Question

我正在编写类似于小行星的游戏，但我不明白如何在背景中产生小行星。

现在我在主类中产生了一颗小行星，但是我想为小行星创建一个类吗？

MAIN CLASS

public void paintComponent(Graphics g)
{
    super.paintComponent(g);
    Graphics2D g2d = (Graphics2D) g;
    if(flag_img)
    {
        background(g2d);  
        logo(g2d);          
        menu(g2d);          
        spaceship(g2d);   
        crediti(g2d);    
    }
}

背景功能（现在）

private void background(Graphics2D g2d) 
{

    asteroidi_g_x+=r.nextInt(4);
    asteroidi_g_y+=r.nextInt(1);
    g2d.drawImage(asteroidi_g[0], asteroidi_g_x,asteroidi_g_y,this);
}

背景功能（我想要的）

private void background(Graphics2D g2d) 
{
    asteroid asteroid = new asteroid[10];
}

和类小行星

public class asteroid extends JPanel implements ActionListener
{
   private BufferedImage images_asteroid;
   private boolean flag_img;

   private JPanel jp;

   private int x,y;

   public asteroide_grande(JPanel jp)
   {
    flag_img = true;
    x = (jp.getWidth()/2);
    y = (jp.getHeight()/2);
    this.jp = jp;

        try {
            images_asterod = ImageIO.read(this.getClass().getResource("images/asteroid/a1.png"));
        } catch(IOException e){flag = false;}
}

@Override
public void paintComponent(Graphics g)
{
    super.paintComponent(g);
   if(flag_img)
  {
        g.drawImage(images_asteroid, 100, 100,this);
  }
}


@Override
public void actionPerformed(ActionEvent e) 
{
    x=x-1;
    y=y+1;
    repaint();
}

类中的方法paintcomponent不起作用

Answer 1

不要让Asteroid班级延长JPanel。而是将其作为模拟小行星数据的类，并具有数据操作方法。您还希望采用draw方法，该方法采用Graphic上下文。像

这样的东西

public class Asteroid {
    Image asteroidImage;
    JPanel panel;
    int x, y;

    public Asteroid(JPanel panel, Image image, int x, int y) {
        this.panel = panel;
        this.asteroidImage = image;
        this.x = x;
        this.y = y;
    }

    public void drawAsteroid(Graphics g) {
        g.drawImage(asteroidImage, x, y, panel);
    }

    public void move() {
        x += 5;
    }
}

现在您拥有了一个小行星模型，您可以创建List个Asteriod个对象并迭代它们并使用它的drawAsteroid方法绘制他们。像

这样的东西

public class GamePanel extends JPanel {
    List<Asteroid> asteroids;
    Image asteroidImage;

    public GamePanel(){
        asteroidImage = ...
        asteroids = new ArrayList<>();
        asteroids.add(new Asteroid(GamePanel.this, asteroidImage, 100, 100));
        // add more asteriods
    }

    @Override
    protected void paintComponent(Graphics g) {
        super.paintComponent(g);
        for (Asteriod asteroid: asteriods) {
            asteriod.drawAsteroid(g);
        }
    }
}

要为它们制作动画，您需要使用javax.swing.Timer。点击How to Use Swing Timers了解更多信息。您希望操纵Asteriod中的Timer数据。使用上面提供的代码，您可以调用它的move方法，然后调用repaint()。像

这样的东西

public GamePanel(){
    ...
    Timer timer = new Timer(30, new ActionListener(){
        public void actionPerformed(ActionEvent e) {
            Iterator it = asteroids.iterator();
            while (it.hasNaext()) {
                Asteroid asteriod = (Asteroid)it.next();
                asteroid.move();
            }
        }
    });
}

您可以看到一组更完整的动画多个对象动画示例here和here以及here和here以及here

这是一个完整的例子。您会在Rectangle2D课程中看到我添加了Astreroid个对象。那就是你想要检查碰撞检测。您应该Rectangle2D和x移动每y次移动Asreroid x和/或y。然后，您可以检查asteroid.rectangle.intersects(someOtherObject)

enter image description here

import java.awt.Dimension;
import java.awt.Graphics;
import java.awt.Image;
import java.awt.event.ActionEvent;
import java.awt.event.ActionListener;
import java.awt.geom.Rectangle2D;
import java.awt.image.BufferedImage;
import java.io.IOException;
import java.util.ArrayList;
import java.util.Iterator;
import java.util.List;
import java.util.Random;
import java.util.logging.Level;
import java.util.logging.Logger;
import javax.imageio.ImageIO;
import javax.swing.JFrame;
import javax.swing.JPanel;
import javax.swing.SwingUtilities;
import javax.swing.Timer;

public class AsteroidBackground extends JPanel {

    private static final int D_W = 400;
    private static final int D_H = 600;
    BufferedImage asteroidImage;
    BufferedImage background;
    List<Asteroid> asteroids;
    Random random = new Random();
    int countToAddAsteroid = 0;
    int y;

    public AsteroidBackground() {
        try {
            asteroidImage = ImageIO.read(getClass().getResource("/resources/small-asteroid.png"));
            background = ImageIO.read(getClass().getResource("/resources/space.png"));
        } catch (IOException ex) {
            Logger.getLogger(AsteroidBackground.class.getName()).log(Level.SEVERE, null, ex);
        }
        asteroids = new ArrayList<>();
        y = 0 - asteroidImage.getHeight();

        Timer timer = new Timer(40, new ActionListener(){
            public void actionPerformed(ActionEvent e) {
                if (countToAddAsteroid >= 25) {
                    int randX = random.nextInt(D_W);
                    asteroids.add(new Asteroid(AsteroidBackground.this, asteroidImage, randX, y));
                    countToAddAsteroid = 0;
                }
                countToAddAsteroid++;
                Iterator it = asteroids.iterator();
                while (it.hasNext()) {
                    Asteroid asteroid = (Asteroid)it.next();
                    if (asteroid.y >= D_H) {
                        it.remove();
                    } else {
                         asteroid.move();
                    } 
                }
                repaint();
            }
        });
        timer.start();
    }

    @Override
    protected void paintComponent(Graphics g) {
        super.paintComponent(g);
        g.drawImage(background, 0, 0, this);
        for (Asteroid asteroid : asteroids) {
            asteroid.drawAsteroid(g);
        }
    }

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

    public class Asteroid {
        Rectangle2D rectangle;
        Image asteroidImage;
        JPanel panel;
        int x, y;

        public Asteroid(JPanel panel, Image image, int x, int y) {
            this.panel = panel;
            this.asteroidImage = image;
            this.x = x;
            this.y = y;
            rectangle = new Rectangle2D.Double(
                    x, y, image.getWidth(panel), image.getHeight(panel));
        }

        public void drawAsteroid(Graphics g) {
            g.drawImage(asteroidImage, x, y, panel);
        }

        public void move() {
            y += 5;
        }
    }

    public static void main(String[] args) {
        SwingUtilities.invokeLater(new Runnable() {
            public void run() {
                JFrame frame = new JFrame();
                frame.add(new AsteroidBackground());
                frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
                frame.pack();
                frame.setLocationRelativeTo(null);
                frame.setVisible(true);
            }
        });
    }
}

动画背景java游戏

1 个答案: