How can I display the contents of a folder in a JTree?

Question

What I am trying to accomplish is to take a pre-defined file path and display every folder and file within that file path inside of a JTree.

Simply;

Folder1
Folder2
    Folder3a
        ->File3a
    ->File2a
    ->File2b

What I have so far is the following:

public class GUI extends JPanel {

public GUI() {

    super(new GridLayout(1, 2, 20, 0));
    setBorder(BorderFactory.createEmptyBorder(0, 10, 0, 10));

    try {
        UIManager.setLookAndFeel(UIManager.getSystemLookAndFeelClassName());
    } catch (final Exception ignored) {
    }

    final JFrame frame = new JFrame();
    frame.setDefaultCloseOperation(WindowConstants.DISPOSE_ON_CLOSE);



    frame.setContentPane(this);
    frame.pack();
    frame.setLocationRelativeTo(null);
    frame.setVisible(true);

}

I would love some direction on how to proceed. Everything this far has been a compilation of a ton of readings I have gone through, and I'm not really sure how to accomplish what I want.

If I go down that route, then that poses one more questions; 1) How can I get the paths of all of the files under the root directory? — Adam Chubbuck, Jun 14 '14 at 05:58
Take a look at [File Browser GUI](http://codereview.stackexchange.com/questions/4446/file-browser-gui) from @AndrewThompson for some ideas — Paul Samsotha, Jun 14 '14 at 06:46

score 0 · Answer 1 · answered Jun 14 '14 at 06:10

public class FileTree extends JPanel {
/** Construct a FileTree */
public FileTree(File dir) {
setLayout(new BorderLayout());

// Make a tree list with all the nodes, and make it a JTree
JTree tree = new JTree(addNodes(null, dir));

// Add a listener
tree.addTreeSelectionListener(new TreeSelectionListener() {
  public void valueChanged(TreeSelectionEvent e) {
    DefaultMutableTreeNode node = (DefaultMutableTreeNode) e
        .getPath().getLastPathComponent();
    System.out.println("You selected " + node);
  }
});

// Lastly, put the JTree into a JScrollPane.
JScrollPane 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 ol = new Vector();
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 files = new Vector();
// 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);
}

/** Main: make a Frame, add a FileTree */
 public static void main(String[] av) {

JFrame frame = new JFrame("FileTree");
frame.setForeground(Color.black);
frame.setBackground(Color.lightGray);
Container cp = frame.getContentPane();

if (av.length == 0) {
  cp.add(new FileTree(new File(".")));
} else {
  cp.setLayout(new BoxLayout(cp, BoxLayout.X_AXIS));
  for (int i = 0; i < av.length; i++)
    cp.add(new FileTree(new File(av[i])));
}

frame.pack();
frame.setVisible(true);
frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
}
}

How can I display the contents of a folder in a JTree?

1 Answers1