/* @ITMillApache2LicenseForJavaFiles@ */ package com.vaadin.terminal.gwt.client.ui.dd; import java.util.HashMap; import java.util.Map; import com.google.gwt.dom.client.Document; import com.google.gwt.dom.client.NativeEvent; import com.google.gwt.dom.client.Style.Unit; import com.google.gwt.dom.client.TableElement; import com.google.gwt.dom.client.TableSectionElement; import com.google.gwt.event.dom.client.MouseOverEvent; import com.google.gwt.user.client.Element; import com.vaadin.terminal.gwt.client.BrowserInfo; /** * DragEvent used by Vaadin client side engine. Supports components, items, * properties and custom payload (HTML5 style). * * */ public class VDragEvent { private static final int DEFAULT_OFFSET = 10; private static int eventId = 0; private VTransferable transferable; private NativeEvent currentGwtEvent; private NativeEvent startEvent; private int id; private HashMap dropDetails = new HashMap(); private Element elementOver; VDragEvent(VTransferable t, NativeEvent startEvent) { transferable = t; this.startEvent = startEvent; id = eventId++; } public VTransferable getTransferable() { return transferable; } /** * Returns the the latest {@link NativeEvent} that relates to this drag and * drop operation. For example on {@link VDropHandler#dragEnter(VDragEvent)} * this is commonly a {@link MouseOverEvent}. * * @return */ public NativeEvent getCurrentGwtEvent() { return currentGwtEvent; } public void setCurrentGwtEvent(NativeEvent event) { currentGwtEvent = event; } int getEventId() { return id; } /** * Detecting the element on which the the event is happening may be * problematic during drag and drop operation. This is especially the case * if a drag image (often called also drag proxy) is kept under the mouse * cursor (see {@link #createDragImage(Element, boolean)}. Drag and drop * event handlers (like the one provided by {@link VDragAndDropManager} ) * should set elmentOver field to reflect the the actual element on which * the pointer currently is (drag image excluded). {@link VDropHandler}s can * then more easily react properly on drag events by reading the element via * this method. * * @return the element in {@link VDropHandler} on which mouse cursor is on */ public Element getElementOver() { if (elementOver != null) { return elementOver; } else if (currentGwtEvent != null) { return currentGwtEvent.getEventTarget().cast(); } return null; } public void setElementOver(Element targetElement) { elementOver = targetElement; } /** * Sets the drag image used for current drag and drop operation. Drag image * is displayed next to mouse cursor during drag and drop. *

* The element to be used as drag image will automatically get CSS style * name "v-drag-element". * * TODO decide if this method should be here or in {@link VTransferable} (in * HTML5 it is in DataTransfer) or {@link VDragAndDropManager} * * TODO should be possible to override behavior. Like to proxy the element * to HTML5 DataTransfer * * @param node */ public void setDragImage(Element node) { setDragImage(node, DEFAULT_OFFSET, DEFAULT_OFFSET); } /** * TODO consider using similar smaller (than map) api as in Transferable * * TODO clean up when drop handler changes * * @return */ public Map getDropDetails() { return dropDetails; } /** * Sets the drag image used for current drag and drop operation. Drag image * is displayed next to mouse cursor during drag and drop. *

* The element to be used as drag image will automatically get CSS style * name "v-drag-element". * * @param element * the dom element to be positioned next to mouse cursor * @param offsetX * the horizontal offset of drag image from mouse cursor * @param offsetY * the vertical offset of drag image from mouse cursor */ public void setDragImage(Element element, int offsetX, int offsetY) { element.getStyle().setMarginLeft(offsetX, Unit.PX); element.getStyle().setMarginTop(offsetY, Unit.PX); VDragAndDropManager.get().setDragElement(element); } /** * @return the current Element used as a drag image (aka drag proxy) or null * if drag image is not currently set for this drag operation. */ public Element getDragImage() { return (Element) VDragAndDropManager.get().getDragElement(); } /** * Automatically tries to create a proxy image from given element. * * @param element * @param alignImageToEvent * if true, proxy image is aligned to start event, else next to * mouse cursor */ public void createDragImage(Element element, boolean alignImageToEvent) { Element cloneNode = (Element) element.cloneNode(true); if (BrowserInfo.get().isIE()) { if (cloneNode.getTagName().toLowerCase().equals("tr")) { TableElement table = Document.get().createTableElement(); TableSectionElement tbody = Document.get().createTBodyElement(); table.appendChild(tbody); tbody.appendChild(cloneNode); cloneNode = table.cast(); } } if (alignImageToEvent) { int absoluteTop = element.getAbsoluteTop(); int absoluteLeft = element.getAbsoluteLeft(); int clientX = startEvent.getClientX(); int clientY = startEvent.getClientY(); int offsetX = absoluteLeft - clientX; int offsetY = absoluteTop - clientY; setDragImage(cloneNode, offsetX, offsetY); } else { setDragImage(cloneNode); } } }