List with checkboxes

[Manish Hatwalne]

I have a particular requirement. -
I need a JList which has list of elements along with checkboxes. But
checkbox should be clicked only if the user clicks on the checkbox itself,
and not otherwise. (So simple renderer won't do). Moreover, clicking on row should only select the row, and not the checkbox shouldn't be clicked unless click is on checkbox itself. While getting data from the list, (selected objects), it should also return if checkbox was clicked fr the particular row or not.
How can I do this? The reason it is a JList because it's legacy code and
there are listeners which do lot of things based on selected items. The
checkbox is new requirement.
What would be the other preferred way of doing this?
TIA,
- Manish

[Gregg Bolinger]

I did this before. I just drudged up my code from a year ago. So I'm not too sure how well I remember it to explain what I did. But you should be able to figure it out.
CheckableItem

public class CheckableItem {
    private String  str;
    private boolean isSelected;
    
    public CheckableItem(String str) {
      this.str = str;
      isSelected = false;
    }
    
    public void setSelected(boolean b) {
      isSelected = b;
    }
    
    public boolean isSelected() {
      return isSelected;
    }
    
    public String toString() {
      return str;
    }
  }
  
  

ChecklistRenderer

class CheckListRenderer extends JCheckBox implements ListCellRenderer {
    
    public CheckListRenderer() {
      setBackground(UIManager.getColor("List.textBackground"));
      setForeground(UIManager.getColor("List.textForeground"));
    }
    public Component getListCellRendererComponent(JList list, Object value,
               int index, boolean isSelected, boolean hasFocus) {
      setEnabled(list.isEnabled());
      setSelected(((CheckableItem)value).isSelected());
      setFont(list.getFont());
      setText(value.toString());
      return this;
    }
  } 

Creating the Array of those Items

public CheckableItem[] createData(Vector strs)
{
       int n = strs.size();
    CheckableItem[] items = new CheckableItem[n];
    for (int i=0;i<n;i++) 
    {
      items[i] = new CheckableItem(strs.get(i).toString());
    }
    return items;
  }
  
  public static void resetCheckBoxes()
  {
  int index = emailVect.size();
  for (int i=0;i<index;i++)
  {
  item = (CheckableItem)selectList.getModel().getElementAt(i);
  item.setSelected(false);
selectList.validate();
  }
  }

The implementation

selectList = new JList(createData(emailVect));
selectList.setFont(fontB);
selectList.setCellRenderer(new CheckListRenderer());
selectList.addMouseListener(new MouseAdapter() 
{
      public void mouseClicked(MouseEvent e) 
      {
if (selectList.isEnabled())
{
        int index = selectList.locationToIndex(e.getPoint());
        item = (CheckableItem)selectList.getModel().getElementAt(index);
        item.setSelected(! item.isSelected());
        Rectangle rect = selectList.getCellBounds(index, index);
        selectList.repaint(rect);
        if (item.isSelected())
        {
        emailList.addElement(item.toString());
        }
        if (!item.isSelected())
        {
        emailList.removeElement(item.toString());
        }
        }
      }
    });   
selectList.setSelectionMode(ListSelectionModel.MULTIPLE_INTERVAL_SELECTION);

Hopefully that will get you the gist of what you need.