Java 右键单击以选择文本JTextPane

在我的JTextPane中，当我选择文本并右键单击时；它提供了复制文本的选项。代码如下：

public LogPane() {
    super();
    JPopupMenu pop = new JPopupMenu();
    final LogPane l = this;
    JMenuItem copy = new JMenuItem("Copy      CTRL+C");
    copy.addActionListener(new ActionListener() {

        @Override
        public void actionPerformed(ActionEvent e) {
            selected = l.getSelectedText();
            if(selected==null)
                return;
            StringSelection clipString = new StringSelection(selected);
            clipbd.setContents(clipString,clipString);
        }

    }); 
    pop.add(copy);
    copy.setEnabled(true);
}

---

因此，右键单击，它提供了复制文本的选项。但是我想要的是，当没有选择任何文本并且用户右键单击时，不应该显示-Copy选项。如何合并更改？

您显示了错误的代码部分。重要的代码部分是您的

鼠标侦听器

，即右键单击时发生的情况

在该

MouseEvent

中，您可以使用，即

---

一个

PopupMenuListener

应该可以做到这一点

public LogPane() {
    super();
    JPopupMenu pop = new JPopupMenu();
    final LogPane l = this;
    final JMenuItem copy = new JMenuItem("Copy      CTRL+C");
    copy.addActionListener(new ActionListener() {

        @Override
        public void actionPerformed(ActionEvent e) {
            selected = l.getSelectedText();
            if(selected==null)
                return;
            StringSelection clipString = new StringSelection(selected);
            clipbd.setContents(clipString,clipString);
        }

    }); 
    pop.add(copy);
    pop.addPopupMenuListener(new PopupMenuListener() {
        public void popupMenuCanceled(PopupMenuEvent e) {}
        public void popupMenuWillBecomeInvisible(PopupMenuEvent e) {}
        public void popupMenuWillBecomeVisible(PopupMenuEvent e) {
            copy.setEnabled(l.getSelectedText() != null);
        }
    });
}

public LogPane() {
    super();
    JPopupMenu pop = new JPopupMenu();
    final LogPane l = this;
    final JMenuItem copy = new JMenuItem("Copy      CTRL+C");
    copy.addActionListener(new ActionListener() {

        @Override
        public void actionPerformed(ActionEvent e) {
            selected = l.getSelectedText();
            if(selected==null)
                return;
            StringSelection clipString = new StringSelection(selected);
            clipbd.setContents(clipString,clipString);
        }

    }); 
    pop.add(copy);
    pop.addPopupMenuListener(new PopupMenuListener() {
        public void popupMenuCanceled(PopupMenuEvent e) {}
        public void popupMenuWillBecomeInvisible(PopupMenuEvent e) {}
        public void popupMenuWillBecomeVisible(PopupMenuEvent e) {
            copy.setEnabled(l.getSelectedText() != null);
        }
    });
}