How can I make this paddle move in my Pong Game?

Question

In java I am trying to create a pong game and so far I have a moving ball that bounces off the walls and a paddle that stays in the same place. What code can I add to make the mouse move the paddle. I want the mouse to click and drag the paddle. I also want the ball to bounce off the paddle. Please help me and give me advice.

import javax.swing.*;
import java.awt.*;


public class Pong2 extends JFrame implements Runnable{

  int ball_x, ball_y, ball_dx, ball_dy, paddle_y;
  int ball_r;

  int x_left, x_right, y_top, y_bottom;

  /**
   * Constructor
   */
  public Pong2(){
    init();

  }

  /**
   * this is where we set up the UI
   */
  protected void init(){
    this.setSize(300,300);
    this.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);     

    ball_x = this.getWidth()/2;
    ball_y = this.getHeight()/2;

    ball_dx = ball_dy = 2;

    ball_r = 30;
     paddle_y = 20;

    this.setVisible(true);
    getFocus(this);

    x_left = this.getInsets().left;
    x_right = this.getWidth() - this.getInsets().right - ball_r;
    y_top = this.getHeight() - this.getInsets().top + ball_r/3;
    y_bottom = this.getInsets().bottom + ball_r;

  }

  /**
   * helper method which we use to get the focus
   */
  public void getFocus(final JFrame frame)
  {
      EventQueue.invokeLater(new Runnable() {
              public void run() {
                  frame.requestFocus();
              }
          });
  }

  /**
   * implementation of the Runnable interface to be able to move the ball, etc.
   */
  public void run(){

    while(true){

      ball_x += ball_dx;
      if(ball_x <= x_left || ball_x >= x_right){
        ball_dx *=-1;
        ball_x += (2*ball_dx);
      }

      ball_y += ball_dy;
      if(ball_y <= y_bottom || ball_y >= y_top){
        ball_dy *=-1;
        ball_y += (2*ball_dy);
      }

      repaint();

      try{
        Thread.sleep(100);
      }catch(InterruptedException ex){
        System.out.println(ex);
      }
    }
  }

  /**
   * all rendering occurs here
   */
  public void paint(Graphics g){

    g.setColor(Color.white);
    g.fillRect(0,0,this.getWidth(),this.getHeight());

    g.setColor(Color.red);
    g.fillOval(ball_x,ball_y, ball_r, ball_r);

    g.setColor(Color.blue);
    g.fillRect(30,40,10,50);

  }

  /**
   * entry point into the program
   */
  public static void main(String[] args){
    // create the class
    Pong2 application = new Pong2();
    new Thread(application).start();

  }

}

Answer 1

You should look into a MouseListener. It responds to:

• When the user clicks
• When the user enters the area being listened to
• When the user exits the area being listened to
• When the user presses a mouse button down
• When the user releases that pressed mouse button

to implement it, simply do

Component.addMouseListener(new MouseListener(){
        @Override
        public void mouseClicked(MouseEvent e){
        }
        @Override
        public void mouseEntered(MouseEvent arg0) {
        }
        @Override
        public void mouseExited(MouseEvent arg0) {
        }
        @Override
        public void mousePressed(MouseEvent arg0) {
        }
        @Override
        public void mouseReleased(MouseEvent arg0) {
        }