Java JLayeredPane来实现窗口背景图片

用JLayeredPane实现在不影响窗口组件布局的情况下，添加一个背景图片：

、

调整窗口大小后：

[java]
package com.han;

import java.awt.BorderLayout;
import java.awt.Container;
import java.awt.Dimension;
import java.awt.Image;
import java.awt.Point;
import java.awt.Rectangle;
import java.awt.Toolkit;
import java.awt.event.ComponentAdapter;
import java.awt.event.ComponentEvent;

import javax.swing.BorderFactory;
import javax.swing.ImageIcon;
import javax.swing.JButton;
import javax.swing.JFrame;
import javax.swing.JLabel;
import javax.swing.JLayeredPane;
import javax.swing.JPanel;

/**www.zzzyk.com
* The JLayeredPane has no layout manager by default, so you have to use
* setBounds() for each component in it. However, you can still assign a layout
* manager to the layered pane.
* 
* Many programs use intermediate containers (such as panels) and their layout
* managers to lay out components on the same layer, but use absolute
* positioning to lay out components on different layers.
* 
* We can use frame.pack() or frame.setSize() whatever its layout method is
* (use a layout manager or not).
* 
* In fact, if we hesitate to use component.setPreferredSize() or
* component.setSize(), we first see the layout method employed to layout this
* component. If it has a layout manager, we use component.setPreferredSize();
* else (no layout manager), we use component.setBounds().
* 
* Concerning the JLayeredPane, the depth is higher, the component is on
* the top (of course, there are some depth conventions, like DEFAULT_LAYER,
* PALETTE_LAYER, ...). Within its depth, the position number is 0, top-most;
* -1, bottom-most; 0, 1, 2, 3, ... from top to bottom.
*
* @author HAN
*
*/
@SuppressWarnings("serial")
public class JLayeredPane_1 extends JFrame {

 public JLayeredPane_1() {
 // TODO Auto-generated constructor stub
 Container container = getContentPane();

 final JLayeredPane layeredPane = new JLayeredPane();
// layeredPane.setBorder(BorderFactory.createTitledBorder(null,
// "layeredPane", TitledBorder.LEADING, TitledBorder.TOP,
// new Font(null, Font.BOLD + Font.ITALIC, 14), Color.RED));
 layeredPane.setBorder(BorderFactory.createTitledBorder("<html>" +
 "layeredPane" +
 "</html>"));
 Dimension dimension = new Dimension(300, 310);
 layeredPane.setPreferredSize(dimension);

 final JPanel panelBg = new JPanel();
 final Image imageBg = Toolkit.getDefaultToolkit()
 .getImage(this.getClass().getResource("/images/Lighthouse.jpg"));
 ImageIcon imageIcon = new ImageIcon(imageBg.getScaledInstance
 (dimension.width, dimension.height, Image.SCALE_FAST));
 final JLabel bg = new JLabel(imageIcon);
 final Point origin = new Point(10, 30);
 final Rectangle rectangle = new Rectangle(origin, dimension);
 panelBg.setBounds(rectangle);
 panelBg.add(bg);

 final JPanel panelContent = new JPanel();
 JButton button = new JButton("button 1");
 JButton button2 = new JButton("button 2");
 JButton button3 = new JButton("button 3");
 panelContent.setBounds(rectangle);
 panelContent.setOpaque(false); // 设置为透明
 panelContent.add(button);
 panelContent.add(button2);
 panelContent.add(button3);

 layeredPane.add(panelBg, new Integer(0)); // the same to layeredPane.add(panelBg);
 layeredPane.add(panelContent, new Integer(1));

 container.add(layeredPane, BorderLayout.CENTER);

 addComponentListener(new ComponentAdapter() {
 public void componentResized(ComponentEvent e) {
// System.out.println(layeredPane.getSize()); //此处必须用getSize()而不是用getPreferredSize()
// System.out.println(layeredPane.getPreferredSize());
 Dimension dimensionNew = layeredPane.getSize();
 Rectangle rectangleNew = new Rectangle(origin, dimensionNew);
 panelBg.setBounds(rectangleNew);
 &

补充：软件开发 , Java ,