I've used an example by Ian F. Darwin关于如何在JTree上显示文件系统,尽管代码对我来说很清楚,但我无法弄清楚为什么我无法展开valueChanged上的树的TreeSelectionListener。下面的代码:无法使用expandPath方法扩展JTree
package ericsonwrp.republica.vintage.caixa;
/*
* Copyright (c) Ian F. Darwin, http://www.darwinsys.com/, 1996-2002.
* All rights reserved. Software written by Ian F. Darwin and others.
* $Id: LICENSE,v 1.8 2004/02/09 03:33:38 ian Exp $
*
* Redistribution and use in source and binary forms, with or without
* modification, are permitted provided that the following conditions
* are met:
* 1. Redistributions of source code must retain the above copyright
* notice, this list of conditions and the following disclaimer.
* 2. Redistributions in binary form must reproduce the above copyright
* notice, this list of conditions and the following disclaimer in the
* documentation and/or other materials provided with the distribution.
*
* THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS''
* AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED
* TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR
* PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS
* BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
* CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
* SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
* INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
* CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
* ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
* POSSIBILITY OF SUCH DAMAGE.
*
* Java, the Duke mascot, and all variants of Sun's Java "steaming coffee
* cup" logo are trademarks of Sun Microsystems. Sun's, and James Gosling's,
* pioneering role in inventing and promulgating (and standardizing) the Java
* language and environment is gratefully acknowledged.
*
* The pioneering role of Dennis Ritchie and Bjarne Stroustrup, of AT&T, for
* inventing predecessor languages C and C++ is also gratefully acknowledged.
*/
import java.awt.BorderLayout;
import java.awt.Color;
import java.awt.Container;
import java.awt.Dimension;
import java.io.File;
import java.util.Collections;
import java.util.Vector;
import javax.swing.BoxLayout;
import javax.swing.JFrame;
import javax.swing.JPanel;
import javax.swing.JScrollPane;
import javax.swing.JTree;
import javax.swing.event.TreeSelectionEvent;
import javax.swing.event.TreeSelectionListener;
import javax.swing.tree.DefaultMutableTreeNode;
import javax.swing.tree.TreePath;
/**
* Display a file system in a JTree view
*
* @version $Id: FileTree.java,v 1.9 2004/02/23 03:39:22 ian Exp $
* @author Ian Darwin
*/
public class FileTree extends JPanel {
/**
*
*/
private static final long serialVersionUID = 1L;
private JTree tree;
private JScrollPane scrollpane;
/** Construct a FileTree */
public FileTree(File dir) {
setLayout(new BorderLayout());
tree = new JTree(addNodes(null, dir));
tree.setRootVisible(false);
// Add a listener
tree.addTreeSelectionListener(new TreeSelectionListener() {
public void valueChanged(TreeSelectionEvent e) {
DefaultMutableTreeNode node = (DefaultMutableTreeNode) e
.getPath().getLastPathComponent();
TreePath p = new TreePath(node.getPath());
tree.expandPath(p); // HERE <<<<<<<<<<<<<<
}
});
scrollpane = new JScrollPane();
scrollpane.getViewport().add(tree);
add(BorderLayout.CENTER, scrollpane);
}
/** Add nodes from under "dir" into curTop. Highly recursive. */
DefaultMutableTreeNode addNodes(DefaultMutableTreeNode curTop, File dir) {
String curPath = dir.getPath();
DefaultMutableTreeNode curDir = new DefaultMutableTreeNode(curPath);
if (curTop != null) { // should only be null at root
curTop.add(curDir);
}
Vector<String> ol = new Vector<String>();
String[] tmp = dir.list();
for (int i = 0; i < tmp.length; i++)
ol.addElement(tmp[i]);
Collections.sort(ol, String.CASE_INSENSITIVE_ORDER);
File f;
Vector<String> files = new Vector<String>();
// Make two passes, one for Dirs and one for Files. This is #1.
for (int i = 0; i < ol.size(); i++) {
String thisObject = (String) ol.elementAt(i);
String newPath;
if (curPath.equals("."))
newPath = thisObject;
else
newPath = curPath + File.separator + thisObject;
if ((f = new File(newPath)).isDirectory())
addNodes(curDir, f);
else
files.addElement(thisObject);
}
// Pass two: for files.
for (int fnum = 0; fnum < files.size(); fnum++)
curDir.add(new DefaultMutableTreeNode(files.elementAt(fnum)));
return curDir;
}
public Dimension getMinimumSize() {
return new Dimension(200, 400);
}
public Dimension getPreferredSize() {
return new Dimension(200, 400);
}
}
这里是我的“文件选择”与此JTree视觉例如:
正如你所看到的,节点应该对的valueChanged扩大,而不会发生(“游戏”是一个文件夹)。
它为我工作。我的猜测是你没有在AWT事件调度线程中显示你的FileTree。所有Swing组件都必须在该线程中创建和操作,但如果在错误的线程中进行管理,JTree特别容易出现奇怪的行为。 – VGR
我没有在不同的线程上操纵任何东西。只有一个主线程,我用setVisible“切换”框架(包括文件选择器之一)。我不确定我是否理解我无法在AWT Event Dispatch线程中显示。你有什么暗示我该怎么做? –
'只有一个主线程,我认为它不是EDT。您应该在EDT上拨打Swing的所有电话 - 您可以使用SwingUtilities.invokeLater()来完成。附注:考虑加载树懒,而不是遍历整个文件路径来构建树。 – copeg