java如何添加子菜单

JMenuBar jmb=new JMenuBar()

JMenu jmF=new JMenu("File")

JMenuItem jmi=new JMenuItem("Exit")//子菜单

看我这个吧:

import java.awt.*

import java.awt.event.*

import java.io.*

public class TestWindow extends Frame implements ActionListener

{

TextArea ta

Button b1,b2

Dialog md

MenuItem open,save,myexit,open1,save1

MenuItem copy,palse

CheckboxMenuItem bold,ita

MenuBar mb

PopupMenu popm

public void createmenu()

{

mb=new MenuBar()

Menu m1=new Menu("文件")

Menu m2=new Menu("编辑")

Menu m3=new Menu("字体")

mb.add(m1)mb.add(m2)m2.add(m3)

open=new MenuItem("打开")

open.addActionListener(this)

save=new MenuItem("保存")

myexit=new MenuItem("退出")

m1.add(open)m1.add(save)m1.add(myexit)

copy=new MenuItem("复制")

palse=new MenuItem("粘贴")

bold=new CheckboxMenuItem("加粗")

ita=new CheckboxMenuItem("倾斜")

m2.add(copy)m2.add(palse)

m3.add(bold)m3.add(ita)

popm=new PopupMenu ()

open1=new MenuItem("打开")

open1.addActionListener(this)

save1=new MenuItem("保存")

popm.add(open1)popm.add(save1)

ta.add(popm)

ta.addMouseListener(new MyMouseEvent(this))

}

class MyMouseEvent extends MouseAdapter

{ TestWindow myparentFrame

MyMouseEvent ( TestWindow m)

{myparentFrame=m }

public void mouseReleased(MouseEvent e)

{if(e.isPopupTrigger())

myparentFrame.popm.show((Component)e.getSource(),e.getX(),e.getY()) }

}

public TestWindow ()

{

addWindowListener(new WindowAdapter(){

public void windowClosing(WindowEvent e)

{

dispose()

System.exit(0)

}

})

ta=new TextArea(10,30)

b1=new Button("d出对话框")

b2=new Button("隐藏对话框")

b1.addActionListener(this)

b2.addActionListener(this)

add(ta,BorderLayout.CENTER)

Panel p1=new Panel()

p1.add(b1)

p1.add(b2)

add(p1,BorderLayout.SOUTH)

setVisible(true)

setSize(400,300)

md=new Dialog(this,"对话框")

md.add(new Label("这是一个对话框"))

md.setSize(100,60)

md.addWindowListener(new WindowAdapter(){

public void windowClosing(WindowEvent e)

{

md.setVisible(false)

}

})

pack()

createmenu()

setMenuBar(mb)

}

public void actionPerformed(ActionEvent e)

{

if(e.getSource()==b1)

md.setVisible(true)

if(e.getSource()==b2)

md.setVisible(false)

if(e.getActionCommand()=="打开")

try{ openfile()}catch(IOException ex){}

}

public void openfile() throws IOException

{

FileDialog fd=new FileDialog(this,"aaa",FileDialog.LOAD)

fd.setVisible(true)

FileInputStream fis=new FileInputStream( fd.getDirectory()+fd.getFile())

String s=""

int n=0

while((n=fis.read())!=-1)

ta.append(""+(char)n)

fis.close()

}

public static void main(String []args)

{

TestWindow tw=new TestWindow()

}

}

import java.awt.*

import javax.swing.*

public class ErjiMenu extends JFrame

{

JPanel jp=new JPanel()

JMenuBar menubar=new JMenuBar()

JMenu m1=new JMenu("菜单")

JMenu m2=new JMenu("菜单")

JMenuItem item1=new JMenuItem("菜单项")

JMenuItem item2=new JMenuItem("菜单项1")

JMenuItem item3=new JMenuItem("菜单项2")

public ErjiMenu()

{

jp.setLayout(new BorderLayout())

m2.add(item2) //m2添加菜单项。

m2.add(item3)

m1.add(item1)

m1.add(m2) //m1把m2添加进去，作为二级菜单.

menubar.add(m1)

jp.add(menubar,BorderLayout.NORTH)

this.add(jp)

this.setBounds(100,100,380,200)

this.setVisible(true)

this.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE)

}

public static void main(String[] args)

{

new ErjiMenu()

}

}

不用JPopupMenu,更简单。

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