JMenuBar未在Java中显示

Question

我正在尝试制作一个带有子菜单的菜单。由于某种原因，我的菜单不会出现，我不知道为什么。JFrame出现，但JMenuBar没有。有人能帮我弄清楚问题出在哪里吗？

public class AWorldPanel extends JPanel {
    /** Declaring all the menu items within the GUI **/
    private JMenuItem Fileitem1 = new JMenuItem("New configuration");
    private JMenuItem Fileitem2 = new JMenuItem("Open configuration file ");
    private JMenuItem Fileitem3 = new JMenuItem("Save");
    private JMenuItem Fileitem4 = new JMenuItem("Save As");
    private JMenuItem Fileitem5 = new JMenuItem("Exit");
    private JMenuItem Viewitem1 = new JMenuItem("Display configuration");
    private JMenuItem Viewitem2 = new JMenuItem("Edit configuration");
    private JMenuItem Viewitem3 = new JMenuItem("Info about Bugs");
    private JMenuItem Viewitem4 = new JMenuItem("Info about Map");
    private JMenuItem Edititem1 = new JMenuItem("Remove");
    private JMenuItem Edititem2 = new JMenuItem("Add");
    private JMenuItem Simulationitem1 = new JMenuItem("Simulation");
    private JMenuItem Helpitem1 = new JMenuItem("Info about application");
    private JMenuItem Helpitem2 = new JMenuItem("Info about author");
    JLabel theLabel;
    JPanel thePanel;
    JButton Run, Pause, Reset;
    JFrame GUI = new JFrame("Graphical User Interface");
    public void AWorldPanel() {
        // Create the container
        JFrame GUI = new JFrame("Graphical User Interface");
        GUI.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
        /** Creating the menu **/
        JMenuBar menubar = new JMenuBar();
        JMenu File = new JMenu("File");
        JMenu View = new JMenu("View");
        JMenu Edit = new JMenu("Edit");
        JMenu Simulation = new JMenu("Simulation");
        JMenu Help = new JMenu("Help");
        /** sub menus **/
        menubar.add(File);
        File.add(Fileitem1);
        File.add(Fileitem2);
        File.add(Fileitem3);
        File.add(Fileitem4);
        File.add(Fileitem5);
        menubar.add(View);
        View.add(Viewitem1);
        View.add(Viewitem2);
        View.add(Viewitem3);
        View.add(Viewitem4);
        menubar.add(Edit);
        Edit.add(Edititem1);
        Edit.add(Edititem2);
        menubar.add(Simulation);
        Simulation.add(Simulationitem1);
        menubar.add(Help);
        Help.add(Helpitem1);
        Help.add(Helpitem2);
    }
    private static void createAndShowGUI() {
        AWorldPanel newworld = new AWorldPanel();
        newworld.GUI.pack();
        newworld.GUI.setVisible(true);
        newworld.GUI.setLocation(300, 100);
        newworld.GUI.setSize(500, 500);
    }
    public static void main(String args[]) {
        javax.swing.SwingUtilities.invokeLater(new Runnable() {
            public void run() {
                createAndShowGUI();
            }
        });
    }
}

Answer 1

您创建了一个菜单，但不将其设置为框架。

使用此：

GUI.setMenuBar(menubar);

创建之后。