setColor的问题
请问各位大虾，为什么下列程序画出来的矩形是黑边的？

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

class DrawRectangle extends JFrame
{
       public static void main(String[] args)
      {
           DrawRectangle dr=new DrawRectangle();
           dr.setSize(200,200);
           dr.setDefaultCloseOperation(dr.EXIT_ON_CLOSE);
           dr.add(new MyPanel());
           dr.setVisible(true);
           
      }
}

class MyPanel extends JPanel
{
      public void paint(Graphics g)
        {
                super.paint(g);
                g.drawRect(20,20,40,40);
                g.setColor(Color.RED);
        }
}
------解决方案--------------------

g.drawRect(20,20,40,40);

g.setColor(Color.RED);

改成

g.setColor(Color.RED);

g.drawRect(20,20,40,40);

就ok了（先设定颜色再画图，要记得呦），lz结贴吧