Java Tutorial/SWT/ScrollBar Event

Add Selection Listener to ScrollBar

   <source lang="java">

/*******************************************************************************

* Copyright (c) 2000, 2004 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.snippets; /*

* Create two ScrolledComposites that scroll in tandem.
*
* For a list of all SWT example snippets see
* http://www.eclipse.org/swt/snippets/
*/

import org.eclipse.swt.SWT; import org.eclipse.swt.custom.ScrolledComposite; import org.eclipse.swt.events.SelectionAdapter; import org.eclipse.swt.events.SelectionEvent; import org.eclipse.swt.events.SelectionListener; import org.eclipse.swt.layout.FillLayout; import org.eclipse.swt.widgets.Button; import org.eclipse.swt.widgets.Display; import org.eclipse.swt.widgets.ScrollBar; import org.eclipse.swt.widgets.Shell; public class ScrollBarSelectionListener {

 public static void main(String[] args) {
   Display display = new Display();
   Shell shell = new Shell(display);
   shell.setLayout(new FillLayout());
   final ScrolledComposite sc1 = new ScrolledComposite(shell, SWT.BORDER | SWT.H_SCROLL
       | SWT.V_SCROLL);
   Button button1 = new Button(sc1, SWT.PUSH);
   button1.setText("Button 1");
   button1.setSize(400, 300);
   sc1.setContent(button1);
   final ScrolledComposite sc2 = new ScrolledComposite(shell, SWT.BORDER | SWT.H_SCROLL
       | SWT.V_SCROLL);
   Button button2 = new Button(sc2, SWT.PUSH);
   button2.setText("Button 2");
   button2.setSize(300, 400);
   sc2.setContent(button2);
   final ScrollBar vBar1 = sc1.getVerticalBar();
   final ScrollBar vBar2 = sc2.getVerticalBar();
   final ScrollBar hBar1 = sc1.getHorizontalBar();
   final ScrollBar hBar2 = sc2.getHorizontalBar();
   SelectionListener listener1 = new SelectionAdapter() {
     public void widgetSelected(SelectionEvent e) {
       int x = hBar1.getSelection() * (hBar2.getMaximum() - hBar2.getThumb())
           / Math.max(1, hBar1.getMaximum() - hBar1.getThumb());
       int y = vBar1.getSelection() * (vBar2.getMaximum() - vBar2.getThumb())
           / Math.max(1, vBar1.getMaximum() - vBar1.getThumb());
       sc2.setOrigin(x, y);
     }
   };
   SelectionListener listener2 = new SelectionAdapter() {
     public void widgetSelected(SelectionEvent e) {
       int x = hBar2.getSelection() * (hBar1.getMaximum() - hBar1.getThumb())
           / Math.max(1, hBar2.getMaximum() - hBar2.getThumb());
       int y = vBar2.getSelection() * (vBar1.getMaximum() - vBar1.getThumb())
           / Math.max(1, vBar2.getMaximum() - vBar2.getThumb());
       sc1.setOrigin(x, y);
     }
   };
   vBar1.addSelectionListener(listener1);
   hBar1.addSelectionListener(listener1);
   vBar2.addSelectionListener(listener2);
   hBar2.addSelectionListener(listener2);
   shell.setSize(400, 300);
   shell.open();
   while (!shell.isDisposed()) {
     if (!display.readAndDispatch())
       display.sleep();
   }
   display.dispose();
 }

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