Java Swing中的蛇游戏-我的蛇只会长成

我试图在Swing中制作经典的Snake游戏,并设法使Snake移动,但是当它移动时,它会变得无限长,因为它永远不会抹掉它的尾巴.

我一直在使用validate()和repaint(),但是没有任何效果.

Problem

这是我的代码：

import java.awt.Graphics;
import java.awt.event.ActionEvent;
import java.awt.event.ActionListener;
import java.awt.event.KeyEvent;
import java.awt.event.KeyListener;

import javax.swing.ImageIcon;
import javax.swing.JPanel;
import javax.swing.Timer;

public class controls extends JPanel implements KeyListener, ActionListener { // Amb aquestes dues implementacions, fem que el programa pugui rebre per teclat

// Mida serp
private int[] longXserp = new int[750];
private int[] longYserp = new int[750];

// Longitut inicial de la serp
private int serplong = 3;

// Moviments que fem
private int moviments = 0;

// Controls
private boolean esquerra = false;
private boolean dreta = false;
private boolean amunt = false;
private boolean avall = false;

// Gràfics de moviment
private ImageIcon serpesquerra;
private ImageIcon serpdreta;
private ImageIcon serpamunt;
private ImageIcon serpavall;

private Timer timer;
private int velocitatserp = 100;
private ImageIcon serp;

public controls() {
    addKeyListener(this);
    setFocusable(true);
    setFocusTraversalKeysEnabled(false);
    timer = new Timer(velocitatserp, this);
    timer.start();
}

public void paint(Graphics g) { // Mètode amb el que imprimim per pantalla. Ha d'anomenar-se "paint", o si no, no funcionarà

    if(moviments == 0) {

        longXserp[2] = 50;
        longXserp[1] = 75;
        longXserp[0] = 100;

        longYserp[2] = 100;
        longYserp[1] = 100;
        longYserp[0] = 100;
    }


    serpdreta = new ImageIcon("src/grafics/serpdreta.png");
    serpdreta.paintIcon(this, g, longXserp[0], longYserp[0]);

    for(int a = 0; a < serplong; a++) {

        if(a == 0 && esquerra) {

            serpesquerra = new ImageIcon("src/grafics/serpesquerra.png");
            serpesquerra.paintIcon(this, g, longXserp[a], longYserp[a]);
        }

        if(a == 0 && dreta) {

            serpdreta = new ImageIcon("src/grafics/serpdreta.png");
            serpdreta.paintIcon(this, g, longXserp[a], longYserp[a]);
        }

        if(a == 0 && amunt) {

            serpamunt = new ImageIcon("src/grafics/serpamunt.png");
            serpamunt.paintIcon(this, g, longXserp[a], longYserp[a]);
        }

        if(a == 0 && avall) {

            serpavall = new ImageIcon("src/grafics/serpavall.png");
            serpavall.paintIcon(this, g, longXserp[a], longYserp[a]);
        }

        if(a != 0) {
            serp = new ImageIcon("src/grafics/serp.png");
            serp.paintIcon(this, g, longXserp[a], longYserp[a]);
        }

    }

    g.dispose();
}


@Override
public void keyPressed(KeyEvent ke) {

    if(ke.getKeyCode() == KeyEvent.VK_RIGHT){ // Si polses la tecla X, la seva variable boolean es posa en true
        moviments++;
        dreta = true;

        if(!esquerra) {
            dreta = true;
        }

        else {
            dreta = false;
            esquerra = true;
        }

        amunt = false;
        avall = false;
    }

    if(ke.getKeyCode() == KeyEvent.VK_LEFT){
        moviments++;
        esquerra = true;

        if(!dreta) {
            esquerra = true;
        }

        else {
            esquerra = false;
            dreta = true;
        }

        amunt = false;
        avall = false;
    }

    if(ke.getKeyCode() == KeyEvent.VK_UP){
        moviments++;
        amunt = true;

        if(!avall) {
            amunt = true;
        }

        else {
            amunt = false;
            avall = true;
        }

        esquerra = false;
        dreta = false;
    }

    if(ke.getKeyCode() == KeyEvent.VK_DOWN){
        moviments++;
        avall = true;

        if(!amunt) {
            avall = true;
        }

        else {
            amunt = true;
            avall = false;
        }

        esquerra = false;
        dreta = false;
    }

}
@Override
public void keyReleased(KeyEvent ke) {
    // TODO Auto-generated method stub

}
@Override
public void keyTyped(KeyEvent ke) {
    // TODO Auto-generated method stub

}
@Override
public void actionPerformed(ActionEvent ae) {

    timer.start();

    if(dreta) {

        for(int d = serplong-1; d>=0; d--) {
            longYserp[d+1] = longYserp[d];
        }

        for(int e = serplong; e>= 0; e--) {
            if(e==0) {
                longXserp[e] = longXserp[e] + 25;
            }

            else {
                longXserp[e] = longXserp[e-1];
            }

            if(longXserp[e] > 850) {
                longXserp[e] = 25;

            }
        }

        repaint(); // Mètode per refrescar els gràfics tornant a cridar al mètode paint(). Es usa quan es realitzan canvis sobre els gràfics
    }

    if(esquerra) {

        for(int d = serplong-1; d>=0; d--) {
            longYserp[d+1] = longYserp[d];
        }

        for(int d = serplong; d>= 0; d--) {
            if(d==0) {
                longXserp[d] = longXserp[d] - 25;
            }

            else {
                longXserp[d] = longXserp[d-1];
            }

            if(longXserp[d] < 25) {
                longXserp[d] = 850;

            }
        }

        repaint();
    }

    if(amunt) {

        for(int d = serplong-1; d>=0; d--) {
            longXserp[d+1] = longXserp[d];
        }

        for(int d = serplong; d>= 0; d--) {
            if(d==0) {
                longYserp[d] = longYserp[d] - 25;
            }

            else {
                longYserp[d] = longYserp[d-1];
            }

            if(longYserp[d] < 75) {
                longYserp[d] = 625;

            }
        }

        repaint();
    }

    if(avall) {

        for(int d = serplong-1; d>=0; d--) {
            longXserp[d+1] = longXserp[d];
        }

        for(int d = serplong; d>= 0; d--) {
            if(d==0) {
                longYserp[d] = longYserp[d] + 25;
            }

            else {
                longYserp[d] = longYserp[d-1];
            }

            if(longYserp[d] > 625) {
                longYserp[d] = 75;

            }
        }

        repaint();
    }
}   
}

几天来我一直在努力找出问题所在.上面的代码有什么问题？

解决方法:

public void paint(Graphics g) { ..

应该是：

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

请注意两个重要的区别：

>为属于或扩展JComponent的任何类覆盖paintComponent.
>自定义绘画时调用super方法以擦除以前的图形.

现在,我将更详细地介绍其他代码：

> serpdreta =新的ImageIcon(“ src / grafics / serpdreta.png”);这种类型的资源加载不应以绘画方法完成,而绘画方法应在最短的时间内完成.而是在构造类时加载图像,并将其存储为类的字段,以便在需要时使用.
>但是,当应用程序运行时,该路径可能会失败.被变成一个罐子.通常不包括src目录.
>应用程序资源将在部署时变成嵌入式资源,因此明智的做法是立即开始访问它们.必须通过URL而不是文件来访问embedded-resource.有关如何形成URL,请参见info. page for embedded resource.
>如果是应用程序.需要绘制图像,创建图像而不是ImageIcon.
>为了在加载图像时获得更好的反馈,请使用ImageIO.read(..)而不是创建ImageIcon,因为它会静默失败,而ImageIO将提供有关任何问题原因的有用信息.
>对于Swing,我们通常使用key bindings,而不是较低级别的KeyListener.

标签：swing,custom-painting,java,embedded-resource
来源： https://codeday.me/bug/20191109/2013078.html