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javaswingcomboboxactionlistener

windowbuilder combobox actionPerformed issue

I'm working on a simple hospital appointment system. My comboboxes are dependant one to another.
interface.

The issue is when I click the City combobox and select a city, it enters the county actionListener too. Why?

private void initialize() {

City cities = new City();
Hospital hospitals = new Hospital();

frame = new JFrame();
frame.setBounds(100, 100, 450, 300);
frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
frame.getContentPane().setLayout(null);

JLabel lblCity = new JLabel("City");
lblCity.setBounds(25, 25, 25, 14);
frame.getContentPane().add(lblCity);

JComboBox<String> cityBox = new JComboBox<String>(); // CITY

JComboBox<String> hospitalBox = new JComboBox();
hospitalBox.setBounds(99, 141, 265, 22);
frame.getContentPane().add(hospitalBox);

JComboBox<String> comboClinic = new JComboBox<String>(); // CLINIC
comboClinic.setEditable(true);
comboClinic.setBounds(99, 101, 265, 22);
frame.getContentPane().add(comboClinic);  // CLINIC

JComboBox<String> countyBox = new JComboBox<String>();  // COUNTY
countyBox.addActionListener(new ActionListener() {
    public void actionPerformed(ActionEvent e) {
        // do something
});
countyBox.setEditable(true);

countyBox.setBounds(99, 61, 265, 22);
frame.getContentPane().add(countyBox); // COUNTY

cityBox.setEditable(true);  // CITY

cityBox.addItem("Istanbul");
cityBox.addItem("Ankara");
cityBox.addItem("Izmir");

cityBox.addActionListener(new ActionListener() {
    public void actionPerformed(ActionEvent e) {
        if (cityBox.getSelectedItem().equals("Istanbul")) {
            countyBox.removeAllItems(); hospitalBox.removeAllItems();
            String istanbul[] = cities.getIstanbul();
            countyBox.setSelectedItem("Select county");
            
            for (int i = 0; i < istanbul.length; i++) countyBox.addItem(istanbul[i]);
            comboClinic.setSelectedItem("Select clinic");
        }
        else if(cityBox.getSelectedItem().equals("Ankara")) {
            countyBox.removeAllItems(); hospitalBox.removeAllItems();
            String ankara[] = cities.getAnkara();
            countyBox.setSelectedItem("Select county");
            
            for (int i = 0; i < ankara.length; i++) countyBox.addItem(ankara[i]);
            comboClinic.setSelectedItem("Select clinic");
        }
        else if(cityBox.getSelectedItem().equals("Izmir")) {
            countyBox.removeAllItems(); hospitalBox.removeAllItems();
            String izmir[] = cities.getIzmir();
            countyBox.setSelectedItem("Select county");
            
            for (int i = 0; i < izmir.length; i++) countyBox.addItem(izmir[i]);                 
            comboClinic.setSelectedItem("Select clinic");
        }
            
    }
});
cityBox.setSelectedItem("Select City");

cityBox.setBounds(99, 21, 265, 22);
frame.getContentPane().add(cityBox); // CITY

as you can see there when i select a city, it arranges the cities counties but it also enters the county actionListener too

Solution

  • Within your event-handling block, you make the following call:

    countyBox.setSelectedItem("Select county");

    Per the javadoc on JComboBox

    ActionListeners added to the combo box will be notified with an ActionEvent when this method is called.

    Thus, you the ActionListener you have added to the countyBox is responding.