java - JDateChooser focusListener

Question

我正在尝试将 focusListener 添加到 JDateChooser，以便当用户选择 dateOfBirth 时，当焦点丢失时，它会在文本字段上显示年龄。但它不起作用这是我尝试过的方法，

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

I'm trying to add a focusListener to JDateChooser, so that when the user chooses the dateOfBirth it displays age on the textfield when the focus is lost.

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

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));
    }
});

<小时/>

请参阅此问题答案中的另一个示例:

• Using JCalendar in a JDialog

<小时/>

离题

关于此行(以及其他类似行):

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，因为这些方法导致组件的精确位置。是Layout Managers负责处理组件的尺寸和定位。这些都是强调这一点的有趣主题:

• 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