如何通过按键在 java 中重新开始游戏？

Question

我是 java 的新手，不知道如何重新开始我的游戏。我看过其他帖子，但 none work/I 无法找出代码。如何编写代码以按 "y" 或 "n" 重新开始游戏？我试过用代码重置它，但它不理解代码。也许我没有导入正确的东西？

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


public class Game extends JPanel
{
   private static final int FRAME = 400;
   private static final Color BACKGROUND = new Color(50, 150, 255);  
   private BufferedImage myImage;
   private Graphics myBuffer;
   private Ball ball;
   private Target tar;
   private Timer t; 
   private int hits;


   public Game()
   {

      // instantiate myImage and myBuffer
      myImage =  new BufferedImage(FRAME, FRAME, BufferedImage.TYPE_INT_RGB);
  myBuffer = myImage.getGraphics();
  myBuffer.setColor(BACKGROUND);
  myBuffer.fillRect(0, 0, FRAME,FRAME);

  // Randomly places the ball in the middle of the screen away from any edge
  int xPos = (int)(Math.random()*(FRAME-100) + 50);
  int yPos = (int)(Math.random()*(FRAME-100)+ 50);


   // instantiate the Ball object

  ball = new Ball(xPos, yPos, 50, Color.BLACK);

  // instantiate the target object
   tar = new Target();

  // instantiate the hits counter object
  hits =0;

  // instantiate the Timer object and start it
  // Screen refreshes every 5 milliseconds (1/200 second)
  t = new Timer(5, new Listener());
  t.start();
  addKeyListener(new Key());
  setFocusable(true);

   }


    /**
   * Draws the current state of the image on the screen.
   */ 
   public void paintComponent(Graphics g)
   {
     g.drawImage(myImage, 0, 0, getWidth(), getHeight(), null);  
   }




   /**
    * The target jumps around the screen, and the ball 
    * tries to catch it. Every time they collide, the hit increases
    * by one. Once the score is greater than 5, the game stops.
    */
       private class Listener implements ActionListener
   {
      public void actionPerformed(ActionEvent e)
      { 
         myBuffer.setColor(BACKGROUND);
     myBuffer.fillRect(0,0,FRAME,FRAME);
     collide(ball, tar);
     ball.draw(myBuffer);
     tar.draw(myBuffer);
     tar.bounce();
     myBuffer.setColor(Color.BLACK);
     myBuffer.setFont(new Font("Monospaced", Font.BOLD, 24));
     myBuffer.drawString("Count: " + hits, FRAME - 150, 25);
     if(hits==5)
     {
       t.stop();
     }

     repaint();
  }


    }

     private void collide(Ball b, Target tar)
   {
      double d = distance(b.getX(), b.getY(), tar.getX(), tar.getY()); 

      if (d <= b.getRadius() + tar.getRadius())
  {

    tar.jump(FRAME, FRAME);     
    hits ++;    
  } 

 }





   /**
 * Finds the distance between two points using the distance formula
 * @param x1 the x-coordinate of the first object
 * @param y1 the y-coordinate of the first object
 * @param x2 Comment...
 * @param y2 Comment...
 * @return
 */
       private double distance(double x1, double y1, double x2, double y2)
   {
      double dist = 0;      

      dist = Math.sqrt( Math.pow(x2 - x1, 2) + Math.pow(y2 - y1, 2));


      return dist;   
   }

 //keys move the ball
  private class Key extends KeyAdapter
 {
  public void keyPressed(KeyEvent e)
  {

    if(ball.getY() > 15)
     {
      if(e.getKeyCode() == KeyEvent.VK_W)
      ball.setY( ball.getY()-30 );
     }
    if(ball.getY() < 385)
    {
      if(e.getKeyCode() == KeyEvent.VK_S)
      ball.setY( ball.getY()+30 );
    } 
    if(ball.getX() > 15)
    {
      if(e.getKeyCode() == KeyEvent.VK_A)
      ball.setX( ball.getX()-30 );
    } 
    if(ball.getX() < 385)
    {
      if(e.getKeyCode() == KeyEvent.VK_D)
      ball.setX( ball.getX()+30 );
    } 

      }
    }
 }

Answer 1

我建议您使用键盘 class。这是我的旧版本：

package FishGame;

import java.awt.event.KeyEvent;
import java.awt.event.KeyListener;

/**
 *
 * @author alexr
 */
public class Keyboard implements KeyListener {
    private static boolean[] keys = new boolean[1024];

    public static boolean isKeyDown(int keyCode) {
        if(0 <= keyCode && keyCode < keys.length) 
            return keys[keyCode];

        return false;
    }

    @Override
    public void keyPressed(KeyEvent e) {
        int keyCode = e.getKeyCode();
        if(0 <= keyCode && keyCode < keys.length) 
            keys[keyCode] = true;
    }

    @Override
    public void keyReleased(KeyEvent e) {
        int keyCode = e.getKeyCode();
        if(0 <= keyCode && keyCode < keys.length) 
            keys[keyCode] = false;
    }

    @Override
    public void keyTyped(KeyEvent e) {}

}

然后像这样导入您在游戏中使用的几个键：

import static java.awt.event.KeyEvent.VK_R;

然后在你的游戏状态中使用它：

if(Keyboard.isKeyDown(VK_R) && Main.state != Main.STATE.MENU) 
    Main.restartGame();

如何通过按键在 java 中重新开始游戏？

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