JComboBox and ArrayList

[Kevin Magee]

Hi,
I'm having problems filling a JComboBox with the
contents of an ArrayList.
The JComboBox is not appearing onscreen. I'm
using JPanel, and all other components are displayed except the combobox. This is my first time using swing, so any help would be greatly
appreciated.

  
 private JComboBox textChoice = new JComboBox(); 
 
 parent.theData.fillChoice(textChoice);                   
 title9 = new Label("Select Student Name:");
 add(title9);
 add(textChoice);
 public void fillChoice(JComboBox list){
 list.removeAll();                  
      
 for (int i = 0; i < textstore.size(); i++){
   alumni= (Alumnus) textstore.get(i);
   list.addItem(alumni.getSurname());}
   } // fillChoice  

[Bosun Bello]

I don't really use swing. But I believe becuse of the hierarchy, you have to add a Jcombo box/Jlist to a frame, and then set the size and show the frame. I stand corrected though...

[Paul Stevens]

Here is a simple example showing how to do this.

import java.awt.*;
import java.awt.event.*;
import javax.swing.*;
import java.util.*;
public class ComboTest extends JFrame {
   private JComboBox alumList;
   private JButton   getAlum ;
   private ArrayList buttons = new ArrayList();
   public ComboTest() {
    
      Vector alums = new Vector();
      
      Alumni alum = new Alumni("Name 1", "Location 1");
      alums.addElement(alum);
      alum = new Alumni("Name 2", "Location 2");
      alums.addElement(alum);
      alum = new Alumni("Name 3", "Location 3");
      alums.addElement(alum);
      alum = new Alumni("Name 4", "Location 4");
      alums.addElement(alum);
      alum = new Alumni("Name 5", "Location 5");
      alumList =  new JComboBox( alums );
      getAlum  =  new JButton ( "Get Alum" );
      getAlum.addActionListener(new ActionListener() {
          public void actionPerformed(ActionEvent e) {
            Alumni alum =
            (Alumni)alumList.getSelectedItem();
            System.out.println("You selected: " + alum.getName() + " " + alum.getLocation());
          }
       });
      
      getContentPane().setLayout(new FlowLayout());
      getContentPane().add( alumList);
      getContentPane().add( getAlum);
      addWindowListener( new java.awt.event.WindowAdapter() {
        public void windowClosing(java.awt.event.WindowEvent evt) {
            System.exit( 0 );
        }
      });
    
      setSize(new Dimension(400, 200));
 
    }
    public static void main(String args[]) {
        new ComboTest().show();
    }
    
    class Alumni {
       
       private String name;
       private String location;
       
       public Alumni (String name, String location) {
          this.name = name;
          this.location=location; 
       } 
       
       public String getName() {
          return name;
       }
       
       public String getLocation() {
          return location;
       }
       
       public String toString() {
          return name;
       }
    }
}

[Kevin Magee]

Thanks,
The code I had given was already a part of a program using JPanel and JFrame. I was just not sure of way JComboBoxes work, especially with
ArrayLists or Vectors.

[Paul Stevens]

If you notice you do not have to extract what you want in the box, just create a toString() for your class.