Question

When I use HelpBroker.setCurrentID("[some help id]"), JavaHelp correctly shows the page I want but the associated topic is not automatically selected/highlighted in the table of contents. This makes it difficult for a user to know where in the topic tree the current page is located.

Is there any way to programmatically highlight the current topic in the TOC when I use a HelpBroker to navigate to a specific Help page?

Note that when the user follows links within the Java help system, the new topic is properly selected in the table of contents.

Answer 1

You should be able to just call the navigate() function, the rest are helpers. id is the id of course, and nodeLabel is the visible text on the node you want to select. Do note that this code doesn’t check for errors, namely preventing trying to go somewhere that doesn’t exist.

import java.awt.Component;
import java.util.Enumeration;
import javax.help.*;
import javax.help.plaf.basic.BasicTOCNavigatorUI;
import javax.swing.JTree;
import javax.swing.JScrollPane;
import javax.swing.tree.TreeModel;
import javax.swing.tree.TreePath;
import javax.swing.tree.DefaultMutableTreeNode;

public class Nav
{
    private static DefaultMutableTreeNode match = null;

    private Nav()
    {
    }

    public static void navigate(HelpSet set, HelpBroker broker, String id, String nodeLabel)
    {
        broker.setCurrentID(id);
        JHelp jhelp = new JHelp(set);
        JHelpNavigator nav = getNavigator(jhelp);
        JTree tree = getTree(nav);
        TreeModel model = tree.getModel();
        Object root = model.getRoot();
        match = null;
        findNode(model, root, nodeLabel);
        TreePath path = new TreePath(match.getPath());
        tree.setSelectionPath(path);
        tree.scrollPathToVisible(path);
    }

    //http://www.google.com/codesearch/p?hl=en#WiboLAWeTd0/xena/ext/src/javahelp/jhMaster/JavaHelp/src/new/javax/help/WindowPresentation.java&t=0&d=30&l=272
    private static JHelpNavigator getNavigator(JHelp jhelp)
    {
        JHelpNavigator nav = null;
        for (Enumeration e = jhelp.getHelpNavigators(); e.hasMoreElements(); ) 
        {
            nav = (JHelpNavigator) e.nextElement();
            if (nav.getNavigatorName().equals("TOC"))
            {
                return nav;
            }
        }
        return null;
    }

    //http://forums.sun.com/thread.jspa?threadID=350180#1459484
    private static JTree getTree(JHelpNavigator nav)
    {
        JTree tree = null;
        Component[] components = nav.getComponents();
        int count = components.length;
        int i = 0;
        while(i < count && !(components[i] instanceof JScrollPane))
        {
            i++;
        }
        if(i < count)
        {
            JScrollPane sp = (JScrollPane) components[i];
            components = sp.getViewport().getComponents();
            count = components.length;
            i = 0;
            while(i < count && !(components[i] instanceof JTree))
            {
                i++;
            }
            tree = (JTree) components[i];
        }
        return tree;
    }

    //http://www.rkcole.com/articles/swing/TraverseJtree-2000-11-17.html
    private static void findNode(TreeModel model, Object o, String search)
    {
        if(match != null)
            return;

        int count = model.getChildCount(o);
        for( int i=0;  i < count;  i++ )
        {
            Object child = model.getChild(o, i );
            if (  model.isLeaf( child ) )
            {
                if(search.equals(((TOCItem)((DefaultMutableTreeNode)child).getUserObject()).getName()))
                {
                    match = (DefaultMutableTreeNode)child;
                    return;
                }
            }
            else
                findNode( model, child, search );
        }
    }
}