Module java.desktop

Package java.awt

Class Label

java.lang.Object

java.awt.Component

java.awt.Label

All Implemented Interfaces:

ImageObserver, MenuContainer, Serializable, Accessible

public class Label
extends Component
implements Accessible

A Label object is a component for placing text in a container. A label displays a single line of read-only text. The text can be changed by the application, but a user cannot edit it directly.

For example, the code . . .

 setLayout(new FlowLayout(FlowLayout.CENTER, 10, 10));
 add(new Label("Hi There!"));
 add(new Label("Another Label"));
 

produces the following labels:

Since:

1.0

See Also:

• Serialized Form

Nested Class Summary

Nested Classes

Modifier and Type	Class	Description
protected class	Label.AccessibleAWTLabel	This class implements accessibility support for the Label class.

Nested classes/interfaces declared in class java.awt.Component

Component.AccessibleAWTComponent, Component.BaselineResizeBehavior, Component.BltBufferStrategy, Component.FlipBufferStrategy

Field Summary

Fields

Modifier and Type	Field	Description
static final int	CENTER	Indicates that the label should be centered.
static final int	LEFT	Indicates that the label should be left justified.
static final int	RIGHT	Indicates that the label should be right justified.

Fields declared in class java.awt.Component

accessibleContext, BOTTOM_ALIGNMENT, CENTER_ALIGNMENT, LEFT_ALIGNMENT, RIGHT_ALIGNMENT, TOP_ALIGNMENT

Fields declared in interface java.awt.image.ImageObserver

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

Constructor Summary

Constructors

Constructor	Description
Label()	Constructs an empty label.
Label(String text)	Constructs a new label with the specified string of text, left justified.
Label(String text, int alignment)	Constructs a new label that presents the specified string of text with the specified alignment.

Method Summary

Modifier and Type	Method	Description
void	addNotify()	Creates the peer for this label.
AccessibleContext	getAccessibleContext()	Gets the AccessibleContext associated with this Label.
int	getAlignment()	Gets the current alignment of this label.
String	getText()	Gets the text of this label.
protected String	paramString()	Returns a string representing the state of this Label.
void	setAlignment(int alignment)	Sets the alignment for this label to the specified alignment.
void	setText(String text)	Sets the text for this label to the specified text.

Methods declared in class java.awt.Component

action, add, addComponentListener, addFocusListener, addHierarchyBoundsListener, addHierarchyListener, addInputMethodListener, addKeyListener, addMouseListener, addMouseMotionListener, addMouseWheelListener, addPropertyChangeListener, addPropertyChangeListener, applyComponentOrientation, areFocusTraversalKeysSet, bounds, checkImage, checkImage, coalesceEvents, contains, contains, createImage, createImage, createVolatileImage, createVolatileImage, deliverEvent, disable, disableEvents, dispatchEvent, doLayout, enable, enable, enableEvents, enableInputMethods, firePropertyChange, firePropertyChange, firePropertyChange, firePropertyChange, firePropertyChange, firePropertyChange, firePropertyChange, firePropertyChange, firePropertyChange, getAlignmentX, getAlignmentY, getBackground, getBaseline, getBaselineResizeBehavior, getBounds, getBounds, getColorModel, getComponentAt, getComponentAt, getComponentListeners, getComponentOrientation, getCursor, getDropTarget, getFocusCycleRootAncestor, getFocusListeners, getFocusTraversalKeys, getFocusTraversalKeysEnabled, getFont, getFontMetrics, getForeground, getGraphics, getGraphicsConfiguration, getHeight, getHierarchyBoundsListeners, getHierarchyListeners, getIgnoreRepaint, getInputContext, getInputMethodListeners, getInputMethodRequests, getKeyListeners, getListeners, getLocale, getLocation, getLocation, getLocationOnScreen, getMaximumSize, getMinimumSize, getMouseListeners, getMouseMotionListeners, getMousePosition, getMouseWheelListeners, getName, getParent, getPreferredSize, getPropertyChangeListeners, getPropertyChangeListeners, getSize, getSize, getToolkit, getTreeLock, getWidth, getX, getY, gotFocus, handleEvent, hasFocus, hide, imageUpdate, inside, invalidate, isBackgroundSet, isCursorSet, isDisplayable, isDoubleBuffered, isEnabled, isFocusable, isFocusCycleRoot, isFocusOwner, isFocusTraversable, isFontSet, isForegroundSet, isLightweight, isMaximumSizeSet, isMinimumSizeSet, isOpaque, isPreferredSizeSet, isShowing, isValid, isVisible, keyDown, keyUp, layout, list, list, list, list, list, locate, location, lostFocus, minimumSize, mouseDown, mouseDrag, mouseEnter, mouseExit, mouseMove, mouseUp, move, nextFocus, paint, paintAll, postEvent, preferredSize, prepareImage, prepareImage, print, printAll, processComponentEvent, processEvent, processFocusEvent, processHierarchyBoundsEvent, processHierarchyEvent, processInputMethodEvent, processKeyEvent, processMouseEvent, processMouseMotionEvent, processMouseWheelEvent, remove, removeComponentListener, removeFocusListener, removeHierarchyBoundsListener, removeHierarchyListener, removeInputMethodListener, removeKeyListener, removeMouseListener, removeMouseMotionListener, removeMouseWheelListener, removeNotify, removePropertyChangeListener, removePropertyChangeListener, repaint, repaint, repaint, repaint, requestFocus, requestFocus, requestFocus, requestFocus, requestFocusInWindow, requestFocusInWindow, requestFocusInWindow, reshape, resize, resize, revalidate, setBackground, setBounds, setBounds, setComponentOrientation, setCursor, setDropTarget, setEnabled, setFocusable, setFocusTraversalKeys, setFocusTraversalKeysEnabled, setFont, setForeground, setIgnoreRepaint, setLocale, setLocation, setLocation, setMaximumSize, setMinimumSize, setMixingCutoutShape, setName, setPreferredSize, setSize, setSize, setVisible, show, show, size, toString, transferFocus, transferFocusBackward, transferFocusUpCycle, update, validate

Methods declared in class java.lang.Object

clone, equals, finalize, getClass, hashCode, notify, notifyAll, wait, wait, wait

Field Details

LEFT

public static final int LEFT

Indicates that the label should be left justified.

See Also:

• Constant Field Values

CENTER

public static final int CENTER

Indicates that the label should be centered.

See Also:

• Constant Field Values

RIGHT

public static final int RIGHT

Indicates that the label should be right justified.

See Also:

• Constant Field Values

Constructor Details

Label

public Label()
      throws HeadlessException

Constructs an empty label. The text of the label is the empty string "".

Throws:

HeadlessException - if GraphicsEnvironment.isHeadless() returns true.

See Also:

• GraphicsEnvironment.isHeadless()

Label

public Label(String text)
      throws HeadlessException

Constructs a new label with the specified string of text, left justified.

Parameters:

text - the string that the label presents. A null value will be accepted without causing a NullPointerException to be thrown.

Throws:

HeadlessException - if GraphicsEnvironment.isHeadless() returns true.

See Also:

• GraphicsEnvironment.isHeadless()

Label

public Label(String text,
 int alignment)
      throws HeadlessException

Constructs a new label that presents the specified string of text with the specified alignment. Possible values for alignment are Label.LEFT, Label.RIGHT, and Label.CENTER.

Parameters:

text - the string that the label presents. A null value will be accepted without causing a NullPointerException to be thrown.

alignment - the alignment value.

Throws:

HeadlessException - if GraphicsEnvironment.isHeadless() returns true.

See Also:

• GraphicsEnvironment.isHeadless()

Method Details

addNotify

public void addNotify()

Creates the peer for this label. The peer allows us to modify the appearance of the label without changing its functionality.

Overrides:

addNotify in class Component

See Also:

• Component.isDisplayable()
• Component.removeNotify()
• Component.invalidate()

getAlignment

public int getAlignment()

Gets the current alignment of this label. Possible values are Label.LEFT, Label.RIGHT, and Label.CENTER.

Returns:

the alignment of this label

See Also:

• setAlignment(int)

setAlignment

public void setAlignment(int alignment)

Sets the alignment for this label to the specified alignment. Possible values are Label.LEFT, Label.RIGHT, and Label.CENTER.

Parameters:

alignment - the alignment to be set.

Throws:

IllegalArgumentException - if an improper value for alignment is given.

See Also:

• getAlignment()

getText

public String getText()

Gets the text of this label.

Returns:

the text of this label, or null if the text has been set to null.

See Also:

• setText(java.lang.String)

setText

public void setText(String text)

Sets the text for this label to the specified text.

Parameters:

text - the text that this label displays. If text is null, it is treated for display purposes like an empty string "".

See Also:

• getText()

paramString

protected String paramString()

Returns a string representing the state of this Label. 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 class Component

Returns:

the parameter string of this label

getAccessibleContext

public AccessibleContext getAccessibleContext()

Gets the AccessibleContext associated with this Label. For labels, the AccessibleContext takes the form of an AccessibleAWTLabel. A new AccessibleAWTLabel instance is created if necessary.

Specified by:

getAccessibleContext in interface Accessible

Overrides:

getAccessibleContext in class Component

Returns:

an AccessibleAWTLabel that serves as the AccessibleContext of this Label

Since:

1.3