[Help] Viewing filesystem with JTree

artur_spruce_at_yahoo.com
Date: 03/28/05 

Date: 28 Mar 2005 07:45:46 -0800

Hi,

I know this subject has been discussed here before, but I don't want to
deal with tree models etc. I built a custom tree node (code at end) and
hooked it to a JTree like this:

pathTree = new JTree(new FileTreeNode("/"));

but it only displays the root node and then all the first-level files
and directories as leaves. How do I make them display as expandable
nodes? Apparently none of the getChildCount(), getAllowsChildren(), or
isLeaf() help.

(I know my implementation of the node is a bit naive as far as
synchronization and order.)

Or maybe I can't do it this way?

TIA,

AdSR

---- FileTreeNode ----
package fileviewer;

import java.io.File;
import java.util.Enumeration;
import java.util.Hashtable;

import javax.swing.tree.TreeNode;

public class FileTreeNode implements TreeNode {
        private TreeNode parent;
        private File file;
        private Hashtable children;

        public FileTreeNode(String path) {
                this(path, null);
        }

        public FileTreeNode(String path, TreeNode parent) {
                file = new File(path);
                children = new Hashtable();
        }

        public TreeNode getChildAt(int childIndex) {
                String[] names = file.list();
                String name = names[childIndex];
                if (children.containsKey(name))
                        return (TreeNode)children.get(name);
                FileTreeNode child = new FileTreeNode(name, this);
                children.put(name, child);
                return child;
        }

        public int getChildCount() {
                if (file.isDirectory()) {
                        return file.list().length;
                }
                return 0;
        }

        public TreeNode getParent() {
                return parent;
        }

        public int getIndex(TreeNode node) {
                String name = ((FileTreeNode)node).file.getName();
                String[] names = file.list();
                for (int i=0; i<names.length; i++)
                        if (names[i].equals(name))
                                return i;
                return -1;
        }

        public boolean getAllowsChildren() {
                return file.isDirectory();
        }

        public boolean isLeaf() {
                return !file.isDirectory();
        }

        public Enumeration children() {
                return new ChildrenEnumeration();
        }

        public String toString() {
                return file.getName();
        }

        private class ChildrenEnumeration implements Enumeration {
                String[] names;
                int index;

                public ChildrenEnumeration() {
                        names = file.list();
                }

                public boolean hasMoreElements() {
                        return index < names.length - 1;
                }

                public Object nextElement() {
                        String name = names[index];
                        index++;
                        if (children.containsKey(name))
                                return children.get(name);
                        FileTreeNode child = new FileTreeNode(name, FileTreeNode.this);
                        children.put(name, child);
                        return child;
                }
        }
}