| /******************************************************************************* |
| * Copyright (c) 2000, 2007 IBM Corporation and others. |
| * All rights reserved. This program and the accompanying materials |
| * are made available under the terms of the Eclipse Public License v1.0 |
| * which accompanies this distribution, and is available at |
| * http://www.eclipse.org/legal/epl-v10.html |
| * |
| * Contributors: |
| * IBM Corporation - initial API and implementation |
| *******************************************************************************/ |
| package org.eclipse.swt.dnd; |
| |
| import org.eclipse.swt.SWT; |
| import org.eclipse.swt.graphics.*; |
| import org.eclipse.swt.internal.Callback; |
| import org.eclipse.swt.internal.carbon.DataBrowserCallbacks; |
| import org.eclipse.swt.internal.carbon.OS; |
| import org.eclipse.swt.widgets.*; |
| |
| /** |
| * This class provides a default drag under effect (eg. select, insert and scroll) |
| * when a drag occurs over a <code>Table</code>. |
| * |
| * <p>Classes that wish to provide their own drag under effect for a <code>Table</code> |
| * can extend the <code>TableDropTargetEffect</code> and override any applicable methods |
| * in <code>TableDropTargetEffect</code> to display their own drag under effect.</p> |
| * |
| * Subclasses that override any methods of this class must call the corresponding |
| * <code>super</code> method to get the default drag under effect implementation. |
| * |
| * <p>The feedback value is either one of the FEEDBACK constants defined in |
| * class <code>DND</code> which is applicable to instances of this class, |
| * or it must be built by <em>bitwise OR</em>'ing together |
| * (that is, using the <code>int</code> "|" operator) two or more |
| * of those <code>DND</code> effect constants. |
| * </p> |
| * <p> |
| * <dl> |
| * <dt><b>Feedback:</b></dt> |
| * <dd>FEEDBACK_SELECT, FEEDBACK_SCROLL</dd> |
| * </dl> |
| * </p> |
| * |
| * @see DropTargetAdapter |
| * @see DropTargetEvent |
| * |
| * @since 3.3 |
| */ |
| public class TableDropTargetEffect extends DropTargetEffect { |
| static final int SCROLL_HYSTERESIS = 150; // milli seconds |
| |
| TableItem scrollItem; |
| long scrollBeginTime; |
| DataBrowserCallbacks callbacks = null; |
| |
| static Callback AcceptDragProc; |
| static { |
| AcceptDragProc = new Callback(TableDropTargetEffect.class, "AcceptDragProc", 5); //$NON-NLS-1$ |
| int acceptDragProc = AcceptDragProc.getAddress(); |
| if (acceptDragProc == 0) SWT.error(SWT.ERROR_NO_MORE_CALLBACKS); |
| } |
| |
| static int AcceptDragProc(int theControl, int itemID, int property, int theRect, int theDrag) { |
| DropTarget target = FindDropTarget(theControl, theDrag); |
| if (target == null) return 0; |
| return (target.feedback & DND.FEEDBACK_SELECT) != 0 ? 1 : 0; |
| } |
| |
| static DropTarget FindDropTarget(int theControl, int theDrag) { |
| if (theControl == 0) return null; |
| Display display = Display.findDisplay(Thread.currentThread()); |
| if (display == null || display.isDisposed()) return null; |
| Widget widget = display.findWidget(theControl); |
| if (widget == null) return null; |
| return (DropTarget)widget.getData(DropTarget.DROPTARGETID); |
| } |
| |
| /** |
| * Creates a new <code>TableDropTargetEffect</code> to handle the drag under effect on the specified |
| * <code>Table</code>. |
| * |
| * @param table the <code>Table</code> over which the user positions the cursor to drop the data |
| */ |
| public TableDropTargetEffect(Table table) { |
| super(table); |
| } |
| |
| int checkEffect(int effect) { |
| // Some effects are mutually exclusive. Make sure that only one of the mutually exclusive effects has been specified. |
| if ((effect & DND.FEEDBACK_SELECT) != 0) effect = effect & ~DND.FEEDBACK_INSERT_AFTER & ~DND.FEEDBACK_INSERT_BEFORE; |
| if ((effect & DND.FEEDBACK_INSERT_BEFORE) != 0) effect = effect & ~DND.FEEDBACK_INSERT_AFTER; |
| return effect; |
| } |
| |
| /** |
| * This implementation of <code>dragEnter</code> provides a default drag under effect |
| * for the feedback specified in <code>event.feedback</code>. |
| * |
| * For additional information see <code>DropTargetAdapter.dragEnter</code>. |
| * |
| * Subclasses that override this method should call <code>super.dragEnter(event)</code> |
| * to get the default drag under effect implementation. |
| * |
| * @param event the information associated with the drag enter event |
| * |
| * @see DropTargetAdapter |
| * @see DropTargetEvent |
| */ |
| public void dragEnter(DropTargetEvent event) { |
| if (callbacks == null) { |
| Table table = (Table) control; |
| DataBrowserCallbacks callbacks = new DataBrowserCallbacks (); |
| OS.GetDataBrowserCallbacks (table.handle, callbacks); |
| callbacks.v1_acceptDragCallback = AcceptDragProc.getAddress(); |
| OS.SetDataBrowserCallbacks(table.handle, callbacks); |
| } |
| scrollBeginTime = 0; |
| scrollItem = null; |
| } |
| |
| /** |
| * This implementation of <code>dragLeave</code> provides a default drag under effect |
| * for the feedback specified in <code>event.feedback</code>. |
| * |
| * For additional information see <code>DropTargetAdapter.dragLeave</code>. |
| * |
| * Subclasses that override this method should call <code>super.dragLeave(event)</code> |
| * to get the default drag under effect implementation. |
| * |
| * @param event the information associated with the drag leave event |
| * |
| * @see DropTargetAdapter |
| * @see DropTargetEvent |
| */ |
| public void dragLeave(DropTargetEvent event) { |
| scrollBeginTime = 0; |
| scrollItem = null; |
| } |
| |
| /** |
| * This implementation of <code>dragOver</code> provides a default drag under effect |
| * for the feedback specified in <code>event.feedback</code>. The class description |
| * lists the FEEDBACK constants that are applicable to the class. |
| * |
| * For additional information see <code>DropTargetAdapter.dragOver</code>. |
| * |
| * Subclasses that override this method should call <code>super.dragOver(event)</code> |
| * to get the default drag under effect implementation. |
| * |
| * @param event the information associated with the drag over event |
| * |
| * @see DropTargetAdapter |
| * @see DropTargetEvent |
| * @see DND#FEEDBACK_SELECT |
| * @see DND#FEEDBACK_SCROLL |
| */ |
| public void dragOver(DropTargetEvent event) { |
| Table table = (Table) control; |
| int effect = checkEffect(event.feedback); |
| |
| TableItem item = (TableItem)getItem(table, event.x, event.y); |
| |
| if ((effect & DND.FEEDBACK_SCROLL) == 0) { |
| scrollBeginTime = 0; |
| scrollItem = null; |
| } else { |
| if (item != null && item.equals(scrollItem) && scrollBeginTime != 0) { |
| if (System.currentTimeMillis() >= scrollBeginTime) { |
| Rectangle area = table.getClientArea(); |
| int headerHeight = table.getHeaderHeight(); |
| int itemHeight= table.getItemHeight(); |
| Point pt = new Point(event.x, event.y); |
| pt = table.getDisplay().map(null, table, pt); |
| TableItem nextItem = null; |
| if (pt.y < area.y + headerHeight + 2 * itemHeight) { |
| int index = Math.max(0, table.indexOf(item)-1); |
| nextItem = table.getItem(index); |
| } |
| if (pt.y > area.y + area.height - 2 * itemHeight) { |
| int index = Math.min(table.getItemCount()-1, table.indexOf(item)+1); |
| nextItem = table.getItem(index); |
| } |
| if (nextItem != null) table.showItem(nextItem); |
| scrollBeginTime = 0; |
| scrollItem = null; |
| } |
| } else { |
| scrollBeginTime = System.currentTimeMillis() + SCROLL_HYSTERESIS; |
| scrollItem = item; |
| } |
| } |
| |
| // store current effect for selection feedback |
| ((DropTarget)event.widget).feedback = effect; |
| } |
| } |