Class FocusAdapter

java.lang.Object

java.awt.event.FocusAdapter

All Implemented Interfaces:

FocusListener, EventListener

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.

Since:

1.1

See Also:

• FocusEvent
• FocusListener
• Tutorial: Writing a Focus Listener

Constructor Summary

Constructors

Modifier	Constructor	Description
protected	FocusAdapter()	Constructs a FocusAdapter.

Method Summary

Modifier and Type	Method	Description
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 declared in class Object

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

Modifier and Type	Method	Description
protected Object	clone()	Answers a new instance of the same class as the receiver, whose slots have been filled in with the values in the slots of the receiver.
boolean	equals(Object o)	Compares the argument to the receiver, and answers true if they represent the same object using a class specific comparison.
protected void	finalize()	Deprecated, for removal: This API element is subject to removal in a future version. May cause performance issues, deadlocks and hangs.
final Class<? extends Object>	getClass()	Answers the unique instance of java.lang.Class which represents the class of the receiver.
int	hashCode()	Answers an integer hash code for the receiver.
final void	notify()	Causes one thread which is waiting on the receiver to be made ready to run.
final void	notifyAll()	Causes all threads which are waiting on the receiver to be made ready to run.
String	toString()	Answers a string containing a concise, human-readable description of the receiver.
final void	wait()	Causes the thread which sent this message to be made not ready to run pending some change in the receiver (as indicated by notify or notifyAll).
final void	wait(long time)	Causes the thread which sent this message to be made not ready to run either pending some change in the receiver (as indicated by notify or notifyAll) or the expiration of the timeout.
final void	wait(long time, int frac)	Causes the thread which sent this message to be made not ready to run either pending some change in the receiver (as indicated by notify or notifyAll) or the expiration of the timeout.

Constructor Details

FocusAdapter

protected FocusAdapter()

Constructs a FocusAdapter.

Method Details

focusGained

public void focusGained(FocusEvent e)

Invoked when a component gains the keyboard focus.

Specified by:

focusGained in interface FocusListener

Parameters:

e - the event to be processed

focusLost

public void focusLost(FocusEvent e)

Invoked when a component loses the keyboard focus.

Specified by:

focusLost in interface FocusListener

Parameters:

e - the event to be processed