tests/org.eclipse.swt.tests.gtk/ManualTests/org/eclipse/swt/tests/gtk/snippets/Bug258196_VirtualTreeResizing.java

/*******************************************************************************
 * Copyright (c) 2018 Red Hat and others.
 *
 * This program and the accompanying materials
 * are made available under the terms of the Eclipse Public License 2.0
 * which accompanies this distribution, and is available at
 * https://www.eclipse.org/legal/epl-2.0/
 *
 * SPDX-License-Identifier: EPL-2.0
 *
 * Contributors:
 *     Red Hat - initial API and implementation
 *******************************************************************************/
package org.eclipse.swt.tests.gtk.snippets;

import org.eclipse.swt.SWT;
import org.eclipse.swt.layout.FillLayout;
import org.eclipse.swt.widgets.Display;
import org.eclipse.swt.widgets.Shell;
import org.eclipse.swt.widgets.Tree;
import org.eclipse.swt.widgets.TreeItem;

public class Bug258196_VirtualTreeResizing {
	public static void main(String[] args) {
		final Display display = new Display();
		final Shell shell = new Shell(display);
		shell.setLayout (new FillLayout());
		final Tree tree = new Tree(shell, SWT.VIRTUAL | SWT.BORDER);
		tree.addListener(SWT.SetData, event -> {
			final TreeItem item = (TreeItem)event.item;
			TreeItem parentItem = item.getParentItem();
			String text = null;
			if (parentItem == null) {
				text = "node "+tree.indexOf(item);
			} else {
				text = parentItem.getText()+" - "+parentItem.indexOf(item);
			}
			item.setData(text);
			item.setItemCount(10);
			display.asyncExec(() -> {
				if (!item.isDisposed()) {
					item.setText(item.getData().toString());
				}
			});
		});
		tree.setItemCount(20);
		shell.setSize(400, 300);
		shell.open();
		while (!shell.isDisposed ()) {
			if (!display.readAndDispatch ()) display.sleep ();
		}
		display.dispose ();
	}
}