Class DDEventHandleStrategy

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