Thread: Please help this is strange.

ok here is my code i followed my instructors working example to the letter and i am getting this error

H:\Pong\src\pong\Controls.java:54: error: non-static variable frame cannot be referenced from a static context
frame.paper.draw();
1 error

i am a beginning Java student and i am not asking for anyone to do my project for me just some help solving this error thanks

/*
 * To change this template, choose Tools | Templates
 * and open the template in the editor.
 */
package pong;
import java.awt.*;
import java.awt.event.*;
import javax.swing.*;
/**
 *<p>Pong<p>
 *<p>The Game<p>
 *<p>Copyright; 2012<p>
 *<p>Alien Software<p> 
 * @author Jason Miller
 * @version 0.5.1
 */
public class Controls extends JFrame implements ActionListener{
    private FlowLayout flo = new FlowLayout();
    private JButton btnStart,btnStop;
    private Timer tmrMoveBall = new Timer(10,new BallMover());
 
    private PongCollisions frame;
 
        public Controls(){
            btnStart = new JButton("Start");
            btnStop = new JButton("Stop");
 
            this.setLayout(flo);
            add(btnStart);
            add(btnStop);
 
            btnStart.addActionListener(this);
            btnStop.addActionListener(this);
        }      
     public Controls(PongCollisions frame){
         this();
         this.frame = frame;
     }
 
    @Override
    public void actionPerformed(ActionEvent ae) {
        if(ae.getSource() == btnStart){
            tmrMoveBall.start();
        }else{
            tmrMoveBall.stop();
        }
 
    }
 
    private static class BallMover implements ActionListener {
 
        @Override
        public void actionPerformed(ActionEvent ae) {
            frame.paper.draw();
        }
    }
}

Originally Posted by MillerJLee79

ok here is my code i followed my instructors working example to the letter and i am getting this error

H:\Pong\src\pong\Controls.java:54: error: non-static variable frame cannot be referenced from a static context
frame.paper.draw();
1 error

You are missing something. The code that you posted does not define a PongCollisions class, and I get three errors:

Controls.java:22: cannot find symbol
symbol  : class PongCollisions
location: class pong.Controls
    private PongCollisions frame;
            ^
Controls.java:35: cannot find symbol
symbol  : class PongCollisions
location: class pong.Controls
     public Controls(PongCollisions frame){
                     ^
Controls.java:54: non-static variable frame cannot be referenced from a static context
            frame.paper.draw();
            ^
3 errors

Are you absolutely sure that you are compiling the exact code that you posted?


Cheers!

Z

Is this your full code?'

The class BallMover should not be static. Make it non static. That would resolve the issue