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JDK 5 Documentation v1.5.0, Java 2 SDK 英文文档
Label (Java 2 Platform SE 5.0) - JDK 5 Documentation v1.5.0, Java 2 SDK 英文文档
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:
- JDK1.0
- See Also:
- Serialized Form
|
Nested Class Summary |
protected class |
Label.AccessibleAWTLabel
This class implements accessibility support for the
Label class. |
|
Field Summary |
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. |
|
Constructor Summary |
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. |
| Methods inherited from 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, 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, getPeer, 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, requestFocusInWindow, requestFocusInWindow, reshape, resize, resize, setBackground, setBounds, setBounds, setComponentOrientation, setCursor, setDropTarget, setEnabled, setFocusable, setFocusTraversalKeys, setFocusTraversalKeysEnabled, setFont, setForeground, setIgnoreRepaint, setLocale, setLocation, setLocation, setMaximumSize, setMinimumSize, setName, setPreferredSize, setSize, setSize, setVisible, show, show, size, toString, transferFocus, transferFocusBackward, transferFocusUpCycle, update, validate |
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.
- Since:
- JDK1.0t.
- See Also:
- Constant Field Values
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()
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()
getAlignment
public int getAlignment()
- Gets the current alignment of this label. Possible values are
Label.LEFT, Label.RIGHT, and
Label.CENTER.
- 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
Submit a bug or feature
For further API reference and developer documentation, see Java 2 SDK SE Developer Documentation. That documentation contains more detailed, developer-targeted descriptions, with conceptual overviews, definitions of terms, workarounds, and working code examples. Copyright 2004 Sun Microsystems, Inc. All rights reserved. Use is subject to license terms. Also see the documentation redistribution policy.
