Java Swing How to - Create JTree from file name

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Question

We would like to know how to create JTree from file name.

Answer

import java.awt.BorderLayout;
import java.awt.Component;
import java.awt.Container;
import java.awt.Dimension;
import java.io.File;
import java.util.Arrays;
import java.util.Collections;
import java.util.Comparator;
import java.util.Vector;
/*from  w w  w .j av a 2  s. com*/
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.filechooser.FileSystemView;
import javax.swing.tree.DefaultMutableTreeNode;
import javax.swing.tree.DefaultTreeCellRenderer;

public class Main extends JPanel {
  File projectFile = new File(".");

  public Main(File dir) {
    setLayout(new BorderLayout());
    JTree tree = new JTree(addNodes(null, projectFile));
    tree.setCellRenderer(new MyTreeCellRenderer());
    tree.addTreeSelectionListener(new TreeSelectionListener() {
      public void valueChanged(TreeSelectionEvent e) {
        DefaultMutableTreeNode node = (DefaultMutableTreeNode) e.getPath()
            .getLastPathComponent();
        System.out.println("You selected " + node);
      }
    });

    JScrollPane scrollpane = new JScrollPane();
    scrollpane.getViewport().add(tree);
    add(scrollpane, BorderLayout.CENTER);
  }

  DefaultMutableTreeNode addNodes(DefaultMutableTreeNode curTop, File dir) {
    DefaultMutableTreeNode curDir = new DefaultMutableTreeNode(dir);
    if (curTop != null) {
      curTop.add(curDir);
    }
    File[] tmp = dir.listFiles();
    Vector<File> ol = new Vector<File>();
    ol.addAll(Arrays.asList(tmp));
    Collections.sort(ol, new Comparator<File>() {
      @Override
      public int compare(File o1, File o2) {
        int result = o1.getName().compareTo(o2.getName());
        if (o1.isDirectory() && o2.isFile()) {
          result = -1;
        } else if (o2.isDirectory() && o1.isFile()) {
          result = 1;
        }
        return result;
      }
    });
    for (int i = 0; i < ol.size(); i++) {
      File file = ol.elementAt(i);
      DefaultMutableTreeNode node = new DefaultMutableTreeNode(file);
      if (file.isDirectory()) {
        addNodes(node, file);
      }
      curDir.add(node);
    }
    return curDir;
  }

  public Dimension getMinimumSize() {
    return new Dimension(200, 400);
  }

  public Dimension getPreferredSize() {
    return new Dimension(200, 400);
  }

  public static void main(String[] av) {
    JFrame frame = new JFrame();
    Container cp = frame.getContentPane();
    cp.add(new Main(new File(".")));
    frame.pack();
    frame.setVisible(true);
    frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
  }
}

class MyTreeCellRenderer extends DefaultTreeCellRenderer {
  FileSystemView fsv = FileSystemView.getFileSystemView();
  @Override
  public Component getTreeCellRendererComponent(JTree tree, Object value,
      boolean sel, boolean expanded, boolean leaf, int row, boolean hasFocus) {
    System.out.println(value);
    super.getTreeCellRendererComponent(tree, value, sel, expanded, leaf, row,
        hasFocus);
    if (value instanceof DefaultMutableTreeNode) {
      value = ((DefaultMutableTreeNode) value).getUserObject();
      if (value instanceof File) {
        File file = (File) value;
        if (file.isFile()) {
          setIcon(fsv.getSystemIcon(file));
          setText(file.getPath());
        } else {
          setIcon(fsv.getSystemIcon(file));
          setText(file.getName());
        }
      }
    }
    return this;
  }
}

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