공 나와서 부딪히면 끝나는 게임 공 여러개 소환 가능 + 시간 지나면 공 추가

ballGame.java

package com.company;

import java.awt.*;
import java.awt.event.KeyEvent;
import java.awt.event.KeyListener;
import java.awt.event.WindowEvent;
import java.awt.event.WindowListener;
import java.util.ArrayList;

public class Report2 extends Frame implements WindowListener, KeyListener, Runnable {

  class Enemy {
    int x = 200;
    int y = 200;
    int dx;
    int dy;

    public Enemy() {
      this.dx = (int) (Math.random() * 20 - 10);
      this.dy = (int) (Math.random() * 20 - 10);
    }
  }

  private ArrayList<Enemy> enemys = new ArrayList<>();
  Thread th;

  int jx = 200, jy = 350;
  boolean keyL = false, keyR = false, keyU = false, keyD = false;
  boolean isFinish = false;
  Graphics vg;
  Image vi;
  int timeCnt = 0;

  public Report2() {
    super("Report2");
    addWindowListener(this);
    addKeyListener(this);
    setSize(400, 400);
    setResizable(false);
    setVisible(true);

    for (int i = 0; i < 2; i++) {
      enemys.add(new Enemy());
    }

    th = new Thread(this);
  }

  public void update(Graphics g) {
    if (vi == null) {
      vi = createImage(400, 400);
      vg = vi.getGraphics();
    }
    paint(vg);
    g.drawImage(vi, 0, 0, this);
  }

  public void paint(Graphics g) {
    g.setColor(Color.black);
    g.fillRect(0, 0, 400, 400);
    g.setColor(Color.red);
    g.fillRect(jx, jy, 10, 10);
    g.setColor(Color.blue);

    for (Enemy enemy : enemys) {
      g.fillOval(enemy.x, enemy.y, 10, 10);
    }
  }

  @Override
  public void run() {
    while (!isFinish) {
      try {
        Thread.sleep(30);
        timeCnt += 1;
        System.out.println("cnt: " + timeCnt + " enemy len: " + enemys.size());
      } catch (Exception e) {
      }

      if (keyL) jx -= 5;
      if (keyR) jx += 5;
      if (keyU) jy -= 5;
      if (keyD) jy += 5;
      if (jx < 0) jx = 0;
      if (jx >= 400) jx = 400 - 20;
      if (jy < 0) jy = 0;
      if (jy >= 400) jy = 400 - 20;

      for (Enemy enemy : enemys) {
        enemy.x += enemy.dx;
        enemy.y += enemy.dy;

        if (enemy.x < 0 || enemy.x > 400) enemy.dx *= -1;
        if (enemy.y < 0 || enemy.y > 400) enemy.dy *= -1;
        if (Math.abs(enemy.x - jx) < 10 && Math.abs(enemy.y - jy) < 10) isFinish = true;
      }

      if (timeCnt % 100 == 0) {
        enemys.add(new Enemy());
      }

      repaint();
    }
  }


  @Override
  public void windowOpened(WindowEvent e) {
  }

  @Override
  public void windowDeactivated(WindowEvent e) {
  }

  @Override
  public void windowActivated(WindowEvent e) {
  }

  @Override
  public void windowDeiconified(WindowEvent e) {
  }

  @Override
  public void windowIconified(WindowEvent e) {
  }

  @Override
  public void windowClosed(WindowEvent e) {
  }

  @Override
  public void windowClosing(WindowEvent e) {
    System.exit(0);
  }

  @Override
  public void keyTyped(KeyEvent e) {
  }

  public void keyPressed(KeyEvent e) {
    switch (e.getKeyCode()) {
      case KeyEvent.VK_SPACE: {
        th.start();
      }
      break;
      case KeyEvent.VK_LEFT:
        keyL = true;
        break;
      case KeyEvent.VK_RIGHT:
        keyR = true;
        break;
      case KeyEvent.VK_UP:
        keyU = true;
        break;
      case KeyEvent.VK_DOWN:
        keyD = true;
        break;
    }
  }

  public void keyReleased(KeyEvent e) {
    switch (e.getKeyCode()) {
      case KeyEvent.VK_LEFT:
        keyL = false;
        break;
      case KeyEvent.VK_RIGHT:
        keyR = false;
        break;
      case KeyEvent.VK_UP:
        keyU = false;
        break;
      case KeyEvent.VK_DOWN:
        keyD = false;
        break;
    }
  }

  public static void main(String[] args) {
    Report2 rp = new Report2();
  }
}