Help with JOptionPane

[javaman1]

I am writing a GUI program to calculate sales tax. I am trying to make it more robust by making it catch an exception of the user enters somthing other than a double. I try to compile this code, but it tells me that on the lines where "JOptionPane" appears, that the compiler cannot find the symbol. Help? Thanks.

import javax.swing.*;
import java.awt.*;
import java.awt.event.*;
import java.text.DecimalFormat;

class TaxGUI extends JFrame
{


    private JLabel billLabel = new JLabel("Bill");
    private JLabel totalLabel = new JLabel("Bill + tax");
    private JTextField billField = new JTextField("$00.0");
    private JTextField totalField = new JTextField("$00.0");
    private JButton taxButton = new JButton(">>>>>");

    public TaxGUI()
    {
        JPanel dataPanel = new JPanel(new GridLayout(2,2,20,10));

        dataPanel.add(billLabel);
        dataPanel.add(billField);
        dataPanel.add(totalLabel);
        dataPanel.add(totalField);

        JPanel buttonPanel = new JPanel();
        buttonPanel.add(taxButton);

        Container container = getContentPane();
        container.add(dataPanel, BorderLayout.NORTH);
        container.add(buttonPanel, BorderLayout.SOUTH);

        taxButton.addActionListener(new TaxListener());
    }

    private class TaxListener implements ActionListener
    {
        public void actionPerformed(ActionEvent e)
        {
            double bill = 0;
            while(true)
            {
                try
                {
                    String input = billField.getText();
                    bill = Double.parseDouble(input);
                    break;
                }
                catch(Exception ex)
                {
                    JOptionPane.showMessageDialog("You need to enter a number!", "Error", JOptionPane.ERROR_MESSAGE);
                    JOptionPane.setVisisble(true);
                    String input = billField.getText();
                    bill = Double.parseDouble(input);
                }
            }

            bill = bill + (bill * .05);
            bill = roundTwoDecimals(bill);
            totalField.setText("$" + bill);
        }
    }

    private double roundTwoDecimals(double d)
    {
        DecimalFormat twoDForm = new DecimalFormat("#.##");
        return Double.valueOf(twoDForm.format(d));
    }
}

[venerik]

Have a close look at the signature of the three overloaded showMessageDialog methods of JOptionPane at JOptionPane. Yours does not match.

[javaman1]

Thanks! I got it!

[venerik]

You're welcome.

[javaman1]

Another question though, is there a way to make a JFrame visible in a location other than the top left corner of the screen?

[venerik]

Nope, all frames must stick to to the top left corner... ;)

No, seriously, it is possible of course. Have a look here: How to Make Frames

[javaman1]

Thanks again!