Same JTree instance across 2 tabs

[Chinmay Bajikar]

Hi,
I have a JTree being shown in a JTabbedPane.
Now i need to add a new tab and have the same tree being shown over there too.
Any changes dont to the tree (add/remove nodes) should reflect in both the tabs.
But that isnt happenning now.
One view is updated,but the 2nd view remains the same.
After some minimize/maximize the view in other pane is updated.
What might be the issue??

Thanks,
Chinmay

[Ben Wood]

Hi,

You could try calling

validate();
repaint();

on the component.

[Craig Wood]

I made a single TreeModel, made two JTrees from it and added one to each of two tabs in a JTabbedPane. The JTrees both seem to update automatically from the TreeModel after add/remove events on the other JTree. Here's the test code I made up to explore this:

import java.awt.*;
import java.awt.event.*;
import javax.swing.*;
import javax.swing.event.*;
import javax.swing.tree.*;
 
public class TreeTest
{
    JTabbedPane tabbedPane;
    DefaultMutableTreeNode selectedNode;
 
    public TreeTest()
    {
        DefaultTreeModel model = createModel();
        JTree tree1 = new JTree(model);
        tree1.addTreeSelectionListener(new BirdTreeListener());
        JTree tree2 = new JTree(model);
        tree2.addTreeSelectionListener(new BirdTreeListener());
        tabbedPane = new JTabbedPane();
        tabbedPane.addTab("tree 1", tree1);
        tabbedPane.addTab("tree 2", tree2);
        tabbedPane.addChangeListener(new ChangeListener()
        {
            public void stateChanged(ChangeEvent e)
            {
                JTree tree = (JTree)tabbedPane.getSelectedComponent();
                selectedNode = findSelectedNode(tree);    // reset selectedNode
                if(selectedNode == null)
                    System.out.println("selectedNode = null");
                else
                    System.out.println("selectedNode = " + selectedNode.toString());
            }
        });
    }
 
    public JPanel getUIPanel()
    {
        final JButton
            remove = new JButton("remove node"),
            add    = new JButton("add node");
        ActionListener l = new ActionListener()
        {
            public void actionPerformed(ActionEvent e)
            {
                if(selectedNode == null)
                    return;
                JTree tree = (JTree)tabbedPane.getSelectedComponent();
                DefaultTreeModel model = (DefaultTreeModel)tree.getModel();
                JButton button = (JButton)e.getSource();
                if(button == remove)
                {
                    model.removeNodeFromParent(selectedNode);
                    selectedNode = null;
                }
                if(button == add)
                {
                    DefaultMutableTreeNode newNode =
                        new DefaultMutableTreeNode("node inserted here");
                    model.insertNodeInto(newNode, selectedNode,
                                                  selectedNode.getChildCount());
                }
            }
        };
        remove.addActionListener(l);
        add.addActionListener(l);
        JPanel panel = new JPanel();
        ((FlowLayout)panel.getLayout()).setHgap(50);
        panel.add(remove);
        panel.add(add);
        return panel;
    }
 
    private DefaultMutableTreeNode findSelectedNode(JTree tree)
    {
        TreePath[] paths = tree.getSelectionPaths();
        if(tree.isSelectionEmpty())
            return null;
        return (DefaultMutableTreeNode)paths[0].getLastPathComponent();
    }
 
    private DefaultTreeModel createModel()
    {
        DefaultMutableTreeNode root = new DefaultMutableTreeNode("birds");
        DefaultMutableTreeNode
            gulls        = new DefaultMutableTreeNode("gulls"),
                ivory    = new DefaultMutableTreeNode("ivory"),
                laughing = new DefaultMutableTreeNode("laughing"),
                western  = new DefaultMutableTreeNode("western"),
            raptors            = new DefaultMutableTreeNode("raptors"),
                osprey         = new DefaultMutableTreeNode("osprey"),
                red_shouldered = new DefaultMutableTreeNode("red-shouldered"),
                red_tailed     = new DefaultMutableTreeNode("red-tailed"),
            songbirds    = new DefaultMutableTreeNode("songbirds"),
                cardinal = new DefaultMutableTreeNode("cardinal"),
                sparrow  = new DefaultMutableTreeNode("sparrow"),
                wren     = new DefaultMutableTreeNode("wren");
        root.insert(gulls, 0);
        root.insert(raptors, 1);
        root.insert(songbirds, 2);
        gulls.insert(ivory, 0);
        gulls.insert(laughing, 1);
        gulls.insert(western, 2);
        raptors.insert(osprey, 0);
        raptors.insert(red_shouldered, 1);
        raptors.insert(red_tailed, 2);
        songbirds.insert(cardinal, 0);
        songbirds.insert(sparrow, 1);
        songbirds.insert(wren, 2);
        return new DefaultTreeModel(root);
    }
 
    private class BirdTreeListener implements TreeSelectionListener
    {
        public void valueChanged(TreeSelectionEvent e)
        {
            TreePath[] paths = e.getPaths();
            for(int j = 0; j < paths.length; j++)
                if(e.isAddedPath(j))
                    selectedNode =
                        (DefaultMutableTreeNode)paths[j].getLastPathComponent();
        }
    }
 
    public static void main(String[] args)
    {
        TreeTest test = new TreeTest();
        JFrame f = new JFrame();
        f.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
        f.getContentPane().add(test.getUIPanel(), "North");
        f.getContentPane().add(test.tabbedPane);
        f.setSize(400,400);
        f.setLocation(200,200);
        f.setVisible(true);
    }
}