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Adding KeyListener in Java

This a small game. Here I made 2 rectangles of same size. I want to move them whenever a person presses a key on keyboard. But I dont know how to add KeyListener. I had looked through previous answers here but I couldn't catch my mistake. I even searched the google but no clue. This is my code:

import java.awt.*;
import javax.swing.*;
import java.awt.event.*;
class PongGame extends JComponent implements ActionListener
int ballX = 200;
int ballY = 340;
short ballX_Direction = 1;
short ballY_Direction = 1;
static int Direction1 = 300;
static int Direction2 = 300;
private static keyListener move;
public static void main(String args)
JFrame frame = new JFrame("Pong Game");
PongGame game = new PongGame();
frame.add(game);
frame.pack();
frame.setSize(900,700);
frame.setLocationRelativeTo(null);
frame.setVisible(true);
frame.setResizable(false);
Timer t = new Timer(2,game);
t.start();

public void paintComponent(Graphics g)
g.setColor(new Color(0,242,237));
g.fillRect(0,0,900,700);
g.setColor(Color.black);int a = 60;
for(int i = 1;i<=5;i++)
g.fillRect(444,0+a,12,65);
a = a+125;

g.setColor(Color.blue);
g.fillRect(100,Direction2,15,100);
g.fillRect(770,Direction1,15,100);
g.setColor(Color.red);
g.fillOval(ballX,ballY,20,20);
repaint();

public void actionPerformed(ActionEvent e)
ballX = ballX + ballX_Direction;
ballY = ballY + ballY_Direction;
if(ballY >= 660) ballY_Direction = -1;
if(ballY <= 0) ballY_Direction = 1;

if(ballX >= 444-20 && ballY >= 60-20 && ballX <= 444-20 && ballY <= 185-20)
ballX_Direction = -1;

if(ballX >= 444-20 && ballY >= 185-20 && ballX <= 444-20 && ballY <= 250-20)
ballX_Direction = -1;

if(ballX >= 444-20 && ballY >= 250-20 && ballX <= 444-20 && ballY <= 375-20)
ballX_Direction = -1;

if(ballX >= 444-20 && ballY >= 375-20 && ballX <= 444-20 && ballY <= 500-20)
ballX_Direction = -1;

if(ballX >= 444-20 && ballY >= 500-20 && ballX <= 444-20 && ballY <= 625-20)
ballX_Direction = -1;

repaint();



class keyListener implements KeyListener
public void keyPressed(KeyEvent e)
int key = e.getKeyCode();
if(key == KeyEvent.VK_UP)

PongGame.Direction1 = PongGame.Direction1 - 25

if(key == KeyEvent.VK_DOWN)

PongGame.Direction1 = PongGame.Direction1 - 25;

if(key == '1')

PongGame.Direction2 -= 25;

if(key == '4')

PongGame.Direction2 += 25;


public void keyReleased(KeyEvent e)
public void keyTyped(KeyEvent e)



KeyListener

1 Answer
1

JFrame has a method for that:

frame.addKeyListener(new keyListener());


It needs to be added to a GUI part, in particular a part that has focus, since that is the thing the OS tells about input.

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