為Java的JLayeredPane組件添加窗口背景圖片

用JLayeredPane實現在不影響窗口組件布局的情況下，添加一個背景圖片：

、

調整窗口大小后：

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;
/**

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.
</p>

We can use frame.pack() or frame.setSize() whatever its layout method is 
(use a layout manager or not).
</p>

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().
</p>

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("<b><i>" +
         "<u><span style="font-family:SansSerif;color:red;font-size:large;">layeredPane" +
         "</span></u></i></b>"));
 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); // 設置為透明
 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()); //此處必須用getSize()而不是用getPreferredSize()
//              System.out.println(layeredPane.getPreferredSize());

         Dimension dimensionNew = layeredPane.getSize();
         Rectangle rectangleNew = new Rectangle(origin, dimensionNew);
         panelBg.setBounds(rectangleNew);
         panelContent.setBounds(rectangleNew);
         bg.setIcon(new ImageIcon(imageBg.getScaledInstance
         (dimensionNew.width, dimensionNew.height, Image.SCALE_FAST)));
     }
 });

}
/**

@param args
@throws Exception 
*/
public static void main(String[] args) {
 // TODO Auto-generated method stub
 JLayeredPane_1 frame = new JLayeredPane_1();
 frame.pack();
 frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
 frame.setVisible(true);
}



}</p>
</pre>來自：http://blog.csdn.net/gaowen_han/article/details/8164720