| /******************************************************************************* |
| * Copyright (c) 2009, 2011 David Green and others. |
| * All rights reserved. This program and the accompanying materials |
| * are made available under the terms of the Eclipse Public License v2.0 |
| * which accompanies this distribution, and is available at |
| * https://www.eclipse.org/legal/epl-2.0/ |
| * |
| * SPDX-License-Identifier: EPL-2.0 |
| * |
| * Contributors: |
| * David Green - initial API and implementation |
| *******************************************************************************/ |
| |
| package org.eclipse.mylyn.internal.wikitext.ui.editor.dnd; |
| |
| import java.util.List; |
| |
| import org.eclipse.core.runtime.ISafeRunnable; |
| import org.eclipse.jface.dialogs.MessageDialog; |
| import org.eclipse.jface.util.LocalSelectionTransfer; |
| import org.eclipse.jface.util.SafeRunnable; |
| import org.eclipse.jface.util.TransferDropTargetListener; |
| import org.eclipse.jface.viewers.ISelection; |
| import org.eclipse.jface.viewers.IStructuredSelection; |
| import org.eclipse.mylyn.internal.wikitext.ui.WikiTextUiPlugin; |
| import org.eclipse.mylyn.internal.wikitext.ui.editor.operations.AbstractDocumentCommand; |
| import org.eclipse.mylyn.internal.wikitext.ui.editor.operations.CommandManager; |
| import org.eclipse.mylyn.internal.wikitext.ui.editor.operations.InsertLocation; |
| import org.eclipse.mylyn.internal.wikitext.ui.editor.operations.MoveSectionsCommand; |
| import org.eclipse.mylyn.wikitext.parser.outline.OutlineItem; |
| import org.eclipse.osgi.util.NLS; |
| import org.eclipse.swt.dnd.DND; |
| import org.eclipse.swt.dnd.DropTargetEvent; |
| import org.eclipse.swt.dnd.Transfer; |
| import org.eclipse.swt.graphics.Point; |
| import org.eclipse.swt.graphics.Rectangle; |
| import org.eclipse.swt.widgets.Control; |
| import org.eclipse.swt.widgets.TreeItem; |
| import org.eclipse.ui.PlatformUI; |
| |
| /** |
| * @author David Green |
| */ |
| public class OutlineDropTargetListener implements TransferDropTargetListener { |
| |
| private static final double THRESHOLD_BEFORE = 0.25f; |
| |
| private static final double THRESHOLD_AFTER = 0.75f; |
| |
| private final CommandManager commandManager; |
| |
| public OutlineDropTargetListener(CommandManager commandManager) { |
| this.commandManager = commandManager; |
| } |
| |
| public void dragEnter(DropTargetEvent event) { |
| // ignore |
| } |
| |
| public void dragLeave(DropTargetEvent event) { |
| // ignore |
| } |
| |
| public void dragOperationChanged(DropTargetEvent event) { |
| // ignore |
| } |
| |
| public void dropAccept(DropTargetEvent event) { |
| // ignore |
| } |
| |
| public void dragOver(DropTargetEvent event) { |
| // Based on XMLContentOutlineConfiguration |
| event.feedback = DND.FEEDBACK_SELECT; |
| float relativeLocation = computeRelativeLocation(event); |
| if (relativeLocation > THRESHOLD_AFTER) { |
| // point was mostly below the item |
| event.feedback = DND.FEEDBACK_INSERT_AFTER; |
| } else if (relativeLocation < THRESHOLD_BEFORE) { |
| // point was mostly above the item |
| event.feedback = DND.FEEDBACK_INSERT_BEFORE; |
| } |
| // always provide expand/scroll capability when dragging |
| event.feedback |= DND.FEEDBACK_EXPAND | DND.FEEDBACK_SCROLL; |
| } |
| |
| public void drop(DropTargetEvent event) { |
| List<OutlineItem> dropItems = getDropItems(event); |
| if (dropItems != null) { |
| InsertLocation location = computeInsertLocation(event); |
| Object targetData = event.item.getData(); |
| |
| final AbstractDocumentCommand command = computeCommand(targetData, dropItems, location); |
| if (command != null) { |
| if (command.isEnabled()) { |
| SafeRunnable.run(new ISafeRunnable() { |
| public void handleException(Throwable exception) { |
| WikiTextUiPlugin.getDefault().log(exception); |
| MessageDialog.openError( |
| PlatformUI.getWorkbench().getActiveWorkbenchWindow().getShell(), |
| Messages.OutlineDropTargetListener_0, |
| NLS.bind(Messages.OutlineDropTargetListener_1, |
| new Object[] { exception.getMessage() })); |
| } |
| |
| public void run() throws Exception { |
| commandManager.perform(command); |
| } |
| }); |
| } else { |
| MessageDialog.openInformation(PlatformUI.getWorkbench().getActiveWorkbenchWindow().getShell(), |
| Messages.OutlineDropTargetListener_2, |
| NLS.bind(Messages.OutlineDropTargetListener_3, new Object[] { command.getProblemText() })); |
| } |
| } |
| } |
| } |
| |
| private AbstractDocumentCommand computeCommand(Object targetData, List<OutlineItem> dropItems, |
| InsertLocation location) { |
| return new MoveSectionsCommand((OutlineItem) targetData, dropItems, location); |
| } |
| |
| /** |
| * get the outline items being dropped, or null if there are none or if the event does not qualify for a drop. |
| */ |
| @SuppressWarnings("unchecked") |
| private List<OutlineItem> getDropItems(DropTargetEvent event) { |
| if (event.operations == DND.DROP_NONE || event.item == null) { |
| return null; |
| } |
| Object targetData = event.item.getData(); |
| if (!(targetData instanceof OutlineItem)) { |
| return null; |
| } |
| |
| ISelection selection = LocalSelectionTransfer.getTransfer().getSelection(); |
| if (selection instanceof IStructuredSelection && !selection.isEmpty()) { |
| IStructuredSelection structuredSelection = (IStructuredSelection) selection; |
| List<?> list = structuredSelection.toList(); |
| if (!list.isEmpty()) { |
| for (Object i : list) { |
| if (!(i instanceof OutlineItem)) { |
| return null; |
| } |
| } |
| return (List<OutlineItem>) list; |
| } |
| } |
| return null; |
| } |
| |
| private InsertLocation computeInsertLocation(DropTargetEvent event) { |
| float relativeLocation = computeRelativeLocation(event); |
| if (relativeLocation < THRESHOLD_BEFORE) { |
| return InsertLocation.BEFORE; |
| } else if (relativeLocation > THRESHOLD_AFTER) { |
| return InsertLocation.AFTER; |
| } |
| return InsertLocation.WITHIN; |
| } |
| |
| private float computeRelativeLocation(DropTargetEvent event) { |
| if (event.item == null) { |
| return 0.5f; |
| } else if (event.item instanceof TreeItem) { |
| TreeItem treeItem = (TreeItem) event.item; |
| Control control = treeItem.getParent(); |
| Point controlRelativeEventLocation = control.toControl(new Point(event.x, event.y)); |
| Rectangle bounds = treeItem.getBounds(); |
| return (float) (controlRelativeEventLocation.y - bounds.y) / (float) bounds.height; |
| } else { |
| return 0.0f; |
| } |
| } |
| |
| public Transfer getTransfer() { |
| return LocalSelectionTransfer.getTransfer(); |
| } |
| |
| public boolean isEnabled(DropTargetEvent event) { |
| return getTransfer().isSupportedType(event.currentDataType) && getDropItems(event) != null; |
| } |
| } |