java - 如何使用计时器在java中使图像每x秒随机出现一次？

Question

我正在开发一款游戏，我需要“击中”一只老鼠，它就会消失，您将获得 1 分。我让它在每次启动应用程序时随机出现，但我希望使用 Timer() 或其他东西每 x 秒随机绘制图像。

我的游戏屏幕代码如下所示:

import java.awt.Color;
import java.awt.Cursor;
import java.awt.Dimension;
import java.awt.Font;
import java.awt.Graphics;
import java.awt.Image;
import java.awt.Point;
import java.awt.Toolkit;
import java.awt.event.ActionEvent;
import java.awt.event.ActionListener;
import java.util.Random;

import javax.swing.ImageIcon;
import javax.swing.JButton;
import javax.swing.JPanel;
import javax.swing.JTextField;

public class Gamevenster extends JPanel implements Runnable {
        public String Gamestatus = "active";
        private Thread thread;
        //public Main game;

    public int random(int min, int max) {
         int range = (max - min) + 1;     
        return (int)(Math.random() * range) + min;
    }

    public void paintComponent(Graphics g) {
        super.paintComponent(g);

        g.drawImage(achtergrond, 0, 0, this.getWidth(), this.getHeight(), null);
        //g.drawImage(muisje, 10, 10, null);
        g.drawImage(muisje, random(0, this.getWidth()), random(0, this.getHeight()), null);
    }

    private static final long serialVersionUID = 1L;

        Image achtergrond, muisje;
        JTextField invoer;
        JButton raden;
        JButton menu;

        Gamevenster() {
        setLayout(null);

        ImageIcon icon = new ImageIcon(this.getClass().getResource("assets/achtergrondspel.png"));
        achtergrond = icon.getImage();      

        ImageIcon icon2 = new ImageIcon(this.getClass().getResource("assets/muisje.png"));
        muisje = icon2.getImage();   

        //Get the default toolkit  
        Toolkit toolkit = Toolkit.getDefaultToolkit();  

        //Load an image for the cursor  
        Image image = toolkit.getImage("src/assets/hand.png");  

        //Create the hotspot for the cursor  
        Point hotSpot = new Point(0,0);

        //Create the custom cursor  
        Cursor cursor = toolkit.createCustomCursor(image, hotSpot, "Hand");

        //Use the custom cursor  
        setCursor(cursor);

        // setLayout( null );

        // Invoer feld
        invoer = new JTextField(10);
        invoer.setLayout(null);
        invoer.setBounds(150, 474, 290, 60); // Verander positie onder aan scherm is int 1

        // Button voor raden
        raden = new JButton("Raden");
        raden.setLayout(null);
        raden.setBounds(10, 474, 130, 60);
        raden.setFont(new Font("Dialog", 1, 20));
        raden.setForeground(Color.white);
        raden.setBackground(new Color(46, 204, 113));
        raden.setPreferredSize(new Dimension(130, 60));

        // Menu knop
        menu = new JButton("Menu");
        menu.setLayout(null);
        menu.setBounds(450, 474, 130, 60);
        menu.setFont(new Font("Dialog", 1, 20));
        menu.setForeground(Color.white);
        menu.setBackground(new Color(46, 204, 113));
        menu.setPreferredSize(new Dimension(130, 60));

        // Toevoegen aan screen
        add(invoer);
        //add(raden);
        add(menu);

        menu.addActionListener(new ActionListener() {

public void actionPerformed(ActionEvent e) {
        String i = invoer.getText();
        System.out.println("Er is gedrukt! " + i);
                }
            });
        }

        public void start(){
            thread = new Thread(this,"spelloop");
            thread.start();
        }

        public void run() {
            // TODO Auto-generated method stub
            while(Gamestatus=="active"){
                System.out.println("Gameloop werkt");
            }
        }
}

如你所见，我正在使用 g.drawImage(muisje, random(0, this.getWidth()), random(0, this.getHeight()), null);

因此它会在启动时随机添加图像。

当应用程序打开时，如何使用计时器每 x 秒执行一次此操作？

Answer 1

"How can I use a timer to do this every x seconds when the app is openend?"

看看这个例子。我从互联网上收集了图像，但您可以使用图像文件执行相同的操作。我所做的是使用 URL 和 BufferedImage 数组，每 500 毫秒获得一个随机索引，然后 repaint() 面板

注意如果您要使用图像文件，您可能需要查看 this answer还有。

import java.awt.Color;
import java.awt.Dimension;
import java.awt.Graphics;
import java.awt.event.ActionEvent;
import java.awt.event.ActionListener;
import java.awt.image.BufferedImage;
import java.io.IOException;
import java.net.MalformedURLException;
import java.net.URL;
import java.util.Random;
import javax.imageio.ImageIO;
import javax.swing.JFrame;
import javax.swing.JPanel;
import javax.swing.SwingUtilities;
import javax.swing.Timer;

public class TestImageRotate {

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

    private static class ImagePanel extends JPanel {

        URL[] urls;
        BufferedImage[] images;
        Random rand = new Random();

        public ImagePanel() {
            urls = new URL[5];
            try {
                urls[0] = new URL("http://www.atomicframework.com/assetsY/img/stackoverflow_chicklet.png");
                urls[1] = new URL("http://www.iconsdb.com/icons/download/orange/stackoverflow-256.png");
                urls[2] = new URL("http://img.1mobile.com/market/screenshot/50/com.dd.stackoverflow/0.png");
                urls[3] = new URL("http://www.iconsdb.com/icons/download/orange/stackoverflow-4-512.png");
                urls[4] = new URL("http://www.iconsdb.com/icons/preview/light-gray/stackoverflow-xxl.png");

                images = new BufferedImage[5];
                images[0] = ImageIO.read(urls[0]);
                images[1] = ImageIO.read(urls[1]);
                images[2] = ImageIO.read(urls[2]);
                images[3] = ImageIO.read(urls[3]);
                images[4] = ImageIO.read(urls[4]);

            } catch (MalformedURLException ex) {
                ex.printStackTrace();
            } catch (IOException ex) {
                ex.printStackTrace();
            }
            setBackground(Color.BLACK);

            Timer timer = new Timer(500, new ActionListener(){
                @Override
                public void actionPerformed(ActionEvent e) {
                    repaint();
                }
            });
            timer.start();
        }

        private int random() {
            int index = rand.nextInt(5);
            return index;
        }

        @Override
        protected void paintComponent(Graphics g) {
            super.paintComponent(g);
            BufferedImage img = images[random()];
            g.drawImage(img, 0, 0, 400, 400, 0, 0,
                    img.getWidth(), img.getHeight(), this);
        }

        @Override
        public Dimension getPreferredSize() {
            return new Dimension(400, 400);
        }
    }
}

<小时/>

注意Timer代码。这就是我所做的一切

Timer timer = new Timer(500, new ActionListener(){
    @Override
    public void actionPerformed(ActionEvent e) {
        repaint();
    }
});
timer.start();

对于 .grawImage，我使用 BufferedImages 数组中的随机索引

@Override
protected void paintComponent(Graphics g) {
    super.paintComponent(g);
    BufferedImage img = images[random()];
    g.drawImage(img, 0, 0, 400, 400, 0, 0,
                           img.getWidth(), img.getHeight(), this);
}

<小时/>

更新示例。晚上我关闭了 IDE。太懒了，所以我只是想边走边想出这个。如果你还是不明白，明天我起床时我会添加一个真实的例子。

基本上，您希望为鼠标图像的 x 和 y 位置提供全局变量

int x = 0;
int y = 0;

当你绘制图像时，你想要使用这些位置

g.drawImage(img, x, y, whatEverWidth, whatEverHeight, this);

在计时器中，您可以在绘画之前随机修改x和y。让我们使用一些逻辑。

假设您的屏幕宽度为 500，屏幕高度为 500，鼠标图像宽度为 100，鼠标图像高度为 100

• 因此最大 x 位置将为 400 = 屏幕宽度 - 鼠标图像宽度
• 最大 y 位置将为 400 = 屏幕高度 - 鼠标图像高度

现在我们有了我们的范围。我们知道最小 x 位置为 0，最小 y 位置为 0。因此，我们希望每个 x 和 y 都有一个 0 到 400 之间的随机数。所以在计时器中你可以这样做

Timer timer = new Timer(1000, new ActionListener(){
    public void actionPerformed(ActionEvent e) {
        x = rand.nextInt(400) + 1;     
        y = rand.nextInt(400) + 1;
        repaint();   
    }
});

每次调用重新绘制时，这都会在随机位置重新绘制鼠标图像。

<小时/>

更新2

我不知道还有什么需要解释的。我只是做了我指出的那些事情(用我的原始代码)，只是添加了x和y并使用它们来绘制图像，并在计时器中获得了一个随机位置。它对我来说效果很好。我不知道你做错了什么。

import java.awt.Color;
import java.awt.Dimension;
import java.awt.Graphics;
import java.awt.event.ActionEvent;
import java.awt.event.ActionListener;
import java.awt.image.BufferedImage;
import java.io.IOException;
import java.net.MalformedURLException;
import java.net.URL;
import java.util.Random;
import javax.imageio.ImageIO;
import javax.swing.JFrame;
import javax.swing.JPanel;
import javax.swing.SwingUtilities;
import javax.swing.Timer;

public class TestImageRotate {

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

    private static class ImagePanel extends JPanel {

        URL[] urls;
        BufferedImage[] images;
        Random rand = new Random();
        private int x = 0;
        private int y = 0;

        public ImagePanel() {
            urls = new URL[5];
            try {
                urls[0] = new URL("http://www.atomicframework.com/assetsY/img/stackoverflow_chicklet.png");
                urls[1] = new URL("http://www.iconsdb.com/icons/download/orange/stackoverflow-256.png");
                urls[2] = new URL("http://img.1mobile.com/market/screenshot/50/com.dd.stackoverflow/0.png");
                urls[3] = new URL("http://www.iconsdb.com/icons/download/orange/stackoverflow-4-512.png");
                urls[4] = new URL("http://www.iconsdb.com/icons/preview/light-gray/stackoverflow-xxl.png");

                images = new BufferedImage[5];
                images[0] = ImageIO.read(urls[0]);
                images[1] = ImageIO.read(urls[1]);
                images[2] = ImageIO.read(urls[2]);
                images[3] = ImageIO.read(urls[3]);
                images[4] = ImageIO.read(urls[4]);

            } catch (MalformedURLException ex) {
                ex.printStackTrace();
            } catch (IOException ex) {
                ex.printStackTrace();
            }
            setBackground(Color.BLACK);

            Timer timer = new Timer(500, new ActionListener(){
                @Override
                public void actionPerformed(ActionEvent e) {
                    x = rand.nextInt(325);
                    y = rand.nextInt(325);
                    repaint();
                }
            });
            timer.start();
        }

        private int random() {
            int index = rand.nextInt(5);
            return index;
        }

        @Override
        protected void paintComponent(Graphics g) {
            super.paintComponent(g);
            BufferedImage img = images[random()];
            g.drawImage(img, x, y, 75, 75, this);
        }

        @Override
        public Dimension getPreferredSize() {
            return new Dimension(400, 400);
        }
    }
}