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java.awt
public class: TextField [javadoc | source]
java.lang.Object
   java.awt.Component
      java.awt.TextComponent
         java.awt.TextField

All Implemented Interfaces:
    Accessible, MenuContainer, Serializable, ImageObserver

Direct Known Subclasses:
   

A TextField object is a text component that allows for the editing of a single line of text.

For example, the following image depicts a frame with four text fields of varying widths. Two of these text fields display the predefined text "Hello".

The preceding text describes this image.

Here is the code that produces these four text fields:


TextField tf1, tf2, tf3, tf4;
// a blank text field
tf1 = new TextField();
// blank field of 20 columns
tf2 = new TextField("", 20);
// predefined text displayed
tf3 = new TextField("Hello!");
// predefined text in 30 columns
tf4 = new TextField("Hello", 30);

Every time the user types a key in the text field, one or more key events are sent to the text field. A KeyEvent may be one of three types: keyPressed, keyReleased, or keyTyped. The properties of a key event indicate which of these types it is, as well as additional information about the event, such as what modifiers are applied to the key event and the time at which the event occurred.

The key event is passed to every KeyListener or KeyAdapter object which registered to receive such events using the component's addKeyListener method. (KeyAdapter objects implement the KeyListener interface.)

It is also possible to fire an ActionEvent. If action events are enabled for the text field, they may be fired by pressing the Return key.

The TextField class's processEvent method examines the action event and passes it along to processActionEvent. The latter method redirects the event to any ActionListener objects that have registered to receive action events generated by this text field.

Nested Class Summary:
protected class  TextField.AccessibleAWTTextField  This class implements accessibility support for the TextField class. It provides an implementation of the Java Accessibility API appropriate to text field user-interface elements. 
Field Summary
 int columns    The number of columns in the text field. A column is an approximate average character width that is platform-dependent. Guaranteed to be non-negative. 
 char echoChar    The echo character, which is used when the user wishes to disguise the characters typed into the text field. The disguises are removed if echoChar = 0. 
transient  ActionListener actionListener     
Fields inherited from java.awt.TextComponent:
text,  editable,  selectionStart,  selectionEnd,  backgroundSetByClientCode,  textListener
Fields inherited from java.awt.Component:
peer,  parent,  appContext,  x,  y,  width,  height,  foreground,  background,  font,  peerFont,  cursor,  locale,  bufferStrategy,  ignoreRepaint,  visible,  enabled,  dropTarget,  popups,  focusTraversalKeys,  LOCK,  minSize,  minSizeSet,  prefSize,  prefSizeSet,  maxSize,  maxSizeSet,  componentOrientation,  newEventsOnly,  componentListener,  focusListener,  hierarchyListener,  hierarchyBoundsListener,  keyListener,  mouseListener,  mouseMotionListener,  mouseWheelListener,  inputMethodListener,  windowClosingException,  actionListenerK,  adjustmentListenerK,  componentListenerK,  containerListenerK,  focusListenerK,  itemListenerK,  keyListenerK,  mouseListenerK,  mouseMotionListenerK,  mouseWheelListenerK,  textListenerK,  ownedWindowK,  windowListenerK,  inputMethodListenerK,  hierarchyListenerK,  hierarchyBoundsListenerK,  windowStateListenerK,  windowFocusListenerK,  eventMask,  isInc,  incRate,  TOP_ALIGNMENT,  CENTER_ALIGNMENT,  BOTTOM_ALIGNMENT,  LEFT_ALIGNMENT,  RIGHT_ALIGNMENT,  isPacked,  backgroundEraseDisabled,  eventCache,  accessibleContext
Constructor:
 public TextField() throws HeadlessException 
    Constructs a new text field.
    Throws:
    HeadlessException - if GraphicsEnvironment.isHeadless() returns true.
    Also see:
    java.awt.GraphicsEnvironment#isHeadless
    exception: HeadlessException - if GraphicsEnvironment.isHeadless() returns true.
 public TextField(String text) throws HeadlessException 
    Constructs a new text field initialized with the specified text.
    Parameters:
    text - the text to be displayed. If text is null, the empty string "" will be displayed.
    Throws:
    HeadlessException - if GraphicsEnvironment.isHeadless() returns true.
    Also see:
    java.awt.GraphicsEnvironment#isHeadless
    exception: HeadlessException - if GraphicsEnvironment.isHeadless() returns true.
 public TextField(int columns) throws HeadlessException 
    Constructs a new empty text field with the specified number of columns. A column is an approximate average character width that is platform-dependent.
    Parameters:
    columns - the number of columns. If columns is less than 0, columns is set to 0.
    Throws:
    HeadlessException - if GraphicsEnvironment.isHeadless() returns true.
    Also see:
    java.awt.GraphicsEnvironment#isHeadless
    exception: HeadlessException - if GraphicsEnvironment.isHeadless() returns true.
 public TextField(String text,
    int columns) throws HeadlessException 
    Constructs a new text field initialized with the specified text to be displayed, and wide enough to hold the specified number of columns. A column is an approximate average character width that is platform-dependent.
    Parameters:
    text - the text to be displayed. If text is null, the empty string "" will be displayed.
    columns - the number of columns. If columns is less than 0, columns is set to 0.
    Throws:
    HeadlessException - if GraphicsEnvironment.isHeadless() returns true.
    Also see:
    java.awt.GraphicsEnvironment#isHeadless
    exception: HeadlessException - if GraphicsEnvironment.isHeadless() returns true.
Method from java.awt.TextField Summary:
addActionListener,   addNotify,   constructComponentName,   echoCharIsSet,   eventEnabled,   getAccessibleContext,   getActionListeners,   getColumns,   getEchoChar,   getListeners,   getMinimumSize,   getMinimumSize,   getPreferredSize,   getPreferredSize,   minimumSize,   minimumSize,   paramString,   preferredSize,   preferredSize,   processActionEvent,   processEvent,   removeActionListener,   setColumns,   setEchoChar,   setEchoCharacter,   setText
Methods from java.awt.TextComponent:
addNotify,   addTextListener,   areInputMethodsEnabled,   enableInputMethods,   eventEnabled,   getAccessibleContext,   getBackground,   getCaretPosition,   getCharacterBounds,   getIndexAtPoint,   getInputMethodRequests,   getListeners,   getSelectedText,   getSelectionEnd,   getSelectionStart,   getText,   getTextListeners,   isEditable,   paramString,   processEvent,   processTextEvent,   removeNotify,   removeTextListener,   select,   selectAll,   setBackground,   setCaretPosition,   setEditable,   setSelectionEnd,   setSelectionStart,   setText
Methods from java.awt.Component:
action,   add,   addComponentListener,   addFocusListener,   addHierarchyBoundsListener,   addHierarchyListener,   addInputMethodListener,   addKeyListener,   addMouseListener,   addMouseMotionListener,   addMouseWheelListener,   addNotify,   addPropertyChangeListener,   addPropertyChangeListener,   adjustListeningChildrenOnParent,   applyComponentOrientation,   applyCompoundShape,   applyCurrentShape,   areBoundsValid,   areFocusTraversalKeysSet,   areInputMethodsEnabled,   autoProcessMouseWheel,   bounds,   canBeFocusOwner,   canBeFocusOwnerRecursively,   checkGD,   checkImage,   checkImage,   checkTreeLock,   checkWindowClosingException,   clearCurrentFocusCycleRootOnHide,   clearMostRecentFocusOwnerOnHide,   coalesceEvents,   constructComponentName,   contains,   contains,   containsFocus,   countHierarchyMembers,   createBufferStrategy,   createBufferStrategy,   createHierarchyEvents,   createImage,   createImage,   createVolatileImage,   createVolatileImage,   deliverEvent,   disable,   disableEvents,   dispatchEvent,   dispatchEventImpl,   dispatchMouseWheelToAncestor,   doLayout,   enable,   enable,   enableEvents,   enableInputMethods,   eventEnabled,   eventTypeEnabled,   findUnderMouseInWindow,   firePropertyChange,   firePropertyChange,   firePropertyChange,   firePropertyChange,   firePropertyChange,   firePropertyChange,   firePropertyChange,   firePropertyChange,   firePropertyChange,   getAccessControlContext,   getAccessibleContext,   getAccessibleIndexInParent,   getAccessibleStateSet,   getAlignmentX,   getAlignmentY,   getBackBuffer,   getBackground,   getBaseline,   getBaselineResizeBehavior,   getBounds,   getBounds,   getBoundsOp,   getBufferStrategy,   getColorModel,   getComponentAt,   getComponentAt,   getComponentListeners,   getComponentOrientation,   getContainer,   getContainingWindow,   getCursor,   getCursor_NoClientCode,   getDropTarget,   getFocusCycleRootAncestor,   getFocusListeners,   getFocusTraversalKeys,   getFocusTraversalKeysEnabled,   getFocusTraversalKeys_NoIDCheck,   getFont,   getFontMetrics,   getFont_NoClientCode,   getForeground,   getGraphics,   getGraphicsConfiguration,   getGraphicsConfiguration_NoClientCode,   getGraphics_NoClientCode,   getHWPeerAboveMe,   getHeight,   getHierarchyBoundsListeners,   getHierarchyListeners,   getIgnoreRepaint,   getInputContext,   getInputMethodListeners,   getInputMethodRequests,   getKeyListeners,   getListeners,   getLocale,   getLocation,   getLocation,   getLocationOnScreen,   getLocationOnScreen_NoTreeLock,   getLocationOnWindow,   getMaximumSize,   getMinimumSize,   getMouseListeners,   getMouseMotionListeners,   getMousePosition,   getMouseWheelListeners,   getName,   getNativeContainer,   getNextFocusCandidate,   getNormalShape,   getObjectLock,   getOpaqueShape,   getParent,   getParent_NoClientCode,   getPeer,   getPreferredSize,   getPropertyChangeListeners,   getPropertyChangeListeners,   getSiblingIndexAbove,   getSiblingIndexBelow,   getSize,   getSize,   getToolkit,   getToolkitImpl,   getTraversalRoot,   getTreeLock,   getWidth,   getX,   getY,   gotFocus,   handleEvent,   hasFocus,   hide,   imageUpdate,   initializeFocusTraversalKeys,   inside,   invalidate,   invalidateIfValid,   invalidateParent,   isAutoFocusTransferOnDisposal,   isBackgroundSet,   isCoalescingEnabled,   isCursorSet,   isDisplayable,   isDoubleBuffered,   isEnabled,   isEnabledImpl,   isFocusCycleRoot,   isFocusOwner,   isFocusTraversable,   isFocusTraversableOverridden,   isFocusable,   isFontSet,   isForegroundSet,   isInstanceOf,   isLightweight,   isMaximumSizeSet,   isMinimumSizeSet,   isMixingNeeded,   isNonOpaqueForMixing,   isOpaque,   isPreferredSizeSet,   isRecursivelyVisible,   isSameOrAncestorOf,   isShowing,   isValid,   isVisible,   isVisible_NoClientCode,   keyDown,   keyUp,   layout,   lightweightPaint,   lightweightPrint,   list,   list,   list,   list,   list,   locate,   location,   lostFocus,   minimumSize,   mixOnHiding,   mixOnReshaping,   mixOnShowing,   mixOnValidating,   mixOnZOrderChanging,   mouseDown,   mouseDrag,   mouseEnter,   mouseExit,   mouseMove,   mouseUp,   move,   nextFocus,   numListening,   paint,   paintAll,   paintHeavyweightComponents,   paramString,   pointRelativeToComponent,   postEvent,   postsOldMouseEvents,   preferredSize,   prepareImage,   prepareImage,   print,   printAll,   printHeavyweightComponents,   processComponentEvent,   processEvent,   processFocusEvent,   processHierarchyBoundsEvent,   processHierarchyEvent,   processInputMethodEvent,   processKeyEvent,   processMouseEvent,   processMouseMotionEvent,   processMouseWheelEvent,   relocateComponent,   remove,   removeComponentListener,   removeFocusListener,   removeHierarchyBoundsListener,   removeHierarchyListener,   removeInputMethodListener,   removeKeyListener,   removeMouseListener,   removeMouseMotionListener,   removeMouseWheelListener,   removeNotify,   removePropertyChangeListener,   removePropertyChangeListener,   repaint,   repaint,   repaint,   repaint,   requestFocus,   requestFocus,   requestFocus,   requestFocus,   requestFocusHelper,   requestFocusHelper,   requestFocusInWindow,   requestFocusInWindow,   requestFocusInWindow,   requestFocusInWindow,   reshape,   resize,   resize,   revalidate,   setAutoFocusTransferOnDisposal,   setBackground,   setBounds,   setBounds,   setBoundsOp,   setComponentOrientation,   setCursor,   setDropTarget,   setEnabled,   setFocusTraversalKeys,   setFocusTraversalKeysEnabled,   setFocusTraversalKeys_NoIDCheck,   setFocusable,   setFont,   setForeground,   setGraphicsConfiguration,   setIgnoreRepaint,   setLocale,   setLocation,   setLocation,   setMaximumSize,   setMinimumSize,   setName,   setPreferredSize,   setRequestFocusController,   setSize,   setSize,   setVisible,   show,   show,   size,   subtractAndApplyShape,   subtractAndApplyShapeBelowMe,   toString,   transferFocus,   transferFocus,   transferFocusBackward,   transferFocusBackward,   transferFocusUpCycle,   update,   updateCursorImmediately,   updateGraphicsData,   updateZOrder,   validate
Methods from java.lang.Object:
clone,   equals,   finalize,   getClass,   hashCode,   notify,   notifyAll,   toString,   wait,   wait,   wait
Method from java.awt.TextField Detail:
 public synchronized  void addActionListener(ActionListener l) 
    Adds the specified action listener to receive action events from this text field. If l is null, no exception is thrown and no action is performed.

    Refer to AWT Threading Issues for details on AWT's threading model.

 public  void addNotify() 
    Creates the TextField's peer. The peer allows us to modify the appearance of the TextField without changing its functionality.
 String constructComponentName() 
    Construct a name for this component. Called by getName() when the name is null.
 public boolean echoCharIsSet() 
    Indicates whether or not this text field has a character set for echoing.

    An echo character is useful for text fields where user input should not be echoed to the screen, as in the case of a text field for entering a password.

 boolean eventEnabled(AWTEvent e) 
 public AccessibleContext getAccessibleContext() 
    Gets the AccessibleContext associated with this TextField. For text fields, the AccessibleContext takes the form of an AccessibleAWTTextField. A new AccessibleAWTTextField instance is created if necessary.
 public synchronized ActionListener[] getActionListeners() 
    Returns an array of all the action listeners registered on this textfield.
 public int getColumns() 
    Gets the number of columns in this text field. A column is an approximate average character width that is platform-dependent.
 public char getEchoChar() 
    Gets the character that is to be used for echoing.

    An echo character is useful for text fields where user input should not be echoed to the screen, as in the case of a text field for entering a password. If echoChar = 0, user input is echoed to the screen unchanged.

    A Java platform implementation may support only a limited, non-empty set of echo characters. This function returns the echo character originally requested via setEchoChar(). The echo character actually used by the TextField implementation might be different.

 public T[] getListeners(Class<T> listenerType) 
    Returns an array of all the objects currently registered as FooListeners upon this TextField. FooListeners are registered using the addFooListener method.

    You can specify the listenerType argument with a class literal, such as FooListener.class. For example, you can query a TextField t for its action listeners with the following code:

    ActionListener[] als = (ActionListener[])(t.getListeners(ActionListener.class));
    If no such listeners exist, this method returns an empty array.
 public Dimension getMinimumSize() 
    Gets the minumum dimensions for this text field.
 public Dimension getMinimumSize(int columns) 
    Gets the minumum dimensions for a text field with the specified number of columns.
 public Dimension getPreferredSize() 
    Gets the preferred size of this text field.
 public Dimension getPreferredSize(int columns) 
    Gets the preferred size of this text field with the specified number of columns.
 public Dimension minimumSize() 
Deprecated! As - of JDK version 1.1, replaced by getMinimumSize().

 public Dimension minimumSize(int columns) 
Deprecated! As - of JDK version 1.1, replaced by getMinimumSize(int).

 protected String paramString() 
    Returns a string representing the state of this TextField. 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.
 public Dimension preferredSize() 
Deprecated! As - of JDK version 1.1, replaced by getPreferredSize().

 public Dimension preferredSize(int columns) 
Deprecated! As - of JDK version 1.1, replaced by getPreferredSize(int).

 protected  void processActionEvent(ActionEvent e) 
    Processes action events occurring on this text field by dispatching them to any registered ActionListener objects.

    This method is not called unless action events are enabled for this component. Action events are enabled when one of the following occurs:

    • An ActionListener object is registered via addActionListener.
    • Action events are enabled via enableEvents.

    Note that if the event parameter is null the behavior is unspecified and may result in an exception.

 protected  void processEvent(AWTEvent e) 
    Processes events on this text field. If the event is an instance of ActionEvent, it invokes the processActionEvent method. Otherwise, it invokes processEvent on the superclass.

    Note that if the event parameter is null the behavior is unspecified and may result in an exception.

 public synchronized  void removeActionListener(ActionListener l) 
    Removes the specified action listener so that it no longer receives action events from this text field. If l is null, no exception is thrown and no action is performed.

    Refer to AWT Threading Issues for details on AWT's threading model.

 public  void setColumns(int columns) 
    Sets the number of columns in this text field. A column is an approximate average character width that is platform-dependent.
 public  void setEchoChar(char c) 
    Sets the echo character for this text field.

    An echo character is useful for text fields where user input should not be echoed to the screen, as in the case of a text field for entering a password. Setting echoChar = 0 allows user input to be echoed to the screen again.

    A Java platform implementation may support only a limited, non-empty set of echo characters. Attempts to set an unsupported echo character will cause the default echo character to be used instead. Subsequent calls to getEchoChar() will return the echo character originally requested. This might or might not be identical to the echo character actually used by the TextField implementation.

 public synchronized  void setEchoCharacter(char c) 
Deprecated! As - of JDK version 1.1, replaced by setEchoChar(char).

 public  void setText(String t) 
    Sets the text that is presented by this text component to be the specified text.