Automatically scrolling to an item in a JList

Question

Hi all,
i have several jlists with about 30 - 50 items and i would like to take the user directly to an item in the list as he enters characters that match a list item. Are there any existing interfaces with this behaviour? If not, has anyone written something similar to this?
Thanks!

Answer 1

Hi Linzie,
the following code will automatically scroll the JList to the item entered in the JTextField:public class X extends JApplet {
     public void init() {
          final int CELL_HEIGHT = 15; //or figure out how to get it dynamically
          String[] items = new String[50]; //test items (format: item XX)
          for (int x = 0; x < items.length; x++) items[x] = "item " + x;
          final JList lst = new JList(items);
          final JScrollPane scroll = new JScrollPane(lst);
          Container c = getContentPane();
          c.setLayout(new BorderLayout());
          final JTextField text = new JTextField(20);
          text.addActionListener(new ActionListener() {
               public void actionPerformed(ActionEvent e) {
                    String s = text.getText();
                    try {
                    int val = Integer.parseInt(s.substring(s.lastIndexOf(' ')+1, s.length()));
                    //this automatically scrolls to show
                    //the required cell of the JList
                    scroll.getVerticalScrollBar().setValue(val * CELL_HEIGHT);
                    lst.setSelectedIndex(val);
                    } catch(NumberFormatException ex) {
          c.add(text, BorderLayout.NORTH);
          c.add(scroll, BorderLayout.CENTER);
}Cheers!