Pin Re-Verification

Question

I'm still at the beginner stage of learning Java and I'm currently having a problem in trying to re-enter the PIN code that I first entered to ensure that I entered it correct the second time. It's like setting up a passcode for your mobile device when I open it. Here's where the problem happens:

int firstSet, secondSet;
firstSet = Integer.parseInt(jTextField2.getText());
jTextField2.setText("");
jLabel1.setText("Re-Enter PIN");
secondSet = Integer.parseInt(jTextField2.getText());
if(firstSet==secondSet)
{
    jLabel1.setText("PIN VERIFIED");
}
else
{
    jLabel1.setText("PIN INCORRECT");
}

This is the error I'm getting:

Exception in thread "AWT-EventQueue-0" java.lang.NumberFormatException: For input string: ""

I hope that someone can help me. :)

Answer 1

You have the problem here

jTextField2.setText("");
// ... 
secondSet = Integer.parseInt(jTextField2.getText());

---

You are setting the value of jTextField2.text to "" and when you try: secondSet = Integer.parseInt(jTextField2.getText()); you're getting an empty String from .getText(), so method Integer.parseInt() is complaining with NumberFormatException

As pointed in the Integer:parseInt(String) API

Throws: NumberFormatException - if the string does not contain a parsable integer.

All this code is executed without interruption, so if you want to do this in this way with only one method call.

First delete this line:

jTextField2.setText("");

And use 2 text fields.

firstSet =  Integer.parseInt(jTextField2.getText());
secondSet = Integer.parseInt(jTextField3.getText());
//                                     ^ here!!!!

---

ADD-ON

In order to avoid similar problems when ueser enter non valid data, or no dagta at all I would recommend you to safe-parse the values of

try {
    firstSet = Integer.parseInt(jTextField2.getText());
    secondSet = Integer.parseInt(jTextField3.getText());
} catch (NumberFormatException e) {
    jLabel1.setText("PIN NOT VALID; TRY AGAIN!!!");
}

ALTERNATIVE if you want to use same jTextField and ask user 2 times to repeat the PIN CODE you must adapt your method in order to perform 2 actions:

• Ask user for pin + accept
• Method call: convert pin and save it in a class attribute.
• Erase JTextField
• Ask user again for pin + accept
• Method call: if in class attribute you have a pin stored, compare with user input.

Example

class YourClass {
    int firstSet = 0; // global attribute!

    public void yourListenerMethod() {
        // if firstSet == 0 is first attempt
        if (firstSet == 0) {
            firstSet = Integer.parseInt(jTextField2.getText());
            jTextField2.setText("");
            jLabel1.setText("Re-Enter PIN");
        //
        // if firstSet != 0 is second attempt so compare
        } else {
            int secondSet = Integer.parseInt(jTextField2.getText());
            if(firstSet==secondSet)
            {
                jLabel1.setText("PIN VERIFIED");
                // reset the pin if necessary
                firstSet = 0;
            }
            else
            {
                jLabel1.setText("PIN INCORRECT");
                // reset the pin if necessary
            }
        }
    }
}