windowbuilder combobox actionPerformed问题

Question

我正在开发一个简单的医院预约系统。我的组合框相互依赖。
.

问题是当我单击城市组合框和 select 一个城市时，它也进入了县 actionListener。为什么？

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

正如你看到的那样，当我 select 一个城市时，它安排了城市县，但它也进入了县 actionListener

Answer 1

在您的事件处理块中，您进行以下调用：

countyBox.setSelectedItem("Select county");

根据 JComboBox 上的 javadoc

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

因此，您添加到 countyBox 的 ActionListener 正在响应。

windowbuilder combobox actionPerformed问题

windowbuilder combobox actionPerformed issue

java

swing

combobox

actionlistener