动画背景java游戏 [英] animated background java game

问题描述

我正在编写一个类似于小行星的游戏，但我不明白如何在后台生成小行星.

I was programming a game similar to asteroid, but I do not understand how to spawn the asteroids in the background.

现在我在主类中生成了一个小行星，但我想为小行星创建一个类，我怎么做?

now i spawn an asteroid in the main class but i want create a class for the asteroid ho i do it?

主类

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);    
    }
}

后台功能(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);
}

后台功能(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

method paintcomponent in class doesn't work

推荐答案

1. 不要让您的 Asteroid 类扩展 JPanel.而是将它作为一个类来模拟小行星数据并具有数据操作方法.您还需要使用 Graphic 上下文的 draw 方法.类似的东西

1. Don't have your Asteroid class extends JPanel. Instead have it as a class that model's asteroid data and has data manipulation methods. You'll also want to have a draw method that take a Graphic context. Something like

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;
    }
}

现在你有了一个小行星模型，你可以创建一个 Asteriod 对象的 List 并遍历它们并使用它的 drawAsteroid方法来绘制它们.类似的东西

Now you have a model of an asteroid, you can create a List of Asteriod objects and iterate through them and use it's drawAsteroid method to paint them. Something like

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);
        }
    }
}

要为它们设置动画，您需要使用 javax.swing.Timer.在 如何使用 Swing 计时器 中查看更多信息.您需要操作 Timer 中的 Asteriod 数据.使用上面提供的代码，您只需调用它的move 方法，然后调用repaint().类似的东西

To animate them, you'll want to use a javax.swing.Timer. See more at How to Use Swing Timers. You'll want to manipulate the Asteriod data in the Timer. With the code provided above, you can just call it's move method, then call repaint(). Something like

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();
            }
        }
    });
}

<小时>

您可以在此处和此处 和此处 和这里 和这里

这是一个完整的例子.您会看到我在 Astreroid 类中包含了一个 Rectangle2D 对象.这只是如果您想检查碰撞检测.您应该随着 x 的每个 Asreroid 移动移动 Rectangle2D x 和/或 y> 和 y.然后你可以检查 asteroid.rectangle.intersects(someOtherObject)

Here's a full example. You'll see I included a Rectangle2D object in the Astreroid class. That's just if you want to check for collision detection. You should move the Rectangle2D x and/or y with every Asreroid movement of x and y. Then you can check if asteroid.rectangle.intersects(someOtherObject)

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);
            }
        });
    }
}

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