JPanel未显示在我的JFrame中，但显示在新窗口中

Question

I believe I am doing something simple wrong; and my research has got me no where.

I created a stand alone Java application, that I am trying to convert to run as an applet. (Being an applet is a requirement).

I created a JPanel class MazePanel,and I am trying to display it as an applet. When I run my Applet in Netbeans, 2 windows load. One is a blank Applet window, while the other is my Maze. I want the Maze (which is implemented in MazePanel), to display in my applet. Can anyone take a look at this, and tell me what I am doing wrong.

public class MazeApplet extends JApplet {


protected JFrame frame;
protected JPanel jPanel;
protected MazeBuilder builder;
protected MazeFactory factory;

public MazeApplet() {
    //Set up frame
    frame = new JFrame("Maze -- Builder");
    frame.setLayout(new BorderLayout());

    frame.setVisible(true);
    frame.setResizable((true));

}

public void init() {

    factory = new ShoutMazeFactory();
    builder = new FactoryMazeBuilder(factory);
    Maze maze = MazeGameBuilder.createMaze(builder);
    maze.setCurrentRoom(1);
    jPanel = (new Maze.MazePanel(maze));
//Add jPanel to Frame
    frame.getContentPane().add(jPanel);
    frame.pack();
    }
}

Below is the JPanel Class I am trying to display

public class MazePanel extends JPanel{

protected Maze maze = new Maze();
  public void paint(Graphics g) {
Dimension dim = getSize(); 
g.setColor(Color.white);
g.fillRect(0, 0, dim.width, dim.height);    
g.setColor(Color.black);
  maze.draw(g);
  }    
}

Answer 1

While working in an applet you can't create a new frame which is the reason for the creation of the frame.

Start you initial panel in the init() block and then make panels visible or invisible depending on the need.