SwtBackgroundDemo.java

package ch.jgraber.blog;

import org.eclipse.swt.SWT;
import org.eclipse.swt.events.SelectionAdapter;
import org.eclipse.swt.events.SelectionEvent;
import org.eclipse.swt.graphics.Point;
import org.eclipse.swt.layout.FillLayout;
import org.eclipse.swt.widgets.Button;
import org.eclipse.swt.widgets.Composite;
import org.eclipse.swt.widgets.Display;
import org.eclipse.swt.widgets.Event;
import org.eclipse.swt.widgets.Listener;
import org.eclipse.swt.widgets.ProgressBar;
import org.eclipse.swt.widgets.Shell;

/**
 * Test Background Work for SWT based on tutorial on
 * http://www.java2s.com/Code/JavaAPI
 * /org.eclipse.swt.widgets/DisplayasyncExecRunnablerun.htm
 * 
 * @author Johnny Graber
 */

public class SwtBackgroundDemo {

	/**
	 * @param args
	 */
	public static void main(String[] args) {
		final SwtBackgroundDemo window = new SwtBackgroundDemo();
		window.open();
	}

	protected ProgressBar progress;

	/**
	 * Open the window
	 */
	public void open() {

		final Display s_display = Display.getDefault();
		final Shell s_shell = new Shell(s_display);
		s_shell.setSize(new Point(200, 200));

		s_shell.setText("BackgroundWork Test");
		s_shell.setLayout(new FillLayout());
		s_shell.addListener(SWT.Traverse, new Listener() {
			public void handleEvent(Event event) {
				if (event.detail == SWT.TRAVERSE_ESCAPE)
					s_shell.dispose();
			}
		});

		Composite s_composite = new Composite(s_shell, SWT.NONE);
		s_composite.setLayout(new FillLayout(SWT.VERTICAL));
		final Button workButton = new Button(s_composite, SWT.FLAT);
		workButton.setText("Bereit!");
		workButton.setLocation(new Point(0, 0));
		workButton.setSize(100, 50);

		progress = new ProgressBar(s_composite, SWT.HORIZONTAL | SWT.SMOOTH);

		workButton.addSelectionListener(new SelectionAdapter() {
			public void widgetSelected(SelectionEvent arg0) {
				progress.setSelection(0);
				workButton.setEnabled(false);
				new LongRunningOperation(s_display, progress, workButton)
						.start();
				workButton.setText("SelectionListener beendet!");
			}
		});

		final Button workButtonSlow = new Button(s_composite, SWT.FLAT);
		workButtonSlow.setText("Bereit! [Blockiert]");
		workButtonSlow.setLocation(new Point(0, 0));
		workButtonSlow.setSize(100, 50);
		workButtonSlow.addSelectionListener(new SelectionAdapter() {
			public void widgetSelected(SelectionEvent arg0) {
				progress.setSelection(0);
				workButtonSlow.setEnabled(false);
				
				// simuliert lange dauernde Aktion
				for (int i = 0; i < 100; i++) {
					try {
						Thread.sleep(100);
					} catch (InterruptedException e) {
						System.out.println(e.getMessage());
					}

					progress.setSelection(progress.getSelection() + 1);
				}

				workButtonSlow.setText("Thread beendet");
				workButtonSlow.setEnabled(true);
			}
		});

		s_shell.layout();
		s_shell.open();
		while (!s_shell.isDisposed()) {
			if (!s_display.readAndDispatch())
				s_display.sleep();
		}

	}

	class LongRunningOperation extends Thread {
		private Display display;
		private ProgressBar progressBar;
		private Button workButton;

		/**
		 * Alles übergeben was aus diesem Thread erreichbar sein soll
		 */
		public LongRunningOperation(Display display, ProgressBar progressBar,
				Button workButton) {
			this.display = display;
			this.progressBar = progressBar;
			this.workButton = workButton;
		}

		/**
		 * Länger laufende Methode um eine Verarbeitung zu simulieren
		 */
		public void run() {
			for (int i = 0; i < 100; i++) {
				try {
					Thread.sleep(100);
				} catch (InterruptedException e) {
					System.out.println(e.getMessage());
				}
				progressBar.setSelection(progressBar.getSelection() + 1);
				// ProgressBar kann nur via asyncExec aktualisiert werden!
				display.asyncExec(new Runnable() {
					public void run() {
						if (progressBar.isDisposed())
							return;
						progressBar.setSelection(progressBar.getSelection() + 1);
					}
				});
			}

			// Gleiches gilt für alle GUI-Elemente
			display.asyncExec(new Runnable() {
				public void run() {
					if (workButton.isDisposed())
						return;
					workButton.setText("Thread beendet");
					workButton.setEnabled(true);
				}
			});
		}
	}
}