Hello, i am trying to add a keyboard event listener to my Jpanel. But i am having no sucess.

This is my board.java

package snake;
import java.applet.Applet;
import java.awt.*;
import java.awt.event.*;
import java.awt.geom.*;
import java.awt.image.ImageObserver;
import java.util.logging.Level;
import java.util.logging.Logger;
import javax.swing.ImageIcon;
import javax.swing.JComponent;
import java.awt.Image;
import javax.swing.JPanel;
import java.awt.event.ActionEvent;
import java.awt.event.ActionListener;
import java.awt.event.KeyAdapter;
import java.awt.event.KeyEvent;


public class board extends JPanel implements KeyListener
{
      Image body;
      Image head;
      int WIDTH = 300;
      int HEIGHT = 300;
      int ALL_DOTS = 900;
      int Dot_Size = 10;
      int x[] = new int[ALL_DOTS];
      int y[] = new int[ALL_DOTS];
      int dots;
      int sleep = 200;
      boolean start = true;
      boolean right = true;
      boolean left = false;
      boolean up = false;
      boolean down = false;
      

      public board()
      {
        setBackground(Color.black);
        requestFocus();
        addKeyListener(this);
        
        dots = 3;
        ImageIcon head_image = new ImageIcon(this.getClass().getResource("reddot.png"));
        ImageIcon body_image = new ImageIcon(this.getClass().getResource("greendot.png"));
        
        head = head_image.getImage();
        body = body_image.getImage();

        start();
        
      }
            

      public void start()
      {
          for (int z = 0; z < dots; z++) {
            x[z] = 50 - z*Dot_Size;
            y[z] = 50;
      }
          

      }
      public void GameOver(Graphics g)
      {
        String msg = "Game Over";
        Font small = new Font("Helvetica", Font.BOLD, 14);
        FontMetrics metr = this.getFontMetrics(small);

        g.setColor(Color.white);
        g.setFont(small);
        g.drawString(msg,(150-metr.stringWidth(msg)/2),(300/2));
       }

      public void collision()
      {
            if (x[0] > WIDTH)
            {
                start=false;
            }
      }


      public void paint(Graphics g)
      {
          if (start)
          {
              super.paint(g);
                for (int z = 0; z < dots; z++) {
                    if (z == 0) {
                        g.drawImage(head, x[z], y[z], this);
                    } else {
                        g.drawImage(body, x[z], y[z], this);
                    }
                }


            try {
                Thread.sleep(sleep);
            } catch (InterruptedException ex) {
                Logger.getLogger(board.class.getName()).log(Level.SEVERE, null, ex);
            }

            collision();
            move();
          
          }
          else GameOver(g);
       
        
      
       }


       public void move()
       {
           for (int z = dots; z > 0; z--)
           {
                x[z] = x[(z - 1)];

           }
           if (right)
           {
                x[0] += Dot_Size;
           }                        
            repaint();    
       }

    public void keyTyped(KeyEvent e) {
       System.out.println("Hello");
    }

    public void keyPressed(KeyEvent e) {
        System.out.println("Hello");
    }

    public void keyReleased(KeyEvent e) {
        System.out.println("Hello");
    }




}

this is my main.java

package snake;
import java.applet.Applet;
import java.awt.Color;
import java.awt.event.KeyListener;
import javax.swing.JFrame;
public class Main extends JFrame {

    public Main() {


        add(new board());
        setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
        setSize(320, 340);
        setLocationRelativeTo(null);
        setTitle("Snake");
        setFocusable(true); 
        setResizable(false);
        setVisible(true);
    }

    public static void main(String[] args) {
        new Main();
    }





}

i have now changed board.java to

package snake;
import java.applet.Applet;
import java.awt.*;
import java.awt.event.*;
import java.awt.geom.*;
import java.awt.image.ImageObserver;
import java.util.logging.Level;
import java.util.logging.Logger;
import javax.swing.ImageIcon;
import javax.swing.JComponent;
import java.awt.Image;
import javax.swing.JPanel;
import java.awt.event.ActionEvent;
import java.awt.event.ActionListener;
import java.awt.event.KeyAdapter;
import java.awt.event.KeyEvent;


public class board extends JPanel 
{
      Image body;
      Image head;
      int WIDTH = 300;
      int HEIGHT = 300;
      int ALL_DOTS = 900;
      int Dot_Size = 10;
      int x[] = new int[ALL_DOTS];
      int y[] = new int[ALL_DOTS];
      int dots;
      int sleep = 200;
      boolean start = false;
      boolean gameover = false;
      boolean right = true;
      boolean left = false;
      boolean up = false;
      boolean down = false;
      

      public board()
      {
        addMouseListener(new Mouse());
        addKeyListener(new Keyboard());
       
        dots = 3;
        ImageIcon head_image = new ImageIcon(this.getClass().getResource("reddot.png"));
        ImageIcon body_image = new ImageIcon(this.getClass().getResource("greendot.png"));
        head = head_image.getImage();
        body = body_image.getImage();
        start();
        
      }


      public void start()
      {
              for (int z = 0; z < dots; z++)
              {
                x[z] = 50 - z*Dot_Size;
                y[z] = 50;
              }
      }

      public void paint(Graphics g)
      {
         
            if(start)
            {
                  super.paint(g);
                    for (int z = 0; z < dots; z++) {
                        if (z == 0) {
                            g.drawImage(head, x[z], y[z], this);
                        } else {
                            g.drawImage(body, x[z], y[z], this);
                        }
                    }


                try {
                    Thread.sleep(sleep);
                } catch (InterruptedException ex) {
                    Logger.getLogger(board.class.getName()).log(Level.SEVERE, null, ex);
                }

                collision();
                move();
            }
            else if (!gameover)
            {
                    String msg = "Click to start";
                    Font small = new Font("Helvetica", Font.BOLD, 14);
                    FontMetrics metr = this.getFontMetrics(small);

                    g.setColor(Color.white);
                    g.setFont(small);
                    g.drawString(msg,(150-metr.stringWidth(msg)/2),(300/2));

            }
            else
            {
                String msg = "Game Over";
                Font small = new Font("Helvetica", Font.BOLD, 14);
                FontMetrics metr = this.getFontMetrics(small);
                g.setColor(Color.white);
                g.setFont(small);
                g.drawString(msg,(150-metr.stringWidth(msg)/2),(300/2));
            }
       }


       public void move()
       {
           for (int z = dots; z > 0; z--)
           {
                x[z] = x[(z - 1)];

           }
           if (right)
           {
                x[0] += Dot_Size;
           }
            repaint();
           
       }

      public void collision()
      {
            if (x[0] > WIDTH)
            {
                start=false;
                gameover=true;

                
            }
      }



    public class Keyboard implements KeyListener
    {
        public void keyTyped(KeyEvent e) {
            System.out.println("yes");
        }

        public void keyPressed(KeyEvent e) {
            System.out.println("yes");
        }

        public void keyReleased(KeyEvent e) {
            System.out.println("yes");
        }
    }








    public class Mouse implements MouseListener
    {
        public void mousePressed(MouseEvent e)
        {
           start = true;
           repaint();
        }

        public void mouseClicked(MouseEvent e) {}

        public void mouseReleased(MouseEvent e) {}

        public void mouseEntered(MouseEvent e) {}

        public void mouseExited(MouseEvent e) {}
     }




     



}

and still i get nothing. What am i missing

Make the following code change

public board()      {   
		setFocusable(true);
		addMouseListener(new Mouse());       
		addKeyListener(new Keyboard());

Remove the setFocusable(true) from the main.

Edited 6 Years Ago by thomas_naveen: typo

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