JOptionPane Input to int

Question

Hello all, I am trying to make a JOptionPane get an input and assign it to an int but I am getting some problems with the variable types.

I am trying something like this:

Int ans = (Integer) JOptionPane.showInputDialog(frame,
            "Text",
            JOptionPane.INFORMATION_MESSAGE,
            null,
            null,
            "[sample text to help input]");

But I am getting:

Exception in thread "main" java.lang.ClassCastException: java.lang.String cannot
be cast to java.lang.Integer

Which sounds logical yet, I cannot think of another way to make this happen.

Thanks in advance

Answer 1

Simply use:

int ans = Integer.parseInt( JOptionPane.showInputDialog(frame,
        "Text",
        JOptionPane.INFORMATION_MESSAGE,
        null,
        null,
        "[sample text to help input]"));

You cannot cast a String to an int, but you can convert it using Integer.parseInt(string).

Answer 2

This because the input that the user inserts into the JOptionPane is a String and it is stored and returned as a String.

Java cannot convert between strings and number by itself, you have to use specific functions, just use:

int ans = Integer.parseInt(JOptionPane.showInputDialog(...))

Answer 3

Please note that Integer.parseInt throws an NumberFormatException if the passed string doesn't contain a parsable string.