public interface KeyboardEvents
Page.registerKey()  or at the widget level via
 Canvas.keyDown(), Canvas.keyPress(), and Canvas.keyUp(). Details about the key events can be retrieved via static methods on the EventHandler class. See the following APIs:
EventHandler.getKey() - name of the
 pressed key.     (Note this may differ from the native     event.key)EventHandler.getKeyEventCharacter()
 - the character that was typed. This is derived from the       reported characterValue and will
 only be populated for keyPress events on character keys.EventHandler.getKeyEventCharacterValue() - the characterValue from the event.       This is
 populated for keyPress events on character keys.EventHandler.getKeyEventKey() - the
 reported       event.key      from the native browser event.EventHandler.getKeyEventCode() - the
 reported       event.code      from the native browser event.EventHandler.shiftKeyDown(), EventHandler.altKeyDown() and EventHandler.ctrlKeyDown().  As with other Smart GWT event handling code, returning
 false will suppress the default native browser behavior.
 Note: browsers
 do not allow cancellation of some keys' default behaviors. These cases vary by browser, and
 wherever native cancellation is supported, returning false from your event handler should be
 sufficient to suppress the behavior. 
 Some specific cases where default behavior
 cancellation is not always possible include: 
f1, f3,
 f5, etc) which trigger native browser behavior.         [These can be suppressed in
 Internet Explorer and Mozilla Firefox but not in some other          browsers such as Safari /
 Chrome, etc]Alt+f3Windows / Apple key to show OS level menu)