Thread: Populating a 2D array with textfield values

I have to code an assignment for a college course. Long story short, part of the assignment requires me to take information from two textfields (variable names payment and time) and then enter them into a multidimensional array every time someone uses the enter button on a GUI. Then, after entering in all their payment and time amounts the user will press the "Run Report" button which will take information from the 2D array and list the information followed by some calculations like average, totals for time and payment, etc. I'm pretty much good to go on everything I think except this 2D array thing. The GUI is built and I'm trying to build functionality for the "Enter" button. I'm not real sure how to properly implement this though. Here's what I have so far.

I first declared some global variables and the array:

 
public class TutorUI extends javax.swing.JFrame {
 
double[][] ptArray = new double[20][2];
double i = 0;
double j = 0;

Then added some coding for the enter button:

private void enterActionPerformed(java.awt.event.ActionEvent evt) {
 
/*gets the value from the two text fields and sets them equal to the
variables*/
double paymentValue = Double.parseDouble(payment.getText());
 
double timeValue = Double.parseDouble(time.getText());
 
//Checks for negative numbers and throws exception if found.
if (paymentValue < 0)
{
IllegalArgumentException exception
= new IllegalArgumentException("Invalid payment amount.");
throw exception;
 
}
 
//Checks for negative numbers and throws exception if found.
if (timeValue < 0)
{
IllegalArgumentException exception
= new IllegalArgumentException("Invalid time amount.");
throw exception;
}
 
//Sets the variables to column 1 and column 2.
ptArray[0][0] = timeValue;
ptArray[0][1] = paymentValue;

Basically I want to set the timeValue to column 1 and paymentValue to column 2 and then the array just adds a new row each time someone enters new data. I feel like maybe I'm going about this in the wrong way since when I try to test the array by appending the data to the textarea it spits out gibberish. I've tried about 20 different ways to get this to work and this is just one of the many. Any help, tips, links to tutorials, etc. will be greatly appreciated. Thanks.

Ok, quick question:

private void enterActionPerformed(java.awt.event.ActionEvent evt) {                                      
 
        /*gets the value from the two text fields and sets them equal to the
         variables*/
        double paymentValue = Double.parseDouble(payment.getText());
 
        double timeValue = Double.parseDouble(time.getText());
 
        int index = 0;
        //Checks for negative numbers and throws exception if found.
        if (paymentValue < 0)
            {
                IllegalArgumentException exception
                = new IllegalArgumentException("Invalid payment amount.");
                throw exception;
 
        }
 
        //Checks for negative numbers and throws exception if found.
        if (timeValue < 0)
        {
            IllegalArgumentException exception
            = new IllegalArgumentException("Invalid time amount.");
            throw exception;
        }
//Sets the variables to column 1 and colum 2.
        ptArray[index][0] = timeValue;
        ptArray[index][1] = paymentValue;
        index++;
 
 
 
    }

This should just enter it into the array and store it in memory correct?

And then I want to append the list of information from the array to the textarea after I click the runReport button:

private void runReportActionPerformed(java.awt.event.ActionEvent evt) {                                          
       int index = 0;
 
       for (int i = 0; i < index; i++){
            reportArea.append("Time: " + ptArray[i][0] + "Payment: " + ptArray[i][1]);
        }
 
    }

I'm doing something wrong but I'm not sure what since nothing shows up in the text area. Assuming that I am storing the data in the array properly, am I referencing it wrong somehow when I try to use the runReport button? Thanks again for the help.

LOL Yeah, good point. Got to fix that.

 
private void runReportActionPerformed(java.awt.event.ActionEvent evt) {                                          
 
       for (int i = 0; i < ptArray.length; i++){
            reportArea.append("Time: " + ptArray[i][0] + "Payment: " + ptArray[i][1]);
        }

Ok, I set it to this and it works good. Problem now is that it's brought another issue since it appears to run through the full 20 rows that I set in the initial declaration at

 
double[][] ptArray = new double[20][2];

This is something I had trouble understanding earlier. I really wanted to set this to i or something so that there isn't a set variable and instead it creates a new row each time I enter information. I kept getting errors though with everything I tried. Also, it appears to only keep 1 row in memory instead of adding a new row for each pair of data entered. Any ideas? Thanks again for all the posts. It's been incredibly helpful.