com.google.gwt.touch.client

Class TouchScroller

java.lang.Object

com.google.gwt.touch.client.TouchScroller

public class TouchScroller
extends Object

Adds touch based scrolling to a scroll panel.

Touch based scrolling is only supported on devices that support touch events and do not implement native touch based scrolling.

Constructor Summary

Constructors

Modifier	Constructor and Description
protected	TouchScroller() Construct a new TouchScroller.

Method Summary

Modifier and Type	Method and Description
static TouchScroller	createIfSupported() Return a new TouchScroller.
static TouchScroller	createIfSupported(HasScrolling widget) Return a new TouchScroller that augments the specified scrollable widget if supported, and null otherwise.
Momentum	getMomentum() Get the Momentum that controls scrolling after the user completes a gesture.
HasScrolling	getTargetWidget() Get the target HasScrolling widget that this scroller affects.
protected Touch	getTouchFromEvent(TouchEvent<?> event) Get touch from event.
static boolean	isSupported() Runtime check for whether touch scrolling is supported in this browser.
protected void	onDragEnd(TouchEvent<?> event) Called when the object's drag sequence is complete.
protected void	onDragMove(TouchEvent<?> event) Called when the object has been dragged to a new position.
protected void	onDragStart(TouchEvent<?> event) Called when the object has started dragging.
protected void	onTouchCancel(TouchEvent<?> event) Called when the user cancels a touch.
protected void	onTouchEnd(TouchEvent<?> event) Called when the user releases a touch.
protected void	onTouchMove(TouchEvent<?> event) Called when the user moves a touch.
protected void	onTouchStart(TouchEvent<?> event) Called when the user starts a touch.
void	setMomentum(Momentum momentum) Set the Momentum that controls scrolling after the user completes a gesture.
void	setTargetWidget(HasScrolling widget) Set the target HasScrolling widget that this scroller affects.

Methods inherited from class java.lang.Object

equals, finalize, getClass, hashCode, toString

Constructor Detail

TouchScroller

protected TouchScroller()

Construct a new TouchScroller. This constructor should be called using the static method createIfSupported().

See Also:

createIfSupported()

Method Detail

createIfSupported

public static TouchScroller createIfSupported()

Return a new TouchScroller.

Returns:

a new TouchScroller if supported, and null otherwise

createIfSupported

public static TouchScroller createIfSupported(HasScrolling widget)

Return a new TouchScroller that augments the specified scrollable widget if supported, and null otherwise.

Parameters:

widget - the scrollable widget

Returns:

a new TouchScroller if supported, and null otherwise

isSupported

public static boolean isSupported()

Runtime check for whether touch scrolling is supported in this browser. Returns true if touch events are supported but touch based scrolling is not natively supported.

Returns:

true if touch scrolling is supported, false if not

getMomentum

public Momentum getMomentum()

Get the Momentum that controls scrolling after the user completes a gesture.

Returns:

the scrolling Momentum, or null if disabled

getTargetWidget

public HasScrolling getTargetWidget()

Get the target HasScrolling widget that this scroller affects.

Returns:

the target widget

setMomentum

public void setMomentum(Momentum momentum)

Set the Momentum that controls scrolling after the user completes a gesture.

Parameters:

momentum - the scrolling Momentum, or null to disable

setTargetWidget

public void setTargetWidget(HasScrolling widget)

Set the target HasScrolling widget that this scroller affects.

Parameters:

widget - the target widget, or null to disbale

getTouchFromEvent

protected Touch getTouchFromEvent(TouchEvent<?> event)

Get touch from event.

Parameters:

event - the event

Returns:

the touch object

onDragEnd

protected void onDragEnd(TouchEvent<?> event)

Called when the object's drag sequence is complete.

Parameters:

event - the touch event

onDragMove

protected void onDragMove(TouchEvent<?> event)

Called when the object has been dragged to a new position.

Parameters:

event - the touch event

onDragStart

protected void onDragStart(TouchEvent<?> event)

Called when the object has started dragging.

Parameters:

event - the touch event

onTouchCancel

protected void onTouchCancel(TouchEvent<?> event)

Called when the user cancels a touch. This can happen if the user touches the screen with too many fingers.

Parameters:

event - the touch event

onTouchEnd

protected void onTouchEnd(TouchEvent<?> event)

Called when the user releases a touch.

Parameters:

event - the touch event

onTouchMove

protected void onTouchMove(TouchEvent<?> event)

Called when the user moves a touch.

Parameters:

event - the touch event

onTouchStart

protected void onTouchStart(TouchEvent<?> event)

Called when the user starts a touch.

Parameters:

event - the touch event