java turtle 图形和迭代

Question

import java.awt.*;
public class TurtleGraphicsDemo2 {
  public static void main(String[] args) {      
    World worldObj = new World();
    Turtle myrtleTheTurtle = new Turtle(0, 0, worldObj); 
    drawLine(myrtleTheTurtle, Color.RED, 10, 20, 50, 20);      //invokes the first drawLine() method
    drawLine(myrtleTheTurtle, 100, 150, 50, -45);               //invokes the second drawLine() method
    drawLine(myrtleTheTurtle, 100, 150, 100, 60);                //invokes the second drawLine() method
    drawLine(myrtleTheTurtle, Color.BLUE, 10, 40, 100, 40);   //invokes the first drawLine() method     
  }//end of main method 
}//end of class

错误如下:

TurtleGraphicsDemo2.java:19:错误:找不到符号

   drawLine(myrtleTheTurtle, Color.RED, 10, 20, 50, 20);      
   ^

符号:方法drawLine(Turtle,Color,int,int,int,int) 位置:类TurtleGraphicsDemo2

我的编程老师给了我们这个来实验，但我收到了一个drawLine错误，有人知道为什么吗？我对Java没有太多经验，只有Python。如果您能解决这个问题，或者知道我如何解决它，谢谢。如果没有，谢谢您的浏览:)

Answer 1

您只能使用Graphics2D在Canvas内绘制线条

   class MyCanvas extends Canvas {

      public MyCanvas () {
         setBackground (Color.GRAY);
         setSize(300, 300);
      }

      public void paint (Graphics g) {
         Graphics2D g2;
         g2 = (Graphics2D) g;
         g2.drawString ("It is a custom canvas area", 70, 70);
      }
   }