java - 在屏幕上移动对象

Question

我正在尝试在屏幕上同时移动两个球体。然而，它们并不是彼此独立地移动。相反，一个人依赖于另一个人的运动。请帮帮我。这是代码:-

绘制

    import javax.swing.*;
    import java.awt.*;
    import java.awt.event.*;
    class Draw extends JPanel implements ActionListener
    {
        Timer timer[] = new Timer[2];
        int velX = 2, velY = 2;
        Sphere sphere[] = new Sphere[2];
        public Draw()
        {
            for(int i=0;i<2;i++)
            {
                sphere[i] = new Sphere();
                timer[i] = new Timer(5,this);
            }
        }
        public void paintComponent(Graphics g)
        {
            super.paintComponent(g);
            for(int i=0;i<2;i++)
                drawing(g,sphere[i].color,sphere[i].radius);
        } 
        public void drawing(Graphics g,Color color, int radius)
        {
             for(int i=0;i<2;i++){
                g.setColor(color);
                g.fillOval(sphere[i].x,sphere[i].y,radius*2,radius*2);
                timer[i].start();
            }
        }
        public void actionPerformed(ActionEvent evt)
        {
            for(int i=0;i<2;i++){
            if(sphere[i].x<0 || sphere[i].x>970)
            {
                velX = -velX;
            }
            if(sphere[i].y<0 || sphere[i].y>650)
            {
                velY = -velY;
            }
            sphere[i].x += velX;
            sphere[i].y += velY;
            repaint();
        }
        }
        public static void main(String args[])
        {
            JFrame jf = new JFrame("Renderer");
            jf.getContentPane().add(new Draw(),BorderLayout.CENTER);
            jf.setBounds(0,0,1024,720);
            jf.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
            jf.setVisible(true);
        }
    }

球体

    import java.awt.Color;
    class Sphere
    {
        public int x;
        public int y;
        public int radius;
        Color color;
        public Sphere()
        {
            this.x = (int)(Math.random()*800);
            this.y = (int)(Math.random()*600);
            this.radius = (int)(Math.random()*50);
            this.color = new Color((int)(Math.random()*255),
    (int)(Math.random()*255),(int)(Math.random()*255));
        }
        public Sphere(int x,int y,int radius, Color color)
        {
            this.x = x;
            this.y = y;
            this.radius = radius;
            this.color = color;
        }
    }

Answer 1

两个对象的 x/y 增量相同，例如，您需要将这些值包含在 Sphere 对象中

class Sphere {

    int velX;
    int velY;

    public int x;
    public int y;
    public int radius;
    Color color;

    public Sphere(int xDelta, int yDelta) {
        velX = xDelta;
        velY = yDelta;
        this.x = (int) (Math.random() * 800);
        this.y = (int) (Math.random() * 600);
        this.radius = (int) (Math.random() * 50);
        this.color = new Color((int) (Math.random() * 255),
                                                     (int) (Math.random() * 255), (int) (Math.random() * 255));
    }

    void move(Dimension size) {
        x += velX;
        y += velY;

        if (x < 0) {
            x = 0;
            velX *= -1;
        } else if (x + (radius * 2) > size.width) {
            x = size.width - (radius * 2);
            velX *= -1;
        }
        if (y < 0) {
            y = 0;
            velY *= -1;
        } else if (y + (radius * 2) > size.height) {
            y = size.height - (radius * 2);
            velY *= -1;
        }
    }

    public Sphere(int x, int y, int radius, Color color) {
        this.x = x;
        this.y = y;
        this.radius = radius;
        this.color = color;
    }

}

然后，在您的 actionPerformed 方法中，您只需调用 update...

@Override
public void actionPerformed(ActionEvent evt) {
    for (int i = 0; i < 2; i++) {
        sphere[i].move(getSize());
    }
    repaint();
}

此外，您不需要两个 Timer，您只需要一个，它可用于在每次勾选时更新两个球体...

import java.awt.BorderLayout;
import java.awt.Color;
import java.awt.Dimension;
import java.awt.Graphics;
import java.awt.event.ActionEvent;
import java.awt.event.ActionListener;
import java.util.Random;
import javax.swing.JFrame;
import javax.swing.JPanel;
import javax.swing.Timer;

class Draw extends JPanel implements ActionListener {

    Timer timer;
    Sphere sphere[] = new Sphere[2];

    public Draw() {
        Random rnd = new Random();
        for (int i = 0; i < 2; i++) {
            sphere[i] = new Sphere(rnd.nextInt(4) + 1, rnd.nextInt(4) + 1);
        }
        timer = new Timer(16, this);
        timer.start();
    }

    @Override
    protected void paintComponent(Graphics g) {
        super.paintComponent(g);
        for (int i = 0; i < 2; i++) {
            drawing(g, sphere[i].color, sphere[i].radius);
        }
    }

    public void drawing(Graphics g, Color color, int radius) {
        for (int i = 0; i < 2; i++) {
            g.setColor(color);
            g.fillOval(sphere[i].x, sphere[i].y, radius * 2, radius * 2);
        }
    }

    @Override
    public void actionPerformed(ActionEvent evt) {
        for (int i = 0; i < 2; i++) {
            sphere[i].move(getSize());
        }
        repaint();
    }

    public static void main(String args[]) {
        JFrame jf = new JFrame("Renderer");
        jf.getContentPane().add(new Draw(), BorderLayout.CENTER);
        jf.setBounds(0, 0, 1024, 720);
        jf.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
        jf.setVisible(true);
    }

    class Sphere {

        int velX;
        int velY;

        public int x;
        public int y;
        public int radius;
        Color color;

        public Sphere(int xDelta, int yDelta) {
            velX = xDelta;
            velY = yDelta;
            this.x = (int) (Math.random() * 800);
            this.y = (int) (Math.random() * 600);
            this.radius = (int) (Math.random() * 50);
            this.color = new Color((int) (Math.random() * 255),
                                                         (int) (Math.random() * 255), (int) (Math.random() * 255));
        }

        void move(Dimension size) {
            x += velX;
            y += velY;

            if (x < 0) {
                x = 0;
                velX *= -1;
            } else if (x + (radius * 2) > size.width) {
                x = size.width - (radius * 2);
                velX *= -1;
            }
            if (y < 0) {
                y = 0;
                velY *= -1;
            } else if (y + (radius * 2) > size.height) {
                y = size.height - (radius * 2);
                velY *= -1;
            }
        }

        public Sphere(int x, int y, int radius, Color color) {
            this.x = x;
            this.y = y;
            this.radius = radius;
            this.color = color;
        }

    }
}

此外，您不应该在“绘制”过程中启动计时器，它们应该提前启动