现在的程序里五子棋下棋是点击方格然后棋子出现在左上角的交叉处，怎样修改能点击交叉处直接下棋子

Question

package wuziqi;

import javax.imageio.ImageIO;
import javax.swing.*;

import java.awt.*;
import java.awt.event.*;
import java.awt.image.BufferedImage;
import java.io.File;
import java.io.IOException;

public class 五子棋 extends JFrame implements MouseListener,Runnable{
public static void main(String args[]){
五子棋 ff = new 五子棋();
}
int height = Toolkit.getDefaultToolkit().getScreenSize().height;
int width = Toolkit.getDefaultToolkit().getScreenSize().width;
BufferedImage bgImage = null;//缓存图片

int x = 0;
int y = 0;

int allChess [][] = new int [19][19];//设置棋盘大小
boolean isBlack = true;
boolean canPlay = true;

String message = "黑方先行";
int maxTime = 0;
Thread t = new Thread(this);//创建一个线程
int blackTime = 0;
int whiteTime = 0;
String blackMessage = "无限制";
String whiteMessage = "无限制";

public 五子棋(){
    this.setTitle("五子棋");
    this.setSize(600,600);//设置窗体大小
    this.setResizable(true);//窗体是否可改变大小
    this.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);//单击窗口的关闭按钮       
    this.setLocation((width - 500)/2,   (height - 500)/2);//离显示屏上下，左右像素       
    this.addMouseListener(this);//处理鼠标事件        
    this.setVisible(true); //窗体可视

    t.start();//开始线程
    //t.suspend();
    this.repaint();

    try{
        bgImage = ImageIO.read(new File("E:/image/bgImage.jpg"));
    } catch (IOException e){
        e.printStackTrace();//运行时自动将io流异常初始化，并打印出程序的异常信息
    }       
}

public void paint(Graphics g){
    BufferedImage bi = new BufferedImage(500,500,BufferedImage.TYPE_INT_ARGB);
    Graphics g2 = bi.createGraphics();

    g2.drawImage(bgImage, 0,0, this);//信息参数
    g2.setColor(Color.black);
    g2.setFont(new Font("黑体",Font.BOLD,25));
    g2.drawString("游戏信息: " + message, 20,60);
    g2.setFont(new Font("宋体",Font.BOLD,20));        
    g2.setColor(Color.white);
    g2.fillRect(15, 460,185, 25);
    g2.fillRect(255, 460,185, 25);
    g2.setColor(Color.black );
    g2.drawString("黑方时间:"+blackMessage, 20,480);
    g2.drawString("白方时间:"+whiteMessage, 260,480);       

    g2.setColor(Color.yellow);
    g2.fill3DRect(390, 90, 90, 30,true);//x坐标，y坐标，长，宽，false凹 true凸
    g2.fill3DRect(390, 140, 90, 30,true);
    g2.fill3DRect(390,190, 90, 30,true);
    g2.fill3DRect(390,240, 90, 30,true);
    g2.fill3DRect(390,290, 90, 30,true);
    g2.fill3DRect(390, 340, 90, 30,true);
    g2.fill3DRect(390, 395, 90, 30,true);


    g2.setColor(Color.red);
    g2.drawString("开始游戏", 394, 113);//框体中的内容，x坐标。y坐标
    g2.drawString("游戏设置", 394, 163);
    g2.drawString("游戏说明", 394, 213);
    g2.drawString("暂停", 412,263);
    g2.drawString("继续", 412, 313);
    g2.drawString("认输", 412, 363);
    g2.drawString("退出", 412, 418);



    g2.setColor(Color.black);
    for(int i=0;i<19;i++){
          g2.drawLine(10, 70+20*i, 370, 70+20*i);
          g2.drawLine(10+20*i, 70, 10+20*i, 430);//绘制棋盘，drawLine(x1,y1,x2,y2)
    }

    g2.fillOval(66, 126, 8, 8);
    g2.fillOval(306, 126, 8, 8);
    g2.fillOval(306, 366, 8, 8);
    g2.fillOval(66, 366, 8, 8);
    g2.fillOval(306, 246, 8, 8);        
    g2.fillOval(186, 126, 8, 8);
    g2.fillOval(66, 246, 8, 8);
    g2.fillOval(186, 366, 8, 8);
    g2.fillOval(186, 246, 8, 8);//设置棋盘上的九个星

    for(int i=0;i<19;i++){
        for(int j=0;j<19;j++){
            if(allChess[i][j] == 1){
                int tempX = i*20+10;
                int tempY = j*20+70;
                g2.fillOval(tempX-8, tempY-8, 16, 16);                  
            }
            if(allChess[i][j] == 2){
                int tempX = i*20+10;
                int tempY = j*20+70;
                g2.setColor(Color.white);
                g2.fillOval(tempX-8, tempY-8, 16, 16);
                g2.setColor(Color.black);
                g2.drawOval(tempX-8, tempY-8, 16, 16);
            }               
        }
    }
    g.drawImage(bi, 0, 0, this);
}

public void mouseClicked (MouseEvent e){}

public void mouseExited (MouseEvent e){}

public void mouseEntered (MouseEvent e){}

public void mouseReleased (MouseEvent e){}

public void mousePressed (MouseEvent e){
    //System.out.println("X坐标："+e.getX()+" "+"Y坐标"+e.getY());
    if(canPlay == true){
        x = e.getX();
        y = e.getY();
        if(x >=10 && x<=370 && y>=70 && y<=430){
            x = (x-10)/20;
            y = (y-70)/20;
            if(allChess[x][y] == 0){
                if(isBlack == true){
                allChess[x][y] = 1;
                isBlack = false;
                message = "轮到白方";
                }else {
                    allChess[x][y] = 2;
                    isBlack = true;
                    message = "轮到黑方";
                }
                boolean winFlag = this.checkWin();
                if (winFlag == true){
                    JOptionPane.showMessageDialog(this, "游戏结束！"+" "+(allChess[x][y]==1? "黑方" :"白方")+"获胜！");
                   canPlay = false;
                }                   
          }else {
                JOptionPane.showMessageDialog(this, "当前位置已经有棋子，请重新落子！");
            }                                               
            this.repaint();         
       }        
    }                       
    if(e.getX()>=390 && e.getY()>=70 && e.getX()<=480 && e.getY()<=100){
        int result = JOptionPane.showConfirmDialog(this, "是否重新开始游戏？");
        if (result == 0){
            for (int i =0;i<19;i++){
                for (int j =0;j<19;j++){
                    allChess[i][j] = 0;
                    canPlay = true;
                }
            }
            //allChess = new int[19][19];
            message = "黑方先行";
            isBlack = true;
            blackTime = maxTime;
            whiteTime = maxTime;
            if(maxTime>0){
                blackMessage = maxTime/3600+":"+(maxTime/60-maxTime/3600*60)+":"+(maxTime-maxTime/60*60);
                whiteMessage = maxTime/3600+":"+(maxTime/60-maxTime/3600*60)+":"+(maxTime-maxTime/60*60);
                t.resume();
            }else{
                blackMessage = "无限制";
                whiteMessage = "无限制";
            }
            this.repaint();
        }
    }
    if(e.getX()>=390 && e.getX()<=480 && e.getY()>=120 && e.getY()<=150){
        String input = JOptionPane.showInputDialog("请输入游戏的最大时间(分钟),如果输入0，表示没有时间限制：");
        try{
            maxTime = Integer.parseInt(input)*60;
            if(maxTime<0){
                JOptionPane.showMessageDialog(this, "请输入正确信息，不允许输入负数！");
            }
            if(maxTime == 0){
                int result = JOptionPane.showConfirmDialog(this, "设置完成,是否重新开始游戏？");
                if (result == 0){
                    for (int i =0;i<19;i++){
                        for (int j =0;j<19;j++){
                            allChess[i][j] = 0;
                        }
                    }
                    //allChess = new int[19][19];
                    message = "黑方先行";
                    isBlack = true;
                    blackTime = maxTime;
                    whiteTime = maxTime;
                    blackMessage = "无限制";
                    whiteMessage = "无限制";
                    this.repaint();
                }
            }
            if(maxTime>0){                  
                int result = JOptionPane.showConfirmDialog(this, "设置完成,是否重新开始游戏？");
                if (result == 0){
                    for (int i =0;i<19;i++){
                        for (int j =0;j<19;j++){
                            allChess[i][j] = 0;
                        }
                    }
                    //allChess = new int[19][19];
                    message = "黑方先行";
                    isBlack = true;
                    blackTime = maxTime;
                    whiteTime = maxTime;
                    blackMessage = maxTime/3600+":"+(maxTime/60-maxTime/3600*60)+":"+(maxTime-maxTime/60*60);
                    whiteMessage = maxTime/3600+":"+(maxTime/60-maxTime/3600*60)+":"+(maxTime-maxTime/60*60);
                    t.resume();
                    this.repaint();
                }
            }
        }catch (NumberFormatException e1){
            JOptionPane.showMessageDialog(this, "请输入正确信息！");
        }
    }
    if(e.getX()>=390 && e.getX()<=480 && e.getY()>=170 && e.getY()<=200){
        JOptionPane.showMessageDialog(this, "这是一个五子棋游戏程序，黑白双方轮流下棋，当某一方连到五子时游戏结束！");
    }
    if(e.getX()>=390 && e.getX()<=480 && e.getY()>=220 && e.getY()<=250){
        JOptionPane.showMessageDialog(this, "游戏已暂停");
        canPlay = false;
    }
    if(e.getX()>=390 && e.getX()<=480 && e.getY()>=270 && e.getY()<=300){
        JOptionPane.showMessageDialog(this, "游戏继续进行");          
            canPlay = true;         
    }
    if(e.getX()>=390 && e.getX()<=480 && e.getY()>=320 && e.getY()<=350){
        int result = JOptionPane.showConfirmDialog(this, "是否确认认输？");
        System.out.println(result);
        if(result == 0){
            if(isBlack == true){
                   JOptionPane.showMessageDialog(this, "黑方已经认输，游戏结束！");
            }
            else {
                JOptionPane.showMessageDialog(this, "白方已经认输，游戏结束！");
            }
            canPlay = false;
        }
    }

    if(e.getX()>=390 && e.getX()<=480 && e.getY()>=420 && e.getY()<=450){
        JOptionPane.showMessageDialog(this, "游戏结束");
        System.exit(0);
    }
}
private boolean checkWin(){
    boolean flag = false;
            int count = 1;              
            int color = allChess[x][y];
            /*
            int i = 1;
            while (color == allChess[x+i][y]){
                count ++;
                i++;
            }
            i = 1;
            while (color == allChess[x-i][y]){
                count ++;
                i++;
            }
            if(count >= 5){
                flag = true;
            }

            int i2 = 1;
            int count2 = 1;
            while (color == allChess[x][y+i2]){
                count2 ++;
                i2++;
            }
            i2 = 1;
            while (color == allChess[x][y-i2]){
                count2 ++;
                i2++;
            }
            if(count2 >= 5){
                flag = true;
            }

            int i3 =1;
            int count3 = 1;
            while (color == allChess[x+i3][y-i3]){
                count3 ++;
                i3++;
            }
            i3 = 1;
            while (color == allChess[x-i3][y+i3]){
                count3 ++;
                i3++;
            }
            if(count3 >= 5){
                flag = true;
            }

            int i4 =1;
            int count4 = 1;
            while (color == allChess[x+i4][y+i4]){
                count4 ++;
                i4++;
            }
            i4 = 1;
            while (color == allChess[x-i4][y-i4]){
                count4 ++;
                i4++;
            }
            if(count4 >= 5){
                flag = true;
            }*/
            count =this.checkCount(1, 0, color);
            if(count >= 5){
                flag = true;
            }else {
                count = this.checkCount(0, 1, color);
                if(count >= 5){
                    flag = true;
                }else {
                    count = this.checkCount(1, -1, color);
                    if(count >= 5){
                        flag = true;
                    }else {
                        count = this.checkCount(1, 1, color);
                        if(count >= 5){
                            flag = true;
                        }
                    }
                }
            }
            return flag;
}

private int checkCount(int xChange , int yChange ,int color){
    int count = 1;
    int tempX = xChange;
    int tempY = yChange;
    while (x + xChange >=0 && x+xChange<=18 && y+yChange>=0 && y+yChange<=18 && color == allChess[x+xChange][y+yChange]){
        count ++;
        if(xChange != 0)
            xChange ++;
        if(yChange != 0){
            if(yChange > 0)
                yChange ++;
            else {
                yChange --;
            }
        }
    }
    xChange = tempX;
    yChange = tempY; 
    while (x - xChange >=0 && x-xChange<=18 && y-yChange>=0 && y-yChange<=18 && color == allChess[x-xChange][y-yChange]){
        count ++;
        if(xChange != 0)
            xChange ++;
        if(yChange != 0){
            if(yChange > 0)
                yChange ++;
            else {
                yChange --;         
            }
        }
    }
    return count;       
}   
public void run(){
    if (maxTime > 0){
        while (true){
            if (isBlack){
                blackTime --;
                if (blackTime == 0){
                    JOptionPane.showMessageDialog(this, "黑方超时，游戏结束！");
                }
            }else{
                whiteTime --;
                if (whiteTime == 0){
                    JOptionPane.showMessageDialog(this, "白方超时，游戏结束！");
                }
            }
            blackMessage = blackTime/3600+":"+(blackTime/60-blackTime/3600*60)+":"+(blackTime-blackTime/60*60);
            whiteMessage = whiteTime/3600+":"+(whiteTime/60-whiteTime/3600*60)+":"+(whiteTime-whiteTime/60*60);
            this.repaint();             
            try{
                Thread.sleep(1000);
            }catch(InterruptedException e){
                e.printStackTrace();                    
            }               
        }
    }
}

}

Answer 1

修改下代码，要点：
1、除以的分母用 20.0 才能保证结果是 double 类型，然后用 Math.round 自动完成四舍五入，
2、Math.round() 返回的是四舍五入后的 long 类型，再转回为 int ，更正代码重新编译后就能正常运行了

public void mousePressed(MouseEvent e) {
        System.out.println("X坐标："+e.getX()+" "+"Y坐标"+e.getY());
        int clickPointX = e.getX();
        int clickPointY = e.getY();

        x = clickPointX;
        y = clickPointY;
        if (canPlay == true) {
            if (clickPointX >= 10 && clickPointX <= 370 && clickPointY >= 70 && clickPointY <= 430) {

                long multipX = Math.round((clickPointX - 10) / 20.0);
                long multipY = Math.round((clickPointY - 70) / 20.0);
                x = Integer.parseInt(String.valueOf(multipX));
                y = Integer.parseInt(String.valueOf(multipY));

测试过代码，没问题的。
此外，类命名要用英文驼峰的，不建议用中文的，可以用 FiveChessGame。
代码还可以优化，这里为了测试没有优化，你可以把后面的 e.getX() 和 e.getY() 都替换成这里定义的临时变量 clickPointX 和 clickPointY。