Question

public class ATMgui extends JFrame implements ActionListener {

    /**
     * 
     */
    private static final long serialVersionUID = 1L;
    public static final int WIDTH = 500;
    public static final int HEIGHT = 200;
    private ATMbizlogic theBLU;// short for the Business Logic Unit
    public JLabel totalBalanceLabel;
    public JTextField withdrawTextField;
    public JTextField depositTextField;
    public JTextField pinTextField;

    /**
     * Creates a new instance of ATMgui
     */
    public ATMgui() {
        setTitle("ATM Transactions");
        setSize(WIDTH, HEIGHT);
        setDefaultCloseOperation(javax.swing.WindowConstants.EXIT_ON_CLOSE);

        Container contentPane = getContentPane();
        contentPane.setBackground(Color.BLACK);
        contentPane.setLayout(new BorderLayout());


        // Do the panel for the rest stop
        JLabel start = new JLabel("Welcome To Your Account", JLabel.CENTER);
        Font curFont = start.getFont();
        start.setFont(new Font(curFont.getFontName(), curFont.getStyle(), 25));
        start.setForeground(Color.BLUE);
        start.setOpaque(true);
        start.setBackground(Color.BLACK);


        pinTextField = new JTextField();
        JLabel pinLabel = new JLabel("Enter your PIN below:", JLabel.CENTER);
        pinLabel.setForeground(Color.RED);
        pinLabel.setOpaque(true);
        pinLabel.setBackground(Color.WHITE);



        JButton pinButton = new JButton("Enter Pin OK");
        pinButton.addActionListener(this);
        pinButton.setBackground(Color.red);

        JPanel pinPanel = new JPanel();
        pinPanel.setLayout(new GridLayout(3, 1, 100, 0));

        pinPanel.add(pinLabel);
        pinPanel.add(pinTextField);
        pinPanel.add(pinButton);

        contentPane.add(pinPanel, BorderLayout.WEST);


        JPanel headingPanel = new JPanel();
        headingPanel.setLayout(new GridLayout());
        headingPanel.add(start);

        contentPane.add(headingPanel, BorderLayout.NORTH);


        // Do the panel for the amount & type of transactions
        withdrawTextField = new JTextField();
        JLabel withdrawLabel = new JLabel("Withdraw (0.00)", JLabel.CENTER);
        withdrawLabel.setForeground(Color.RED);
        withdrawLabel.setOpaque(true);
        withdrawLabel.setBackground(Color.WHITE);



        depositTextField = new JTextField();
        JLabel depositLabel = new JLabel("Deposit (0.00)", JLabel.CENTER);
        depositLabel.setForeground(Color.RED);
        depositLabel.setOpaque(true);
        depositLabel.setBackground(Color.WHITE);



        JButton txButton = new JButton("Transactions OK");
        txButton.addActionListener(this);
        txButton.setBackground(Color.red);




        JPanel txPanel = new JPanel();
        txPanel.setLayout(new GridLayout(5, 1, 30, 0));

        txPanel.add(withdrawLabel);
        txPanel.add(withdrawTextField);
        txPanel.add(depositLabel);
        txPanel.add(depositTextField);
        txPanel.add(txButton);

        contentPane.add(txPanel, BorderLayout.EAST);
        txPanel.setVisible(true);


        totalBalanceLabel = new JLabel("Your balance after transactions: ", JLabel.CENTER);
        totalBalanceLabel.setForeground(Color.BLUE);
        totalBalanceLabel.setOpaque(true);
        totalBalanceLabel.setBackground(Color.BLACK);


        contentPane.add(totalBalanceLabel, BorderLayout.SOUTH);


        theBLU = new ATMbizlogic();
    }

    public void actionPerformed(ActionEvent e) {
        String actionCommand = e.getActionCommand();

        // Container contentPane = getContentPane();

        if (actionCommand.equals("Transactions OK")) {
            try {
                double deposit = Double.parseDouble(depositTextField.getText().trim());
                double withdraw = Double.parseDouble(withdrawTextField.getText().trim());
                theBLU.computeBalance(withdraw, deposit);
                totalBalanceLabel.setText("Your balance after transactions: " + theBLU.getBalance());

            } catch (ATMexception ex) {
                totalBalanceLabel.setText("Error: " + ex.getMessage());
            } catch (Exception ex) {
                totalBalanceLabel.setText("Error in deposit or withdraw amount: " + ex.getMessage());
            }
        } else if (actionCommand.equals("Enter Pin OK")) {

            try {

                double pin = Double.parseDouble(pinTextField.getText().trim());
                theBLU.checkPin(pin);

                totalBalanceLabel.setText("Your balance after transactions: " + theBLU.getBalance());



            } catch (ATMexception ex) {
                totalBalanceLabel.setText("Error: " + ex.getMessage());
            } catch (Exception ex) {
                totalBalanceLabel.setText("Error in pin: " + ex.getMessage());

            }
        } else {
            System.out.println("Error in button interface.");
        }
    }

    public static void main(String[] args) {
        ATMgui gui = new ATMgui();
        gui.setVisible(true);
    }
}

Answer 1

Since the code pasted by you is not working, I had made a small program for you, have a look, and see what changes can you do to incorporate that in your case :

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

public class PanelTest extends JFrame
{
    private JPanel eastPanel;

    public PanelTest()
    {
        setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
        setLocationByPlatform(true);

        Container container = getContentPane();

        eastPanel = new JPanel();
        eastPanel.setBackground(Color.DARK_GRAY);

        JPanel westPanel = new JPanel();
        westPanel.setBackground(Color.YELLOW);

        JPanel centerPanel = new JPanel();
        centerPanel.setBackground(Color.BLUE);

        container.add(eastPanel, BorderLayout.LINE_START);
        container.add(centerPanel, BorderLayout.CENTER);
        container.add(westPanel, BorderLayout.LINE_END);
        eastPanel.setVisible(false);

        JButton showButton = new JButton("Click Me to Display EAST JPanel");
        showButton.addActionListener(new ActionListener()
        {
            public void actionPerformed(ActionEvent ae)
            {
                eastPanel.setVisible(true);
            }
        });

        JButton hideButton = new JButton("Click Me to Hide EAST JPanel");
        hideButton.addActionListener(new ActionListener()
        {
            public void actionPerformed(ActionEvent ae)
            {
                eastPanel.setVisible(false);
            }
        });

        container.add(hideButton, BorderLayout.PAGE_START);
        container.add(showButton, BorderLayout.PAGE_END);

        setSize(300, 300);
        setVisible(true);
    }

    public static void main(String... args)
    {
        SwingUtilities.invokeLater(new Runnable()
        {
            public void run()
            {
                new PanelTest();
            }
        });
    }
}

And from future, never use NORTH, EAST, WEST and SOUTH for BorderLayout. They have been replaced with PAGE_START, LINE_START, LINE_END and PAGE_END respectively.

A BorderLayout object has five areas. These areas are specified by the BorderLayout constants:

• PAGE_START
• PAGE_END
• LINE_START
• LINE_END
• CENTER

Version note:
Before JDK release 1.4, the preferred names for the various areas were different, ranging from points of the compass (for example, BorderLayout.NORTH for the top area) to wordier versions of the constants we use in our examples. The constants our examples use are preferred because they are standard and enable programs to adjust to languages that have different orientations.

I had modified the checkPin(...) method of the ATMLogin class to return a boolean instead of void, so that inside the actionPerformed(...) method of the ATMgui class, if this thing returns true, then only to set the required JPanel to visible, else nothing is to be done.

Do check the code and see what changes you can do to make it work for your end.

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

public class ATMgui extends JFrame implements ActionListener 
{

    /**
     * 
     */
    private static final long serialVersionUID = 1L;
    public static final int WIDTH = 500;
    public static final int HEIGHT = 200;
    private ATMbizlogic theBLU;// short for the Business Logic Unit
    private JPanel txPanel;
    public JLabel totalBalanceLabel;
    public JTextField withdrawTextField;
    public JTextField depositTextField;
    public JTextField pinTextField;

    /**
     * Creates a new instance of ATMgui
     */
    public ATMgui() 
    {
        setTitle("ATM Transactions");
        setSize(WIDTH, HEIGHT);
        setDefaultCloseOperation(javax.swing.WindowConstants.EXIT_ON_CLOSE);

        Container contentPane = getContentPane();
        contentPane.setBackground(Color.BLACK);
        contentPane.setLayout(new BorderLayout());


        // Do the panel for the rest stop
        JLabel start = new JLabel("Welcome To Your Account", JLabel.CENTER);
        Font curFont = start.getFont();
        start.setFont(new Font(curFont.getFontName(), curFont.getStyle(), 25));
        start.setForeground(Color.BLUE);
        start.setOpaque(true);
        start.setBackground(Color.BLACK);


        pinTextField = new JTextField();
        JLabel pinLabel = new JLabel("Enter your PIN below:", JLabel.CENTER);
        pinLabel.setForeground(Color.RED);
        pinLabel.setOpaque(true);
        pinLabel.setBackground(Color.WHITE);



        JButton pinButton = new JButton("Enter Pin OK");
        pinButton.addActionListener(this);
        pinButton.setBackground(Color.red);

        JPanel pinPanel = new JPanel();
        pinPanel.setLayout(new GridLayout(3, 1, 100, 0));

        pinPanel.add(pinLabel);
        pinPanel.add(pinTextField);
        pinPanel.add(pinButton);

        contentPane.add(pinPanel, BorderLayout.WEST);


        JPanel headingPanel = new JPanel();
        headingPanel.setLayout(new GridLayout());
        headingPanel.add(start);

        contentPane.add(headingPanel, BorderLayout.NORTH);


        // Do the panel for the amount & type of transactions
        withdrawTextField = new JTextField();
        JLabel withdrawLabel = new JLabel("Withdraw (0.00)", JLabel.CENTER);
        withdrawLabel.setForeground(Color.RED);
        withdrawLabel.setOpaque(true);
        withdrawLabel.setBackground(Color.WHITE);



        depositTextField = new JTextField();
        JLabel depositLabel = new JLabel("Deposit (0.00)", JLabel.CENTER);
        depositLabel.setForeground(Color.RED);
        depositLabel.setOpaque(true);
        depositLabel.setBackground(Color.WHITE);



        JButton txButton = new JButton("Transactions OK");
        txButton.addActionListener(this);
        txButton.setBackground(Color.red);




        txPanel = new JPanel();
        txPanel.setLayout(new GridLayout(5, 1, 30, 0));

        txPanel.add(withdrawLabel);
        txPanel.add(withdrawTextField);
        txPanel.add(depositLabel);
        txPanel.add(depositTextField);
        txPanel.add(txButton);

        contentPane.add(txPanel, BorderLayout.EAST);
        txPanel.setVisible(false);


        totalBalanceLabel = new JLabel("Your balance after transactions: ", JLabel.CENTER);
        totalBalanceLabel.setForeground(Color.BLUE);
        totalBalanceLabel.setOpaque(true);
        totalBalanceLabel.setBackground(Color.BLACK);


        contentPane.add(totalBalanceLabel, BorderLayout.SOUTH);


        theBLU = new ATMbizlogic();
    }

    public void actionPerformed(ActionEvent e) 
    {
        String actionCommand = e.getActionCommand();

        // Container contentPane = getContentPane();

        if (actionCommand.equals("Transactions OK")) 
        {
            try 
            {
                double deposit = Double.parseDouble(depositTextField.getText().trim());
                double withdraw = Double.parseDouble(withdrawTextField.getText().trim());
                theBLU.computeBalance(withdraw, deposit);
                totalBalanceLabel.setText("Your balance after transactions: " + theBLU.getBalance());

            } 
            /*catch (ATMexception ex) 
            {
                totalBalanceLabel.setText("Error: " + ex.getMessage());
            }*/ 
            catch (Exception ex) 
            {
                totalBalanceLabel.setText("Error in deposit or withdraw amount: " + ex.getMessage());
            }
        } 
        else if (actionCommand.equals("Enter Pin OK")) 
        {

            try 
            {               
                double pin = Double.parseDouble(pinTextField.getText().trim());
                if(theBLU.checkPin(pin))
                    txPanel.setVisible(true);
                totalBalanceLabel.setText("Your balance after transactions: " + theBLU.getBalance());               
            } 
            /*catch (ATMexception ex) 
            {
                totalBalanceLabel.setText("Error: " + ex.getMessage());
            }*/ 
            catch (Exception ex) 
            {
                totalBalanceLabel.setText("Error in pin: " + ex.getMessage());
                ex.printStackTrace();
            }
        } 
        else 
        {
            System.out.println("Error in button interface.");
        }
    }

    public static void main(String[] args) 
    {
        ATMgui gui = new ATMgui();
        gui.setVisible(true);
    }
}

class ATMbizlogic 
{

    private double totalBalance;
    private boolean rightPinEntered;

    /**
     * Creates a new instance of ATMbizlogic
     */
    public ATMbizlogic() 
    {
        totalBalance = 0.0;
        rightPinEntered =  true;
    }

    public void computeBalance(double withdraw, double deposit)
    //throws ATMexception 
    {
        if(withdraw <=0)
        {
            System.out.println("Negative withdraw not allowed");
            //throw new ATMexception("Negative withdraw not allowed");
        }   

        if(deposit <=0)
        {
            System.out.println("Negative deposit not allowed");
            //throw new ATMexception("Negative deposit not allowed");
        }   

         double balance = deposit - withdraw;

        totalBalance = totalBalance + balance;
    }

    public boolean checkPin(double pin)
    //throws ATMexception 
    {
        if(pin <=0)
        {
            System.out.println("Negative pin not allowed");
            rightPinEntered = false;
            //throw new ATMexception("Negative pin not allowed");
        }   
        /*else if(rightPinEntered == false)
        {
            System.out.println("Can not take another pin");
            rightPinEntered = false;
            //throw new ATMexception("Can not take another pin");
        }*/ 
        else if(pin<1111 || pin>9999)
        {
            System.out.println("Enter a valid pin");
            rightPinEntered = false;
            //throw new ATMexception("Enter a valid pin");
        }
        else
        {       
            rightPinEntered = true;
        }

        return rightPinEntered;
    }

    public double getBalance()
    {
        return totalBalance;
    }
}