用java编图形界面，想要用图片作为窗口的背景怎样实现？求大哥些帮帮忙

直接改窗体的背景不太好,因为窗体的重画方法的调用时机不太好弄.
实现方法如下.
继承PANEL类,实现一个自己的panel类,然后重写paint()方法来搞定.
下边是实现的代码.你参考一下.

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import java.awt.Graphics;

import javax.swing.ImageIcon;
import javax.swing.JFrame;
import javax.swing.JPanel;

public class Img extends JFrame {

public Img() {

setSize(400, 500);
setDefaultCloseOperation(EXIT_ON_CLOSE);
getContentPane().setLayout(null);
JPanel panel = new MyImage();
panel.setBounds(0, 0, 400, 500);
getContentPane().add(panel);
setVisible(true);
}

public static void main(String[] args) {
new Img();
}

class MyImage extends JPanel {
public MyImage() {
setLayout(null);
}

public void paint(Graphics g) {
super.paint(g);
ImageIcon img = new ImageIcon("G:\\4.jpg");
g.drawImage(img.getImage(), 0, 0, 400, 500, this);
}
}
}

调容器实例, 然后setbackground