com.vaadin.client.ui

Class TouchScrollDelegate.TouchScrollHandler

java.lang.Object

com.vaadin.client.ui.TouchScrollDelegate.TouchScrollHandler

All Implemented Interfaces:

com.google.gwt.event.dom.client.TouchStartHandler, com.google.gwt.event.shared.EventHandler

Enclosing class:

TouchScrollDelegate

public static class TouchScrollDelegate.TouchScrollHandler
extends Object
implements com.google.gwt.event.dom.client.TouchStartHandler

A helper class for making a widget scrollable. Uses native scrolling if supported by the browser, otherwise registers a touch start handler delegating to a TouchScrollDelegate instance.

Constructor Summary

Constructors

Constructor and Description
TouchScrollHandler() Constructs a scroll handler.
TouchScrollHandler(com.google.gwt.user.client.ui.Widget widget, com.google.gwt.dom.client.Element... scrollables) Deprecated. Use GWT.create(Class) and init(Widget, Element...) instead of this constructor to enable overriding.

Method Summary

Modifier and Type	Method and Description
void	addElement(com.google.gwt.dom.client.Element scrollable) Registers the given element as scrollable.
void	debug(com.google.gwt.dom.client.Element e)
protected com.google.gwt.user.client.ui.Widget	getWidget()
void	init(com.google.gwt.user.client.ui.Widget widget, com.google.gwt.dom.client.Element... scrollables) Attaches the scroll handler to the widget.
void	onTouchStart(com.google.gwt.event.dom.client.TouchStartEvent event)
void	removeElement(com.google.gwt.dom.client.Element scrollable) Unregisters the given element as scrollable.
protected boolean	requiresDelegate() Checks if a delegate for scrolling is required or if the native scrolling of the device should be used.
void	setElements(com.google.gwt.dom.client.Element... scrollables) Registers the given elements as scrollable, removing previously registered scrollables from this handler.

Methods inherited from class java.lang.Object

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

Constructor Detail

TouchScrollHandler

public TouchScrollHandler()

Constructs a scroll handler. You must call init(Widget, Element...) before using the scroll handler.

TouchScrollHandler

@Deprecated
public TouchScrollHandler(com.google.gwt.user.client.ui.Widget widget,
                                      com.google.gwt.dom.client.Element... scrollables)

Deprecated. Use GWT.create(Class) and init(Widget, Element...) instead of this constructor to enable overriding.

Attaches the scroll handler to the widget. This method must be called before calling any other methods in this class.

Parameters:

widget - The widget that contains scrollable elements

scrollables - The elements of the widget that should be scrollable.

Method Detail

init

public void init(com.google.gwt.user.client.ui.Widget widget,
                 com.google.gwt.dom.client.Element... scrollables)

Attaches the scroll handler to the widget. This method must be called once before calling any other method in this class.

Parameters:

widget - The widget that contains scrollable elements

scrollables - The elements of the widget that should be scrollable.

onTouchStart

public void onTouchStart(com.google.gwt.event.dom.client.TouchStartEvent event)

Specified by:

onTouchStart in interface com.google.gwt.event.dom.client.TouchStartHandler

debug

public void debug(com.google.gwt.dom.client.Element e)

addElement

public void addElement(com.google.gwt.dom.client.Element scrollable)

Registers the given element as scrollable.

removeElement

public void removeElement(com.google.gwt.dom.client.Element scrollable)

Unregisters the given element as scrollable. Should be called when a previously-registered element is removed from the DOM to prevent memory leaks.

setElements

public void setElements(com.google.gwt.dom.client.Element... scrollables)

Registers the given elements as scrollable, removing previously registered scrollables from this handler.

Parameters:

scrollables - The elements that should be scrollable

requiresDelegate

protected boolean requiresDelegate()

Checks if a delegate for scrolling is required or if the native scrolling of the device should be used. By default, relies on BrowserInfo.requiresTouchScrollDelegate(), override to change the behavior.

Returns:

true if a Javascript delegate should be used for scrolling, false to use the native scrolling of the device

getWidget

protected com.google.gwt.user.client.ui.Widget getWidget()

Returns:

The widget this TouchScrollDelegate.TouchScrollHandler is connected to.