/*******************************************************************************
* 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.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 Table
.
*
*
Classes that wish to provide their own drag under effect for a Table
* can extend the TableDropTargetEffect
and override any applicable methods
* in TableDropTargetEffect
to display their own drag under effect.
super
method to get the default drag under effect implementation.
*
* The feedback value is either one of the FEEDBACK constants defined in
* class DND
which is applicable to instances of this class,
* or it must be built by bitwise OR'ing together
* (that is, using the int
"|" operator) two or more
* of those DND
effect constants.
*
*
TableDropTargetEffect
to handle the drag under effect on the specified
* Table
.
*
* @param table the Table
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 dragEnter
provides a default drag under effect
* for the feedback specified in event.feedback
.
*
* For additional information see DropTargetAdapter.dragEnter
.
*
* Subclasses that override this method should call super.dragEnter(event)
* 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 dragLeave
provides a default drag under effect
* for the feedback specified in event.feedback
.
*
* For additional information see DropTargetAdapter.dragLeave
.
*
* Subclasses that override this method should call super.dragLeave(event)
* 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 dragOver
provides a default drag under effect
* for the feedback specified in event.feedback
. The class description
* lists the FEEDBACK constants that are applicable to the class.
*
* For additional information see DropTargetAdapter.dragOver
.
*
* Subclasses that override this method should call super.dragOver(event)
* 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;
}
}