Retrieving array data for JList items

Question

I have an (access) database table which contains data I would like to populate into a list in my java program. The table consists of multiple columms (id, name, etc)

What I would like is a JList listing all the name(s) and then when an item from the list has been double clicked I would like the id number for that item to be inserted into another table.

I have already implemented the list and populated it with the records from the db table (name column). What I'm having trouble with is when the user double-clicks on the item, how do I can I get get the ID for that video? The database call which populates the list selects multiple columns and puts them all into an array, not quite sure how I can link that list item to the array.

Here is what I got so far...

The java class

  ArrayList list = new ArrayList();
  ArrayList video = new ArrayList();
  list = VideoData.getVideoList();

  JList videolist = new JList();;  
  Vector data = new Vector();;  

  for (int i=0; i < list.size(); i++) {
           video = (ArrayList) list.get(i);
           data.addElement(video.get(3));
       }

  videolist.setListData(data);
  videolist.setSelectedIndex(0);
  videolist.addMouseListener(new ActionJList(videolist));
  videolist.setFixedCellWidth(300);
  add(new JScrollPane(videolist));

What getVideoList() contains

ArrayList list = new ArrayList();

try {
    ResultSet res = stmt.executeQuery("SELECT * FROM Items ORDER BY VidID ASC");
    while (res.next()) { // there is a result
      ArrayList sub = new ArrayList();
      sub.add(res.getString("VidID"));;
      sub.add(res.getString("Name"));
      sub.add(res.getString("Writer"));
       // add sub array  to list
      list.add(sub); 
    }
} catch (Exception e) {
    System.out.println(e);
    return null;
}

return list;

The current doulbe-click function is the following (which I found on the net)

  public void mouseClicked(MouseEvent e){     
   if(e.getClickCount() == 2){ // double click
     int index = list.locationToIndex(e.getPoint());
     ListModel dlm = list.getModel();
     Object item = dlm.getElementAt(index);;
     list.ensureIndexIsVisible(index);
     System.out.println("Double clicked on " + item);
     }
   }

.. From this item only tells me what is listed inside the JList cell, What I need to to be able to do is get the other array data for that selected item.

Answer 1

(I have used generics <...> to make the code more readable.)

As @HovercraftFullOfEels said, the JList may contain a entire video object:

static class Video {
    String vidID;
    String name;
    String writer;

    @Override
    public String toString() {
        return writer; // For JList display
    }
}

The usage then goes as follows.

List<Video> list = VideoData.getVideoList();

JList videolist = new JList();

Vector<Video> data = new Vector<Video>();  
for (int i=0; i < list.size(); i++) {
    Video video = list.get(i);
    data.addElement(video);
}

videolist.setListData(data);
videolist.setSelectedIndex(0);
videolist.addMouseListener(new ActionJList(videolist));
videolist.setFixedCellWidth(300);
add(new JScrollPane(videolist));

with getVideoList as:

List<Video> getVideoList() {
List<Video> list = new ArrayList<Video>();

try {
    ResultSet res = stmt.executeQuery("SELECT VidID, Name, Writer FROM Items ORDER BY VidID ASC");
    while (res.next()) { // there is a result
        Video sub = new Video();
        sub.vidID = res.getString("VidID");
        sub.name = res.getString("Name");
        sub.writer = res.getString("Writer");
        list.add(sub); 
    }
        res.close();
} catch (Exception e) {
    System.out.println(e);
    return null;
}

return list;
}

Answer 2

The JList should be populated with objects that contain all the information needed. Then simply cast the item retrieved (or if using a generic JList, then no need to cast). To get the List to display your items correctly, give it a custom renderer (or a weak way to do this is to give your object a toString() method, but using a renderer is much better). Your list appears to only hold one of the fields returned from the database rather than all the relevant data, and I'd change this.

Answer 3

You can make a hashmap with name as a key and id as value. populate this hashmap while populating JList. in mouseClick event you can get ID using function hashmap.get(name);