如何在JPanel中添加背景图片？

Question

我完全按照优秀的指南进行操作，但它不起作用，我想单击一个按钮来更改程序的背景。我很乐意更改图片

代码指南 https:/ /stackhowto.com/how-to-set-background-image-in-java-swing/

public class Main {
    public static void main(String[] args) {
        JFrame frame = new JFrame("Display an image in the background");
        final ImageIcon icon = new ImageIcon("background.png");
        JTextArea text = new JTextArea()
        {
             Image img = icon.getImage();
            // instance initializer
            {setOpaque(false);}
            public void paintComponent(Graphics graphics)
            {
                graphics.drawImage(img, 0, 0, this);
                super.paintComponent(graphics);
            }
        };
        JScrollPane pane = new JScrollPane(text);
        Container content = frame.getContentPane();
        content.add(pane, BorderLayout.CENTER);
        frame.setDefaultCloseOperation(3);
        frame.setSize(400, 300);
        frame.setVisible(true);
    }
}