Java JPanel将不会显示在JFrame中

Question

This is my first time on stackoverflow and I am having an issue which I can't seem to get to the bottom of. I am trying to independently develop a small desktop game which uses a class called "Frame.java" to create a JFrame with all the menus and such that I need using a method called "create()", which returns the frame. I'm also using another class called "MainPanel.java", which extends JPanel, to create an instance of MainPanel to add to the frame's contentpane. However, when I run all the code in my little driver program, nothing seems to be displaying. any help would be appreciated!

public class MainPanel extends JPanel{

    //the background image of the game
    private BufferedImage img = null; 
    //GUI components of the game
    private JPanel gameWindow, gameWindowHolder, gameInfoHolder, LevelPanel, RevenuePanel,
                    ActionPanel, TimePanel;

    public MainPanel(String path, int width, int height){

        //create BufferedImage based on path
        img = new ImageHelper().createBufferedImage(path);
        //use img to create JPanel gameWindow
        gameWindow = ImageHelper.makeImageComponent(img, width, height);

        gameInfoHolder = new JPanel();
        gameInfoHolder.setPreferredSize(new Dimension(width+10, height+10));
        gameInfoHolder.setBackground(Color.black);
        gameInfoHolder.add(gameWindow);

        //set size of this MainPanel
        setPreferredSize(new Dimension(width+300, height+10));
        //add gameInfoHolder to MainPanel
        add(gameInfoHolder);

    }

    public void paint(Graphics g) {
        super.paintComponent(g);

    }
}

---

public class Driver {


public static void main( String []args){
    JFrame frame = Frame.create();

    JPanel panel = new MainPanel("images/backgrounds/jessicaAlba.jpg", 330, 500);

    frame.getContentPane().add(panel);

    frame.pack();
    frame.setVisible(true);
}

}

---

public class ImageHelper {


//
//Returns an ImageIcon object based on the path
//
public ImageIcon createImageIcon(String path, String description){

    URL imgURL = getClass().getResource(path);
    if (imgURL != null)
        return new ImageIcon(imgURL, description);
    else {
        System.err.println("Couldn't find this file: " + path + ". Check path.");
        return null;
    }
}

//
//Returns an Image object based on the path
//
public Image createImage(String path){

    URL imgURL = getClass().getResource(path);
    Toolkit kit = Toolkit.getDefaultToolkit();

    if (imgURL != null){
        return kit.createImage(imgURL);
    }
    else {
        System.err.println("Couldn't find this file: " + path + ". Check path.");
        return null;
    }

}

//
//Returns a BufferedImage object based on the path
//
public BufferedImage createBufferedImage(String path){
    BufferedImage image;
    URL imgURL = getClass().getResource(path);
    try
    {
        image = ImageIO.read(imgURL);
    }
    catch (IOException e)
    {
        System.err.println("Couldn't find this file: \""+ path +"\". Check path.");
        return null;
    }
    return image;
}

//
//Returns a JPanel object composed of the image found in the path.
//
public static JPanel makeImageComponent(String path, int width, int height){
    BufferedImage image;
    JLabel picLabel;
    ImageIcon icon;

    JPanel panel = new JPanel();
    JPanel panel2 = new JPanel();
    ImageHelper h = new ImageHelper();

    image = h.createBufferedImage(path);
    image = resize(image, width, height);
    icon = new ImageIcon(image);

    panel.setPreferredSize(new Dimension(width, height));
    panel2.setPreferredSize(new Dimension(width+10, height+10));

    panel2.setBackground(Color.black);
    picLabel = new JLabel(icon);
    panel.add(picLabel);
    panel2.add(panel);

    return panel2;
}

//
//Returns a JPanel object composed of the BufferedImage object in the argument
//
public static JPanel makeImageComponent(BufferedImage image, int width, int height){
    JLabel picLabel;
    ImageIcon icon;

    JPanel panel = new JPanel();
    image = resize(image, width, height);
    icon = new ImageIcon(image);
    panel.setPreferredSize(new Dimension(width, height));
    picLabel = new JLabel(icon);
    panel.add(picLabel);

    return panel;
}

//
//Resizes the BufferedImage object to the specified new width and new height.
//
public static BufferedImage resize(BufferedImage img, int newW, int newH) {  
    int w = img.getWidth();  
    int h = img.getHeight();  
    BufferedImage dimg = new BufferedImage(newW, newH, img.getType());  
    Graphics2D g = dimg.createGraphics();  
    g.setRenderingHint(RenderingHints.KEY_INTERPOLATION, RenderingHints.VALUE_INTERPOLATION_BILINEAR);  
    g.drawImage(img, 0, 0, newW, newH, 0, 0, w, h, null);  
    g.dispose();  
    return dimg;  
}
}

Answer 1

Nothing is displayed as you're short-circuiting the paint 'stack' with super.paintComponent so no child components will be painted.

public void paint(Graphics g) {
   super.paintComponent(g);
}

As this is really serving no purpose it can be removed and the added panels will be displayed.