ej.mwt.event

Class PointerEventDispatcher

java.lang.Object

ej.mwt.event.EventDispatcher

ej.mwt.event.PointerEventDispatcher

public class PointerEventDispatcher
extends EventDispatcher

Dispatches the pointer events received on a desktop to its children.

Pointer events are grouped in sessions. A session starts when the pointer is pressed, and ends when the pointer is released or when it exits the pressed widget.

While no widget consumes the events, they are sent to the widget that is under the pointer (see Desktop.getWidgetAt(int, int)), then sent to all its parent hierarchy.

Once a widget has consumed an event, it will be the only one to receive the next events during the session.

Field Summary

Fields

Modifier and Type	Field and Description
static int	EXITED The "exited" action.

Constructor Summary

Constructors

Constructor and Description
PointerEventDispatcher(Desktop desktop) Creates a desktop event dispatcher.

Method Summary

Modifier and Type	Method and Description
protected DesktopEventGenerator	createEventGenerator() Creates the event generator which is responsible for generating exit events to the widgets.
boolean	dispatchEvent(int event) Dispatches an event.
void	dispose() Disposes this event dispatcher.
Widget	getConsumerWidget() Returns the widget which has consumed the ongoing pointer session.
protected DesktopEventGenerator	getEventGenerator() Gets the event generator of this dispatcher.
Widget	getPressedHierarchyLeaf() Returns the leaf widget of the hierarchy which is subscribed to the ongoing pointer session.
void	initialize() Initializes this event dispatcher.
static boolean	isExited(int event) Returns whether or not the given event is an exited event.

Methods inherited from class ej.mwt.event.EventDispatcher

getDesktop, sendEventToWidget, sendEventToWidgetHierarchy

Methods inherited from class java.lang.Object

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

Field Detail

EXITED

public static final int EXITED

The "exited" action.

See Also:

Constant Field Values

Constructor Detail

PointerEventDispatcher

public PointerEventDispatcher(Desktop desktop)

Creates a desktop event dispatcher.

Parameters:

desktop - the desktop to dispatch in.

Method Detail

createEventGenerator

protected DesktopEventGenerator createEventGenerator()

Creates the event generator which is responsible for generating exit events to the widgets. By default, a desktop event generator is created.

Returns:

the event generator.

See Also:

DesktopEventGenerator

dispatchEvent

public boolean dispatchEvent(int event)

Description copied from class: EventDispatcher

Dispatches an event.

Specified by:

dispatchEvent in class EventDispatcher

Parameters:

event - the event to dispatch.

Returns:

true if the event dispatcher has dealt with the event, false otherwise.

dispose

public void dispose()

Description copied from class: EventDispatcher

Disposes this event dispatcher.

After this call, all that has been allocated or started in the EventDispatcher.initialize() method must be disposed or stopped.

Overrides:

dispose in class EventDispatcher

getConsumerWidget

@Nullable
public Widget getConsumerWidget()

Returns the widget which has consumed the ongoing pointer session.

When a pointer event is been consumed during a pointer session, it becomes the only widget to be subscribed to this session.

The reference to this widget is initialized when a pointer event is consumed ; and it is reset when the pointer is released or when the pointer is dragged outside of the bounds of the widget.

Returns:

the consumer widget, or null if there is none.

getEventGenerator

@Nullable
protected DesktopEventGenerator getEventGenerator()

Gets the event generator of this dispatcher.

Returns:

the event generator of this dispatcher.

getPressedHierarchyLeaf

@Nullable
public Widget getPressedHierarchyLeaf()

Returns the leaf widget of the hierarchy which is subscribed to the ongoing pointer session.

When a pointer session is started, all the enabled widgets under the pointer become subscribed to this session.

The reference to this widget is initialized when the pointer is pressed ; it is updated when the pointer is dragged outside of the bounds of the widget or when a pointer event is consumed ; and it is reset when the pointer is released or when the pointer is dragged outside of the bounds of each subscribed widgets.

Returns:

the leaf widget of the subscribed hierarchy, or null if there is none.

initialize

public void initialize()

Description copied from class: EventDispatcher

Initializes this event dispatcher.

For example, this method can be used to create an event generator.

Overrides:

initialize in class EventDispatcher

isExited

public static final boolean isExited(int event)

Returns whether or not the given event is an exited event.

Parameters:

event - the event to check.

Returns:

true if the given event is an exited event, false otherwise.