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Mortgage calculator - How do I make controls unavailable based on radio button

Posted on 2006-06-18
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Last Modified: 2010-03-31
Hi,
I have posted my mortgage calculator below. Everything seems to work fine. The calculator lets you select a radio button to determine if you want to select pre-determined loans or enter your own parameters. This works fine, but I would like to make the predefined radio buttons unavailable if the user selects user parameters, and the user parameters unavailable if the user selects pre-defined loans. I would also like to dim the unavailable one if that is possible.
Any assistance would be appreciated.
Thanks,
Jon


      //week3 Jan Scha

/* Mortgage Monyhly Payment Calculator with graphical user interface
Programmer:  J.Schab
Date:        June 10,2006
Filename:    Mortgage.java
Purpose:     This project accepts the mortgage amountand allows  the user to select one of 3
pre-determined loans.The program then calculates the monthly mortgage payment and displays
it in currency format. The program then displays the payment number, the monthly principle
paid, the monthly interest paid, and the current loan balance.There is a quit button to
exit the application, and a clear button to clear user entered fields as well as the amortization table.
in order to calculate a new mortgage. The program will also clear the payment field should
the user press any key while positioned in the input textfield for amount.


 */



import javax.swing.*;
import javax.swing.border.*;
import javax.swing.JScrollPane.*;
import java.awt.*;
import java.awt.event.*;
import javax.swing.event.*;
import java.text.NumberFormat;
import java.util.Locale;
import java.text.*;
import java.text.DecimalFormat;



class Mortgage extends JFrame
{


    //Program variables

    double yearlyRate[] =
    {
        // array of interest rates
        5.35, 5.50, 5.75
    };
    int term[] =
    {
        //array of terms
        7, 15, 30
    };
    int termMonths[] =
    {
        //array of terms in months
        84, 180, 360
    };

    int payment = 0; // payment counter
    int i = 0; // used as index
    // initialize variable for monthly interest rate
    double monthlyInterest = 0.00;
    double principle = 0.00;
    // initialize mothly principle paid field
    double monthlyPrinciplePaid = 0.00;
    double interestRateMonthly = 0.00;
    double monthlyPayment;
    int amount = 0;
    double yearinRate = 0.00;
    int termin = 0;
    int monthCount = 0;


    private JLabel headerJLabel;

    Border rowborder = new EmptyBorder(3, 10, 3, 10);
    // Format output
    DecimalFormat currency = new DecimalFormat("$0.00");


    // JLabel and JTextField for the mortgage amount
    private JLabel amountJLabel;
    private JTextField amountJTextField;

    // JLabel for monthly mortgage payment
    private JLabel monthpayJLabel;

    // JTextArea for displaying payment
    private JTextArea outputJTextArea;

    // Label for asking user choice
    private JLabel choiceJLabel;

    // JButton to initiate calculations
    private JButton calculateJButton;

    // JButton to display amortization table
    private JButton displayJButton;

    // JButton to clear entries
    private JButton clearJButton;

    // JButton to quit
    private JButton quitJButton;

    // JLabel and JTextField for interest percentage rate
      private JLabel interestJLabel;
      private JTextField interestJTextField;

       // JLabel and JTextField for mortgage term
      private JLabel termJLabel;
    private JTextField termJTextField;



    // Create radio panel for pre-determined loans
    JPanel radioPanel = new JPanel();
    JRadioButton aButton = new JRadioButton("7 Years at 5.35%", true);
    JRadioButton bButton = new JRadioButton("15 Years at 5.50%", false);
    JRadioButton cButton = new JRadioButton("30 Years at 5.75%", false);

    JTextArea displayArea = new JTextArea(10, 75);
    JScrollPane scroll = new JScrollPane(displayArea);



    // Create radio panel for method choice
    JPanel choicePanel = new JPanel();
    JRadioButton predefButton = new JRadioButton("Pre-defined Loans", true);
    JRadioButton entryButton = new JRadioButton("User Supplied Parameters", false);






    // no-argument constructor
    public Mortgage()



    {
        createUserInterface();
    }

    // create and position the GUI components; register event handlers
    private void createUserInterface()
    {
        // get content pane for attaching GUI components
        Container contentPane = getContentPane();

        setTitle("Mortgage Calculator"); // set title bar text


        // enable specific positioning of GUI components
        contentPane.setLayout(null);

        // set up amountJLabel
        amountJLabel = new JLabel();
        amountJLabel.setBounds(76, 5, 104, 26); // set size and position
        amountJLabel.setText("Mortgage amount:");
        contentPane.add(amountJLabel);

        // set up choiceJLabel
            choiceJLabel = new JLabel();
            choiceJLabel.setBounds(166, 50, 104, 26); // set size and position
            choiceJLabel.setText("Select a method");
            contentPane.add(choiceJLabel);


        // set up amountJTextField
        amountJTextField = new JTextField();
        amountJTextField.setBounds(200, 5, 56, 26); // set size and position
        amountJTextField.setHorizontalAlignment(JTextField.RIGHT);
        contentPane.add(amountJTextField);
        amountJTextField.addKeyListener(

        new KeyAdapter() // anonymous inner class
        {
            // event handler for key pressed in amountJTextField
            public void keyPressed(KeyEvent event)
            {
                amountJTextFieldkeyPressed(event);
            }

        } // end anonymous inner class

        ); // end call to addKeyListener


        // set up interestJLabel
        interestJLabel = new JLabel("Annual interest rate:");
        interestJLabel.setBounds(226, 170, 115, 26);
        interestJLabel.setText("Annual interest rate:");
        contentPane.add(interestJLabel);

        // set up interestJTextField
        interestJTextField = new JTextField();
        interestJTextField.setBounds(370, 170, 56, 26);
        interestJTextField.setHorizontalAlignment(JTextField.RIGHT);
        contentPane.add(interestJTextField);
        interestJTextField.addKeyListener(

        new KeyAdapter() // anonymous inner class
        {
            // evend handler for key pressed in interestJTextField
            public void keyPressed(KeyEvent event)
            {
                interestJTextFieldkeyPressed(event);
            }

        } // end anonymous inner class


        ); // end call to addKeyListener

        // set up termJLabel for term of loan
        termJLabel = new JLabel();
        termJLabel.setBounds(226, 130, 140, 26);
        termJLabel.setText("Mortgage length (Years):");
        contentPane.add(termJLabel);

        // set up termJTextField to receive term of loan
        termJTextField = new JTextField();
        termJTextField.setBounds(370, 130, 56, 26);
        termJTextField.setHorizontalAlignment(JTextField.RIGHT);
        contentPane.add(termJTextField);
        termJTextField.addKeyListener(

        new KeyAdapter() // anonymous inner class
        {
            // event handler for key pressed in termJTextField
            public void keyPressed(KeyEvent event)
            {
                termJTextFieldkeyPressed(event);
            }

        } // end anonymous inner class

        ); // end call to addKeyListener





        ButtonGroup bgroup = new ButtonGroup();
        bgroup.add(aButton);
        bgroup.add(bButton);
        bgroup.add(cButton);
        radioPanel.setLayout(new FlowLayout(FlowLayout.LEFT, 4, 4));
        radioPanel.add(aButton);
        radioPanel.add(bButton);
        radioPanel.add(cButton);
        contentPane.add(radioPanel);
        radioPanel.setBorder(rowborder);
        radioPanel.setBounds(30, 120, 195, 95); // set size and position



        ButtonGroup choicegroup = new ButtonGroup();
        choicegroup.add(predefButton);
        choicegroup.add(entryButton);
        choicePanel.setLayout(new FlowLayout(FlowLayout.LEFT, 4, 4));
        choicePanel.add(predefButton);
        choicePanel.add(Box.createRigidArea(new Dimension(50,0)));
        choicePanel.add(entryButton);
        contentPane.add(choicePanel);
        choicePanel.setBorder(rowborder);
        //choicePanel.setBounds(130, 225, 195, 95); // set size and position
        choicePanel.setBounds(29, 75, 500, 95);


        // set up calculateJButton
        calculateJButton = new JButton();
        calculateJButton.setBounds(26, 220, 90, 26); // set size and position
        calculateJButton.setText("Calculate");
        contentPane.add(calculateJButton);
        calculateJButton.addActionListener(

        new ActionListener() // anonymous inner class
        {
            // event handler called when calculateJButton is pressed
            public void actionPerformed(ActionEvent event)
            {

                calculateJButtonActionPerformed(event);
            }

        } // end anonymous inner class

        ); // end call to addActionListener


        // set up displayJButton
        displayJButton = new JButton();
        displayJButton.setBounds(26, 280, 200, 26); // set size and position
        displayJButton.setText("Display Amortization Table");
        contentPane.add(displayJButton);
        displayJButton.addActionListener(

        new ActionListener() // anonymous inner class
        {
            // event handler called when clearJButton is pressed
            public void actionPerformed(ActionEvent event)
            {
                displayJButtonActionPerformed(event);
            }

        } // end anonymous inner class

        ); // end call to addActionListener




        // set up clearJButton
        clearJButton = new JButton();
        clearJButton.setBounds(120, 430, 90, 26); // set size and position
        clearJButton.setText("Clear");
        contentPane.add(clearJButton);
        clearJButton.addActionListener(

        new ActionListener() // anonymous inner class
        {
            // event handler called when clearJButton is pressed
            public void actionPerformed(ActionEvent event)
            {
                clearJButtonActionPerformed(event);
            }

        } // end anonymous inner class

        ); // end call to addActionListener


        // set up quitJButton
        quitJButton = new JButton();
        quitJButton.setBounds(270, 430, 90, 26); // set size and position
        quitJButton.setText("Quit");
        contentPane.add(quitJButton);
        quitJButton.addActionListener(

        new ActionListener() // anonymous inner class
        {
            // event handler called when quitJButton is pressed
            public void actionPerformed(ActionEvent event)
            {
                quitJButtonActionPerformed(event);
            }

        } // end anonymous inner class

        ); // end call to addActionListener


        // set up outputJTextArea
        outputJTextArea = new JTextArea();
        contentPane.add(outputJTextArea);
        outputJTextArea.setBounds(300, 220, 56, 26); // set size and position
        outputJTextArea.setEditable(false);

        //set up monthpayJLabel
        monthpayJLabel = new JLabel();
        monthpayJLabel.setBounds(176, 220, 156, 26); // set size and position
        monthpayJLabel.setText("Monthly Payment:");
        contentPane.add(monthpayJLabel);

        scroll.setBorder(BorderFactory.createEmptyBorder(10, 10, 10, 10));
        contentPane.add(scroll);
        scroll.setBounds(20, 300, 440, 130); // set size and position
        setVisible(true);





    } // end method createUserInterface

    // called when user presses key in amountJTextField
    private void amountJTextFieldkeyPressed(KeyEvent event)
    {
        outputJTextArea.setText(""); // clear outputJTextArea
        displayArea.setText(""); // clear display
        payment = 0; // reset payment counter
    }

    // method called when user clicks calculateJButton
    private void calculateJButtonActionPerformed(ActionEvent event)
    {
        try
        {
            // check which radio buttonis selected and set index
            if (aButton.isSelected())
            {
                i = 0;
            }


            if (bButton.isSelected())
            {
                i = 1;
            }


            if (cButton.isSelected())
            {
                i = 2;
            }


            // check which radio buttonis selected and set index
                  if (predefButton.isSelected())
                  {
                  interestRateMonthly = (yearlyRate[i] / 12) / 100;
              monthCount = (term[i] * 12);
                  }


                  if (entryButton.isSelected())
                  {
                  yearinRate = Double.parseDouble(interestJTextField.getText());
                  termin = Integer.parseInt(termJTextField.getText());
              interestRateMonthly = (yearinRate / 12) / 100;
              monthCount = (termin * 12);
                              }





            //define display area titles
            String titles = "Month \t Principal\t Interest\tBalance\n";
            //put titles in display area
            displayArea.setText(titles);
            // initialize loan balance field
            double loanbalance = 0.00;

            // initialize payment counter

            // clear outputJTextArea
            outputJTextArea.setText("");
            // clear display area
            displayArea.setText("");
            // Calculate months from years

            // get mortgage amount
            amount = Integer.parseInt(amountJTextField.getText());
            //create variable to store decreasing principle
            principle = amount;
            // Calculate monthly interest



            // Calculate monthly payment
            monthlyPayment = (amount * interestRateMonthly) / (1-Math.pow(1 +
                interestRateMonthly,  - monthCount));




            // Output payment amount
            outputJTextArea.setText(currency.format(monthlyPayment));



        }

        catch (NumberFormatException ex){}
    }





    // method called when user clicks clearJButton
    private void clearJButtonActionPerformed(ActionEvent event)
    {
        try
        {

            monthlyPrinciplePaid = 0.00;
            outputJTextArea.setText(""); // clear outputJTextArea
            amountJTextField.setText(""); // clear amountJTextField
            displayArea.setText(""); // clear display area
            termJTextField.setText(""); // clear term text box area
            interestJTextField.setText(""); // clear term text box area
            payment = 0; // reset payment counter




        }
        catch (NumberFormatException ex){}
    }


    // method called when user clicks displayJButton
    private void displayJButtonActionPerformed(ActionEvent event)
    {
        try
        {

            // reset values in case user presses display more than once
            principle = Integer.parseInt(amountJTextField.getText());
            monthlyPrinciplePaid = 0.00;
            displayArea.setText(""); // clear display
            payment = 0;
            monthlyPrinciplePaid = 0.00;

            //define display area titles
            String titles = "Month \t Principal\t Interest\tBalance\n";
            //put titles in display area
            displayArea.setText(titles);
            // initialize loan balance field


            // loop for creating amortization table
            for (int a = 0; a < monthCount; a = a + 1)
            {
                //increment payment counter
                payment++;
                // calculate monthly interest
                monthlyInterest = principle * interestRateMonthly;
                // calculate monthly principle
                monthlyPrinciplePaid = monthlyPayment - monthlyInterest; //
                //save declining balance
                principle = principle - monthlyPrinciplePaid;


                // display amortization table
                displayArea.append(payment + "\t" + currency.format
                    (monthlyPrinciplePaid) + "\t" + currency.format
                    (monthlyInterest) + "\t" + currency.format(Math.abs
                    (principle)) + "\n");
                displayArea.setCaretPosition(0);


            }
        }

        catch (NumberFormatException ex){}
    }




    // method called when user clicks quitJButton
    private void quitJButtonActionPerformed(ActionEvent event)
    {
        try
        {
            System.exit(0);

        }
        catch (NumberFormatException ex){}
    }


    // called when user presses key in termJTextField
    private void termJTextFieldkeyPressed(KeyEvent event)
    {
        outputJTextArea.setText(""); // clear outputJTextArea
    }

    // called when user presses key in interestJTextField
    private void interestJTextFieldkeyPressed(KeyEvent event)
    {
        outputJTextArea.setText(""); // clear outputJTextArea
    }


    // main method
    public static void main(String[]args)
    {
        Mortgage application = new Mortgage();
        application.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
        application.setSize(480, 500);
        application.setVisible(true);
    } // end method main

} // end class Mortgage
0
Comment
Question by:ghost8067
  • 3
4 Comments
 
LVL 9

Expert Comment

by:matthew016
ID: 16929242
U need to implement ActionListener
and tell the program that when u click on, for example, predefButton,
u want to execute instrructions to disable the buttons of the user defined functions.

class Mortgage extends JFrame implements ActionListener
{
[...]

        ButtonGroup choicegroup = new ButtonGroup();
        predefButton.addActionListener(this);
        entryButton.addActionListener(this);
        choicegroup.add(predefButton);
        choicegroup.add(entryButton);
[...]
// Initially the predefined is selected so disable the user defined functions
            termJTextField.setEnabled(false);
            interestJTextField.setEnabled(false);
[...]
      public void actionPerformed(ActionEvent e) {
// if predefButton is selected, disable user defined functions
            if(e.getSource() == predefButton) {
                  aButton.setEnabled(true);
                  bButton.setEnabled(true);
                  cButton.setEnabled(true);
                  termJTextField.setEnabled(false);
                  interestJTextField.setEnabled(false);
            }
// if entryButton is selected, disable pre-defined functions
            else if(e.getSource() == entryButton) {
                  termJTextField.setEnabled(true);
                  interestJTextField.setEnabled(true);
                  aButton.setEnabled(false);
                  bButton.setEnabled(false);
                  cButton.setEnabled(false);
            }
      }
0
 
LVL 9

Expert Comment

by:matthew016
ID: 16929254
I resume :

1)
u need to tell the class that it listens to actions. (implements ActionListener)


2)
tell which component send actions to the class
(        predefButton.addActionListener(this);
        entryButton.addActionListener(this);
So in this case, we registered predefButton and entryButton.
)


3)
code the function actionPerformed, it's the method invoked when an action is fired from a registered component
(in this case predefButton, entryButton)

In this method u need to check wich component fired action
if(e.getSource() == ...
0
 

Author Comment

by:ghost8067
ID: 16929403
Matthew,
Thanks for gowing my knowledge. It is working well. I have one additional question.( I am not sure if I'm supposed to do this. If it is not correct etiquette please let me know.) The labels on the radio button dim when disabled. Is there a way I can dim the labels for my text boxes on my user entries when disabled?
Thanks for your help.
Jon
0
 
LVL 9

Accepted Solution

by:
matthew016 earned 500 total points
ID: 16929580
Yes, u can use setEnabled like i showed u for the radiobuttons and textfields,

so u get
[...]
            termJTextField.setEnabled(false);
            interestJTextField.setEnabled(false);
            termJLabel.setEnabled(false);
            interestJLabel.setEnabled(false);
[...]
      public void actionPerformed(ActionEvent e) {
            if(e.getSource() == predefButton) {
                  aButton.setEnabled(true);
                   bButton.setEnabled(true);
                  cButton.setEnabled(true);
                  termJLabel.setEnabled(false);
                  interestJLabel.setEnabled(false);
                  termJTextField.setEnabled(false);
                  interestJTextField.setEnabled(false);
            }
            else if(e.getSource() == entryButton) {
                  termJTextField.setEnabled(true);
                  interestJTextField.setEnabled(true);
                  termJLabel.setEnabled(true);
                  interestJLabel.setEnabled(true);
                  aButton.setEnabled(false);
                  bButton.setEnabled(false);
                  cButton.setEnabled(false);
            }
      }

If I were u I 'd create a method :
public void setEnabledUserDefinedFct(boolean bool) {
                  termJTextField.setEnabled(bool);
                  interestJTextField.setEnabled(bool);
                  termJLabel.setEnabled(bool);
                  interestJLabel.setEnabled(bool);
}
and same thing for predefined fields :
public void setEnabledPreDefinedFct(boolean bool) {
                  aButton.setEnabled(bool);
                  bButton.setEnabled(bool);
                  cButton.setEnabled(bool);
}
then u call these two methods.

[...]
            setEnabledUserDefinedFct(false);
[...]
      public void actionPerformed(ActionEvent e) {
            if(e.getSource() == predefButton) {
                  setEnabledPreDefinedFct(true);
                  setEnabledUserDefinedFct(false);
            }
            else if(e.getSource() == entryButton) {
                        setEnabledUserDefinedFct(true);
                  setEnabledPreDefinedFct(false);
            }
      }

It's better to use functions because if u decide to add another field and disable/enable it when selecting one of the radiobuttons,
u just need to add one line in the appropriate function, and not three lines if we didnt have the function.
0

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