Java(TM) 2 Platform, Standard Edition, v1.2.2 API Specification: Class FocusAdapter - JDK 5 Documentation v1.2.2, Java 2 SDK 英文文档

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Java^TM 2 Platform
Standard Edition

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java.awt.event
Class FocusAdapter

java.lang.Object
  |
  +--java.awt.event.FocusAdapter

Direct Known Subclasses:: BasicSplitPaneUI.FocusHandler, BasicTabbedPaneUI.FocusHandler

public abstract class FocusAdapter
extends Object
implements FocusListener

An abstract adapter class for receiving keyboard focus events. The methods in this class are empty. This class exists as convenience for creating listener objects.

Extend this class to create a FocusEvent listener and override the methods for the events of interest. (If you implement the FocusListener interface, you have to define all of the methods in it. This abstract class defines null methods for them all, so you can only have to define methods for events you care about.)

Create a listener object using the extended class and then register it with a component using the component's addFocusListener method. When the component gains or loses the keyboard focus, the relevant method in the listener object is invoked, and the FocusEvent is passed to it.

See Also:: FocusEvent, FocusListener, Tutorial: Writing a Focus Listener, Reference: The Java Class Libraries (update file)

Constructor Summary

FocusAdapter()


Method Summary

void focusGained(FocusEvent e)
          Invoked when a component gains the keyboard focus.

void focusLost(FocusEvent e)
          Invoked when a component loses the keyboard focus.

Methods inherited from class java.lang.Object

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

Constructor Detail

FocusAdapter

public FocusAdapter()

Method Detail

focusGained

public void focusGained(FocusEvent e)

Invoked when a component gains the keyboard focus.

Specified by:: focusGained in interface FocusListener

focusLost

public void focusLost(FocusEvent e)

Invoked when a component loses the keyboard focus.

Specified by:: focusLost in interface FocusListener