在按钮操作上向JPanel添加背景图像
调用JButton时，将背景图像添加到JPanel / JLabel的最佳方法是什么？ 我知道如何获得JButton动作等。 当按下该按钮时，我无法弄清楚或找到一种方法来改变背景图像。
这是一个例子：
import java.awt.BorderLayout; import java.awt.Container; import java.awt.Dimension; import java.awt.Graphics; import java.awt.Image; import java.awt.event.ActionEvent; import java.awt.event.ActionListener; import java.net.URL; import java.util.concurrent.ExecutionException; import javax.imageio.ImageIO; import javax.swing.ImageIcon; import javax.swing.JButton; import javax.swing.JFrame; import javax.swing.JPanel; import javax.swing.SwingUtilities; import javax.swing.SwingWorker; public class ModifiableBackgroundFrame extends JFrame implements ActionListener { private static final long serialVersionUID = 1L; private ImageIcon image; private JPanel pan; private JButton btn; private int count = 0; private static final String[] images = {"http://www.dvd-ppt-slideshow.com/images/ppt-background/background-3.jpg", "http://www.psdgraphics.com/wp-content/uploads/2009/02/abstract-background.jpg", "http://hdwallpaperpics.com/wallpaper/picture/image/background.jpg", "http://www.highresolutionpics.info/wp-content/uploads/images/beautiful-on-green-backgrounds-for-powerpoint.jpg"}; public ModifiableBackgroundFrame() { super("The title"); image = new ImageIcon(); btn = new JButton("Change background"); btn.setFocusPainted(false); btn.addActionListener(this); pan = new JPanel() { private static final long serialVersionUID = 1L; @Override public void paintComponent(Graphics g) { g.drawImage(image.getImage(), 0, 0, null); } }; pan.setPreferredSize(new Dimension(400, 400)); Container contentPane = getContentPane(); contentPane.setLayout(new BorderLayout()); contentPane.add(pan, BorderLayout.CENTER); contentPane.add(btn, BorderLayout.SOUTH); pack(); setDefaultCloseOperation(EXIT_ON_CLOSE); setLocationRelativeTo(null); setVisible(true); } public static void main(String[] args) { SwingUtilities.invokeLater(new Runnable() { @Override public void run() { new ModifiableBackgroundFrame(); } }); } @Override public void actionPerformed(ActionEvent e) { btn.setEnabled(false); btn.setText("Loading..."); new SwingWorker() { @Override protected Image doInBackground() throws Exception { return ImageIO.read(new URL(images[count++ % 4])); } @Override protected void done() { try { image.setImage(get()); pan.repaint(); } catch(InterruptedException e) { e.printStackTrace(); } catch(ExecutionException e) { e.printStackTrace(); } btn.setText("Change background"); btn.setEnabled(true); } }.execute(); } } 在JButton的actionPerformed ，您可以调用JLabel.setIcon（Icon）来设置背景图像。
final JLabel label = new JLabel(); button.addActionListener(new ActionListener() { public void actionPerformed(ActionEvent e) { label.setIcon(new ImageIcon(SOME_IMAGE)); } }