Package com.vaadin.client.ui.dd

Class DDEventHandleStrategy

java.lang.Object

com.vaadin.client.ui.dd.DDEventHandleStrategy

public class DDEventHandleStrategy
extends Object

Strategy to handle native preview events for VDragAndDropManager. The strategy could be overridden via GWT Deferred Binding mechanism.

Since:

7.4.4

Author:

Vaadin Ltd

Constructor Summary

Constructors

Constructor	Description
DDEventHandleStrategy()

Method Summary

Modifier and Type	Method	Description
protected VDropHandler	findDragTarget(com.google.gwt.dom.client.Element target, VDragAndDropManager.DDManagerMediator mediator)	Find drag handler for the target element.
com.google.gwt.dom.client.Element	getTargetElement(com.google.gwt.user.client.Event.NativePreviewEvent event, VDragAndDropManager.DDManagerMediator mediator)	Get target element for event.
protected void	handleDragEnter(com.google.gwt.dom.client.Element target, VDragAndDropManager.DDManagerMediator mediator)	Handles drag enter on new element.
boolean	handleDragImageEvent(com.google.gwt.dom.client.Element target, com.google.gwt.user.client.Event.NativePreviewEvent event, VDragAndDropManager.DDManagerMediator mediator)	Handles event when drag image element ( VDragAndDropManager.getDragElement() return value) is not null or event is touch event.
protected void	handleDragLeave(VDragAndDropManager.DDManagerMediator mediator, boolean clearServerCallback)	Handles drag leave on old element.
protected void	handleDragOver(com.google.gwt.dom.client.Element target, VDragAndDropManager.DDManagerMediator mediator)	Handles drag over on element.
void	handleEvent(com.google.gwt.dom.client.Element targetElement, com.google.gwt.user.client.Event.NativePreviewEvent event, VDragAndDropManager.DDManagerMediator mediator)	Final phase of event handling.
void	handleKeyDownEvent(com.google.gwt.user.client.Event.NativePreviewEvent event, VDragAndDropManager.DDManagerMediator mediator)	Handles key down event.
protected void	handleMouseMove(com.google.gwt.dom.client.Element target, com.google.gwt.user.client.Event.NativePreviewEvent event, VDragAndDropManager.DDManagerMediator mediator)	Called to handle Event.ONMOUSEMOVE event.
protected void	handleMouseOut(com.google.gwt.dom.client.Element target, com.google.gwt.user.client.Event.NativePreviewEvent event, VDragAndDropManager.DDManagerMediator mediator)	Called to handle Event.ONMOUSEOUT event.
protected void	handleMouseOver(com.google.gwt.dom.client.Element target, com.google.gwt.user.client.Event.NativePreviewEvent event, VDragAndDropManager.DDManagerMediator mediator)	Called to handle Event.ONMOUSEOVER event.
protected void	handleMouseUp(com.google.gwt.dom.client.Element target, com.google.gwt.user.client.Event.NativePreviewEvent event, VDragAndDropManager.DDManagerMediator mediator)	Called to handle Event.ONMOUSEUP event.
protected void	handleTouchEnd(com.google.gwt.dom.client.Element target, com.google.gwt.user.client.Event.NativePreviewEvent event, VDragAndDropManager.DDManagerMediator mediator)	Called to handle Event.ONTOUCHEND event.
boolean	isDragInterrupted(com.google.gwt.user.client.Event.NativePreviewEvent event, VDragAndDropManager.DDManagerMediator mediator)	Returns true if event interrupts Drag and Drop.
void	restoreDragImage(String originalImageDisplay, VDragAndDropManager.DDManagerMediator mediator, com.google.gwt.user.client.Event.NativePreviewEvent event)	Restores drag image after temporary update by updateDragImage(NativePreviewEvent, DDManagerMediator).
String	updateDragImage(com.google.gwt.user.client.Event.NativePreviewEvent event, VDragAndDropManager.DDManagerMediator mediator)	Updates drag image DOM element.

Methods inherited from class java.lang.Object

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

Constructor Detail

DDEventHandleStrategy

public DDEventHandleStrategy()

Method Detail

isDragInterrupted

public boolean isDragInterrupted(com.google.gwt.user.client.Event.NativePreviewEvent event,
                                 VDragAndDropManager.DDManagerMediator mediator)

Returns true if event interrupts Drag and Drop.

Parameters:

event - GWT event to handle

mediator - VDragAndDropManager data accessor

Returns:

whether true interrupts DnD

handleKeyDownEvent

public void handleKeyDownEvent(com.google.gwt.user.client.Event.NativePreviewEvent event,
                               VDragAndDropManager.DDManagerMediator mediator)

Handles key down event. Default implementation doesn't do anything.

Parameters:

event - key down GWT event

mediator - VDragAndDropManager data accessor

getTargetElement

public com.google.gwt.dom.client.Element getTargetElement(com.google.gwt.user.client.Event.NativePreviewEvent event,
                                                          VDragAndDropManager.DDManagerMediator mediator)

Get target element for event.

Parameters:

event - GWT event to find target

mediator - VDragAndDropManager data accessor

Returns:

target element for event

updateDragImage

public String updateDragImage(com.google.gwt.user.client.Event.NativePreviewEvent event,
                              VDragAndDropManager.DDManagerMediator mediator)

Updates drag image DOM element. This method updates drag image position and adds additional styles. Default implementation hides drag element to be able to get target element by the point (see getTargetElement(NativePreviewEvent, DDManagerMediator). Method restoreDragImage(String, DDManagerMediator, NativePreviewEvent) is used later on to restore the drag element in its state before temporary update. Returns "display" CSS style property of the original drag image. This value will be passed to the restoreDragImage(String, DDManagerMediator, NativePreviewEvent) method.

Parameters:

event - GWT event for active DnD operation

mediator - VDragAndDropManager data accessor

Returns:

"display" CSS style property of drag image element to restore it later on

restoreDragImage

public void restoreDragImage(String originalImageDisplay,
                             VDragAndDropManager.DDManagerMediator mediator,
                             com.google.gwt.user.client.Event.NativePreviewEvent event)

Restores drag image after temporary update by updateDragImage(NativePreviewEvent, DDManagerMediator).

Parameters:

originalImageDisplay - original "display" CSS style property of drag image element

mediator - VDragAndDropManager data accessor

event - GWT event for active DnD operation

handleDragImageEvent

public boolean handleDragImageEvent(com.google.gwt.dom.client.Element target,
                                    com.google.gwt.user.client.Event.NativePreviewEvent event,
                                    VDragAndDropManager.DDManagerMediator mediator)

Handles event when drag image element ( VDragAndDropManager.getDragElement() return value) is not null or event is touch event. If method returns true then event processing will be stoped.

Parameters:

target - target element over which DnD event has happened

event - GWT event for active DnD operation

mediator - VDragAndDropManager data accessor

Returns:

true is strategy handled the event and no further steps to handle required.

handleDragEnter

protected void handleDragEnter(com.google.gwt.dom.client.Element target,
                               VDragAndDropManager.DDManagerMediator mediator)

Handles drag enter on new element.

Parameters:

mediator - VDragAndDropManager data accessor

target - target element over which DnD event has happened

handleDragOver

protected void handleDragOver(com.google.gwt.dom.client.Element target,
                              VDragAndDropManager.DDManagerMediator mediator)

Handles drag over on element.

Parameters:

mediator - VDragAndDropManager data accessor

target - target element over which DnD event has happened

handleEvent

public void handleEvent(com.google.gwt.dom.client.Element targetElement,
                        com.google.gwt.user.client.Event.NativePreviewEvent event,
                        VDragAndDropManager.DDManagerMediator mediator)

Final phase of event handling.

Parameters:

targetElement - target element over which DnD event has happened

event - GWT event for active DnD operation

mediator - VDragAndDropManager data accessor

handleMouseMove

protected void handleMouseMove(com.google.gwt.dom.client.Element target,
                               com.google.gwt.user.client.Event.NativePreviewEvent event,
                               VDragAndDropManager.DDManagerMediator mediator)

Called to handle Event.ONMOUSEMOVE event.

Parameters:

target - target element over which DnD event has happened

event - ONMOUSEMOVE GWT event for active DnD operation

mediator - VDragAndDropManager data accessor

handleTouchEnd

protected void handleTouchEnd(com.google.gwt.dom.client.Element target,
                              com.google.gwt.user.client.Event.NativePreviewEvent event,
                              VDragAndDropManager.DDManagerMediator mediator)

Called to handle Event.ONTOUCHEND event.

Parameters:

target - target element over which DnD event has happened

event - ONTOUCHEND GWT event for active DnD operation

mediator - VDragAndDropManager data accessor

handleMouseUp

protected void handleMouseUp(com.google.gwt.dom.client.Element target,
                             com.google.gwt.user.client.Event.NativePreviewEvent event,
                             VDragAndDropManager.DDManagerMediator mediator)

Called to handle Event.ONMOUSEUP event.

Parameters:

target - target element over which DnD event has happened

event - ONMOUSEUP GWT event for active DnD operation

mediator - VDragAndDropManager data accessor

handleMouseOut

protected void handleMouseOut(com.google.gwt.dom.client.Element target,
                              com.google.gwt.user.client.Event.NativePreviewEvent event,
                              VDragAndDropManager.DDManagerMediator mediator)

Called to handle Event.ONMOUSEOUT event.

Parameters:

target - target element over which DnD event has happened

event - ONMOUSEOUT GWT event for active DnD operation

mediator - VDragAndDropManager data accessor

handleDragLeave

protected void handleDragLeave(VDragAndDropManager.DDManagerMediator mediator,
                               boolean clearServerCallback)

Handles drag leave on old element.

Parameters:

mediator - VDragAndDropManager data accessor

handleMouseOver

protected void handleMouseOver(com.google.gwt.dom.client.Element target,
                               com.google.gwt.user.client.Event.NativePreviewEvent event,
                               VDragAndDropManager.DDManagerMediator mediator)

Called to handle Event.ONMOUSEOVER event.

Parameters:

target - target element over which DnD event has happened

event - ONMOUSEOVER GWT event for active DnD operation

mediator - VDragAndDropManager data accessor

findDragTarget

protected VDropHandler findDragTarget(com.google.gwt.dom.client.Element target,
                                      VDragAndDropManager.DDManagerMediator mediator)

Find drag handler for the target element.

Parameters:

target - target element over which DnD event has happened

mediator - VDragAndDropManager data accessor

Returns:

drop handler of target element