Question

我必须制作一个绘制Sierpinski Triangle的程序。

import javax.swing.*;
import java.awt.*;
import java.awt.event.*;

public class SierpinskiPanel extends JPanel{

    private SierpinskiFrame frame;

    public SierpinskiPanel(SierpinskiFrame f){
        frame = f;
    }

也就是说，我无法在递归方法中访问变量g。我将如何使变量可访问或将方法放入方法paintComponent中？

    public void drawSierp(int width, int height, int x, int y){
        int leftCornY = height;
        int rightCornY = height;
        int rightCornX = width;
        if(width == 1 && height == 1){
            g.drawRect(x, y, 1, 1);
        }
        else{
            drawSierp(width/4, height/4, x, leftCornY);
            drawSierp(width/4, height/4, rightCornX, rightCornY);
            drawSierp(width/4, height/4, width/2, height/2);
        }
    }

    public void paintComponent(Graphics g){
        super.paintComponent(g);
        int w = frame.getWidth();
        int h = frame.getHeight();
        int xCoord = frame.getX();
        int yCoord = frame.getY();
        drawSierp(w, h, xCoord, yCoord);
    }
}

Answer 1

将方法更改为

public void drawSierp(Graphics g, int width, int height, int x, int y)

，最初从paintComponent调用为

drawSierp(g, w, h, xCoord, yCoord);

当然，您也需要从else块调用中传递它。

Answer 2

您尚未将对象g传递给drawSierp()。因此该方法应该获取传入的参数。

public void drawSierp(int width, int height, int x, int y, Graphics g){
        int leftCornY = height;
        int rightCornY = height;
        int rightCornX = width;
        if(width == 1 && height == 1){
            g.drawRect(x, y, 1, 1);
        }
        else{
            drawSierp(width/4, height/4, x, leftCornY, g); // Pass the object g'
            drawSierp(width/4, height/4, rightCornX, rightCornY, g); // Pass the object 'g'
            drawSierp(width/4, height/4, width/2, height/2 , g); // Pass the object 'g'
        }
    }

调用函数时，应提供所有参数。

我无法在单独的方法中访问变量

2 个答案: