org.eclipse.swt.snippets.Snippet8.java Source code

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Here is the source code for org.eclipse.swt.snippets.Snippet8.java

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/*******************************************************************************
 * 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 example snippet: create a tree (lazy)
 *
 * For a list of all SWT example snippets see
 * http://www.eclipse.org/swt/snippets/
 */
import java.io.*;

import org.eclipse.swt.*;
import org.eclipse.swt.graphics.*;
import org.eclipse.swt.layout.*;
import org.eclipse.swt.widgets.*;

public class Snippet8 {

    public static void main(String[] args) {
        final Display display = new Display();
        final Shell shell = new Shell(display);
        shell.setText("Lazy Tree");
        shell.setLayout(new FillLayout());
        final Tree tree = new Tree(shell, SWT.BORDER);
        File[] roots = File.listRoots();
        for (int i = 0; i < roots.length; i++) {
            TreeItem root = new TreeItem(tree, 0);
            root.setText(roots[i].toString());
            root.setData(roots[i]);
            new TreeItem(root, 0);
        }
        tree.addListener(SWT.Expand, event -> {
            final TreeItem root = (TreeItem) event.item;
            TreeItem[] items = root.getItems();
            for (int i1 = 0; i1 < items.length; i1++) {
                if (items[i1].getData() != null)
                    return;
                items[i1].dispose();
            }
            File file = (File) root.getData();
            File[] files = file.listFiles();
            if (files == null)
                return;
            for (int i2 = 0; i2 < files.length; i2++) {
                TreeItem item = new TreeItem(root, 0);
                item.setText(files[i2].getName());
                item.setData(files[i2]);
                if (files[i2].isDirectory()) {
                    new TreeItem(item, 0);
                }
            }
        });
        Point size = tree.computeSize(300, SWT.DEFAULT);
        int width = Math.max(300, size.x);
        int height = Math.max(300, size.y);
        shell.setSize(shell.computeSize(width, height));
        shell.open();
        while (!shell.isDisposed()) {
            if (!display.readAndDispatch())
                display.sleep();
        }
        display.dispose();
    }
}