Tree in combobox

Question

hi,
i have combobox and it shows the list of something. So what i need is to change that list to the Tree. Any ideas?

Answer 1

Well....
1) you could write your own component (model, listener UI, component etc.).
2) you could cheat
3) you could look for one elsewhere - e.g. search google for "JComboTree" or similar
1) Writing a new component isn't too hard. You'd be putting a JTree into a scrollpane into a popup and getting that to appear when the user clicked a button. Structuring that properly to uyse MVC would be, err, "educational".
2) Assuming you didn't want the tree to expand/collapse you could cheat by writing a list cell renderer that would put branches before the text/icon for each node. This would simply require that the renderer could determine the depth of each item in the list.
A very quick approach would be to use something like this:
public class TreeNodeListCellRenderer extends DefaultListCellRenderer {
    public Component getListCellRendererComponent(JList list, Object value, int index, boolean isSelected, boolean cellHasFocus)
        // Assumes everything in the list is some "Node" class...
        YourNode node = (YourNode)value;
        // Cheesy - convert node to string, adding on as many spaces as the node is deep in the tree
        // Obviously you'd use a StringBuffer (or have an icon of the right width in front of the text) but this should suffice to demonstrate
        String text = node.getValue().toString();
        while(node != null) {
           node = node.getParent();
           text = " " + text;
        return super.getListCellRendererComponent(list, text, index, isSelected, cellHasFocus);
}Hope this helps.