我的java（JFrame）播放器移动脚本赢得'；行不通

我正在制作一个自上而下的2d生存游戏，玩家必须躲避敌人的炮弹才能生存，但我遇到了一个问题，可能会稍微影响我第一个真正java项目的游戏性，这个问题是玩家不能以任何形式移动，如果炮弹已经实现，那么玩家在产卵到这个世界后会立即失败

代码如下：

package maximiza;

import java.awt.*;
import java.awt.event.KeyEvent;

import javax.swing.*;

public class Game extends JFrame {

    private static final long serialVersionUID = 1L;

    public int xPosition = 240;
    public int yPosition = 240;
    public int speed = 10;
    
    public int playerSize = 20;
    
    public Game()
    {
        setTitle("Maximiza");
        setSize(500, 500);
        setVisible(true);
        setDefaultCloseOperation(EXIT_ON_CLOSE);
    }
    
    public void paint(Graphics g)
    {
        g.setColor(Color.yellow);
        g.fillRect(xPosition, yPosition, playerSize, playerSize);
    }
    
    public void init()
    {
        addKeyListener(new Input(this));
    }
    
    public static void main(String [] args)
    {
        boolean living = true;
        Game g = new Game();
        g.init();
        while(living)
        {
            g.paint(null);
        }
    }

    public void keyPressed(KeyEvent e) {
        int key = e.getKeyCode();
    
        if(key == KeyEvent.VK_UP) {
            yPosition += speed;
        } else if(key == KeyEvent.VK_DOWN) {
            yPosition -= speed;
        }
    }
    
    public void keyReleased(KeyEvent e) {
        
    }
}

输入脚本：

package maximiza;

import java.awt.event.KeyAdapter;
import java.awt.event.KeyEvent;

public class Input extends KeyAdapter {
    
    Game game;
    
    public Input(Game game) {
        this.game = game;
    }
    
    public void keyPressed(KeyEvent e) {
        game.keyPressed(e);
    }
    
    public void keyReleased(KeyEvent e) {
        game.keyReleased(e);
    }
}

---

感谢您提供的帮助。

首先有几个问题：

不要不必要地扩展

JFrame

，您可以创建一个

JPanel

，只需将其添加到

JFrame

永远不要重写

paint

，而是像

JPanel

一样使用

JComponent

并重写

paintComponent

，不要忘记调用

super.paintComponent

作为重写方法中的第一条语句。另外，切勿直接调用

paint

或

paintComponent

，而应使用

JComponent#repaint（）

阅读上述内容

所有Swing组件都应在上创建

不要调用

setSize

使用适当的布局管理器，在需要向布局管理器提供尺寸提示的地方覆盖

getPreferredSize

，然后在将框架设置为可见之前调用

JFrame#pack（）

我建议使用而不是

KeyListener

不能在与UI组件相同的线程上使用while循环，否则UI将冻结而不更新，而是使用

我自己正在创建我自己的，您可以将其作为未来努力或可能面临的问题的参考，例如添加游戏循环、将游戏对象逻辑与游戏面板/屏幕分离、消除锯齿等

下面是您的代码，其中包含上述建议以帮助您入门，以及一些注释，指出您还可以添加或更改哪些内容，以使您的游戏在发展过程中更具可重用性：

要重新迭代，您可以进行更多的更改（我已经对代码进行了注释，以提供提示），但我没有为您执行这些操作，因为这只会是一个扰流器！）

import java.awt.*;
import java.awt.event.ActionEvent;
import java.awt.event.KeyEvent;
import javax.swing.*;

public class Game {

    private GamePanel gamePanel;

    public Game() {
        createAndShowUI();
    }

    public static void main(String[] args) {
        SwingUtilities.invokeLater(Game::new);
    }

    private void createAndShowUI() {
        JFrame frame = new JFrame("Maximiza");
        frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);

        gamePanel = new GamePanel();

        gamePanel.getInputMap(JComponent.WHEN_IN_FOCUSED_WINDOW).put(KeyStroke.getKeyStroke(KeyEvent.VK_UP, 0, false), "UP pressed");
        gamePanel.getActionMap().put("UP pressed", new AbstractAction() {
            @Override
            public void actionPerformed(ActionEvent e) {
                gamePanel.moveUp(); // this would be something like gameObject.moveDown()
            }
        });
        gamePanel.getInputMap(JComponent.WHEN_IN_FOCUSED_WINDOW).put(KeyStroke.getKeyStroke(KeyEvent.VK_DOWN, 0, false), "DOWN pressed");
        gamePanel.getActionMap().put("DOWN pressed", new AbstractAction() {
            @Override
            public void actionPerformed(ActionEvent e) {
                gamePanel.moveDown(); // this would be something like gameObject.moveDown()
            }
        });

        frame.add(gamePanel);
        frame.pack();
        frame.setVisible(true);

        // a more approrpiate game loop can be used as we only need to call repaint 60 times per second not more or less.
        // fixed step: https://stackoverflow.com/questions/13739693/java-swing-based-game-framework-any-advice/13740162#13740162
        // variable step: https://github.com/davidkroukamp/SwingGameLibrary/blob/main/src/za/co/swinggamelibrary/GameLoop.java
        Thread gameLoop = new Thread(() -> {
            boolean living = true;
            while (living) {
                gamePanel.repaint();

                // lets sleep a bit not to eat up processor time unnecessarily needs a better implementation of a game loop but thread sleep will do okay for now
                try {
                    Thread.sleep(16);
                } catch (InterruptedException ex) {
                }
            }
        });
        gameLoop.start();
    }

    public class GamePanel extends JPanel {

        // these properties should go into its own game object which is separated from the game panel, and can simply be added to the game panel via a list
        // and in the paintComponent method you simply iterate all the game objects and draw them
        // https://github.com/davidkroukamp/SwingGameLibrary-Samples/blob/main/sample1/src/sgltest/Player.java
        public int xPosition = 240;
        public int yPosition = 240;
        public int speed = 10;

        public int playerSize = 20;

        @Override
        protected void paintComponent(Graphics g) {
            super.paintComponent(g);

            // can make graphics look better too using some rendering hints https://github.com/davidkroukamp/SwingGameLibrary/blob/main/src/za/co/swinggamelibrary/Graphics2DHelper.java
            // should move to game object inside a render(Graphics2D g2d) method which gets called for each game object passing in the graphics parameter
            g.setColor(Color.yellow);
            g.fillRect(xPosition, yPosition, playerSize, playerSize);
        }

        @Override
        public Dimension getPreferredSize() {
            return new Dimension(500, 500);
        }

        // these methods would go into the game object class too under a single move methid which checks booleans on whether to move up or down or whatever
        public void moveUp() {
            yPosition -= speed; // this could probably just set a boolean which your game object will check and update its position accordingly via a move() method thats called before gamePanel.repaint in the thread
        }

        public void moveDown() {
            yPosition += speed; // this could probably just set a boolean which your game object will check and update its position accordingly via a move() method thats called before gamePanel.repaint in the thread
        }

    }
}