Question

给我一个实现多层菜单的例子

比如 “工具”——“邮件和新闻”——“阅读邮件”，那阅读邮件这个菜单怎么实现出来？

Answer 1

import javax.swing.JFrame;
import javax.swing.JMenu;
import javax.swing.JMenuBar;
import javax.swing.JMenuItem;

public class MenuBarDemo extends JFrame {

JMenuBar menuBar;
JMenu file,edit,news;
JMenuItem newsFile,javaFile,open,exit;
JMenuItem undo,redo,copy,cut,paste,find,replace;

public static void main(String[] args) {
new MenuBarDemo().setMenuBar();

}

public void setMenuBar(){
menuBar = new JMenuBar();
this.setJMenuBar(menuBar);
file = new JMenu("文件");
news = new JMenu("新建");

newsFile = this.addItem("文件夹", news);
javaFile = this.addItem("java文件", news);
file.add(news);

open = this.addItem("打开", file);
exit = this.addItem("退出", file);

edit = new JMenu("编辑");

undo = this.addItem("撤销", edit);
redo = this.addItem("重做", edit);
cut = this.addItem("剪切", edit);
copy = this.addItem("拷贝", edit);
paste = this.addItem("粘贴", edit);
find = this.addItem("查找", edit);
replace = this.addItem("替换", edit);

menuBar.add(file);
menuBar.add(edit);

this.setBounds(200, 200, 300, 300);
this.setResizable(false);
this.setVisible(true);

}

public JMenuItem addItem(String name,JMenu menu){
JMenuItem temp = new JMenuItem(name);
menu.add(temp);
return temp;
}

}