Handling exception and getting message dialog to show

Question

I'm trying to get the user to input an integer into the textfield. The try catch block should handle the exception when the user enters a non-integer. A message dialog should appear, telling the user that they should input something else but I can't seem to get it to do so.

    class ButtonListener implements ActionListener
    {
        public void actionPerformed (ActionEvent event)
        {
            try
            {
                String r = radiusField.getText ();
                int radius = Integer.parseInt (r);
                double area = Math.PI * radius * radius;
                areaArea.setText ("" + area);
            }

            catch (InputMismatchException ex)
            {
                JOptionPane.showMessageDialog (null, "Error in number format: Reenter the number");
                radiusField.setText ("");
                areaArea.setText ("");
            }
        }
    }

Answer 1

Use NumberFormatException instead of InputMismatchException:

catch (NumberFormatException ex) {
  /* ... */
}