ch.unifr.pai.twice.dragndrop.client
Class DragNDrop

java.lang.Object
  ch.unifr.pai.twice.dragndrop.client.DragNDrop

public class DragNDrop
extends java.lang.Object

The main entry point of the drag and drop functionality provided for multi-pointer, touch and single-pointer scenarios.

Author:

Oliver Schmid

Nested Class Summary

(package private) static interface	DragNDrop.DragNDropIntf The contract interface for the device specific implementations of the drag and drop functionality
(package private) static class	DragNDrop.ValueHolder<T> A helper class to hold a value

Field Summary

private static DragNDrop.DragNDropIntf

handler The device dependent drag and drop handler implementation (instantiated by deferred binding)

Constructor Summary

private

DragNDrop(com.google.gwt.user.client.ui.Widget w, int offsetX, int offsetY, DragConfiguration conf) A private constructor to handle the initialization of the handler

Method Summary

static void	makeDraggable(Draggable w) Registers a widget to be draggable
static void	makeDraggable(Draggable w, DragConfiguration conf) Registers a widget to be draggable while providing a specific DragConfiguration which shall be applied to the drags for this widget
static void	makeDraggable(Draggable w, DragConfiguration conf, com.google.gwt.dom.client.Element dragProxyTemplate) Registers a widget to be draggable while providing a DragConfiguration which shall be applied to the drags for this widget as well as a HTML element to be a template for the drag proxy (the element which is shown in a semi-transparent way below the mouse pointer during the drag)
static void	makeDraggable(Draggable w, com.google.gwt.dom.client.Element dragProxyTemplate) Registers a widget to be draggable while providing a HTML element to be a template for the drag proxy (the element which is shown in a semi-transparent way below the mouse pointer during the drag)
static void	removeDropHandler(com.google.gwt.event.dom.client.HasMouseOverHandlers w) Unregisters the widget implementing HasMouseOverHandlers to be a drop handler.
static void	setDropHandler(com.google.gwt.event.dom.client.HasMouseOverHandlers w, DropTargetHandler dropHandler, boolean hoverAware) This method allows to register a widget that implements HasMouseOverHandlers to become a drop target.

Methods inherited from class java.lang.Object

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

Field Detail

handler

private static DragNDrop.DragNDropIntf handler

The device dependent drag and drop handler implementation (instantiated by deferred binding)

Constructor Detail

DragNDrop

private DragNDrop(com.google.gwt.user.client.ui.Widget w,
                  int offsetX,
                  int offsetY,
                  DragConfiguration conf)

A private constructor to handle the initialization of the handler

Parameters:

w - - the widget to be dragged

offsetX - - the offset on the X-axis between the left border of the widget to be dragged and the mouse position on which the drag started

offsetY - - the offset on the Y-axis between the top border of the widget to be dragged and the mouse position on which the drag started

conf - - the configuration of the way how the drag shall be executed (DragConfiguration)

Method Detail

makeDraggable

public static void makeDraggable(Draggable w)

Registers a widget to be draggable

Parameters:

w - - the widget that shall be made draggable

makeDraggable

public static void makeDraggable(Draggable w,
                                 com.google.gwt.dom.client.Element dragProxyTemplate)

Registers a widget to be draggable while providing a HTML element to be a template for the drag proxy (the element which is shown in a semi-transparent way below the mouse pointer during the drag)

Parameters:

w - - the widget that shall be made draggable

dragProxyTemplate - - a HTML element which acts as a template for the drag proxy of this widget. If not defined, the proxy will be a visual copy of the draggable widget.

makeDraggable

public static void makeDraggable(Draggable w,
                                 DragConfiguration conf)

Registers a widget to be draggable while providing a specific DragConfiguration which shall be applied to the drags for this widget

Parameters:

w - - the widget that shall be made draggable

conf - - the DragConfiguration which shall be applied to a drag of this widget

makeDraggable

public static void makeDraggable(Draggable w,
                                 DragConfiguration conf,
                                 com.google.gwt.dom.client.Element dragProxyTemplate)

Registers a widget to be draggable while providing a DragConfiguration which shall be applied to the drags for this widget as well as a HTML element to be a template for the drag proxy (the element which is shown in a semi-transparent way below the mouse pointer during the drag)

Parameters:

w - - the widget that shall be made draggable

conf - - the DragConfiguration which shall be applied to a drag of this widget

dragProxyTemplate - - a HTML element which acts as a template for the drag proxy of this widget. If not defined, the proxy will be a visual copy of the draggable widget.

setDropHandler

public static void setDropHandler(com.google.gwt.event.dom.client.HasMouseOverHandlers w,
                                  DropTargetHandler dropHandler,
                                  boolean hoverAware)

This method allows to register a widget that implements HasMouseOverHandlers to become a drop target. The corresponding methods of the provided DropTargetHandler will be invoked if a widget is dragged while hovering this widget.

Parameters:

w - - the widget that shall be registered as a drop target

dropHandler - - the DropTargetHandler defining the actions that shall be taken if a widget is dragged while hovering the widget

hoverAware - - to make a drop target aware if a widget hovers it might have negative impact for the performance. If the drop target does not need to react on the hovering of dragged widgets but only on drops of them while overlaying the widgets area, this property should be set to false. If this property is set to false, the methods DropTargetHandler.onHover(String, Widget, Element, com.google.gwt.user.client.Event, Double, Double) and DropTargetHandler.onHoverEnd(String, Widget, Element, com.google.gwt.user.client.Event) will not be triggered.

removeDropHandler

public static void removeDropHandler(com.google.gwt.event.dom.client.HasMouseOverHandlers w)

Unregisters the widget implementing HasMouseOverHandlers to be a drop handler.

Parameters:

w -