Extend this class to create a
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
method. When the component gains or loses the keyboard focus,
the relevant method in the listener object is invoked,
FocusEvent is passed to it.
FocusAdapterprotected FocusAdapter()Constructs a
focusGainedpublic void focusGained(FocusEvent e)Invoked when a component gains the keyboard focus.
focusLostpublic void focusLost(FocusEvent e)Invoked when a component loses the keyboard focus.