java - 右键单击选择文本 JTextPane

Question

在我的 JTextPane 中，当我选择文本并单击鼠标右键时；它提供了复制文本的选项。下面是代码:

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);
}

所以在右键单击时，它会提供复制文本的选项。但我想要的是，当没有选择文本并且用户右键单击时 - 不应显示复制选项。应该如何合并更改？

Answer 1

PopupMenuListener 应该可以解决问题。

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);
        }
    });
}