Question

I’d like to add to a database, and my editable comboBoxModel when I enter a new name into the comboBox. I have the method for adding to the database down fine, I’m just trying to get it to somehow listen to an entry being added to the ComboBox.

What’s the Best way to do this?

I’ve read the Java tutorial on Editable ComboBoxes, and noted where it said:

An editable combo box fires an action event when the user chooses an item from the menu and when the user types Enter. Note that the menu remains unchanged when the user enters a value into the combo box. If you want, you can easily write an action listener that adds a new item to the combo box’s menu each time the user types in a unique value.

So I thought to myself, ok lets try this, and looked up some examples. Here is my attempt, essentially copy pasted out of the example I found, with my variable names:

playerNameComboBox.addActionListener(new ActionListener() {

    @Override
    public void actionPerformed(ActionEvent e) {
        if (e.getActionCommand().equals("comboBoxEdited")) {
            System.out.println("Adding new player!");
            IController.Util.getInstance().addNewPlayer();
            playerNameComboBox.insertItemAt(playerNameComboBox.getSelectedItem(), 0);
        }
    }
});

When I type in a new name, and press enter, it does nothing. No new database entry and no addtional option on the ComboBox. I haven’t attached an action command to the ComboBox as I thought the example above assumed it would have that as default, and so did I.

But how do I get it to shout out that action command when I press enter, with the focus on the comboBox? I would have thought that comboBoxes would have had some sort of default behaviour to shout that out? Do I need to use an if(playerNameComboBox.hasFocus()) statement? Should I implement some kind of keylistener when my comboBox hasFocus()?

I’m very new at Java, so I’m unsure as to how this sort of thing should be done; any help is very much appreciated.

Answer 1

As requested, here is my short example in which names may be added to a JComboBox.

import java.awt.event.ActionEvent;
import java.awt.event.ActionListener;
import javax.swing.*;

public class Test extends JFrame {

    private JComboBox box;

    public static void main(String[] args) {
        new Test();
    }

    public Test()
    {
        super();
        setSize(200, 100);
        setDefaultCloseOperation(EXIT_ON_CLOSE);

        box = new JComboBox();
        box.setEditable(true);
        getContentPane().add(box);

        box.addActionListener(new ActionListener() { 
            @Override 
            public void actionPerformed(ActionEvent e) { 
                if (e.getActionCommand().equals("comboBoxEdited")) { 
                    System.out.println("Adding new player!");
                    box.insertItemAt(box.getSelectedItem(), 0);
                } 
            } 
        });

        setVisible(true);
    }
}