Java Tutorial/SWT/ScrollBar Event

Add Selection Listener to ScrollBar

/*******************************************************************************
 * 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();
  }
}