Question

求助java大神(java究竟怎么画图，初学者很疑惑)为什么我下面这个画不了，怎么改才能画呢?

import java.awt.Color;
import java.awt.Graphics;
import java.awt.image.BufferedImage;

import javax.swing.JFrame;

public class showWIN extends JFrame{
private static final long serialVersionUID = 1L;
public static void main(String[] args) {
BufferedImage bi = new BufferedImage(120,120, BufferedImage.TYPE_INT_ARGB);
Graphics g = bi.createGraphics();
g = g.create(0, 0, 100, 100);
g.setColor(Color.BLACK);
JFrame frame = new JFrame("hello SWING");
frame.setResizable(false);
frame.setSize(500,500);
frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
//**********//
frame.paint(g);

//**********//
frame.setTitle("tu");
frame.setVisible(true);

}

}

Answer 1

你需要重写paint 的方法
class MyPanel extends JPanel{

public void paint(Graphics g){

super.paint(g);

g.drawOval(100, 100, 30, 30);
}
}
这样才能画，