为什么我的平台不绘制当使用数组列表的 for 循环(访问多个平台)时

Why doesn't my Platform draw When using for loops (to access multiple platforms) with array lists

这些都是我的 类,我正在尝试用数组列表来制作平台游戏来容纳我的平台,这样我就可以随时随地添加更多平台。出于某种原因,它没有绘制平台。

有人可以帮我解决这个问题或给我一个替代方案吗?

注意:有些变量和方法我还没有使用过,或者在我重新创建代码时忘记删除了。 包游戏;

import Game.Frame;

public class Main {
        public static void main(String[] args) {
            new Frame();
        }
}

    package Game;

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

public class Frame extends JFrame {
    GamePanel panel;
    public Frame() {
        panel = new GamePanel();
        this.add(panel);
        this.setTitle("Platformer Game");
        this.setResizable(false);
        this.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
        this.pack();
        this.setLocationRelativeTo(null);
        this.setVisible(true);
    }
}
package Game;

import javax.swing.*;
import java.awt.*;
import java.awt.event.*;
import java.util.*;
import java.util.Timer;

public class GamePanel extends JPanel implements ActionListener{
        Player player1;
        Map map1;
        final int SCREEN_WIDTH = 1000;
        final int SCREEN_HEIGHT = 600;
        final int PLAYER_WIDTH = 50;
        final int PLAYER_HEIGHT = 60;
        final Dimension SCREEN_SIZE = new Dimension(SCREEN_WIDTH,SCREEN_HEIGHT);
        boolean falling = false;
        boolean playing = true;
        Image backgroundImage;
        Thread gameThread;
        Image image;
        Graphics graphics;
        Timer gameTimer;
        ArrayList<Map> platform = new ArrayList<>();

        public GamePanel() {
            java.net.URL imgIcon = Main.class.getResource(
                    "/Resources/spaceImage.jpg");
            backgroundImage = new ImageIcon(imgIcon).getImage();
            newPlayer();
            newMap();

            this.setFocusable(true);
            this.setPreferredSize(SCREEN_SIZE);
            this.setOpaque(true);
            this.addKeyListener(new KeyListener(

            ) {
                @Override
                public void keyTyped(KeyEvent e) {}

                @Override
                public void keyPressed(KeyEvent e) {
                    KeyPressed(e);
                }

                @Override
                public void keyReleased(KeyEvent e) {
                    KeyReleased(e);
                }
            });
            gameTimer = new Timer();
            gameTimer.schedule(new TimerTask(){

                @Override
                public void run() {
                    player1.move();
                    repaint();
                }
            }, 0 , 17);
        }

        public void paint(Graphics g) {
            image = createImage(getWidth(),getHeight());
            graphics = image.getGraphics();
            draw(graphics);
            g.drawImage(image, 0,0, null);

        }
        public void draw(Graphics g) {
            Graphics2D g2D = (Graphics2D) g;
            g2D.drawImage(backgroundImage, 0,0, null);
            player1.paint(g);
            for(Map map1: platform) {
                map1.paint(g2D);
            }
        }
        public void KeyPressed(KeyEvent e) {
            if(e.getKeyChar()=='a') {
                player1.keyLeft = true;
            }
            if(e.getKeyChar()=='d') player1.keyRight = true;
            if(e.getKeyChar()=='s') player1.keyDown = true;
            if(e.getKeyChar()=='w') player1.keyUp = true;
        }


        public void KeyReleased(KeyEvent e) {
            if(e.getKeyChar()=='a') player1.keyLeft = false;
            if(e.getKeyChar()=='d') player1.keyRight = false;
            if(e.getKeyChar()=='s') player1.keyDown = false;
            if(e.getKeyChar()=='w') player1.keyUp = false;
        }

        public void newPlayer() {
            player1 = new Player((SCREEN_WIDTH/2)-(PLAYER_WIDTH/2), (SCREEN_HEIGHT/2)-(PLAYER_WIDTH/2), PLAYER_WIDTH, PLAYER_HEIGHT, this);
        }

        public void newMap() {
            for(int i=50;i<650;i+=50){
                platform.add(new Map(i,600,50,50));
            }
        }


        public void gameOver() {

        }


    @Override
    public void actionPerformed(ActionEvent e) {

    }
}


package Game;

import Game.GamePanel;

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

public class Player extends Rectangle{
    double velocityY = 0;
    double velocityX = 0;
    final int PLAYER_WIDTH = 50;
    final int PLAYER_HEIGHT = 50;
    static int speed = 2;
    GamePanel panel;
    boolean keyRight = false;
    boolean keyLeft = false;
    boolean keyUp = false;
    boolean keyDown = false;
    Rectangle hitbox;

    public Player(int x, int y, int PLAYERWIDTH, int PLAYERHEIGHT, GamePanel panel) {
        super(x,y,PLAYERWIDTH,PLAYERHEIGHT);
        this.panel = panel;

        hitbox = new Rectangle();
    }



    public void paint(Graphics g) {
        Graphics2D g2D = (Graphics2D) g;
        g2D.setColor(Color.red);
        g2D.fillRect(x, y, PLAYER_WIDTH, PLAYER_HEIGHT);
    }

    public void move() {
        if(keyLeft && keyRight || !keyLeft && !keyRight) {
            velocityX *= 0.8;
        }
        if(keyLeft && !keyRight) {
            velocityX--;
        }
        if(keyRight && !keyLeft) {
            velocityX++;
        }
        if(velocityX > 0 && velocityX < 0.75) velocityX = 0;
        if(velocityX < 0 && velocityX > -0.75) velocityX = 0;

        if(velocityX > 7) velocityX = 7;
        if(velocityX < -7) velocityX = -7;

        if(keyUp) {
            velocityY = -6;
        }
        velocityY += 0.3;


        y += velocityY;
        x += velocityX;

        hitbox.x = x;
        hitbox.y = y;
    }

}


package Game;

import java.awt.*;

public class Map {
    int PLATFORM_WIDTH = 600;
    int PLATFORM_HEIGHT = 150;
    int x;
    int y;
    Rectangle hitbox;
    public Map(int x, int y, int PLATFORM_WIDTH, int PLATFORM_HEIGHT) {
        this.x = x;
        this.y = y;
        this.PLATFORM_WIDTH = PLATFORM_WIDTH;
        this.PLATFORM_HEIGHT = PLATFORM_HEIGHT;

        hitbox = new Rectangle(x,y,PLATFORM_WIDTH, PLATFORM_HEIGHT);
    }

    public void paint(Graphics g) {
        Graphics2D g2D = (Graphics2D) g;
        g2D.setColor(Color.gray);
        g2D.fillRect(x,y,PLATFORM_WIDTH,PLATFORM_HEIGHT);
    }

}

因此您将屏幕高度设置为 600final int SCREEN_HEIGHT = 600;,然后将您的平台 y 位置也设置为 600platform.add(new Map(i,600,50,50));

因为它们永远不会移动,这会将它们绘制到屏幕外,所以,一个快速的解决方案是将 y 位置更改为可见范围内的某个位置,也许 550,这样你就会看到它们(首先)。

观察

有很多有趣的想法,我不确定您是否完全理解 API 的工作原理。

先看看:

这将使您更好地了解绘制系统在 Swing 中的工作原理以及您应该如何使用它。

话虽如此,Swing 默认是双缓冲的,因此您不需要自己的后备缓冲区,只需覆盖 paintComponent 并绘制到 Graphics 上下文

@Override
protected void paintComponent(Graphics g) {
    super.paintComponent(g);
    Graphics2D g2d = (Graphics2D) g.create();
    draw(g2d);
    g2d.dispose();
}

这将有助于消除一个可能的问题领域。

Swing 也不是线程安全的,因此您应该避免从事件调度线程的上下文之外为 UI(或声明 UI 所依赖的)创建日期。

您应该使用 javax.swing.Timer,而不是使用 java.util.Timer,它将在 EDT 的上下文中生成它的回调。

有关详细信息,请参阅 Concurrency in Swing and How to Use Swing Timers

gameTimer = new Timer(5, new ActionListener() {
    @Override
    public void actionPerformed(ActionEvent e) {
        player1.move();
        repaint();
    }
});
gameTimer.start();

KeyListener 因引起问题而广为人知,有更好的系统可以解决这些问题,请参阅 How to Use Key Bindings 了解更多详情。

我也不确定 Player

是怎么回事
public class Player extends Rectangle {

    double velocityY = 0;
    double velocityX = 0;
    final int PLAYER_WIDTH = 50;
    final int PLAYER_HEIGHT = 50;
    static int speed = 2;
    GamePanel panel;
    boolean keyRight = false;
    boolean keyLeft = false;
    boolean keyUp = false;
    boolean keyDown = false;
    Rectangle hitbox;

    public Player(int x, int y, int PLAYERWIDTH, int PLAYERHEIGHT, GamePanel panel) {
        super(x, y, PLAYERWIDTH, PLAYERHEIGHT);
        this.panel = panel;

        hitbox = new Rectangle();
    }

    public void paint(Graphics g) {
        Graphics2D g2D = (Graphics2D) g;
        g2D.setColor(Color.red);
        g2D.fillRect(x, y, PLAYER_WIDTH, PLAYER_HEIGHT);
    }

您从 Rectangle 扩展它,但随后您在其中创建了另一个 Rectangle,我根本不知道所有实例字段在做什么(您基本上忽略了传入的内容,有利于你的财产)

你可以做类似的事情并使用 Player 作为 hotbox 本身

public class Player extends Rectangle {

    enum Direction {
        UP, DOWN, LEFT, RIGHT
    }

    private double velocityY = 0;
    private double velocityX = 0;
    private int speed = 2;

    public Player(int x, int y, int width, int height) {
        super(x, y, width, height);
    }

    public void paint(Graphics2D g2D) {
        g2D.setColor(Color.RED);
        g2D.fill(this);
    }

可运行示例...

键绑定可以让您动脑筋,所以我修改了您的代码以支持它们(以及上述更改),让您有更好的想法。

import java.awt.Color;
import java.awt.Dimension;
import java.awt.EventQueue;
import java.awt.Graphics;
import java.awt.Graphics2D;
import java.awt.Image;
import java.awt.Rectangle;
import java.awt.event.ActionEvent;
import java.awt.event.ActionListener;
import java.awt.event.KeyEvent;
import java.awt.image.BufferedImage;
import java.util.ArrayList;
import java.util.Set;
import java.util.TreeSet;
import javax.swing.AbstractAction;
import javax.swing.ActionMap;
import javax.swing.ImageIcon;
import javax.swing.InputMap;
import javax.swing.JFrame;
import javax.swing.JPanel;
import javax.swing.KeyStroke;
import javax.swing.Timer;

public class Test {

    public static void main(String[] args) {
        new Test();
    }

    public Test() {
        EventQueue.invokeLater(new Runnable() {
            @Override
            public void run() {
                JFrame frame = new JFrame();
                frame.add(new GamePanel());
                frame.pack();
                frame.setLocationRelativeTo(null);
                frame.setVisible(true);
            }
        });
    }

    public class GamePanel extends JPanel implements ActionListener {

        protected static final int SCREEN_WIDTH = 1000;
        protected static final int SCREEN_HEIGHT = 600;
        protected static final int PLAYER_WIDTH = 50;
        protected static final int PLAYER_HEIGHT = 60;
        protected static final Dimension SCREEN_SIZE = new Dimension(SCREEN_WIDTH, SCREEN_HEIGHT);
        boolean falling = false;
        boolean playing = true;

        Player player1;
        Map map1;

        Image backgroundImage;
        Timer gameTimer;
        ArrayList<Map> platform = new ArrayList<>();

        public GamePanel() {
            BufferedImage img = new BufferedImage(SCREEN_WIDTH, SCREEN_HEIGHT, BufferedImage.TYPE_INT_RGB);
            Graphics2D g2d = img.createGraphics();
            g2d.setColor(Color.BLUE);
            g2d.fillRect(0, 0, SCREEN_WIDTH, SCREEN_HEIGHT);
            g2d.dispose();
            backgroundImage = new ImageIcon(img).getImage();

            newPlayer();
            newMap();

            InputMap im = getInputMap(WHEN_IN_FOCUSED_WINDOW);
            ActionMap am = getActionMap();

            im.put(KeyStroke.getKeyStroke(KeyEvent.VK_A, 0, false), "Pressed.left");
            im.put(KeyStroke.getKeyStroke(KeyEvent.VK_D, 0, false), "Pressed.right");
            im.put(KeyStroke.getKeyStroke(KeyEvent.VK_W, 0, false), "Pressed.up");
            im.put(KeyStroke.getKeyStroke(KeyEvent.VK_S, 0, false), "Pressed.down");

            im.put(KeyStroke.getKeyStroke(KeyEvent.VK_A, 0, true), "Released.left");
            im.put(KeyStroke.getKeyStroke(KeyEvent.VK_D, 0, true), "Released.right");
            im.put(KeyStroke.getKeyStroke(KeyEvent.VK_W, 0, true), "Released.up");
            im.put(KeyStroke.getKeyStroke(KeyEvent.VK_S, 0, true), "Released.down");

            am.put("Pressed.left", new MoveAction(player1, Player.Direction.LEFT, true));
            am.put("Pressed.right", new MoveAction(player1, Player.Direction.RIGHT, true));
            am.put("Pressed.up", new MoveAction(player1, Player.Direction.UP, true));
            am.put("Pressed.down", new MoveAction(player1, Player.Direction.DOWN, true));

            am.put("Released.left", new MoveAction(player1, Player.Direction.LEFT, false));
            am.put("Released.right", new MoveAction(player1, Player.Direction.RIGHT, false));
            am.put("Released.up", new MoveAction(player1, Player.Direction.UP, false));
            am.put("Released.down", new MoveAction(player1, Player.Direction.DOWN, false));

            gameTimer = new Timer(5, new ActionListener() {
                @Override
                public void actionPerformed(ActionEvent e) {
                    player1.move();
                    repaint();
                }
            });
            gameTimer.start();
        }

        @Override
        public Dimension getPreferredSize() {
            return SCREEN_SIZE;
        }

        @Override
        protected void paintComponent(Graphics g) {
            super.paintComponent(g);
            Graphics2D g2d = (Graphics2D) g.create();
            draw(g2d);
            g2d.dispose();
        }

        public void draw(Graphics2D g2D) {
            g2D.drawImage(backgroundImage, 0, 0, null);
            player1.paint(g2D);
            for (Map map1 : platform) {
                map1.paint(g2D);
            }
        }

        public void newPlayer() {
            player1 = new Player((SCREEN_WIDTH / 2) - (PLAYER_WIDTH / 2), (SCREEN_HEIGHT / 2) - (PLAYER_WIDTH / 2), PLAYER_WIDTH, PLAYER_HEIGHT);
        }

        public void newMap() {
            for (int i = 50; i < 650; i += 50) {
                platform.add(new Map(i, 550, 50, 50));
            }
        }

        public void gameOver() {

        }

        @Override
        public void actionPerformed(ActionEvent e) {

        }
    }

    public class MoveAction extends AbstractAction {

        private Player player;
        private Player.Direction direction;
        private boolean pressed;

        public MoveAction(Player player, Player.Direction direction, boolean pressed) {
            this.player = player;
            this.direction = direction;
            this.pressed = pressed;
        }

        @Override
        public void actionPerformed(ActionEvent e) {
            if (pressed) {
                player.putDirection(direction);
            } else {
                player.removeDirection(direction);
            }
        }

    }

    public class Player extends Rectangle {

        enum Direction {
            UP, DOWN, LEFT, RIGHT
        }

        private double velocityY = 0;
        private double velocityX = 0;
        private int speed = 2;

        private Set<Direction> directions = new TreeSet<>();

        public Player(int x, int y, int width, int height) {
            super(x, y, width, height);
        }

        public void putDirection(Direction direction) {
            directions.add(direction);
        }

        public void removeDirection(Direction direction) {
            directions.remove(direction);
        }

        public void paint(Graphics2D g2D) {
            g2D.setColor(Color.RED);
            g2D.fill(this);
        }

        protected boolean hasDirection(Direction direction) {
            return directions.contains(direction);
        }

        public void move() {
            System.out.println(hasDirection(Direction.UP));
            if (hasDirection(Direction.LEFT) && hasDirection(Direction.RIGHT) || !hasDirection(Direction.LEFT) && !hasDirection(Direction.RIGHT)) {
                velocityX *= 0.8;
            }
            if (hasDirection(Direction.LEFT) && !hasDirection(Direction.RIGHT)) {
                velocityX--;
            }
            if (hasDirection(Direction.RIGHT) && !hasDirection(Direction.LEFT)) {
                velocityX++;
            }
            if (velocityX > 0 && velocityX < 0.75) {
                velocityX = 0;
            }
            if (velocityX < 0 && velocityX > -0.75) {
                velocityX = 0;
            }

            if (velocityX > 7) {
                velocityX = 7;
            }
            if (velocityX < -7) {
                velocityX = -7;
            }

            if (hasDirection(Direction.UP)) {
                velocityY = -6;
            }
            velocityY += 0.3;

            y += velocityY;
            x += velocityX;
        }
    }

    public class Map {

        int width;
        int height;
        int x;
        int y;
        Rectangle hitbox;

        public Map(int x, int y, int width, int height) {
            this.x = x;
            this.y = y;
            this.width = width;
            this.height = height;

            hitbox = new Rectangle(x, y, width, height);
        }

        public void paint(Graphics2D g2D) {
            g2D.setColor(Color.GRAY);
            g2D.fill(hitbox);
        }

    }

}