Displayed nodes in a JTree

Question

Hi, i'm creating a JTree with TreeModel, and make the root as my c: drive. when the tree displayed, i found that it display some files that are actually not available in my c: drive. so, can anyone please tell me what's wrong in this case? thanks in advance!

Answer 1

OK, these are two java files, please check for me. Thanks!
import java.awt.*;
import java.awt.event.*;
import javax.swing.*;
import javax.swing.event.*;
import java.io.*;
public class MyTree extends JFrame implements ActionListener{
File[] rt;
File drive;
private DefaultComboBoxModel comboModel;
MyTreeModel model;
File root = null;
JTree tree;
    public MyTree() {
        initComponents();
public void initComponents() {
setLayout(new BorderLayout());
  setDefaultCloseOperation(javax.swing.WindowConstants.DISPOSE_ON_CLOSE);
panelB = new javax.swing.JPanel();
panelB.setLayout(new BorderLayout());
comboModel = new DefaultComboBoxModel();
selectDrive = new JComboBox(comboModel);
rt=File.listRoots();
  for (int i=0; i<rt.length; i++)
       drive = rt;
     comboModel.addElement(drive);
selectDrive.setModel(comboModel);
selectDrive.addActionListener(this);
selectDrive.setActionCommand("sel_drive");
tree = new JTree();
tscrollPane = new JScrollPane(tree);
displayTree();
panelB.add(selectDrive,BorderLayout.NORTH);
panelB.add(tscrollPane,BorderLayout.CENTER);
add(panelB,BorderLayout.NORTH);
pack();
public void actionPerformed(ActionEvent e) {
     String cmd = e.getActionCommand();
     if(cmd.equals("sel_drive")){
               displayTree();     
public void displayTree(){
     Object obj = comboModel.getSelectedItem();
     String str = obj.toString();
     File f = new File(str);
     model = new MyTreeModel(f);
     tree.setModel(model);
public static void main(String args[]){
     MyTree treefr = new MyTree();
     treefr.setSize(500, 500);
     treefr.setVisible(true);
public JComboBox selectDrive;
public JPanel panelB;
public JScrollPane tscrollPane;
import javax.swing.tree.*;
import javax.swing.event.*;
import java.io.*;
class MyTreeModel implements TreeModel {
public File root;
public MyTreeModel(File rt) {
     root = rt;
public Object getRoot() {
     return root;
public boolean isLeaf(Object node) { 
     File leaf = (File)node;
     return leaf.isFile();      
public int getChildCount(Object parent) {
     File p = (File)parent;
     if(p.isDirectory()){
          System.out.println("Total Files="+p.list().length);
          return p.list().length;
     }else{
          return 0;
public Object getChild(Object parent, int index) {
File p = (File)parent;
String[] children = p.list();
File child = new File(p,children[index]);
try
     return child;
catch (ArrayIndexOutOfBoundsException e)
e.printStackTrace();
return null;
public int getIndexOfChild(Object parent, Object child) {
String cname;
String[] children = ((File)parent).list();
if (children.length>0){
     cname = ((File)child).getName();
     for(int i = 0; i < children.length; i++) {
     if (cname.equals(children[i]))
          return i;
else{
          return -1;
return -1;
public void valueForPathChanged(TreePath path, Object newvalue) {}
public void addTreeModelListener(TreeModelListener l) {}
public void removeTreeModelListener(TreeModelListener l) {}