How to activate JOptionPane from another class?

Question

I have main class with a main GUI from where I want to activate and get values from a new class with a JOptionPane like the code below. Since I already have a main GUI window opened, how and where should I activate/call the class below and finally, how do I get the values from the JOptionPane? Help is preciated! Thanks!

import javax.swing.JOptionPane;
import javax.swing.JPanel;
import javax.swing.JTextField;

public class OptionPaneTest {

    JPanel myPanel = new JPanel();
    JTextField field1 = new JTextField(10);
    JTextField field2 = new JTextField(10);
    myPanel.add(field1);
    myPanel.add(field2);
    JOptionPane.showMessageDialog(null, myPanel);

}

Edit:

InputNewPerson nyPerson = new InputNewPerson();
JOptionPane.showMessageDialog(null, nyPerson);
String test = nyPerson.inputName.getText();

Answer 1

I guess looking at your question, you need something like this. I had made a small JDialog, where you will enter a UserName and Answer, this will then be passed to the original GUI to be shown in the respective fields, as you press the SUBMIT JButton.

Try your hands on this code and ask any question that may arise :

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

/*
 * This is the actual GUI class, which will get
 * values from the JDIalog class.
 */
public class GetDialogValues extends JFrame
{
    private JTextField userField;
    private JTextField questionField;

    public GetDialogValues()
    {
        super("JFRAME");
    }

    private void createAndDisplayGUI(GetDialogValues gdv)
    {       
        setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
        setLocationByPlatform(true);

        JPanel contentPane = new JPanel();
        contentPane.setLayout(new GridLayout(0, 2));

        JLabel userName = new JLabel("USERNAME : ");
        userField = new JTextField();
        JLabel questionLabel = new JLabel("Are you feeling GOOD ?");
        questionField = new JTextField();

        contentPane.add(userName);
        contentPane.add(userField);
        contentPane.add(questionLabel);
        contentPane.add(questionField);

        getContentPane().add(contentPane);
        pack();
        setVisible(true);

        InputDialog id = new InputDialog(gdv, "Get INPUT : ", true);
    }

    public void setValues(final String username, final String answer)
    {
        SwingUtilities.invokeLater(new Runnable()
        {
            public void run()
            {
                userField.setText(username);
                questionField.setText(answer);
            }
        });
    }

    public static void main(String... args)
    {
        Runnable runnable = new Runnable()
        {
            public void run()
            {
                GetDialogValues gdv = new GetDialogValues();
                gdv.createAndDisplayGUI(gdv);
            }
        };
        SwingUtilities.invokeLater(runnable);
    }
}

class InputDialog extends JDialog
{
    private GetDialogValues gdv;
    private JTextField usernameField;
    private JTextField questionField;
    private JButton submitButton;
    private ActionListener actionButton = new ActionListener()
    {
        public void actionPerformed(ActionEvent ae)
        {
            if (usernameField.getDocument().getLength() > 0
                && questionField.getDocument().getLength() > 0)
            {
                gdv.setValues(usernameField.getText().trim()
                    , questionField.getText().trim());
                dispose();
            }
            else if (usernameField.getDocument().getLength() == 0)
            {
                JOptionPane.showMessageDialog(null, "Please Enter USERNAME."
                    , "Invalid USERNAME : ", JOptionPane.ERROR_MESSAGE);
            }
            else if (questionField.getDocument().getLength() == 0)
            {
                JOptionPane.showMessageDialog(null, "Please Answer the question"
                    , "Invalid ANSWER : ", JOptionPane.ERROR_MESSAGE);
            }
        }
    };

    public InputDialog(GetDialogValues gdv, String title, boolean isModal)
    {
        this.gdv = gdv;
        setDefaultCloseOperation(JDialog.DISPOSE_ON_CLOSE);
        setLayout(new BorderLayout());
        setModal(isModal);
        setTitle(title);

        JPanel panel = new JPanel();
        panel.setLayout(new GridLayout(0, 2));
        JLabel usernameLabel = new JLabel("Enter USERNAME : ");
        usernameField = new JTextField();
        JLabel questionLabel = new JLabel("How are you feeling ?");
        questionField = new JTextField();

        panel.add(usernameLabel);
        panel.add(usernameField);
        panel.add(questionLabel);
        panel.add(questionField);

        submitButton = new JButton("SUBMIT");
        submitButton.addActionListener(actionButton);

        add(panel, BorderLayout.CENTER);
        add(submitButton, BorderLayout.PAGE_END);

        pack();
        setVisible(true);
    }
}