JMenuBar被禁用后无法启用 [英] JMenuBar does not enable after being disabled

问题描述

我正在使用getJMenuBar().setEnabled(false)禁用JMenuBar，然后显示FileDialog(因为当FileDialog可见时菜单项仍处于活动状态)，然后在FileDialog关闭后调用getJMenuBar().setEnabled(true)，但菜单项在启用后不会变为活动状态-如果我更改为其他应用程序并返回我的菜单项，则菜单项将变为活动状态.我尝试致电getJMenuBar().revalidate()和/或getJMenuBar().repaint()无济于事.

I'm disabling a JMenuBar before displaying a FileDialog (as the menu items are still active when the FileDialog is visible) using getJMenuBar().setEnabled(false) and then calling getJMenuBar().setEnabled(true) after the FileDialog closes, but the menu items do not become active after being enabled - they will if I change to another application and back to mine. I've tried calling getJMenuBar().revalidate() and/or getJMenuBar().repaint() to no avail.

值得注意的是，我在OS X上使用的是屏幕菜单栏.显示问题的示例代码:

Of note, I'm using a screen menu bar as I'm on OS X. Sample code that shows the problem:

import javax.swing.*; 
import java.awt.*; 
import java.awt.event.ActionEvent; 
import java.awt.event.ActionListener;

public class MenuTest extends JFrame implements ActionListener {

    private JMenuItem menuItemNew = new JMenuItem("New");
    private JMenuItem menuItemOpen = new JMenuItem("Open");
    private JMenuItem menuItemSave = new JMenuItem("Save");
    private JMenu menuFile = new JMenu("File");
    private JMenuBar menuBar = new JMenuBar();

    public MenuTest() {
        super("JMenu Test");
        setSize(300, 300);
        setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);

        menuItemOpen.addActionListener(this);

        menuFile.add(menuItemNew);
        menuFile.add(menuItemOpen);
        menuFile.add(menuItemSave);
        menuBar.add(menuFile);
        setJMenuBar(menuBar);

        setVisible(true);
    }

    public void openFile() {
        getJMenuBar().setEnabled(false);
        FileDialog fd = new FileDialog(this, "Choose a file", FileDialog.LOAD);
        fd.setVisible(true);
        getJMenuBar().setEnabled(true);
    }

    @Override
    public void actionPerformed(ActionEvent e) {
        if (e.getSource() == menuItemOpen) {
            openFile();
        }
    }

    public static void main(String[] arguements) {
        System.setProperty("apple.laf.useScreenMenuBar", "true");
        new MenuTest();
    }

}

提前感谢您的评论/建议！

Thanks in advance for comments / suggestions!

推荐答案

对我来说，我可以通过启用/禁用每个JMenuItem而不是菜单栏或菜单本身来解决此问题.

For me, I could resolve the issue by enabling/disabling each JMenuItem and not the menu bar or menu itself.

我也在EDT上进行了所有操作，以防万一这是问题所在，但无济于事.

I also did everything on the EDT, just in case that was the problem, but it didn't help.

import javax.swing.*; 
import java.awt.*; 
import java.awt.event.ActionEvent; 
import java.awt.event.ActionListener;

public class MenuTest implements ActionListener {

    private JMenuItem menuItemNew = new JMenuItem("New");
    private JMenuItem menuItemOpen = new JMenuItem("Open");
    private JMenuItem menuItemSave = new JMenuItem("Save");
    private JMenu menuFile = new JMenu("File");
    private JMenuBar menuBar = new JMenuBar();
    JFrame frame;
    public MenuTest() {

    }

    public void buildGui(){
        frame = new JFrame("JMenu Test");
        frame.setSize(300, 300);
        frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);

        menuItemOpen.addActionListener(this);

        menuFile.add(menuItemNew);
        menuFile.add(menuItemOpen);
        menuFile.add(menuItemSave);

        menuBar.add(menuFile);
        frame.setJMenuBar(menuBar);

        frame.setVisible(true);
    }

    public void openFile() {
        menuItemNew.setEnabled(false);
        menuItemOpen.setEnabled(false);
        menuItemSave.setEnabled(false);

        FileDialog fd = new FileDialog(frame, "Choose a file", FileDialog.LOAD);
        fd.setVisible(true);

        menuItemNew.setEnabled(true);
        menuItemOpen.setEnabled(true);
        menuItemSave.setEnabled(true);

    }

    @Override
    public void actionPerformed(ActionEvent e) {

            openFile();
        }

    public static void main(String[] arguements) {
        System.setProperty("apple.laf.useScreenMenuBar", "true");
        EventQueue.invokeLater(()->{
            new MenuTest().buildGui();
                });
    }

}

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