这段代码可能有用: /******************************************************************************* * Copyright (c) 2000, 2004 IBM Corporation and others. * All rights reserved. This program and the accompanying materials * are made available under the terms of the Eclipse Public License v1.0 * which accompanies this distribution, and is available at * http://www.eclipse.org/legal/epl-v10.html * * 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.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(); } }
/*******************************************************************************
* Copyright (c) 2000, 2004 IBM Corporation and others.
* All rights reserved. This program and the accompanying materials
* are made available under the terms of the Eclipse Public License v1.0
* which accompanies this distribution, and is available at
* http://www.eclipse.org/legal/epl-v10.html
*
* 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.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();
}
}