主页 / 问题 / 1047085
Accepted
Alice Magic
Asked:2020-11-17 11:22:43 +0000 UTC2020-11-17 11:22:43 +0000 UTC

如何使 JPopupMenu 不可见？

  • 772

无法使用 setVisible() 和 setEnabled() 方法禁用 JPopupMenu。通过这些方法可以毫无问题地处理单个 JMenuItem，但整个菜单不会以任何方式对它们做出反应。如何使上下文菜单仅在需要时出现在右键单击时？什么方法能够完全启用和禁用它？

import javax.swing.*;

public class PopupMenus extends JFrame {
    public PopupMenus() {
        super("PopupMenus");
        setDefaultCloseOperation( EXIT_ON_CLOSE );
        JPopupMenu popup = createPopupMenu();
        ((JComponent)getContentPane()).
                setComponentPopupMenu(popup);
        setSize(300, 200);
        popup.setVisible(false); // Эти строки можно удалить.
        popup.setEnabled(false); // Они не влияют ни на что.
        setVisible(true);
    }
    private JPopupMenu createPopupMenu() {
        JPopupMenu pm = new JPopupMenu();
        JMenuItem good = new JMenuItem("Один");
        JMenuItem excellent = new JMenuItem("Два");
        pm.add(good);
        pm.add(excellent);
        return pm;
    }
    public static void main(String[] args) {
        SwingUtilities.invokeLater(
                PopupMenus::new);
    }
}

字符串

popup.setVisible(false);
popup.setEnabled(false);

不影响上下文菜单的外观。无论如何，它会在您右键单击时出现。需要做什么才能禁用和启用显示整个上下文菜单的功能？

java

1 个回答

  1. Best Answer

    画了一个解决方案。它只是需要setComponentPopupMenu(null)完成。

    boolean showed = true;

PopupMenus() {
    super("PopupMenus");
    setDefaultCloseOperation( EXIT_ON_CLOSE );
    JPopupMenu popup = createPopupMenu();
    ((JComponent)getContentPane()).setComponentPopupMenu(popup);
    setSize(300, 200);

    JPanel jPanel = new JPanel();

    add(jPanel);

    JButton jButton = new JButton("Button");

    jButton.addActionListener(new ActionListener() {
        @Override
        public void actionPerformed(ActionEvent e) {
            if (showed) {
                ((JComponent)getContentPane()).setComponentPopupMenu(null);
                showed = false;
            } else {
                ((JComponent)getContentPane()).setComponentPopupMenu(popup);
                showed = true;
            }
        }
    });

    // Или более коротко
    // jButton.addActionListener(e -> ((JComponent)getContentPane()).setComponentPopupMenu((showed = !showed) ? popup : null));

    jPanel.add(jButton);

    setVisible(true);
}
    • 2

相关问题