JComboBox setSelectedItem does not work

Question

I am trying to set the setSelectedItem of the JComboBox in the constructor of my JPanel class just after populating the combobox.

I am set the value for textbox, but I can't figure out why setSelectedItem does not seem to work. Any ideas?

public StudentProfilePanel(StudentInfo si) {

        yesButton.setBounds(50, 346, 69, 40);
        noButton.setBounds(121, 346, 56, 40);
        this.add(yesButton);
        this.add(noButton);
        setLayout(null);
        comboBoxYear.setModel(new DefaultComboBoxModel(years()));
        comboBoxYear.setBounds(202, 365, 62, 23);
        if(si.birthdate!=null){
            //System.out.println("year value : ["+dateofbirth(si.birthdate)[2]+"]");
            comboBoxYear.setSelectedItem(dateofbirth(si.birthdate)[2]);

        }

        add(comboBoxYear);
        comboBoxMonth.setModel(new DefaultComboBoxModel(new String[]{"01","02","03","04","05","06","07","08","09","10","11","12"}));
        comboBoxMonth.setBounds(285, 365, 56, 23);

        //set month value
        if(si.birthdate!=null){
            //comboBoxMonth.setSelectedItem(dateofbirth(si.birthdate)[1]);
            comboBoxMonth.setSelectedItem("04");
            System.out.println("month value : ["+dateofbirth(si.birthdate)[1]+"]");
        }
        add(comboBoxMonth);
        comboBoxDay.setModel(new DefaultComboBoxModel(days()));
        comboBoxDay.setBounds(351, 365, 54, 23);
        if(si.birthdate!=null){
            //comboBoxDay.setSelectedItem(dateofbirth(si.birthdate)[0]);
            comboBoxDay.setSelectedItem(dateofbirth(si.birthdate)[0]);
        }
        add(comboBoxDay);

        textFieldFirstName = new JTextField();
        textFieldFirstName.setBounds(21, 321, 171, 21);
        add(textFieldFirstName);
        textFieldFirstName.setColumns(10);
        // set the value of first name
        textFieldFirstName.setText(si.firstName);

        textFieldLastName = new JTextField();
        textFieldLastName.setBounds(242, 321, 163, 21);
        add(textFieldLastName);
        textFieldLastName.setColumns(10);
        //set the value of the last name
        textFieldLastName.setText(si.lastName);

        JPanel panelPersonPhoto = new ImagePanel(
                "C:\\Users\\MDJef\\Pictures\\Wallpaper\\General\\11.jpg");
        panelPersonPhoto.setBorder(new TitledBorder(null, "",
                TitledBorder.LEADING, TitledBorder.TOP, null, null));
        panelPersonPhoto.setBounds(21, 20, 384, 291);
        add(panelPersonPhoto);
    }

Thanks very much.

helper methods that I used

    // jf : helper method
    public String[] years() {
        String[] results = new String[90];
        for (int i = 0; i < 90; i++) {
            results[i] = Integer.toString(1900 + i);
        }
        return results;
    }

    // jf : helper method
    public String[] months() {
        String[] results = new String[12];
        for (int i = 0; i < 12; i++) {
            results[i] = Integer.toString(i + 1);
        }
        return results;
    }

    // jf : helper method
    public String[] days() {
        String[] results = new String[31];
        for (int i = 0; i < 31; i++) {
            results[i] = Integer.toString(i + 1);
        }
        return results;
    }

    // jf : helper method
    public String[] dateofbirth(String dob) {
        String[] tokens = dob.split("-");
        return tokens;
    }

Answer 1

The values assigned to the combo box are not the same values you are trying set.

For example, the years are Strings from 1900 - 1990, but if I supply a value 72, there is no matching value in the combo box to match to.

Equally, your days and months methods are only returning values that are not padded (ie 01), where as, in your code, you're trying to set the value using a padded value (ie 04), meaning there is no matching value...

You have a number of options...

You could...

Convert all the values to an int, meaning that the values in the combo box are simply ints. You would then need to convert the date values to ints as well.

This would make your helper code look more like...

public int[] years() {
    int[] results = new String[90];
    for (int i = 0; i < 90; i++) {
        results[i] = 1900 + i;
    }
    return results;
}

public int[] months() {
    int[] results = new String[12];
    for (int i = 0; i < 12; i++) {
        results[i] = i + 1;
    }
    return results;
}

public int[] days() {
    int[] results = new String[31];
    for (int i = 0; i < 31; i++) {
        results[i] = i + 1;
    }
    return results;
}

public int[] dateofbirth(String dob) {
    int[] tokens = dob.split("-");
    int[] values = new int[tokens.length];
    for (int index = 0; index < tokens.length; index++) {
      values[index] = Integer.parse(tokens[index]);
    }
    return index;
}

A better solution

Would be to use a JSpinner, which would take care of date rolling issues and validation automatically.

Check out Using Standard Spinner Models and Editors