Classes which implement this interface provide methods
that deal with the events that are generated as controls
gain and lose focus.
After creating an instance of a class that implements
this interface it can be added to a control using the
addFocusListener method and removed using
the removeFocusListener method. When a
control gains or loses focus, the appropriate method
will be invoked.
After creating an instance of a class that implements this interface it can be added to a control using the
addFocusListenermethod and removed using theremoveFocusListenermethod. When a control gains or loses focus, the appropriate method will be invoked.