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/*
* Copyright (c) 2012, Oracle and/or its affiliates. All rights reserved.
* DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
*
* This code is free software; you can redistribute it and/or modify it
* under the terms of the GNU General Public License version 2 only, as
* published by the Free Software Foundation.
*
* This code is distributed in the hope that it will be useful, but WITHOUT
* ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
* FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License
* version 2 for more details (a copy is included in the LICENSE file that
* accompanied this code).
*
* You should have received a copy of the GNU General Public License version
* 2 along with this work; if not, write to the Free Software Foundation,
* Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
*
* Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
* or visit www.oracle.com if you need additional information or have any
* questions.
*/
import javax.swing.*;
import java.awt.*;
import java.awt.dnd.Autoscroll;
public class JListWithScroll<E> extends JList<E> implements Autoscroll {
private Insets scrollInsets;
public JListWithScroll(E[] listData) {
super(listData);
scrollInsets = new Insets(50, 50, 50, 50);
}
@Override
public Insets getAutoscrollInsets() {
return scrollInsets;
}
@Override
public void autoscroll(Point cursorLoc) {
JViewport viewport = getViewport();
if (viewport == null) {
return;
}
Point viewPos = viewport.getViewPosition();
int viewHeight = viewport.getExtentSize().height;
int viewWidth = viewport.getExtentSize().width;
if ((cursorLoc.y - viewPos.y) < scrollInsets.top) {
viewport.setViewPosition(new Point(viewPos.x, Math.max(viewPos.y - scrollInsets.top, 0)));
} else if (((viewPos.y + viewHeight) - cursorLoc.y) < scrollInsets.bottom) {
viewport.setViewPosition(
new Point(viewPos.x, Math.min(viewPos.y + scrollInsets.bottom, this.getHeight() - viewHeight))
);
} else if ((cursorLoc.x - viewPos.x) < scrollInsets.left) {
viewport.setViewPosition(new Point(Math.max(viewPos.x - scrollInsets.left, 0), viewPos.y));
} else if (((viewPos.x + viewWidth) - cursorLoc.x) < scrollInsets.right) {
viewport.setViewPosition(
new Point(Math.min(viewPos.x + scrollInsets.right, this.getWidth() - viewWidth), viewPos.y)
);
}
}
public JViewport getViewport() {
Component curComp = this;
while (!(curComp instanceof JViewport) && (curComp != null)) {
curComp = curComp.getParent();
}
if(curComp instanceof JViewport) {
return (JViewport) curComp;
} else {
return null;
}
}
}
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