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/*******************************************************************************
* Copyright (c) 2000, 2011 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.internal.cocoa.*;
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
* @see <a href="http://www.eclipse.org/swt/">Sample code and further information</a>
*
* @since 3.3
*/
public class TableDropTargetEffect extends DropTargetEffect {
boolean shouldEnableScrolling;
/**
* 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) {
}
/**
* 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) {
if (shouldEnableScrolling) {
shouldEnableScrolling = false;
OS.objc_msgSend(control.view.id, OS.sel_setShouldScrollClipView_, 1);
control.redraw();
}
}
/**
* 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) {
int effect = checkEffect(event.feedback);
((DropTarget)event.widget).feedback = effect;
if ((effect & DND.FEEDBACK_SCROLL) == 0) {
shouldEnableScrolling = true;
OS.objc_msgSend(control.view.id, OS.sel_setShouldScrollClipView_, 0);
} else {
OS.objc_msgSend(control.view.id, OS.sel_setShouldScrollClipView_, 1);
}
}
}
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