Swing combo boxes - swing

Question

Alright, so I'm simply defining a combo box like so...
JComboBox yearSelect = new JComboBox();
Now, I have not even added this to a panel or anything, I've just defined it. When I run the app, nothing displays.. when I comment out this line.. the app displays the other panels like I want it to.. is there something I'm doing wrong? Maybe I'm forgetting something that has to do with combo boxes? I think it may be something stupid that I'm missing.
Here is my entire constructor for the content.
private Container pane; // content pane
private JPanel calendarPanel; // where our calendar will go
private JPanel datePanel; // where "todays date" will go
private JPanel pnlToolbar; // tool bar for moving in the year
private JPanel bottomPanel;
private JPanel yearPanel;
private JLabel lbCurrentMonth;
private JLabel dateLabel;
private JButton monthBack;
private JButton monthForward;
private JComboBox yearSelect;
private Date today = new Date();
private int currentMonth = today.getMonth();
private int currentYear = today.getYear();
final private String [] days = {"Sunday", "Monday", "Tuesday",
"Wednesday", "Thursday", "Friday",
"Saturday"};
final private String [] months = {"January", "Febuary", "March", "April",
"May", "June", "July", "August",
"September", "October", "November",
"December"};
public Calendar() {
// call the calendar frame class constructor (Window class)
// this function will setup our basic window
super();
// define the current date of the calendar as today
// below are attributes to our window. They define what content
// is on them.
// define our window
pane = window.getContentPane();
pane.setLayout(new BorderLayout());
calendarPanel = new JPanel(new FlowLayout());
calendarPanel.setBorder(BorderFactory.createTitledBorder("Calendar"));
pnlToolbar = new JPanel(new FlowLayout(FlowLayout.CENTER, 40, 5));
pnlToolbar.setSize(300, 45);
//////////////////////////////////////////////////////////////////////
/* setup our lower date panel, that displays todays date
and the year drop down menu */
// for "todays date"
dateLabel = new JLabel(returnDateString());
dateLabel.setFont(new Font(null, Font.BOLD, 12));
datePanel = new JPanel(new FlowLayout(FlowLayout.LEFT, 5, 5));
datePanel.add(new JLabel("Todays Date: "), BorderLayout.WEST);
datePanel.add(dateLabel, BorderLayout.EAST);
// for "year select"
// yearSelect = new JComboBox();
yearPanel = new JPanel(new FlowLayout(FlowLayout.RIGHT, 5, 5));
//yearPanel.add(yearSelect);
bottomPanel = new JPanel(new BorderLayout());
bottomPanel.add(datePanel, BorderLayout.WEST);
//bottomPanel.add(yearPanel, BorderLayout.EAST);
// setup the tool bar panel
lbCurrentMonth = new JLabel(months[currentMonth]);
monthBack = new JButton("<<");
monthForward = new JButton(">>");
monthForward.setEnabled(true);
monthBack.setEnabled(true);
pnlToolbar.add(monthBack);
pnlToolbar.add(lbCurrentMonth);
pnlToolbar.add(monthForward);
// add everything to the content panel
pane.add(calendarPanel, BorderLayout.CENTER);
pane.add(bottomPanel, BorderLayout.SOUTH);
pane.add(pnlToolbar, BorderLayout.NORTH);

Answer 1

You need to add a model to display your data. See JComboBox.setModel.

Answer 2

Yea still nothing, I've attached the rest of my code above. Even when I don't add the object to a panel, it does this. I'm simply instantiating the object, nothing more. Any ideas? Also, I've created a seperate application to make sure I'm doing the combo boxes correctly here is something I noticed. It doesnt the exact same thing in the sperate application.. below.. (very dirty)
public class Main {
public static void main(String[] args) {
String [] selectFill = {"Cat", "Dog"};
JFrame window = new JFrame("Window");
window.setBounds(0, 0 , 800, 600);
window.setVisible(true);
window.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
window.setLayout(null);
//JComboBox selectBox = new JComboBox(selectFill);
JLabel check = new JLabel("Select: ");
JPanel contentPanel = new JPanel(new FlowLayout());
Container pane = window.getContentPane();
pane.add(contentPanel);
pane.setLayout(new FlowLayout());
contentPanel.add(check);
//contentPanel.add(selectBox);
}
}
For some strange reason when I resize the window, or minmize it loads the content. Or.. if I comment out the line for the combo box object it displays the content as well.