JFrame最小化后恢复的重绘问题，在线等

import java.awt.Color;

import java.awt.Container;

import java.awt.Dimension;

import java.awt.Graphics;

import java.awt.Toolkit;



import javax.swing.JFrame;



public class MainFrame extends JFrame{

	public MainFrame(){

		setTitle("");

		Container count=getContentPane();

		

		count.setLayout(null);

		setSize(500,350);

		setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);

		Dimension scr = Toolkit.getDefaultToolkit().getScreenSize();

		Dimension frm = this.getSize();

		setLocation( (scr.width - frm.width) / 2,

		        (scr.height - frm.height) / 2 );//设置窗体居中

		setVisible(true);	

		}

	 public void paint(Graphics g){

	 

	   g.setColor(Color.black);

	 g.drawString("hello,september", 100, 200);

	 g.drawLine(300, 50, 300, 200);

	

	

	  }



	public static void main(String[] args){

		new MainFrame();

		}

}