Swing/ActionListener help?

Quite honestly I'm very new at Java, but any help is greatly appreciated. ^^;

This is a program I have to make for my AP Computer Science class- I have to make a program that calculates a regular polygon.

I have pretty much everything worked out- except the whole "getting input" part.

Code:

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import java.awt.event.ActionEvent;
import java.awt.event.ActionListener;

import javax.swing.JButton;
import javax.swing.JFrame;
import javax.swing.JLabel;
import javax.swing.JPanel;
import javax.swing.JTextField;

public class MainClass extends JPanel {

        private JTextField lenfield = new JTextField("    ");
        private JTextField numfield = new JTextField("    ");
       
  public MainClass() {
        JLabel len = new JLabel("Side Length:");
        JLabel numsides = new JLabel("Number of Sides:");
    JButton calcbutton = new JButton("Calculate");
    calcbutton.addActionListener(new ButtonListener());
    add(len);
    add(lenfield);
    add(numsides);
    add(numfield);
    add(calcbutton);
   

  }

  public static void main(String[] args) {
    JFrame frame = new JFrame();
    frame.getContentPane().add(new MainClass());

    frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
    frame.setSize(200, 200);
    frame.setVisible(true);
  }
}

class ButtonListener implements ActionListener {
  ButtonListener() {
  }

        public void actionPerformed(ActionEvent e){
                String input;
                double len;
                int num;
                input=lenfield.getText();
                len= Double.parseDouble(input);
                input=numfield.getText();
                num=Integer.parseInt(input);
                Polygon poly= new Polygon(num, len);
                System.out.println(len+" "+num);
               
        }
  }

---

But every freakin' time- "lenfield cannot be resolved, numfield cannot be resolved".

(and, yes, I could have done javax.swing.*;, but I got kind of desperate ^^;)

You declare the variable in one class and try to use it in another class, so the errors shouldn't be too surprising. Perhaps you want to make the listener class a private inner class?

Blah, this freaking book lied to me, I practically copied the code word for word. >.>;

Uh... sorry, I'm relatively new at this. How would I go about doing so, just make the actionlistener a private class?

Are you sure that you didn't just copy things wrong? You would remove the end curly brace "}" that is immediately above this line:

Code:

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class ButtonListener implements ActionListener {

---

and add an end curly brace to the bottom. Then change the line above to:

Code:

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private class ButtonListener implements ActionListener {

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Oh. Duh. Looks like I did copy something wrong, I'm a moron. xD

Thanks anyway, dude, I'll be sure to remember in the future!