Question

A driver class, inputoutput class and numberValidator class. The user is to input a number 1-8 using a j-option pane popup box, if what is entered is not 1-8 an error message is supposed to display. If the number is 1-8 the rest of the code (not written here) is supposed to continue to run. I’m getting errors, anyone see where I’m wrong?

///Driver class (excludes package)////

public class Driver {
    public static void main(String[] args) {
       InputOutput inputoutput = new InputOutput();

       inputoutput.displayMenu();
    }
}

///InputOutput class (excludes package and import for JOptionPane)///
public class InputOutput {
    public int displayMenu()
    {

        String stringChoice = JOptionPane.showInputDialog("Restaurant:\n"
                + "1. Pancakes: $10.00\n"
                + "2. Bananas: $1.00\n"
                + "3. Bread: $2.00\n");
        if (numberValidator.isNumeric(stringChoice)){
            choiceNumber = Integer.parseInt(stringChoice);   
        }
        return choiceNumber;
    }

///numberValidator class code (excludes package)///
public class numberValidator {
    public boolean isNumeric(String str)
   {
        boolean valid = true;
        String regex = "[1-8/.]*";
    valid = str.matches(regex);
    return valid;
}
}

Answer 1

What is the error you are getting? Is it simply that it continues running no matter what the user chooses? In my code below, I have added an else that will re-run the displayMenu() method if the chosen value was not a number.

public class InputOutput {
    public int displayMenu()
    {

        String stringChoice = JOptionPane.showInputDialog("Restaurant:\n"
                + "1. Pancakes: $10.00\n"
                + "2. Bananas: $1.00\n"
                + "3. Bread: $2.00\n");
        if (numberValidator.isNumeric(stringChoice)){
            choiceNumber = Integer.parseInt(stringChoice);   
        }
        else {
            return displayMenu();
            }
        return choiceNumber;
    }

But for your problem, wouldn’t it be better to use a dropdown list of options?…

String[] options = new String[]{"Pancakes: $10.00","Bananas: $1.00","Bread: $2.00"}

int chosenIndex = JOptionPane.showOptionDialog(null, "Choose a menu item", "Menu", JOptionPane.YES_NO_OPTION, JOptionPane.QUESTION_MESSAGE, null, options, options[0]);

String chosenValue = options[chosenIndex];