I have my calculator GUI to display as I want it too. When I put in my mortgage amount and choose an option from the drop down box and hit calculate everything works as it should but when I try to manually put in the terms and interest rate and calculate nothing happens. I think I am missing something in the if statements but am not quite sure what. Could someone please look at my code and steer me in the right direction? I really would appreciate any input you could offer.

/**
* SR-mf-003 Change Request 5
* Lisa Condon
* Week 4
* PRG 421 Java Programming II
* Mortgage Calculator with GUI
* Calculate and display mortgage payment amount from user input of amounts
* 7 yrs at 5.35%
* 15 years at 5.5%
* 30 years at 5.75%
* Use an array for the different loans
* Display mortgage payment, loan balance, and interest paid
* Allow user to manually input amount, rate, term if they choose.
* March 29, 2010

* Write a program in java (with GUI)
*/


import javax.swing.*;

import java.awt.*;

import java.text.*;

import java.awt.event.*;



public class MortgageCalculatorWk5A extends JFrame implements ActionListener, ItemListener {

            double userAmount = 0.0;

            double userAmount2 = 0.0;

            double userInterest = 0.0;

            double userTerm = 0.0;

            int months = 0;

            double annualInterestRate [] = {5.35, 5.5, 5.75};

            double monthlyInterest = 0;

            int years [] = {7, 15, 30};

            double loanMonths = 0.0;

            double monthlyPayment = 0.00;

            double loanBalance = 0;

            double currentMonthInterest = 0.00;

            double currentMonthPrinciple = 0.00;

            DecimalFormat eachPayment = new DecimalFormat ("$###,##0.00");;



//Instantiate GUI Component



// row1

JPanel row1 = new JPanel();

JLabel lblAmount = new JLabel(" Mortgage: $", JLabel.LEFT);

JTextField txtAmount = new JTextField(10);



// combo for interest & term

JLabel lblcombo = new JLabel ("Term/Interest");

String cboData[] = {"Select Term","7 years at 5.35%","15 years at 5.50%","30 years at 5.75%"};

JComboBox comboTermInterest = new JComboBox(cboData);


//term

JLabel lblTerm = new JLabel("Term:");

JTextField txtTerm = new JTextField(10);


//interest rate

JLabel lblRate = new JLabel("Interest Rate:");

JTextField txtRate = new JTextField(10);

//payment

JLabel lblPayment = new JLabel("Payment:");

JTextField txtPayment = new JTextField(10);




// row2

JPanel row2= new JPanel(new BorderLayout());

String pad = "                             ";

JLabel lblHeader = new JLabel("Payment #"+pad+"Payment =Amount:"+pad+"Interest Paid:"+pad+"New Balance:");

JTextArea txtResults = new JTextArea(10, 53);

JScrollPane textPane = new JScrollPane(txtResults);





//row 3

JPanel row3 = new JPanel(new GridLayout(1,3,75,1));

JButton calculateButton = new JButton("Calculate");

JButton clearButton = new JButton("Clear");

JButton exitButton = new JButton("Exit");



//Build GUI

public MortgageCalculatorWk5A()            {

            super("Mortgage Calculator");

setBounds(350, 250, 600, 250);
            setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);



row1.add(lblAmount);

row1.add(txtAmount);

row1.add(lblcombo);

row1.add(comboTermInterest);

row1.add(lblTerm);

row1.add(txtTerm);

row1.add(lblRate);

row1.add(txtRate);

row1.add(lblPayment);

row1.add(txtPayment);



txtPayment.setEditable(false);

textPane.setPreferredSize(new Dimension(610,200));


row2.add(lblHeader,BorderLayout.NORTH);
           row2.add(textPane,BorderLayout.CENTER);



//Create Calculate button and add listener
           comboTermInterest.addItemListener(this);
           calculateButton.addActionListener(this);
           clearButton.addActionListener(this);
		   exitButton.addActionListener(this);


row3.add(exitButton);

row3.add(clearButton);

row3.add(calculateButton);



getContentPane().add(row1,BorderLayout.NORTH);
            getContentPane().add(row2,BorderLayout.CENTER);
            getContentPane().add(row3,BorderLayout.SOUTH);



            pack(); }

            // Actions for combo box selection



public void itemStateChanged(ItemEvent event) {

   Object select = event.getItem();

               String selection = select.toString();


   if (selection == cboData[0]) {

  }


   if (selection == cboData[1]) {

	   userInterest = annualInterestRate [0];
       userTerm = years [0];


  }

  if (selection == cboData[2]) {

	   userInterest = annualInterestRate [1];
       userTerm = years [1];

  }

 if (selection == cboData[3]) {

	   userInterest = annualInterestRate [2];
       userTerm = years [2];

  }
}


//Define actions performed for buttons

            public void actionPerformed(ActionEvent e) {

            if (e.getSource() == calculateButton)

            {
			   userAmount = Double.parseDouble(txtAmount.getText());
			   //userInterest = Double.parseDouble (txtInterest.getText());
			   //userTerm = Double.parseDouble (txtTerm.getText());

			   CalculateMonthlyPayment() ;

			   txtPayment.setText( eachPayment.format( monthlyPayment)+"    ");

			   repaint();
			   loanMonths = userTerm * 12;
			   loanBalance = userAmount;

			   for (months = 1; months <= loanMonths; months++)
			   {

				   //monthly interest calculation

				   monthlyInterest = userInterest / (1200.00);

				   //current months interest amount calculation

				   currentMonthInterest = loanBalance * monthlyInterest;

				   //current months principale amount calculation

				   currentMonthPrinciple = monthlyPayment - currentMonthInterest;

				   //current months interest minus loan amount
				  //provides new principle amount
				  loanBalance = loanBalance - currentMonthPrinciple;

				  txtResults.append("    " + months + "\t\t     " + eachPayment.format(monthlyPayment)
				  			+ "\t\t" + eachPayment.format(currentMonthInterest)
				  			+ "\t\t"
				  			+ eachPayment.format(loanBalance) + "\n");
		}

     }

            else if (e.getSource() == clearButton)

            {
			//clear fields

			txtAmount.setText ("");
			txtPayment.setText("");
            txtTerm.setText("");
            txtRate.setText("");
			userAmount = 0.0;
			txtPayment.setText("");
			txtResults.setText("");

  			}

            else if (e.getSource() == exitButton)

            {

				  System.exit(0);

            }

}



//Mortgage Payment Calculations

            double CalculateMonthlyPayment()       {

            return monthlyPayment = (userAmount * ((1 + (userInterest*.01)/12)-1) / (1-(Math.pow(1 + (userInterest/1200),-(userTerm*12)))));

			}

public static void main(String[] args)      {



            new MortgageCalculatorWk5A().setVisible(true);

			}

	}

Good luck in finding help as you won't get it here people are too of themselves to help us :(. Try a more helpful forum like dream.in.code :)

Comments
Yeah, DIC is full of clueless dicks
whinger...

We're happy to help anyone who puts in some effort to help themselves (unlike probable dsmush...).

Skimming over your source I see nowhere that you actually read the values from the screen. As a result, what you put into the input boxes and other user interface controls won't get used, only the defaults.
On changing a user interface control, trigger an event handler that updates the variables you use to calculate the result, that should do the trick.

We're happy to help anyone who puts in some effort to help themselves (unlike probable dsmush...).

Skimming over your source I see nowhere that you actually read the values from the screen. As a result, what you put into the input boxes and other user interface controls won't get used, only the defaults.
On changing a user interface control, trigger an event handler that updates the variables you use to calculate the result, that should do the trick.

Sorry to disappoint but I spent week myself trying. Coming here was my last option...

and so you try to ruin other peoples' threads with your ranting rather than try to help them?
Good show, going to make you a lot of friends here.

This article has been dead for over six months. Start a new discussion instead.