Question

Ok, so I am working on a homework assignment, and I am using SWING to make a GUI for a Java project, and I am running into troubles with JList.

I have a customer object that I have made and set attributes to, and I want to add the object into a TreeMap. I want to hook up the Treemap so that any and all objects that are in the map will populate (the name attribute anyway) inside of the JList.

I have done a lot of looking around, and am seeing a lot about coding these things from scratch but little dealing with Swing implementation. I put my customer object into my map and then I would like for my JList to reflect the map’s contents, but I don’t know how to hook it up.

    customers.put(c.getName(), c);
    this.customerList.(What can I do here? add Customer object?? I can't find what I need);

Thanks for your help!!!

Answer 1

You need to create a custom list model that returns objects to put in each row of a JList. TreeMap can’t be accessed with an index, so you’ll need something else. So the general idea is this: (from JList javadoc):

ListModel bigData = new AbstractListModel() {
    ArrayList customers;
    public int getSize() { return customers.size() }
    public Object getElementAt(int index) { return customers.get(index); }
};

JList bigDataList = new JList(bigData);

this way when you update your collection, just call revalidate() or repaint() on the JList and it will update its contents too.