Java 用画布画多条线 publicstaticvoidmain（字符串[]args）{ 图片myPic=新图片（600600）； Graphics canvas=myPic.getOffScreengGraphics（）； canvas.setColor（Color.WHITE）； canvas.fillRect（0,060600）； canvas.setColor（Color.BLACK）； int-x1； int y1； int-x2； int y2； int标题； x1=300； y1=300； x2=300； y2=300； 航向=0； 字符串键盘=JOptionPane.showInputDialog（null， “输入您的输入”）； 如果（键盘！=null）{ if（keyboard.isEmpty（）| | keyboard.contains（“”）{ JOptionPane.showMessageDialog( 无效的 “请输入输入”， “错误”， JOptionPane.ERROR\u消息）； main（args）； } int counth=0； int countg=0； int countPlus=0； int count减数=0； int countK=0； int countR=0； int countG=0； int countB=0； int countC=0； int countO=0； 对于（int i=0；i

我正试图根据用户输入画一些线

输入为h和f，用于向前移动10个像素（两者的作用相同）和+或-为了改变方向，直线将顺时针移动90度，用于+或逆时针移动-（默认为向上移动）

例如，如果用户输入：“hhh”，该行将向上移动30个像素

我遇到的问题是，我希望用户能够输入hhh+hhh，然后它向上画一条30像素的线，然后转向右侧再画30个像素。然而，在我的程序中，当我输入hhh+hhh时，它只在右边60像素处形成一条直线

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所以我的问题是：当它在指定的方向上看到+或-并画另一条线时，如何让它画一个线转弯

代码完全未经测试，但我建议您：

删除+和-

public static void main(String[] args) {
    Picture myPic = new Picture(600, 600);
    Graphics canvas = myPic.getOffScreenGraphics();

    canvas.setColor(Color.WHITE);
    canvas.fillRect(0, 0, 600, 600);

    canvas.setColor(Color.BLACK);
    int x1;
    int y1;
    int x2;
    int y2;
    int heading;

    x1 = 300;
    y1 = 300;
    x2 = 300;
    y2 = 300;

    heading = 0;



    String keyboard = JOptionPane.showInputDialog(null,
            "Enter your input");

    if (keyboard != null) {
        if (keyboard.isEmpty() || keyboard.contains(" ")) {
            JOptionPane.showMessageDialog(
                    null,
                    "Please enter an input",
                    "Error",
                    JOptionPane.ERROR_MESSAGE);
            main(args);
        }


        int counth = 0;
        int countg = 0;
        int countPlus = 0;
        int countMinus = 0;
        int countK = 0;
        int countR = 0;
        int countG = 0;
        int countB = 0;
        int countC = 0;
        int countO = 0;


        for (int i = 0; i < keyboard.length(); i++) {
            if (keyboard.charAt(i) == '+') {
                if (heading == 0) {
                    heading = 1;
                } else if (heading == 1) {
                    heading = 2;
                } else if (heading == 2) {
                    heading = 3;
                } else if (heading == 3) {
                    heading = 0;
                }
            }
        }
        countPlus++;

        for (int i = 0; i < keyboard.length(); i++) {
            if (keyboard.charAt(i) == '-') {
                if (heading == 0) {
                    heading = 3;
                } else if (heading == 1) {
                    heading = 0;
                } else if (heading == 2) {
                    heading = 1;
                } else if (heading == 3) {
                    heading = 2;
                }
            }
        }
        countMinus++;


        for (int i = 0; i < keyboard.length(); i++) {
            if (keyboard.charAt(i) == 'h' || keyboard.charAt(i) == 'f') {
                if (heading == 0) {
                    counth++;
                    int k = 10 * (counth);
                    canvas.drawLine(x1, y1, x2, y2 + k);

                } else if (heading == 1) {
                    counth++;
                    int k = 10 * (counth);
                    canvas.drawLine(x1, y1, x2 + k, y2);
                } else if (heading == 2) {
                    counth++;
                    int k = 10 * (counth);
                    canvas.drawLine(x1, y1, x2, y2 - k);
                } else if (heading == 3) {
                    counth++;
                    int k = 10 * (counth);
                    canvas.drawLine(x1, y1, x2 - k, y2);
                } else if (heading > 3 || heading < 0) {
                    JOptionPane.showMessageDialog(
                            null,
                            "Your heading is greater than 3 or less than 0",
                            "Error",
                            JOptionPane.ERROR_MESSAGE);
                    main(args);
                }
            }

        }



        for (int i = 0; i < keyboard.length(); i++) {
            if (keyboard.charAt(i) == 'K') {
                canvas.setColor(Color.BLACK);
            }
        }
        countK++;

        for (int i = 0; i < keyboard.length(); i++) {
            if (keyboard.charAt(i) == 'R') {
                canvas.setColor(Color.RED);
            }
        }
        countR++;

        for (int i = 0; i < keyboard.length(); i++) {
            if (keyboard.charAt(i) == 'G') {
                canvas.setColor(Color.GREEN);
            }
        }
        countG++;

        for (int i = 0; i < keyboard.length(); i++) {
            if (keyboard.charAt(i) == 'B') {
                canvas.setColor(Color.BLUE);
            }
        }
        countB++;

        for (int i = 0; i < keyboard.length(); i++) {
            if (keyboard.charAt(i) == 'C') {
                canvas.setColor(Color.CYAN);
            }
        }
        countC++;

        for (int i = 0; i < keyboard.length(); i++) {
            if (keyboard.charAt(i) == 'O') {
                canvas.setColor(Color.BLACK);
            }
        }
        countO++;


        System.out.println("h = " + counth);
        System.out.println("g = " + countg);
        System.out.println("+ = " + countPlus);
        System.out.println("- = " + countMinus);
        System.out.println("K = " + countK);
        System.out.println("R = " + countR);
        System.out.println("G = " + countG);
        System.out.println("B = " + countB);
        System.out.println("C = " + countC);
        System.out.println("O = " + countO);



        myPic.repaint();
    } else {
        System.exit(0);
    }


}

for（int i=0；i3）
航向=0；
if（keyboard.charAt（i）='h'| | keyboard.charAt（i）='f'）
//剪掉标题代码的其余部分
for(int i =0; i < keyboard.length(); i++)
  {
 if(keyboard.charAt(i) == '+')
      heading++;
 if(keyboard.charAt(i) == '-')
      heading--;

if (heading < 0)
    heading = 3;
if (heading > 3)
    heading = 0;

 if(keyboard.charAt(i) == 'h' || keyboard.charAt(i) == 'f') 
 //Snip rest of heading code here
 }