 |
|
|
FileTreePanel.java
|
/*
Copyright (C) 2005 Havard Rast Blok
http://hblok.sourceforge.net
This library is free software; you can redistribute it and/or
modify it under the terms of the GNU Lesser General Public
License as published by the Free Software Foundation; either
version 2.1 of the License, or (at your option) any later version.
This library is distributed in the hope that it will be useful,
but WITHOUT ANY WARRANTY; without even the implied warranty of
MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
Lesser General Public License for more details.
You should have received a copy of the GNU Lesser General Public
License along with this library; if not, write to the Free Software
Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
*/
import java.awt.GridLayout;
import java.io.File;
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.DefaultTreeModel;
import javax.swing.tree.MutableTreeNode;
import javax.swing.tree.TreeModel;
import javax.swing.tree.TreePath;
/**
* Example which displays the directory structure of the system
* in a JTree coponent. The nodes are expandable, and will list
* the sub directories of the selected node.
*
* @author Havard Rast Blok
*
*/
public class FileTreePanel extends JPanel {
/** The model which holds the nodes */
protected TreeModel model;
/** The tree GUI */
protected JTree tree;
/**
* Constructs the panel which holds a JTree with the file structure.
*/
public FileTreePanel() {
//we only need one component
setLayout(new GridLayout(1,1));
//create the top node
MutableTreeNode root = new DefaultMutableTreeNode("Computer");
//get all nodes for top file systems or disks
//On Linux/Unix this will only be '/'
//while on Window there will typically be more: 'A:', 'C:' etc.
File roots[] = File.listRoots();
//loop through all these nodes and add them to the root Computer node
int i = 0;
for(File f : roots) {
DefaultMutableTreeNode node = new DefaultMutableTreeNode(f.getAbsoluteFile().toString());
root.insert(node, i++);
}
//create a tree model with the Computer node as root
model = new DefaultTreeModel(root);
//create a JTree GUI component with the model to display
tree = new JTree(model);
//add a selection listener, to listen for selected nodes
tree.addTreeSelectionListener(new MyTreeSelectionListener());
//create scrollbars
JScrollPane scroll = new JScrollPane(tree);
//and finally add to the panel
add(scroll);
}
/**
* Adds the sub directories, if any, of the given path to the given node.
*
* @param node tree node to add sub directory nodes to
* @param path file system path to search for sub directories
*/
protected void addChildren(MutableTreeNode node, String path) {
//create filter for directories only
DirectoryFileFilter filter = new DirectoryFileFilter();
//get directories
File dir = new File(path);
File subDirs[] = dir.listFiles(filter);
//add sub nodes to given nodes
if (subDirs != null) {
int i = 0;
for (File f : subDirs) {
MutableTreeNode child = new DefaultMutableTreeNode(f.getName());
node.insert(child, i++);
}
}
}
/**
* Inner class which listens for selection events on the tree.
* When one is received, it will get the path of the selected
* node and add sub directory nodes, if any, to it.
*/
class MyTreeSelectionListener implements TreeSelectionListener {
public void valueChanged(TreeSelectionEvent e) {
//get the selected tree path
TreePath path = e.getNewLeadSelectionPath();
//check that a path is in fact selected
if(path == null) {
return;
}
//get the selected node
DefaultMutableTreeNode curNode = (DefaultMutableTreeNode) path.getLastPathComponent();
//get all the nodes in the selected tree path
Object nodes[] = path.getPath();
String dir = "";
//loop through all the tree nodes getting the directory name
//we start from node one, since node 0, the top node, is the Computer node,
//which will have no meaning in the file system path
for (int i = 1; i < nodes.length; i++) {
DefaultMutableTreeNode node = (DefaultMutableTreeNode) nodes[i];
//the user object will hold the directory name
dir += (String)node.getUserObject();
//add the platform independent directory separator character
dir += File.separator;
}
//add the sub directory nodes to the selected one
addChildren(curNode, dir);
//refresh the GUI
repaint();
}
}
public static void main(String[] args) {
//create a JFrame for the example
JFrame frame = new JFrame();
//exit the application when the frame is closed
frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
//we need only one component in the frame
frame.setLayout(new GridLayout(1,1));
frame.add(new FileTreePanel());
//show the frame
frame.pack();
frame.setVisible(true);
}
}
|
|
|
 |
