examples/org.eclipse.swt.snippets/src/org/eclipse/swt/snippets/Snippet274.java

/*******************************************************************************
 * Copyright (c) 2000, 2016 IBM Corporation 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:
 *     IBM Corporation - initial API and implementation
 *******************************************************************************/
package org.eclipse.swt.snippets;

/*
 * Tree snippet: implement standard tree check box behavior (SWT.CHECK)
 *
 * For a list of all SWT example snippets see
 * http://www.eclipse.org/swt/snippets/
 *
 * @since 3.3
 */
import org.eclipse.swt.*;
import org.eclipse.swt.graphics.*;
import org.eclipse.swt.widgets.*;

public class Snippet274 {

	static void checkPath(TreeItem item, boolean checked, boolean grayed) {
		if (item == null) return;
		if (grayed) {
			checked = true;
		} else {
			int index = 0;
			TreeItem[] items = item.getItems();
			while (index < items.length) {
				TreeItem child = items[index];
				if (child.getGrayed() || checked != child.getChecked()) {
					checked = grayed = true;
					break;
				}
				index++;
			}
		}
		item.setChecked(checked);
		item.setGrayed(grayed);
		checkPath(item.getParentItem(), checked, grayed);
	}

	static void checkItems(TreeItem item, boolean checked) {
		item.setGrayed(false);
		item.setChecked(checked);
		TreeItem[] items = item.getItems();
		for (int i = 0; i < items.length; i++) {
			checkItems(items[i], checked);
		}
	}

	public static void main(String[] args) {
		Display display = new Display();
		Shell shell = new Shell(display);
		shell.setText("Snippet 274");
		Tree tree = new Tree(shell, SWT.BORDER | SWT.CHECK);
		tree.addListener(SWT.Selection, event -> {
			if (event.detail == SWT.CHECK) {
				TreeItem item = (TreeItem) event.item;
				boolean checked = item.getChecked();
				checkItems(item, checked);
				checkPath(item.getParentItem(), checked, false);
			}
		});
		for (int i = 0; i < 4; i++) {
			TreeItem itemI = new TreeItem(tree, SWT.NONE);
			itemI.setText("Item " + i);
			for (int j = 0; j < 4; j++) {
				TreeItem itemJ = new TreeItem(itemI, SWT.NONE);
				itemJ.setText("Item " + i + " " + j);
				for (int k = 0; k < 4; k++) {
					TreeItem itemK = new TreeItem(itemJ, SWT.NONE);
					itemK.setText("Item " + i + " " + j + " " + k);
				}
			}
		}
		Rectangle clientArea = shell.getClientArea();
		tree.setBounds(clientArea.x, clientArea.y, 200, 200);
		shell.pack();
		shell.open();
		while (!shell.isDisposed()) {
			if (!display.readAndDispatch()) display.sleep();
		}
		display.dispose();
	}

}