public class JLabel extends JComponent implements 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.AccessibleJLabel
The class used to obtain the accessible role for this object.
|
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_WINDOW
accessibleContext, BOTTOM_ALIGNMENT, CENTER_ALIGNMENT, LEFT_ALIGNMENT, RIGHT_ALIGNMENT, TOP_ALIGNMENT
BOTTOM, CENTER, EAST, HORIZONTAL, LEADING, LEFT, NEXT, NORTH, NORTH_EAST, NORTH_WEST, PREVIOUS, RIGHT, SOUTH, SOUTH_EAST, SOUTH_WEST, TOP, TRAILING, VERTICAL, WEST
ABORT, 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 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. |
Modifier and Type | Method and Description |
---|---|
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.
|
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, update
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
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, 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, transferFocusUpCycle
protected Component labelFor
public JLabel(String text, 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(String text, 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(String text)
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(Icon image, 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(Icon image)
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 LabelUI getUI()
public void setUI(LabelUI ui)
ui
- the LabelUI L&F objectUIDefaults.getUI(javax.swing.JComponent)
public void updateUI()
updateUI
in class JComponent
JComponent.updateUI()
public String getUIClassID()
getUIClassID
in class JComponent
JComponent.getUIClassID()
,
UIDefaults.getUI(javax.swing.JComponent)
public String getText()
setText(java.lang.String)
public void setText(String text)
The default value of this property is null.
This is a JavaBeans bound property.
public Icon getIcon()
setIcon(javax.swing.Icon)
public void setIcon(Icon icon)
The default value of this property is null.
This is a JavaBeans bound property.
public Icon getDisabledIcon()
Some look and feels might not render the disabled Icon, in which case they will ignore this.
disabledIcon
propertysetDisabledIcon(javax.swing.Icon)
,
LookAndFeel.getDisabledIcon(javax.swing.JComponent, javax.swing.Icon)
,
ImageIcon
public void setDisabledIcon(Icon disabledIcon)
The default value of this property is null.
disabledIcon
- the Icon to display when the component is disabledgetDisabledIcon()
,
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 displaysetDisplayedMnemonic(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 underlineIllegalArgumentException
- will be thrown if index
is >= length of the text, or < -1public int getDisplayedMnemonicIndex()
setDisplayedMnemonicIndex(int)
protected int checkHorizontalKey(int key, String message)
key
- the property value to checkmessage
- the IllegalArgumentException detail messageIllegalArgumentException
- 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 checkmessage
- the IllegalArgumentException detail messageIllegalArgumentException
- 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(Image img, int infoflags, int x, int y, int w, int h)
img
.imageUpdate
in interface ImageObserver
imageUpdate
in class Component
img
- the image being observedinfoflags
- see imageUpdate
for more informationx
- the x coordinatey
- the y coordinatew
- the widthh
- the heightfalse
if the infoflags indicate that the
image is completely loaded; true
otherwise.ImageObserver
,
Component.imageUpdate(java.awt.Image, int, int, int, int, int)
protected String paramString()
null
.paramString
in class JComponent
public Component getLabelFor()
getDisplayedMnemonic()
,
setDisplayedMnemonic(int)
public void setLabelFor(Component c)
c
- the Component this label is for, or null if the label is
not the label for a componentgetDisplayedMnemonic()
,
setDisplayedMnemonic(int)
public AccessibleContext getAccessibleContext()
getAccessibleContext
in interface Accessible
getAccessibleContext
in class Component
Submit a bug or feature
For further API reference and developer documentation, see Java SE Documentation. That documentation contains more detailed, developer-targeted descriptions, with conceptual overviews, definitions of terms, workarounds, and working code examples.
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