关于repaint(x,y,h,w)重绘两个独立区域的问题！

Question

怎么才能实现使用repaint在同一个窗口内同时绘制两个分离的区域？并且不影响在这两个区域外的文本框和按钮？下面有一个按钮和文本框不能正常显示的代码？希望给帮忙：

package Fichnan.com;
import java.awt.Color;
import java.awt.Font;
import java.awt.Graphics;
import java.awt.GridLayout;
import java.util.Timer;
import java.util.TimerTask;
import javax.swing.JButton;
import javax.swing.JFrame;
import javax.swing.JPanel;
import javax.swing.JTextArea;
public class Play extends JPanel{
private static int barrageX = 500;
public void paint(Graphics g){
System.out.println(111);
g.clearRect(0, 0, 500, 30);
g.clearRect(0, 380, 500, 30);
g.setColor(new Color(0x000000));
g.setFont(new Font(Font.DIALOG,Font.PLAIN ,20));
g.drawString("asd", barrageX, 400);
g.drawString("这是一句会动的话！", barrageX, 20);
}

public void action(JPanel panel){
    Timer timer = new Timer();
    int intervel = 10;
    timer.schedule(new TimerTask(){
        public void run() {
            repaint(0, 0, 500, 30);
            repaint(5, 0, 380, 500, 30);
            System.out.println(222);
            barrageX--;
            if(barrageX<0){
                barrageX = 500;
            }
        }
    }, intervel,intervel);
}


public static void main(String[] args) {

    Play play = new Play();

    JFrame frame = new JFrame();
    frame.add(play);
    frame.setSize(500,500);
    frame.setVisible(true);
    frame.setAlwaysOnTop(true);
    frame.setResizable(true);
    frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
    frame.setLayout(null);

    JPanel panel = new JPanel();
    panel.setBounds(0,0,500,500);
    panel.setLayout(null);
    frame.add(panel);


    JPanel panel1 = new JPanel();
    panel1.setBounds(100,100,100,100);
    panel1.setBackground(Color.black);
    panel1.setLayout(new GridLayout(1,1));
    panel.add(panel1);

    JTextArea text = new JTextArea();
    text.setBounds(100,200,100,100);
    text.setBackground(Color.yellow);
    text.setVisible(true);
    panel.add(text);

    JButton button = new JButton("click");
    button.setBackground(Color.yellow);
    button.setBounds(200,100,100,100);
    panel.add(button);

    play.action(panel);

}

}

Answer 1

http://tieba.baidu.com/p/4951161803