Using IO to create a Combo Box

Question

Hello,
I have failed to find any examples on how to do the following, and have not yet figured out how to do it msyelf.
I want to add the entire contents of a file containg a list of people's personal numbers and their names to a combo box that is then added to the frame.
Here is the code: -
import java.awt.*;
import java.awt.event.*;
import javax.swing.*;
import java.io.*;
import java.util.*;
public class IOCombo extends JFrame
implements ActionListener {
public JButton b1;
public JPanel panel, panel_top, panel_office;
public JFrame frame;
public JLabel officeLabel, personLabel, buttonWorkedLabel;
String OfficeChosen;
String[] Office = {"London", "Paris", "NYC"};
String[] OfficeList;
int[] personalNumber;
public IOCombo() {
frame = new JFrame("IOCombo Test");
panel_top = new JPanel();
panel_office = new JPanel();
panel = new JPanel();
officeLabel = new JLabel("The Office is in ");
personLabel = new JLabel(".");
buttonWorkedLabel = new JLabel(".");
// Exit when the window is closed.
frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
b1 = new JButton("Office");
b1.setVerticalTextPosition(AbstractButton.CENTER);
b1.setHorizontalTextPosition(AbstractButton.LEFT);
b1.setMnemonic(KeyEvent.VK_O);
//Listen for actions
b1.addActionListener(this);
//tooltips for buttons
b1.setToolTipText("Choose an Office and a person and then click to edit that Office's Person.");
JComboBox office = new JComboBox(Office);
office.setSelectedIndex(0);
     office.addActionListener(new ActionListener() {
     public void actionPerformed(ActionEvent e) {
     JComboBox cb = (JComboBox)e.getSource();
     OfficeChosen = (String)cb.getSelectedItem();
try
whichOffice(OfficeChosen);
catch(IOException ex)
//set layout of all panels and add them to frame.
panel_office.add(officeLabel);
panel_office.add(office);
panel_office.add(personLabel);
panel_top.setLayout(new FlowLayout());
panel_top.add(b1);
panel_top.add(buttonWorkedLabel);
     panel.setLayout(new GridLayout(3,0));
panel.add(panel_office);
panel.add(panel_top);
frame.getContentPane().add(panel);
frame.pack();
frame.setVisible(true);
public void actionPerformed(ActionEvent e) {
String buttonPressed = e.getActionCommand();
if (buttonPressed.equals("Office"))
/**This is just a test, removed the Dialog class to
manipulate the office*/
buttonWorkedLabel.setText("Worked");
else {
/** How do I set-up the combo box using the Office Person chosen from the
file and allocate it to the frame?*/
public void whichOffice(String OfficeChos)throws IOException{
officeLabel.setText("The Office chosen is: " + OfficeChos);
String s, name ="";
int personalNum;
BufferedReader fr = null;
fr = new BufferedReader(new FileReader (OfficeChos+".txt"));
while ((s=fr.readLine()) != null)
StringTokenizer st = new StringTokenizer (s," ");
personalNum = Integer.parseInt(st.nextToken());
st.nextToken();
name = st.nextToken() + " " + st.nextToken();
personLabel.setText(personalNum + " " + name);
/** This method only works if the file contains person
how should I change this to read everyone in?
I want to add the entire contents of personal number and name
of the file to a combo box that is then added to the frame.
public static void main(String[] args) {
IOCombo iocombo = new IOCombo();
The file I have set-up currently that works is called "London.txt" and it contains: -
1 = John Smith
Cheers in advance,
Richard.

Answer 1

Hi,
Sorry I cannot get the code you provided to work, not sure if its your code or the ways I have tried to implement it. Please can you check into it and if it works give the completed code.
Reprovided code with formating :-)
import java.awt.*;
import java.awt.event.*;
import javax.swing.*;
import java.io.*;
import java.util.*;
public class IOCombo extends JFrame
                        implements ActionListener {
    public JButton b1;
    public JPanel panel, panel_top, panel_office;
    public JFrame frame;
    public JLabel officeLabel, personLabel, buttonWorkedLabel;
    String OfficeChosen;
    String[] Office = {"London", "Paris", "NYC"};
    String[] OfficeList;
    int[] personalNumber;
    public IOCombo() {
        frame = new JFrame("IOCombo Test");
        panel_top = new JPanel();
        panel_office = new JPanel();
        panel = new JPanel();    
        officeLabel = new JLabel("The Office is in ");
        personLabel = new JLabel(".");
        buttonWorkedLabel = new JLabel(".");
// Exit when the window is closed.
        frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
        b1 = new JButton("Office");
        b1.setVerticalTextPosition(AbstractButton.CENTER);
        b1.setHorizontalTextPosition(AbstractButton.LEFT);
        b1.setMnemonic(KeyEvent.VK_O);
//Listen for actions
        b1.addActionListener(this);
//tooltips for buttons
        b1.setToolTipText("Choose an Office and a person and then click to edit that Office's Person.");
        JComboBox office = new JComboBox(Office);
        office.setSelectedIndex(0);
     office.addActionListener(new ActionListener() {
             public void actionPerformed(ActionEvent e) {
                     JComboBox cb = (JComboBox)e.getSource();
                     OfficeChosen = (String)cb.getSelectedItem();
                        try
                            whichOffice(OfficeChosen);
                        catch(IOException ex)
//set layout of all panels and add them to frame.
        panel_office.add(officeLabel);
        panel_office.add(office);
        panel_office.add(personLabel);
        panel_top.setLayout(new FlowLayout());
        panel_top.add(b1);
        panel_top.add(buttonWorkedLabel);
     panel.setLayout(new GridLayout(3,0));
        panel.add(panel_office);
        panel.add(panel_top);
        frame.getContentPane().add(panel);
        frame.pack();
        frame.setVisible(true);
    public void actionPerformed(ActionEvent e) {
        String buttonPressed = e.getActionCommand();
        if (buttonPressed.equals("Office"))
                /**This is just a test, removed the Dialog class to
                 manipulate the office*/
                buttonWorkedLabel.setText("Worked");
        else {
            /** How do I set-up the combo box using the Office Person chosen from the
             file and allocate it to the frame?*/
    public void whichOffice(String OfficeChos)throws IOException{
        officeLabel.setText("The Office chosen is: " + OfficeChos);
        String s, name ="";
        int personalNum;
        BufferedReader fr = null;
        fr = new BufferedReader(new FileReader ("c:\\java\\kjc\\set\\"+OfficeChos+".txt"));
        while ((s=fr.readLine()) != null)
                StringTokenizer st = new StringTokenizer (s," ");
                personalNum = Integer.parseInt(st.nextToken());
                st.nextToken();
                name = st.nextToken() + "  " + st.nextToken();
                personLabel.setText(personalNum + " " + name);
                /** This method only works if the file contains person
                 how should I change this to read everyone in?
                 I want to add the entire contents of personal number and name
                 of the file to a combo box that is then added to the frame.
    public static void main(String[] args) {
        IOCombo iocombo = new IOCombo();
}Cheers,
Richard