this is updated as the properties relating to the mnemonic change (such as the mnemonic itself, the text...). You should only ever have to call this if you do not wish the default character to be underlined. For example, if the text was 'Save As', with a mnemonic of 'a', and you wanted the 'A' to be decorated, as 'Save As', you would have to invoke setDisplayedMnemonicIndex(5) after invoking setDisplayedMnemonic(KeyEvent.VK_A).
index - Index into the String to underline
IllegalArgumentException - will be thrown if
index is >= length of the text, or < -1
public int getDisplayedMnemonicIndex()
setDisplayedMnemonicIndex(int)
protected int checkHorizontalKey(int key,
String message)
key - the property value to check
message - the IllegalArgumentException detail message
IllegalArgumentException - if key isn't LEFT, CENTER, RIGHT, LEADING or TRAILING.
setHorizontalTextPosition(int),
setHorizontalAlignment(int)
protected int checkVerticalKey(int key,
String message)
key - the property value to check
message - the IllegalArgumentException detail message
IllegalArgumentException - if key isn't TOP, CENTER, or BOTTOM.
setVerticalAlignment(int),
setVerticalTextPosition(int)
public int getIconTextGap()
setIconTextGap(int)
public void setIconTextGap(int iconTextGap)
The default value of this property is 4 pixels.
This is a JavaBeans bound property.
getIconTextGap()
public int getVerticalAlignment()
SwingConstants:
TOP,
CENTER, or
BOTTOM.
SwingConstants,
setVerticalAlignment(int)
public void setVerticalAlignment(int alignment)
The default value of this property is CENTER.
alignment - One of the following constants defined in
SwingConstants:
TOP,
CENTER (the default), or
BOTTOM.
SwingConstants,
getVerticalAlignment()
public int getHorizontalAlignment()
SwingConstants:
LEFT,
CENTER,
RIGHT,
LEADING or
TRAILING.
setHorizontalAlignment(int),
SwingConstants
public void setHorizontalAlignment(int alignment)
This is a JavaBeans bound property.
alignment - One of the following constants defined in
SwingConstants:
LEFT,
CENTER (the default for image-only labels),
RIGHT,
LEADING (the default for text-only labels) or
TRAILING.
SwingConstants,
getHorizontalAlignment()
public int getVerticalTextPosition()
SwingConstants:
TOP,
CENTER, or
BOTTOM.
setVerticalTextPosition(int),
SwingConstants
public void setVerticalTextPosition(int textPosition)
The default value of this property is CENTER.
This is a JavaBeans bound property.
textPosition - One of the following constants defined in
SwingConstants:
TOP,
CENTER (the default), or
BOTTOM.
SwingConstants,
getVerticalTextPosition()
public int getHorizontalTextPosition()
SwingConstants:
LEFT,
CENTER,
RIGHT,
LEADING or
TRAILING.
SwingConstants
public void setHorizontalTextPosition(int textPosition)
textPosition - One of the following constants defined in
SwingConstants:
LEFT,
CENTER,
RIGHT,
LEADING, or
TRAILING (the default).
IllegalArgumentException -
SwingConstants
public boolean imageUpdate(Imageimg, int infoflags, int x, int y, int w, int h)
img.
imageUpdate in interface
ImageObserver
imageUpdate in class
Component
img - the image being observed
infoflags - see
imageUpdate for more information
x - the
x coordinate
y - the
y coordinate
w - the width
h - the height
false if the infoflags indicate that the image is completely loaded;
true otherwise.
ImageObserver,
Component.imageUpdate(java.awt.Image, int, int, int, int, int)
protected StringparamString()
null.
paramString in class
JComponent
public ComponentgetLabelFor()
getDisplayedMnemonic(),
setDisplayedMnemonic(int)
public void setLabelFor(Componentc)
c - the Component this label is for, or null if the label is not the label for a component
getDisplayedMnemonic(),
setDisplayedMnemonic(int)
public AccessibleContextgetAccessibleContext()
getAccessibleContext in interface
Accessible
getAccessibleContext in class
Component