com.vaadin.terminal.gwt.client
Class EventHelper

java.lang.Object
  com.vaadin.terminal.gwt.client.EventHelper

public class EventHelper
extends Object

Helper class for attaching/detaching handlers for Vaadin client side components, based on identifiers in UIDL. Helpers expect Paintables to be both listeners and sources for events. This helper cannot be used for more complex widgets.

Possible current registration is given as parameter. The returned registration (possibly the same as given, should be store for next update.

Pseudocode what helpers do:

 
 if paintable has event listener in UIDL
      if registration is null
              register paintable as as handler for event
      return the registration
 else 
      if registration is not null
              remove the handler from paintable
      return null
 
 
 

Constructor Summary

EventHelper()

Method Summary

static <T extends ComponentConnector & com.google.gwt.event.dom.client.BlurHandler> com.google.gwt.event.shared.HandlerRegistration	updateBlurHandler(T connector, com.google.gwt.event.shared.HandlerRegistration handlerRegistration) Adds or removes a blur handler depending on if the connector has blur listeners on the server side or not.
static <T extends ComponentConnector & com.google.gwt.event.dom.client.FocusHandler> com.google.gwt.event.shared.HandlerRegistration	updateFocusHandler(T connector, com.google.gwt.event.shared.HandlerRegistration handlerRegistration) Adds or removes a focus handler depending on if the connector has focus listeners on the server side or not.

Methods inherited from class java.lang.Object

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

Constructor Detail

EventHelper

public EventHelper()

Method Detail

updateFocusHandler

public static <T extends ComponentConnector & com.google.gwt.event.dom.client.FocusHandler> com.google.gwt.event.shared.HandlerRegistration updateFocusHandler(T connector,
                                                                                                                                                              com.google.gwt.event.shared.HandlerRegistration handlerRegistration)

Adds or removes a focus handler depending on if the connector has focus listeners on the server side or not.

Parameters:

connector - The connector to update. Must implement focusHandler.

handlerRegistration - The old registration reference or null no handler has been registered previously

Returns:

a new registration handler that can be used to unregister the handler later

updateBlurHandler

public static <T extends ComponentConnector & com.google.gwt.event.dom.client.BlurHandler> com.google.gwt.event.shared.HandlerRegistration updateBlurHandler(T connector,
                                                                                                                                                            com.google.gwt.event.shared.HandlerRegistration handlerRegistration)

Adds or removes a blur handler depending on if the connector has blur listeners on the server side or not.

Parameters:

connector - The connector to update. Must implement BlurHandler.

handlerRegistration - The old registration reference or null no handler has been registered previously

Returns:

a new registration handler that can be used to unregister the handler later