Java 当按下我的射击键时，子杀手游戏不能正常射击

我有以下程序，这是一个次级杀手游戏，我有一个问题。我怎么让船在我按下向下键时发射炸弹？到目前为止，我已经多次发布了它。我可以发射第一颗炸弹，但当我试着发射第二颗时，第一颗炸弹消失了，它不会继续它的方式。我在这件事上纠缠了将近两天，请帮帮我

我将向您提供SSCCE代码。 这是一个叫做SubKillerPanel的类，基本上一切都在这里，船在这里，炸弹在这里，潜艇在这里

import java.awt.event.*;
import javax.swing.*;
import java.awt.Graphics;
import java.awt.Color;

public class SubKillerPanel extends JPanel {
    private static final long serialVersionUID = 1L;
    private Timer timer;
    private int width, height;
    private Boat boat;
    private Bomb bomb;
    private Submarine sub;

    public SubKillerPanel() {
        setBackground(Color.WHITE);
        ActionListener action = new ActionListener() {
            public void actionPerformed(ActionEvent evt) {
                if (boat != null) {
                    boat.updateForNewFrame();
                    bomb.updateForNewFrame();
                    sub.updateForNewFrame();
                }
                repaint();
            }
        };

        timer = new Timer( 20, action );
        addMouseListener( new MouseAdapter() {
            public void mousePressed(MouseEvent evt) {
                requestFocus();
            }
        }
);
        addFocusListener( new FocusListener() {
            public void focusGained(FocusEvent evt) {
                timer.start();
                repaint();
            }

            public void focusLost(FocusEvent evt) {
                timer.stop();
                repaint();
            }
        } 
);
        addKeyListener( new KeyAdapter() {
            public void keyPressed(KeyEvent evt) {
                int code = evt.getKeyCode(); // ce tasta a fost apasata
                if (code == KeyEvent.VK_LEFT) {
                    boat.centerX -= 15;
                }
                else 
                    if (code == KeyEvent.VK_RIGHT) {
                        boat.centerX += 15;
                    }
                    else 
                        if (code == KeyEvent.VK_DOWN) {
                            if (bomb.isFalling == false)
                                bomb.isFalling = true;
                                bomb.centerX = boat.centerX;
                                bomb.centerY = boat.centerY;
                        }
            }
        } 
);
}

    public void paintComponent(Graphics g) {
        super.paintComponent(g);
        if (boat == null) {

            width = getWidth();
            height = getHeight();
            boat = new Boat();
            sub = new Submarine();
            bomb = new Bomb();
        }

        if (hasFocus())
            g.setColor(Color.CYAN);
        else {
            g.setColor(Color.RED);
            g.drawString("CLICK TO ACTIVATE", 20, 30);
            g.setColor(Color.GRAY);
        }

        g.drawRect(0,0,width-1,height-1);
        g.drawRect(1,1,width-3,height-3);
        g.drawRect(2,2,width-5,height-5);
        boat.draw(g);
        sub.draw(g);
        bomb.draw(g);
}

    private class Boat {
        int centerX, centerY;

        Boat() {
            centerX = width/2;
            centerY = 80;
        }

        void updateForNewFrame() {
            if (centerX < 0)
                centerX = 0;
            else 
                if (centerX > width)
                    centerX = width;
        }

        void draw(Graphics g) {
            g.setColor(Color.blue);
            g.fillRoundRect(centerX - 40, centerY - 20, 80, 40, 20, 20);
        }       
}

    private class Bomb {
        int centerX, centerY; 
        boolean isFalling; 

        Bomb() {
            isFalling = false;
        }

        void updateForNewFrame() {
            if (isFalling) {
                if (centerY > height) {
                    isFalling = false;
                }
                else 
                    if (Math.abs(centerX - sub.centerX) <= 36 && Math.abs(centerY - sub.centerY) <= 21) {
                        sub.isExploding = true;
                        sub.explosionFrameNumber = 1;
                        isFalling = false; // Bomba reapare in barca
                    }
                    else {
                        centerY += 10;
                    }
            }   
        }

        void draw(Graphics g) { 
            if ( !isFalling ) {
                centerX = boat.centerX;
                centerY = boat.centerY + 23;
            }
             g.setColor(Color.RED);
             g.fillOval(centerX - 8, centerY - 8, 16, 16); 
        }
} 

    private class Submarine {
        int centerX, centerY;
        boolean isMovingLeft;
        boolean isExploding;
        int explosionFrameNumber;

        Submarine() {
            centerX = (int)(width*Math.random());
            centerY = height - 40;
            isExploding = false;
            isMovingLeft = (Math.random() < 0.5);
        }

        void updateForNewFrame() {
            if (isExploding) {
                explosionFrameNumber++;
                if (explosionFrameNumber == 30) {
                    centerX = (int)(width*Math.random());
                    centerY = height - 40;
                    isExploding = false;
                    isMovingLeft = (Math.random() < 0.5);
                }
            }
            else {
                if (Math.random() < 0.04) {
                    isMovingLeft = ! isMovingLeft;
                }
                if (isMovingLeft) {
                    centerX -= 5;
                    if (centerX <= 0) {
                        centerX = 0;
                        isMovingLeft = false;
                    }
                }
                else {
                    centerX += 5;
                    if (centerX > width) {
                        centerX = width;
                        isMovingLeft = true;
                    }
                }
            }
        }

        void draw(Graphics g) {
            g.setColor(Color.BLACK);
            g.fillOval(centerX - 30, centerY - 15, 60, 30);
            if (isExploding) {
                g.setColor(Color.YELLOW);
                g.fillOval(centerX - 4*explosionFrameNumber, centerY - 2*explosionFrameNumber, 
                        8*explosionFrameNumber, 4*explosionFrameNumber);
                g.setColor(Color.RED);
                g.fillOval(centerX - 2*explosionFrameNumber, centerY - explosionFrameNumber/2, 
                        4*explosionFrameNumber, explosionFrameNumber);
            }
        }
    }

}

---

在任何时候，图形都只能跟踪一颗炸弹。您应该构建一个炸弹集合，并在按下向下键时实例化一个新的炸弹，然后遍历所有炸弹集合并根据需要绘制它们

所以，不是私人炸弹

您将拥有

私人列表炸弹

之后，无论你在哪里更新单个
炸弹
，你都可以使用for循环遍历
炸弹列表
，并让它们全部更新，然后如果它们不再被绘制，则将它们从列表中删除。
我明白你的意思，但我不确定怎么做。谢谢你的回答，我会继续努力。@MrSilent你应该仔细阅读关于列表的教程。在此之后，考虑if语句：<代码> if（code＝KyEngv.VkYON）{ <代码> >，在这里，基本上是在炸弹落下时询问它。但是只有一个炸弹，如果它已经掉了，那么VKYLUN什么也不做。你应该做的只是创建一个<代码>新炸弹（）。

然后就让它倒下。根据您所描述的，您的逻辑的其余部分很好，您只需要实现多个炸弹，而不是使用单个炸弹。

import javax.swing.JFrame;

public class SubKiller {
    public static void main(String[] args) {
        JFrame window = new JFrame("Sub Killer Game");
        SubKillerPanel content = new SubKillerPanel();
        window.setContentPane(content);
        window.setSize(700, 700);
        window.setLocation(0,0);
        window.setDefaultCloseOperation( JFrame.EXIT_ON_CLOSE );
        window.setResizable(false);
        window.setVisible(true);
    }
}