How to add listener so that when a combobox value is changed

Question

I have tried to use the suggested methods but unable to determine how I can use action listeners within an action listener as suggested...

I want to change the value of first combo box and want the next combo box to be updated automatically upon change, similarly text box is changed when combobox_1 is changed...

    String[] b = a.getCourseCodes();
    final List f = new ArrayList();

    final JComboBox comboBox = new JComboBox(b);
    comboBox.addActionListener(new ActionListener() {

        public void actionPerformed(ActionEvent arg0) {

            String item = comboBox.getSelectedItem().toString();
         }
    });

    comboBox.setEditable(true);

    comboBox.setBounds(360, 70, 86, 20);
    contentPane.add(comboBox);

    JLabel lblStudentName = new JLabel("Student Name");
    lblStudentName.setBounds(270, 149, 80, 14);
    contentPane.add(lblStudentName);

    String[] v = a.getStudentID(comboBox.getSelectedItem().toString());
    final JComboBox comboBox_1 = new JComboBox(v);
    comboBox_1.addActionListener(new ActionListener() {

        public void actionPerformed(ActionEvent arg0) {

            String item = comboBox_1.getSelectedItem().toString();
         }
    });

    comboBox_1.setBounds(360, 108, 86, 20);
    contentPane.add(comboBox_1);

    textField_3 = new JTextField();
    String y = a.getStudentName(comboBox_1.getSelectedItem().toString());
    textField_3.setText(y);
    textField_3.setEditable(false);
    textField_3.setBounds(360, 146, 86, 20);
    contentPane.add(textField_3);
    textField_3.setColumns(10);

Kindly help by editing the code so can have a clear idea... Thanks

Answer 1

Rather then adding an ItemListener I would simply add an ActionListener which will be triggered every time the selected value is changed. Then you are able to just use comboBox.getSelectedItem() like so:

JComboBox comboBox_1; //you need to declare the comboBox and textField before the ActionListener.
comboBox.addActionListener(new ActionListener() {
    public void actionPerformed(ActionEvent arg0) {
        String[] v = a.getStudentID(comboBox.getSelectedItem().toString());
        comboBox_1.setModel(new DefaultComboBoxModel<String>(v));

        String y = a.getStudentName(comboBox_1.getSelectedItem().toString());
        textField_3.setText(y);
    }
});

Add you could extend this to change the values of your ComboBox or TextField within the actionPerformed method.

I think this is what you mean, though I may be wrong in the intent of your ActionListener.