com.allen_sauer.gwt.dnd.client.drop
Class AbstractDropController

java.lang.Object
  com.allen_sauer.gwt.dnd.client.drop.AbstractDropController

All Implemented Interfaces:

DropController

Direct Known Subclasses:

AbstractPositioningDropController, SimpleDropController, SwtCellPanelDropController, SwtTreeDropController, SwtTreeItemDropController

public abstract class AbstractDropController
extends java.lang.Object
implements DropController

Base class for typical drop controllers. Contains some basic functionality like adjust widget styles.

Constructor Summary

AbstractDropController(com.google.gwt.user.client.ui.Widget dropTarget)

Method Summary

com.google.gwt.user.client.ui.Widget	getDropTarget() Retrieve our drop target widget.
void	onDrop(DragContext context) Called when the draggable widget or its proxy is dropped on our drop target.
void	onEnter(DragContext context) Called when the draggable widget or its proxy engages our drop target.
void	onLeave(DragContext context) Called when the reference widget stops engaging our drop target by leaving the area of the page occupied by our drop target, or after DropController.onDrop(DragContext) to allow for any cleanup.
void	onMove(DragContext context) Called with each mouse movement while the reference widget is engaging our drop target.
void	onPreviewDrop(DragContext context) Called just prior to DropController.onDrop(DragContext) to allow the drop operation to be cancelled by throwing a VetoDragException.

Methods inherited from class java.lang.Object

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

Constructor Detail

AbstractDropController

public AbstractDropController(com.google.gwt.user.client.ui.Widget dropTarget)

Method Detail

getDropTarget

public com.google.gwt.user.client.ui.Widget getDropTarget()

Description copied from interface: DropController

Retrieve our drop target widget.

Specified by:

getDropTarget in interface DropController

Returns:

the widget representing the drop target associated with this controller

onDrop

public void onDrop(DragContext context)

Description copied from interface: DropController

Called when the draggable widget or its proxy is dropped on our drop target. Implementing classes must attach the draggable widget to our drop target in a suitable manner.

Specified by:

onDrop in interface DropController

Parameters:

context - the current drag context

See Also:

DropController.onPreviewDrop(DragContext)

onEnter

public void onEnter(DragContext context)

Description copied from interface: DropController

Called when the draggable widget or its proxy engages our drop target. This occurs when the widget area and the drop target area intersect and there are no drop targets which are descendants of our drop target which also intersect with the widget. If there are, the widget engages with the descendant drop target instead.

Specified by:

onEnter in interface DropController

Parameters:

context - the current drag context

See Also:

DropController.onLeave(DragContext)

onLeave

public void onLeave(DragContext context)

Description copied from interface: DropController

Called when the reference widget stops engaging our drop target by leaving the area of the page occupied by our drop target, or after DropController.onDrop(DragContext) to allow for any cleanup.

Specified by:

onLeave in interface DropController

Parameters:

context - the current drag context

See Also:

DropController.onEnter(DragContext)

onMove

public void onMove(DragContext context)

Description copied from interface: DropController

Called with each mouse movement while the reference widget is engaging our drop target. DropController.onEnter(DragContext) is called before this method is called.

Specified by:

onMove in interface DropController

Parameters:

context - the current drag context

See Also:

DropController.onEnter(DragContext), DropController.onLeave(DragContext)

onPreviewDrop

public void onPreviewDrop(DragContext context)
                   throws VetoDragException

Description copied from interface: DropController

Called just prior to DropController.onDrop(DragContext) to allow the drop operation to be cancelled by throwing a VetoDragException.

Specified by:

onPreviewDrop in interface DropController

Parameters:

context - the current drag context

Throws:

VetoDragException - if the proposed operation is unacceptable