Snippet8.java Source code

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Here is the source code for Snippet8.java

Source

/*
 * Tree example snippet: create a tree (lazy)
 *
 * For a list of all SWT example snippets see
 * http://dev.eclipse.org/viewcvs/index.cgi/%7Echeckout%7E/platform-swt-home/dev.html#snippets
 */
import java.io.File;

import org.eclipse.swt.SWT;
import org.eclipse.swt.graphics.Point;
import org.eclipse.swt.layout.FillLayout;
import org.eclipse.swt.widgets.Display;
import org.eclipse.swt.widgets.Event;
import org.eclipse.swt.widgets.Listener;
import org.eclipse.swt.widgets.Shell;
import org.eclipse.swt.widgets.Tree;
import org.eclipse.swt.widgets.TreeItem;

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, new Listener() {
            public void handleEvent(final Event event) {
                final TreeItem root = (TreeItem) event.item;
                TreeItem[] items = root.getItems();
                for (int i = 0; i < items.length; i++) {
                    if (items[i].getData() != null)
                        return;
                    items[i].dispose();
                }
                File file = (File) root.getData();
                File[] files = file.listFiles();
                if (files == null)
                    return;
                for (int i = 0; i < files.length; i++) {
                    TreeItem item = new TreeItem(root, 0);
                    item.setText(files[i].getName());
                    item.setData(files[i]);
                    if (files[i].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();
    }
}