Java integer confirmation through a loop

Question

for (int i = 0; i < fields.length; i++)
{
    for (int j = 0; j < fields[i].length; j++)
    {
        if (fields[i][j].getText().length() == 0) //IF ZERO OR NOT A NUMBER
        {
            JOptionPane.showMessageDialog(null, "Answers missing");
            return;
        }
        answers[i][j] = Integer.parseInt(fields[i][j].getText());
    }
}

How can I assert that a user will input a number (other than zero)? Is it possible to just add it to the if statement using an OR operator (||)?

CodeBrewer · Answer 1 · 2013-06-09T01:56:21.530

I would add a try-catch block around the line where you parse the int, and have it catch a NumberFormatException. That way, if the user does not input a string that has a "parsable integer", your program won't crash. You could probably put the JOptionPane message in the catch block. This will also catch a situation where the length of the string is 0 so you probably don't need that if statement. You can easily test to see if the number is not zero with an if statement.

Here's how I would code it.

for (int i = 0; i < fields.length; i++)
{
    for (int j = 0; j < fields[i].length; j++)
    {

        try {
            int probableAnswer = Integer.parseInt(fields[i][j].getText());

            if(probableAnswer == 0) {
             JOptionPane.showMessageDialog(null, "Answers missing");
            }
            else {
                answers[i][j] = probableAnswer;
            }

        } //end try block
        catch(NumberFormatException e) {
            JOptionPane.showMessageDialog(null, "Answers missing");
        }
    }
}

http://docs.oracle.com/javase/tutorial/essential/exceptions/index.html

http://docs.oracle.com/javase/1.5.0/docs/api/java/lang/Integer.html#parseInt(java.lang.String)

Java integer confirmation through a loop

1 Answers1