A scrollable JList?

[Barry Andrews]

Hello All,
I am a little confused about how I can make a JList scrollable. I understand that I should create a JScrollPane and add the JList to it, but there must be more because I cannot make this work correctly. When I use the scrollbar to scroll down, I do not see all of the data in the JList. There must be something more that I should do. Can someone please take a look at this sample code and tell me what I need to do to see all of the data without making the JList bigger? Many thanks to you!!!

import java.awt.*;
import javax.swing.*;
import java.util.Vector;
public class ListTest
{
    public ListTest()
    {
       JFrame frame = new JFrame();
       frame.setSize(400,300);
       frame.setLocation(200,200);
       Container c = frame.getContentPane();
       JList list = new JList();
       Dimension dim = new Dimension(150,100);
       list.setPreferredSize(dim);
       JScrollPane sp = new JScrollPane(list);
       sp.setPreferredSize(dim);
       JPanel north = new JPanel();
       JPanel south = new JPanel();
       dim.setSize(400,140);
       north.setPreferredSize(dim);
       south.setPreferredSize(dim);
       north.add(sp);
       c.add(north,"North");
       c.add(south,"South");
       //Create some data
       Vector data = new Vector();
       data.add("Test1");
       data.add("Test2");
       data.add("Test3");
       data.add("Test4");
       data.add("Test5");
       data.add("Test6");
       data.add("Test7");
       data.add("Test8");
       data.add("Test9");
       data.add("Test10");
       data.add("Test12");
       data.add("Test13");
       data.add("Test14");
       data.add("Test15");
       data.add("Test16");
       data.add("Test17");
       data.add("Test18");
       data.add("Test19");
       data.add("Test20");
       data.add("Test21");
       data.add("Test22");
       data.add("Test23");
       list.setListData(data);
       frame.show();
    }
    public static void main(String[] args)
    {
        new ListTest();
    }
}

[Gregg Bolinger]

I think that what you may be doing wrong is the way you are adding items to your list. You need to add the list items to a DefaultListModel. For example:

DefaultListModel listModel = new DefaultListModel();
listModel.addElement(data);
JList list = new JList(listModel);

also, vector is a bit of legacy code. You would be well to use an java.awt.List or an Array.
Hope that helps.

------------------
Happy Coding,
Gregg Bolinger

[Manfred Leonhardt]

Hi Barry,
Your problem is in the following line:
list.setPreferredSize(dim);
What this tells the scrollPane is that its child is the same size as it is supposed to be. If you remove the line shown above the list will be sized according to its contents and all will be well.
Regards,
Manfred.

[Barry Andrews]

OK, I see! So, is there a problem with using a Vector for my data? Gregg seems to think so. What do others think? Gregg, what is the reason for this? Thanks!!!

Barry

[Gregg Bolinger]

There is nothing "wrong" with using a vector. I was just told at one time that it was a bit of legacy code and ArrayList, and Lists have kind of taken the place of Vector.

------------------
Happy Coding,
Gregg Bolinger

[Barry Andrews]

I see. Thanks!