JTree cell width

Question

Hiya
I'm trying to make my jtree's cell width be equal to the width of the entire JTree it is in so that when selected, a highlight bar stretches across the entire jtree rather than just around the text of that node?
I've created a DefaultTreeCellRenderer and attached it to the jtree, and tried overriding the getWidth, getPreferredSize, getBounds, but I can't get it working.
How can I do this?
Thanks

Answer 1

I've written a TreeCellRenderer called TreeCellSpanner for general JTree's based on the TreeList implementation that will span the tree cells to fill the width of the tree.
It is slightly different because I wanted it to work with any JTree, so I couldn't subclass JTree itself to take advantage of some of the hackish things I did with TreeList. So this version has to rely on a much worse hack, but it works for the general case and can be changed by subclassing and overriding the fireTreePathChanged(TreePath) method.
Here is the source:
[http://code.google.com/p/aephyr/source/browse/trunk/src/aephyr/swing/TreeCellSpanner.java]
Example usage is very easy:
     public static void main(String[] args) {
          JTree tree = new JTree();
          TreeCellSpanner spanner = new TreeCellSpanner(tree, tree.getCellRenderer());
          tree.setCellRenderer(spanner);
          JFrame frame = new JFrame();
          frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
          frame.add(new JScrollPane(tree), BorderLayout.CENTER);
          frame.setSize(300, 600);
          frame.setLocationRelativeTo(null);
          frame.setVisible(true);
Caveat: it leaves the root node alone to avoid creating an infinite loop of updating. So all nodes, except for the root node will expand the width of the tree. If you need a root node and want it to expand the width of the tree, then create a dummy root node with the child as the real root node and set root node invisible on the tree.