菜单上的java动作侦听器，而不是菜单项 [英] java action listener on menu, and not on menu item

问题描述

我需要启蒙.

如何添加actionactionListener事件绑定到菜单，而不绑定到菜单ITEM这是演示代码，可以运行(在 menuITEM 上).

how to add action actionListener event bind to the menu, and not bind to the menu ITEM here is the demo code, that works(on menuITEM)..

menuFileItem.addActionListener(
            new ActionListener(){
                public void actionPerformed(ActionEvent e)
                {
                    System.out.println("It works");
                }
            }
        );

但是当我尝试相同时，但仅在菜单本身上它不起作用！

but when i try the same , but just on the MENU itself it doesn't work!

menuFile.addActionListener(
            new ActionListener(){
                public void actionPerformed(ActionEvent e)
                {
                    System.out.println("Plz work... :( ");
                }
            }
        );

是否可以将侦听器添加到菜单中?我教过听众可以添加到一切中.

is it possible to add listener to menu? i taught listener could be added to everything.

推荐答案

您可以将 ActionListener 添加到 JMenu，因为此方法继承自 AbstractButton.(JMenu 文档)

You can add an ActionListener to a JMenu as this method is inherited from AbstractButton. (JMenu Documentation)

JMenu menu = new JMenu("MyMenu");
menu.addActionListener(new ActionListener(){...});

但是，它不打算这样使用:JMenu 忽略 ActionEvent.您应该改用 MenuEvent 和 MenuListener.

But, it is not intended to be used this way: JMenu ignores ActionEvent. You should use MenuEvent and MenuListener instead.

JMenu menu = new JMenu("MyMenu");
menu.addMenuListener(new MenuListener() {

        @Override
        public void menuSelected(MenuEvent e) {
            System.out.println("menuSelected");

        }

        @Override
        public void menuDeselected(MenuEvent e) {
            System.out.println("menuDeselected");

        }

        @Override
        public void menuCanceled(MenuEvent e) {
            System.out.println("menuCanceled");

        }
    });

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