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
Modifier and Type | Class | Description |
---|---|---|
protected class | Label.AccessibleAWTLabel | This class implements accessibility support for the |
Nested classes/interfaces declared in class java.awt.Component
Component.AccessibleAWTComponent, Component.BaselineResizeBehavior, Component.BltBufferStrategy, Component.FlipBufferStrategy
Field Summary
Modifier and Type | Field | Description |
---|---|---|
static int | CENTER | Indicates that the label should be centered. |
static int | LEFT | Indicates that the label should be left justified. |
static 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
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 |
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 Detail
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 Detail
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. Anull
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. Anull
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 Detail
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 classComponent
- 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 foralignment
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 tonull
. - 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. Iftext
isnull
, 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 classComponent
- 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 interfaceAccessible
- Overrides:
-
getAccessibleContext
in classComponent
- Returns:
- an AccessibleAWTLabel that serves as the AccessibleContext of this Label
- Since:
- 1.3