MainClass.java Source code

Introduction

Here is the source code for MainClass.java

Source

import java.awt.event.ActionEvent;
import java.awt.event.ActionListener;

import javax.swing.JButton;
import javax.swing.JFrame;
import javax.swing.JLabel;
import javax.swing.JOptionPane;
import javax.swing.JPanel;
import javax.swing.JTextField;

public class MainClass extends JFrame {
    private JButton buttonOK = new JButton("OK");

    private JTextField textName = new JTextField(15);

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

    public MainClass() {
        this.setSize(325, 100);
        this.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);

        ButtonListener bl = new ButtonListener();

        JPanel panel1 = new JPanel();

        panel1.add(new JLabel("Enter your name: "));
        panel1.add(textName);

        buttonOK.addActionListener(bl);
        panel1.add(buttonOK);

        this.add(panel1);

        this.setVisible(true);
    }

    private class ButtonListener implements ActionListener {
        public void actionPerformed(ActionEvent e) {
            if (e.getSource() == buttonOK) {
                String name = textName.getText();

                if (name.length() == 0) {
                    JOptionPane.showMessageDialog(MainClass.this, "=0", "", JOptionPane.INFORMATION_MESSAGE);
                } else {
                    JOptionPane.showMessageDialog(MainClass.this, "Good morning " + name, "Salutations",
                            JOptionPane.INFORMATION_MESSAGE);
                }
                textName.requestFocus();
            }
        }
    }
}