JDateChooser 焦点监听器

Question

我正在尝试向 JDateChooser 添加一个 focusListener，以便当用户选择 dateOfBirth 时，它会在失去焦点时在文本字段上显示年龄。但它不工作 这是我尝试过的方式，

导入 java.awt.BorderLayout;

public class agecalc extends JFrame {
    private JTextField age;
    private JDateChooser dOB;
    /**
     * Launch the application.
     */
    public static void main(String[] args) {
        EventQueue.invokeLater(new Runnable() {
            public void run() {
                try {
                    agecalc frame = new agecalc();
                    frame.setVisible(true);
                } catch (Exception e) {
                    e.printStackTrace();
                }
            }
        });
    }

    /**
     * Create the frame.
     */
    public agecalc() {

        JPanel panel = new JPanel();
        GroupLayout groupLayout = new GroupLayout(getContentPane());
        groupLayout.setHorizontalGroup(
            groupLayout.createParallelGroup(Alignment.LEADING)
                .addGroup(groupLayout.createSequentialGroup()
                    .addContainerGap()
                    .addComponent(panel, GroupLayout.PREFERRED_SIZE, 290, GroupLayout.PREFERRED_SIZE)
                    .addContainerGap(134, Short.MAX_VALUE))
        );
        groupLayout.setVerticalGroup(
            groupLayout.createParallelGroup(Alignment.LEADING)
                .addGroup(groupLayout.createSequentialGroup()
                    .addGap(20)
                    .addComponent(panel, GroupLayout.PREFERRED_SIZE, 195, GroupLayout.PREFERRED_SIZE)
                    .addContainerGap(47, Short.MAX_VALUE))
        );
        panel.setLayout(null);

        dOB = new JDateChooser();
        dOB.setBounds(97, 52, 95, 20);
        panel.add(dOB);

        age = new JTextField();
        age.setBounds(97, 83, 86, 20);
        panel.add(age);
        age.setColumns(10);
        getContentPane().setLayout(groupLayout);
        setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
        setBounds(100, 100, 450, 300);

                    AGECalc ageCalc=new AGECalc();

        dOB.addFocusListener(ageCalc);
    }
    private class AGECalc implements FocusListener{

        @Override
        public void focusGained(FocusEvent e) {         

        }

        @Override
        public void focusLost(FocusEvent e) {
            // TODO Auto-generated method stub
            Calendar fromDate;
               Calendar toDate;
               Date dateOfBirth= dOB.getDate();
               Date now = new Date();
               fromDate=Calendar.getInstance();
               toDate=Calendar.getInstance();

                   fromDate.setTime(dateOfBirth);
                   toDate.setTime(now);
                   int ageYear = toDate.get(Calendar.YEAR) - (fromDate.get(Calendar.YEAR) );
                   age.setText(Integer.toString(ageYear));
                   System.out.println(ageYear);   



            }
        }






    public JTextField getAge() {
        return age;
    }

    public void setAge(JTextField age) {
        this.age = age;
    }

    public JDateChooser getdOB() {
        return dOB;
    }

    public void setdOB(JDateChooser dOB) {
        this.dOB = dOB;
    }
}

Answer 1

焦点侦听器未添加到JDateChooser。

Answer 2

我正在尝试向 JDateChooser 添加一个 focusListener，这样当 用户选择 dateOfBirth 它在文本字段上显示年龄时 失去焦点。

我建议您实现 PropertyChangeListener 并将其附加到日期选择器，而不是那样。这样，每当用户通过选择日期或手动输入新日期来更新所选值时，文本字段都会更新，无论日期选择器是否失去焦点。

例如：

final JTextField ageTextField = new JTextField(20);
ageTextField.setEditable(false);

JDateChooser dateChooser = new JDateChooser(new Date());
dateChooser.addPropertyChangeListener("date", new PropertyChangeListener() {
    @Override
    public void propertyChange(PropertyChangeEvent evt) {
        Calendar dateofBirth = Calendar.getInstance();
        dateofBirth.setTime((Date)evt.getNewValue());

        Calendar today = Calendar.getInstance();
        int age = today.get(Calendar.YEAR) - dateofBirth.get(Calendar.YEAR);

        if(today.get(Calendar.MONTH) < dateofBirth.get(Calendar.MONTH) ||
          (today.get(Calendar.MONTH) == dateofBirth.get(Calendar.MONTH) && today.get(Calendar.DAY_OF_MONTH) < dateofBirth.get(Calendar.DAY_OF_MONTH))) {                    
            age--;
        }

        ageTextField.setText(String.valueOf(age));
    }
});

---

请参阅此问题答案中的另一个示例：

• Using JCalendar in a JDialog

---

题外话

关于这条线（和其他类似的）：

dOB.setBounds(97, 52, 95, 20);

在使用 Swing 时，强烈建议不要使用 setBounds()、setLocation() 或 setSize() 等方法，因为这些方法会导致组件的精确定位。 Layout Managers 负责处理组件的大小和定位。这些是强调这一点的有趣话题：

• Should I avoid the use of set(Preferred|Maximum|Minimum)Size methods in Java Swing?
• Providing white space in a Swing GUI
• Nested Layout approach