ComboBoxes.java

// ui/ComboBoxes.java
// (c)2016 MindView LLC: see Copyright.txt
// We make no guarantees that this code is fit for any purpose.
// Visit http://mindviewinc.com/Books/OnJava/ for more book information.
// Using drop-down lists
import javax.swing.*;
import java.awt.*;
import static onjava.SwingConsole.*;

public class ComboBoxes extends JFrame {
  private String[] description = {
    "Ebullient", "Obtuse", "Recalcitrant", "Brilliant",
    "Somnescent", "Timorous", "Florid", "Putrescent"
  };
  private JTextField t = new JTextField(15);
  private JComboBox<String> c = new JComboBox<>();
  private JButton b = new JButton("Add items");
  private int count = 0;
  public ComboBoxes() {
    for(int i = 0; i < 4; i++)
      c.addItem(description[count++]);
    t.setEditable(false);
    b.addActionListener(e -> {
      if(count < description.length)
        c.addItem(description[count++]);
    });
    c.addActionListener(e -> t.setText("index: " +
      c.getSelectedIndex() + "   " +
      ((JComboBox)e.getSource()).getSelectedItem()));
    setLayout(new FlowLayout());
    add(t);
    add(c);
    add(b);
  }
  public static void main(String[] args) {
    run(new ComboBoxes(), 200, 175);
  }
}