com.sencha.gxt.core.client.gestures

Class AbstractGestureRecognizer

java.lang.Object

com.sencha.gxt.core.client.gestures.AbstractGestureRecognizer

All Implemented Interfaces:

GestureRecognizer

Direct Known Subclasses:

AbstractTwoTouchGestureRecognizer, DragGestureRecognizer, TapGestureRecognizer

public abstract class AbstractGestureRecognizer
extends Object
implements GestureRecognizer

Abstract starting point for building your own gesture recognition.

Nested Class Summary

Nested Classes

Modifier and Type	Class and Description
static class	AbstractGestureRecognizer.ExtraTouchBehavior Enum specifying how the gesture should treat 'extra' touches that occur, either to ignore them, or cancel the whole gesture.

Field Summary

Fields

Modifier and Type	Field and Description
protected Map<Integer,TouchData>	captured Indicates touches that this gesture owns, and wants all info about, and keeps to itself
protected HasHandlers	eventDelegate
protected AbstractGestureRecognizer.ExtraTouchBehavior	extraTouchBehavior
protected Map<Integer,TouchData>	interested Indicates touches that this gesture wants to see when they end/cancel, but not move or preventDefault/stopPropagation
protected PointerEventsSupport	pointerEventsSupport
protected int	touchCount

Constructor Summary

Constructors

Constructor and Description
AbstractGestureRecognizer(AbstractGestureRecognizer.ExtraTouchBehavior extraTouchBehavior, int touchCount)

Method Summary

Modifier and Type	Method and Description
void	cancel() Ends recognition of the gesture, and fires any cancel events that apply.
protected void	fireEvent(<any> event)
List<TouchData>	getTouches() Gets all actively recognized touches that are being recognized by this gesture.
boolean	handle(NativeEvent event) Takes a browser event, and checks to see if it should decipher a gesture from it.
boolean	handleCancel(NativeEvent cancelEvent) Handles gesture cancel events
boolean	handleEnd(NativeEvent endEvent) Handles gesture end events
boolean	handleMove(NativeEvent moveEvent) Handles gesture move events
protected void	handlePreventDefault(NativeEvent event) Intended to allow subclasses to determine if preventDefault should be called
boolean	handleStart(NativeEvent startEvent) Handles the start of gesture.
protected abstract void	onCancel(List<TouchData> touches) Indicates that one or more touches have been canceled by the browser or by the gesture itself being canceled (see #cancel).
protected abstract void	onEnd(List<TouchData> touches) Indicates that one or more touches have ended.
protected abstract void	onMove(List<TouchData> touches) Indicates that on or more touches are moving
protected abstract boolean	onStart(TouchData startedTouch) Indicates that a touch has started, giving the gesture the chance to exclusively handle this touch as it moves.
void	setCaptured(TouchData touch, boolean capture) Indicates whether or not the gesture is interested in all events about the given touch, and that any event about that touch should be preventDefault'd and stopPropagation'd.
void	setDelegate(HasHandlers eventDelegate) Sets delegate to receive Gesture events
void	setInterest(TouchData touch, boolean interest) Indicates whether or not the gesture are interested in end/cancel events about the given touch.
void	start(List<TouchData> touches) Artificially starts a gesture

Methods inherited from class java.lang.Object

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

Field Detail

interested

protected final Map<Integer,TouchData> interested

Indicates touches that this gesture wants to see when they end/cancel, but not move or preventDefault/stopPropagation

captured

protected final Map<Integer,TouchData> captured

Indicates touches that this gesture owns, and wants all info about, and keeps to itself

touchCount

protected final int touchCount

extraTouchBehavior

protected final AbstractGestureRecognizer.ExtraTouchBehavior extraTouchBehavior

eventDelegate

protected HasHandlers eventDelegate

pointerEventsSupport

protected PointerEventsSupport pointerEventsSupport

Constructor Detail

AbstractGestureRecognizer

public AbstractGestureRecognizer(AbstractGestureRecognizer.ExtraTouchBehavior extraTouchBehavior,
                                 int touchCount)

Method Detail

cancel

public void cancel()

Description copied from interface: GestureRecognizer

Ends recognition of the gesture, and fires any cancel events that apply. Any touch events being recognized by this object will now be ignored.

Specified by:

cancel in interface GestureRecognizer

getTouches

public List<TouchData> getTouches()

Description copied from interface: GestureRecognizer

Gets all actively recognized touches that are being recognized by this gesture.

Specified by:

getTouches in interface GestureRecognizer

Returns:

the touches

handle

public boolean handle(NativeEvent event)

Description copied from interface: GestureRecognizer

Takes a browser event, and checks to see if it should decipher a gesture from it.

Callers of this are expected to do their own vetting to decide if the given event should be handled by this gesture - for example, if a cell accepts a tap on one part of it and a longpress on another, the cell should determine where the touch events occur and send to the right recognizer accordingly.

Specified by:

handle in interface GestureRecognizer

Parameters:

event - the browser event to read for a gesture.

Returns:

true if the gesture is not handling the event and can allow it to be propagated, false to indicate that it has been handled and should not be given to other handlers. Should always return true for any start event.

handleStart

public boolean handleStart(NativeEvent startEvent)

Handles the start of gesture. Typically associated by a touchstart or pointerdown event

Parameters:

startEvent - the start event

Returns:

true if the gesture is not handling the event and can allow it to be propagated, false to indicate that it has been handled and should not be given to other handlers. Should always return true for any start event.

handleMove

public boolean handleMove(NativeEvent moveEvent)

Handles gesture move events

Parameters:

moveEvent - the move event

Returns:

true if the gesture is not handling the event and can allow it to be propagated, false to indicate that it has been handled and should not be given to other handlers. Should always return true for any start event.

handleCancel

public boolean handleCancel(NativeEvent cancelEvent)

Handles gesture cancel events

Parameters:

cancelEvent - the cancel event

Returns:

true if the gesture is not handling the event and can allow it to be propagated, false to indicate that it has been handled and should not be given to other handlers. Should always return true for any start event.

handleEnd

public boolean handleEnd(NativeEvent endEvent)

Handles gesture end events

Parameters:

endEvent - the end event

Returns:

true if the gesture is not handling the event and can allow it to be propagated, false to indicate that it has been handled and should not be given to other handlers. Should always return true for any start event.

setCaptured

public void setCaptured(TouchData touch,
                        boolean capture)

Indicates whether or not the gesture is interested in all events about the given touch, and that any event about that touch should be preventDefault'd and stopPropagation'd. Returning true from #onStart automatically captures the started touch.

Note that if the second argument is true, setInterest(touch, true) is implicit.

Parameters:

touch - the touch data

capture - whether to add or remove catpure on the given touch

setDelegate

public void setDelegate(HasHandlers eventDelegate)

Description copied from interface: GestureRecognizer

Sets delegate to receive Gesture events

Specified by:

setDelegate in interface GestureRecognizer

Parameters:

eventDelegate - the event handler delegate

setInterest

public void setInterest(TouchData touch,
                        boolean interest)

Indicates whether or not the gesture are interested in end/cancel events about the given touch. Designed mostly for use in multi-touch gestures. If interest is declared, onCancel and onEnd will be invoked, but onMove will not.

Note that if the second argument is false, setCaptured(touch, false) is implicit.

Parameters:

touch - the touch to be interested in, but not capture

interest - whether to add or remove interest on the given touch

start

public void start(List<TouchData> touches)

Description copied from interface: GestureRecognizer

Artificially starts a gesture

Specified by:

start in interface GestureRecognizer

Parameters:

touches - the touches to be started

fireEvent

protected void fireEvent(<any> event)

handlePreventDefault

protected void handlePreventDefault(NativeEvent event)

Intended to allow subclasses to determine if preventDefault should be called

Default behavior is to NOT preventDefault

Parameters:

event -

onStart

protected abstract boolean onStart(TouchData startedTouch)

Indicates that a touch has started, giving the gesture the chance to exclusively handle this touch as it moves.

Parameters:

startedTouch - the touch that has begun

Returns:

false to not capture the touch passed in, true to capture it so that later gestures do not hear about it. Returning true is equivelent to calling setCaptured(startedTouch, true)

onMove

protected abstract void onMove(List<TouchData> touches)

Indicates that on or more touches are moving

Parameters:

touches -

onEnd

protected abstract void onEnd(List<TouchData> touches)

Indicates that one or more touches have ended.

Parameters:

touches - data for the now-ended touches (as opposed to #getTouches which no longer has those entries)

onCancel

protected abstract void onCancel(List<TouchData> touches)

Indicates that one or more touches have been canceled by the browser or by the gesture itself being canceled (see #cancel).

Parameters:

touches - data for the now-canceled touches (as opposed to #getTouches which no longer has those entries)