Simple Caesar Cipher in java, encrypts space too

CaesarCipher.java

/**
 * @tbenjis
 * Caesar  cipher cryptography
 * Author: tunde
 * 
 * */
import java.awt.EventQueue;
import javax.swing.JFrame;
import javax.swing.JPanel;
import javax.swing.border.EmptyBorder;
import javax.swing.JOptionPane;
import javax.swing.JTextPane;
import javax.swing.JTextField;
import javax.swing.JButton;
import javax.swing.JLabel;
import java.awt.Font;
import java.awt.event.ActionEvent;
import java.awt.event.ActionListener;

public class CaesarCipher extends JFrame implements ActionListener {

	private JPanel contentPane;
	private JTextField keytxt;
	private JButton btnEncode;
	private JButton btnDecode;

	private String values = "abcdefghijklmnopqrstuvwxyz ";
	private JTextPane textPaneInput;
	private JTextPane textPaneOutput;

	/**
	 * Launch the application.
	 */
	public static void main(String[] args) {
		EventQueue.invokeLater(new Runnable() {
			public void run() {
				try {
					CeaserCipher frame = new CeaserCipher();
					frame.setVisible(true);
				} catch (Exception e) {
					e.printStackTrace();
				}
			}
		});
	}

	/**
	 * Create the frame.
	 */
	public CeaserCipher() {
		setResizable(false);
		setTitle("Ceaser Cipher");
		setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
		setBounds(100, 100, 529, 346);
		contentPane = new JPanel();
		contentPane.setBorder(new EmptyBorder(5, 5, 5, 5));
		setContentPane(contentPane);
		contentPane.setLayout(null);

		textPaneInput = new JTextPane();
		textPaneInput.setBounds(10, 28, 497, 90);
		contentPane.add(textPaneInput);

		textPaneOutput = new JTextPane();
		textPaneOutput.setBounds(10, 207, 497, 90);
		contentPane.add(textPaneOutput);

		keytxt = new JTextField();
		keytxt.setBounds(82, 151, 86, 20);
		contentPane.add(keytxt);
		keytxt.setColumns(10);

		btnEncode = new JButton("Encode");
		btnEncode.setBounds(212, 150, 89, 23);
		contentPane.add(btnEncode);

		btnDecode = new JButton("Decode");
		btnDecode.setBounds(311, 150, 89, 23);
		contentPane.add(btnDecode);

		JLabel lblKey = new JLabel("Key:");
		lblKey.setFont(new Font("Tahoma", Font.BOLD, 11));
		lblKey.setBounds(36, 154, 46, 14);
		contentPane.add(lblKey);

		JLabel lblText = new JLabel("Text:");
		lblText.setFont(new Font("Tahoma", Font.BOLD, 11));
		lblText.setBounds(10, 11, 46, 14);
		contentPane.add(lblText);

		JLabel lblOutput = new JLabel("Output:");
		lblOutput.setFont(new Font("Tahoma", Font.BOLD, 11));
		lblOutput.setBounds(10, 189, 46, 14);
		contentPane.add(lblOutput);

		btnDecode.addActionListener(this);
		btnEncode.addActionListener(this);
	}

	@Override
	public void actionPerformed(ActionEvent e) {
		// TODO Auto-generated method stub		
		
		
		if (e.getSource() == btnEncode)
		{
			try { 
		        Integer.parseInt(keytxt.getText()); 
		        textPaneOutput.setText(Encode(textPaneInput.getText(), Integer.parseInt(keytxt.getText())));
		    } catch(NumberFormatException e1) { 
		        JOptionPane.showMessageDialog(this, "Enter digits only");
		    }
			
		}
		
		if (e.getSource() == btnDecode)
		{
			try { 
		        Integer.parseInt(keytxt.getText()); 
		        textPaneOutput.setText(Decode(textPaneInput.getText(), Integer.parseInt(keytxt.getText())));
		    } catch(NumberFormatException e1) { 
		        JOptionPane.showMessageDialog(this, "Enter digits only");
		    }
			
		}
		
	}

	private String Encode(String text, int key) {
		char charEnc;
		int valEnc;
		int newEnc;
		String encrypted = "";
		text = text.toLowerCase();
		for (int i = 0; i < text.length(); i++) {
			charEnc = text.charAt(i);
			valEnc = values.indexOf(charEnc);
			newEnc = (key + valEnc) % values.length();
			encrypted += values.charAt(newEnc);
		}
		return encrypted.toUpperCase();
	}

	private String Decode(String text, int key) {
		char charEnc;
		int valEnc;
		int newEnc;
		String decoded = "";
		text = text.toLowerCase();
		for (int i = 0; i < text.length(); i++) {
			charEnc = text.charAt(i);
			valEnc = values.indexOf(charEnc);
			newEnc = (valEnc - key) % values.length();
			// check for negative
			if (newEnc < 0) {
				newEnc += Math.abs(values.length());
			}
			decoded += values.charAt(newEnc);
		}
		return decoded.toUpperCase();
	}
}