Hide horizontal and vertical lines in a JTree

Question

Hi,
suppose we have three JTrees in a Windows L&F where the second one shall not show any vertical or horizontal lines for a node. If this restriction would be true for all three JTrees one could invoke
UIManager.put("Tree.paintLines", Boolean.FALSE).
However only the second one must not show any lines. I tried something like
tree.putClientProperty("Tree.paintLines", Boolean.FALSE);
tree.updateUI();But unfortunately this does not work as the lines are still shown. Furthermore we need to set "on/off" the lines dynamically dependend on the user data.
Does anyone have a clue to solve this problem?
Thx.

Answer 1

only tested on windows, but this seems simple enough
import java.awt.*;
import java.awt.event.*;
import javax.swing.*;
import javax.swing.tree.*;
class Testing
  boolean showLines = false;
  public void buildGUI()
    JButton btn = new JButton("Show/Hide Lines");
    final JTree tree = new JTree();
    tree.setUI(new javax.swing.plaf.basic.BasicTreeUI(){
      protected void paintHorizontalLine(Graphics g,JComponent c,int y,int left,int right){
        if(showLines) super.paintHorizontalLine(g,c,y,left,right);
      protected void paintVerticalLine(Graphics g,JComponent c,int x,int top,int bottom){
        if(showLines) super.paintVerticalLine(g,c,x,top,bottom);
    JFrame f = new JFrame();
    f.getContentPane().add(new JScrollPane(tree),BorderLayout.CENTER);
    f.getContentPane().add(btn,BorderLayout.SOUTH);
    f.setSize(200,200);
    f.setLocationRelativeTo(null);
    f.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
    f.setVisible(true);
    btn.addActionListener(new ActionListener(){
      public void actionPerformed(ActionEvent ae){
        showLines = !showLines;
        tree.repaint();
  public static void main(String[] args)
    SwingUtilities.invokeLater(new Runnable(){
      public void run(){
        try{UIManager.setLookAndFeel("com.sun.java.swing.plaf.windows.WindowsLookAndFeel");}catch(Exception e){}
        new Testing().buildGUI();
}