Dialog对象是一个窗口，显示在用户与之交互的基本窗口的顶部.在本章中，我们将看到swing库中定义的预配置对话框.它们是 MessageDialog，ConfirmDialog 和 InputDialog .由于JOptionPane类的静态方法，它们可用.
在下面的示例中，"文件"菜单有三个对应于上述三个对话框的JMenu项;每个都执行 OnClick 事件处理程序.
file = JMenu("File")
msgbtn = JMenuItem("Message",actionPerformed = OnClick)
conbtn = JMenuItem("Confirm",actionPerformed = OnClick)
inputbtn = JMenuItem("Input",actionPerformed = OnClick)
file.add(msgbtn)
file.add(conbtn)
file.add(inputbtn)OnClick()处理程序函数检索Menu的标题项目按钮并调用相应的showXXXDialog()方法.
def OnClick(event):
str = event.getActionCommand()
if str == 'Message':
JOptionPane.showMessageDialog(frame,"this is a sample message dialog")
if str == "Input":
x = JOptionPane.showInputDialog(frame,"Enter your name")
txt.setText(x)
if str == "Confirm":
s = JOptionPane.showConfirmDialog (frame, "Do you want to continue?")
if s == JOptionPane.YES_OPTION:
txt.setText("YES")
if s == JOptionPane.NO_OPTION:
txt.setText("NO")
if s == JOptionPane.CANCEL_OPTION:
txt.setText("CANCEL")如果选择了菜单中的消息选项，则会弹出一条消息.如果单击"输入"选项，则会弹出一个要求输入的对话框.然后输入文本显示在JFrame窗口的文本框中.如果选择了确认选项，则会出现一个包含三个按钮，YES，NO和CANCEL的对话框.用户的选择记录在文本框中.
整个代码在下面和下面给出;
from javax.swing import JFrame, JMenuBar, JMenu, JMenuItem, JTextField
from java.awt import BorderLayout
from javax.swing import JOptionPane
frame = JFrame("Dialog example")
frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE)
frame.setLocation(100,100)
frame.setSize(400,300)
frame.setLayout(BorderLayout())
def OnClick(event):
str = event.getActionCommand()
if str == 'Message':
JOptionPane.showMessageDialog(frame,"this is a sample message dialog")
if str == "Input":
x = JOptionPane.showInputDialog(frame,"Enter your name")
txt.setText(x)
if str == "Confirm":
s = JOptionPane.showConfirmDialog (frame, "Do you want to continue?")
if s == JOptionPane.YES_OPTION:
txt.setText("YES")
if s == JOptionPane.NO_OPTION:
txt.setText("NO")
if s == JOptionPane.CANCEL_OPTION:
txt.setText("CANCEL")
bar = JMenuBar()
frame.setJMenuBar(bar)
file = JMenu("File")
msgbtn = JMenuItem("Message",actionPerformed = OnClick)
conbtn = JMenuItem("Confirm",actionPerformed = OnClick)
inputbtn = JMenuItem("Input",actionPerformed = OnClick)
file.add(msgbtn)
file.add(conbtn)
file.add(inputbtn)
bar.add(file)
txt = JTextField(10)
frame.add(txt, BorderLayout.SOUTH)
frame.setVisible(True)执行上述脚本时，会显示以下窗口，菜单中有三个选项 :
