Main.java Source code

Introduction

Here is the source code for Main.java

Source

import java.awt.event.FocusEvent;
import java.awt.event.FocusListener;

import javax.swing.JFrame;
import javax.swing.JLabel;
import javax.swing.JPanel;
import javax.swing.JTextField;
import javax.swing.border.EmptyBorder;
import javax.swing.event.DocumentEvent;
import javax.swing.event.DocumentListener;
import javax.swing.text.Document;
import javax.swing.text.JTextComponent;

public class Main {
    public static void main(String[] args) {
        JPanel panel = new JPanel();
        JTextField tf1 = new JTextField(10);
        panel.add(tf1);
        JTextField tf2 = new JTextField(10);
        panel.add(tf2);

        new TextPrompt("First Name", tf1);
        new TextPrompt("Last Name", tf2);

        JFrame frame = new JFrame();
        frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
        frame.add(panel);
        frame.pack();
        frame.setLocationRelativeTo(null);
        frame.setVisible(true);
    }
}

class TextPrompt extends JLabel implements FocusListener, DocumentListener {
    JTextComponent component;
    Document document;

    public TextPrompt(String text, JTextComponent component) {
        this.component = component;
        document = component.getDocument();

        setText(text);
        setFont(component.getFont());
        setBorder(new EmptyBorder(component.getInsets()));

        component.addFocusListener(this);
        document.addDocumentListener(this);

        component.add(this);
    }

    public void checkForPrompt() {
        if (document.getLength() == 0)
            setSize(component.getSize());
        else
            setSize(0, 0);
    }

    public void focusGained(FocusEvent e) {
        checkForPrompt();
    }

    public void focusLost(FocusEvent e) {
        setSize(0, 0);
    }

    public void insertUpdate(DocumentEvent e) {
        checkForPrompt();
    }

    public void removeUpdate(DocumentEvent e) {
        checkForPrompt();
    }

    public void changedUpdate(DocumentEvent e) {
    }

}