public boolean addListener ( ListenerController listenerController ) { if ( listenerController != null && ! listeners . containsKey ( listenerController ) ) { List < HandlerRegistration > registrations = new ArrayList < HandlerRegistration > ( ) ; registrations . add ( eventWidget . addMouseDownHandler ( listenerController ) ) ; registrations . add ( eventWidget . addMouseMoveHandler ( listenerController ) ) ; registrations . add ( eventWidget . addMouseOutHandler ( listenerController ) ) ; registrations . add ( eventWidget . addMouseOverHandler ( listenerController ) ) ; registrations . add ( eventWidget . addMouseUpHandler ( listenerController ) ) ; registrations . add ( eventWidget . addMouseWheelHandler ( listenerController ) ) ; listeners . put ( listenerController , registrations ) ; return true ; } return false ; }
Add a new listener controller on this widget . These listeners passively listen to mouse events on the map . They do not interfere with these events .