JOptionPane and reading integers - Beginner Java

Question

I currently have code that reads the month, date, and year a user enters in one line (separated by spaces). Here is the code.

Scanner input = new Scanner(Sys         


        

Answer 1

There are a number of ways to approach the problem depending on ultimately what it is you want to achieve.

JOptionPane allows you to supply Object as the message. If this message is a String it will rendered as is, however, if it is a Component of some kind, it will be simply added to the dialog. This makes JOptionPane a very powerful little API.

public class TestOptionPane07 {

    public static void main(String[] args) {
        new TestOptionPane07();
    }

    public TestOptionPane07() {
        EventQueue.invokeLater(new Runnable() {
            @Override
            public void run() {
                try {
                    UIManager.setLookAndFeel(UIManager.getSystemLookAndFeelClassName());
                } catch (ClassNotFoundException | InstantiationException | IllegalAccessException | UnsupportedLookAndFeelException ex) {
                }

                JTextField fldDay = new JTextField(3);
                JTextField fldMonth = new JTextField(3);
                JTextField fldYear = new JTextField(4);
                JPanel message = new JPanel();
                message.add(fldDay);
                message.add(new JLabel("/"));
                message.add(fldMonth);
                message.add(new JLabel("/"));
                message.add(fldYear);

                int result = JOptionPane.showConfirmDialog(null, message, "Enter Date", JOptionPane.OK_CANCEL_OPTION, JOptionPane.QUESTION_MESSAGE);
                if (result == JOptionPane.OK_OPTION) {
                    String sDay = fldDay.getText();
                    String sMonth = fldMonth.getText();
                    String sYear = fldYear.getText();
                    JOptionPane.showMessageDialog(null, "You enetered " + sDay + "/" + sMonth + "/" + sYear);

                    try {
                        int day = Integer.parseInt(sDay);
                        int month = Integer.parseInt(sMonth);
                        int year = Integer.parseInt(sYear);
                        JOptionPane.showMessageDialog(null, "You enetered " + day + "/" + month + "/" + year);
                    } catch (Exception e) {
                        JOptionPane.showMessageDialog(null, "The values you entered are invalid");
                    }
                }
            }
        });
    }
}

Updated

If I was going to use something like this, I would also use a DocumentFilter to ensure that the user could only enter valid values (examples here)

But you could also use JSpinners

Or JComboBox

Depending on what it is you want to achieve...