| /******************************************************************************* |
| * Copyright (c) 2000, 2008 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.*; |
| import org.eclipse.swt.events.*; |
| import org.eclipse.swt.graphics.*; |
| import org.eclipse.swt.widgets.*; |
| |
| /** |
| * This class provides a default drag under effect (eg. select, insert, scroll and expand) |
| * when a drag occurs over a <code>Tree</code>. |
| * |
| * <p>Classes that wish to provide their own drag under effect for a <code>Tree</code> |
| * can extend the <code>TreeDropTargetEffect</code> class and override any applicable methods |
| * in <code>TreeDropTargetEffect</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_INSERT_BEFORE, FEEDBACK_INSERT_AFTER, FEEDBACK_EXPAND, FEEDBACK_SCROLL</dd> |
| * </dl> |
| * </p><p> |
| * Note: Only one of the styles FEEDBACK_SELECT, FEEDBACK_INSERT_BEFORE or |
| * FEEDBACK_INSERT_AFTER may be specified. |
| * </p> |
| * |
| * @see DropTargetAdapter |
| * @see DropTargetEvent |
| * @see <a href="http://www.eclipse.org/swt/">Sample code and further information</a> |
| * |
| * @since 3.3 |
| */ |
| public class TreeDropTargetEffect extends DropTargetEffect { |
| static final int SCROLL_HYSTERESIS = 150; // milli seconds |
| static final int EXPAND_HYSTERESIS = 1000; // milli seconds |
| |
| int currentEffect = DND.FEEDBACK_NONE; |
| TreeItem currentItem; |
| |
| PaintListener paintListener; |
| TreeItem dropSelection = null; |
| |
| TreeItem insertItem = null; |
| boolean insertBefore = false; |
| |
| TreeItem scrollItem; |
| long scrollBeginTime; |
| |
| TreeItem expandItem; |
| long expandBeginTime; |
| |
| /** |
| * Creates a new <code>TreeDropTargetEffect</code> to handle the drag under effect on the specified |
| * <code>Tree</code>. |
| * |
| * @param tree the <code>Tree</code> over which the user positions the cursor to drop the data |
| */ |
| public TreeDropTargetEffect(Tree tree) { |
| super(tree); |
| } |
| |
| 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) { |
| insertItem = null; |
| currentItem = null; |
| dropSelection = null; |
| expandBeginTime = 0; |
| expandItem = null; |
| 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) { |
| Tree tree = (Tree) control; |
| if (insertItem != null) { |
| tree.setInsertMark(null, false); |
| insertItem = null; |
| } |
| if (currentItem != null) { |
| setDropSelection(tree, null); |
| currentItem = null; |
| } |
| expandBeginTime = 0; |
| expandItem = null; |
| 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>. |
| * |
| * 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_INSERT_BEFORE |
| * @see DND#FEEDBACK_INSERT_AFTER |
| * @see DND#FEEDBACK_SCROLL |
| */ |
| public void dragOver(DropTargetEvent event) { |
| Tree tree = (Tree) control; |
| int effect = checkEffect(event.feedback); |
| |
| TreeItem item = (TreeItem)getItem(tree, event.x, event.y); |
| |
| if ((effect & DND.FEEDBACK_EXPAND) == 0) { |
| expandBeginTime = 0; |
| expandItem = null; |
| } else { |
| if (item != null && item.equals(expandItem) && expandBeginTime != 0) { |
| if (System.currentTimeMillis() >= expandBeginTime) { |
| if (item.getItemCount() > 0 && !item.getExpanded()) { |
| Event e = new Event(); |
| e.x = event.x; |
| e.y = event.y; |
| e.item = item; |
| e.time = (int) System.currentTimeMillis(); |
| tree.notifyListeners(SWT.Expand, e); |
| if (item.isDisposed()) return; |
| item.setExpanded(true); |
| } |
| expandBeginTime = 0; |
| expandItem = null; |
| } |
| } else { |
| expandBeginTime = System.currentTimeMillis() + EXPAND_HYSTERESIS; |
| expandItem = item; |
| } |
| } |
| |
| 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 = tree.getClientArea(); |
| int headerHeight = tree.getHeaderHeight(); |
| int itemHeight= tree.getItemHeight(); |
| Point pt = new Point(event.x, event.y); |
| pt = tree.getDisplay().map(null, tree, pt); |
| TreeItem nextItem = null; |
| if (pt.y < area.y + headerHeight + 2 * itemHeight) { |
| nextItem = previousItem(tree, item); |
| } |
| if (pt.y > area.y + area.height - 2 * itemHeight) { |
| nextItem = nextItem(tree, item); |
| } |
| if (nextItem != null) tree.showItem(nextItem); |
| scrollBeginTime = 0; |
| scrollItem = null; |
| } |
| } else { |
| scrollBeginTime = System.currentTimeMillis() + SCROLL_HYSTERESIS; |
| scrollItem = item; |
| } |
| } |
| |
| if ((effect & DND.FEEDBACK_SELECT) != 0) { |
| if (currentItem != item || (currentEffect & DND.FEEDBACK_SELECT) == 0) { |
| setDropSelection(tree, item); |
| currentEffect = effect; |
| currentItem = item; |
| } |
| } else { |
| setDropSelection(tree, null); |
| } |
| |
| if ((effect & DND.FEEDBACK_INSERT_AFTER) != 0 || |
| (effect & DND.FEEDBACK_INSERT_BEFORE) != 0) { |
| if (currentItem != item || |
| ((effect & DND.FEEDBACK_INSERT_AFTER) != (currentEffect & DND.FEEDBACK_INSERT_AFTER)) || |
| ((effect & DND.FEEDBACK_INSERT_BEFORE) != (currentEffect & DND.FEEDBACK_INSERT_BEFORE))) { |
| setInsertMark(tree, item, (effect & DND.FEEDBACK_INSERT_BEFORE) != 0); |
| currentEffect = effect; |
| currentItem = item; |
| } |
| } else { |
| setInsertMark(tree, null, false); |
| } |
| } |
| |
| void setDropSelection (Tree tree, TreeItem item) { |
| if (item == dropSelection) return; |
| if (dropSelection != null && !dropSelection.isDisposed()) { |
| Rectangle bounds = dropSelection.getBounds(); |
| tree.redraw(bounds.x, bounds.y, bounds.width, bounds.height, true); |
| } |
| dropSelection = item; |
| if (dropSelection != null && !dropSelection.isDisposed()) { |
| Rectangle bounds = dropSelection.getBounds(); |
| tree.redraw(bounds.x, bounds.y, bounds.width, bounds.height, true); |
| } |
| if (dropSelection == null) { |
| if (paintListener != null) { |
| tree.removePaintListener(paintListener); |
| paintListener = null; |
| } |
| } else { |
| if (paintListener == null) { |
| paintListener = new PaintListener() { |
| public void paintControl(PaintEvent e) { |
| if (dropSelection == null || dropSelection.isDisposed()) return; |
| GC gc = e.gc; |
| boolean xor = gc.getXORMode(); |
| gc.setXORMode(true); |
| Rectangle bounds = dropSelection.getBounds(); |
| gc.fillRectangle(bounds.x, bounds.y, bounds.width, bounds.height); |
| gc.setXORMode(xor); |
| } |
| }; |
| tree.addPaintListener(paintListener); |
| } |
| } |
| } |
| |
| void setInsertMark(Tree tree, TreeItem item, boolean before) { |
| if (item == insertItem && before == insertBefore) return; |
| insertItem = item; |
| insertBefore = before; |
| tree.setInsertMark(item, before); |
| } |
| |
| } |