程序8-14：
import java.awt.*;
import java.awt.event.*;
import javax.swing.*;
public class JOptionPaneDemo implements ActionListener{
JFrame frame = new JFrame ("JOptionPane Demo");
JTextField tf = new JTextField();
JButton messageButton,ConfirmButton,InputButton,OptionButton;
public static void main(String args[]) {
JOptionPaneDemo opd = new JOptionPaneDemo();
opd.go();
}
public void go() {
messageButton = new JButton("message dialog");
messageButton.addActionListener(this);
ConfirmButton = new JButton("Confirm dialog");
ConfirmButton.addActionListener(this);
InputButton = new JButton("Input dialog");
InputButton.addActionListener(this);
OptionButton = new JButton("Option dialog");
OptionButton.addActionListener(this);
JPanel jp = new JPanel();
jp.add(messageButton);
jp.add(ConfirmButton);
jp.add(InputButton);
jp.add(OptionButton);
Container cp = frame.getContentPane();
cp.add(jp,BorderLayout.CENTER);
cp.add(tf,BorderLayout.SOUTH);
frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
frame.pack();
frame.setVisible(true);
}
public void actionPerformed(ActionEvent e) {
JButton button = (JButton)e.getSource();
//信息对话框
if (button == messageButton){
JOptionPane.showMessageDialog(frame,
"File not found.",
"An error",
JOptionPane.ERROR_MESSAGE);
}
//确认对话框
if (button == ConfirmButton) {
int select = JOptionPane.showConfirmDialog(frame,
"Create one","Confirm",JOptionPane.YES_NO_OPTION);
if (select == JOptionPane.YES_OPTION)
tf.setText("choose YES");
if (select == JOptionPane.NO_OPTION)
tf.setText("choose NO");
if (select == JOptionPane.CLOSED_OPTION)
tf.setText("Closed");
}
//输入对话框
if (button == InputButton) {
Object[] possibleValues = { "First","Second","Third" };
Object selectedValue = JOptionPane.showInputDialog(frame,
"Choose one","Input",JOptionPane.INFORMATION_MESSAGE,null,
possibleValues,possibleValues[0]);
if(selectedValue != null)
tf.setText(selectedValue.toString());
else
tf.setText("Closed");
}
//选项对话框
if (button == OptionButton) {
Object[] options = { "OK","CANCEL" };
int select = JOptionPane.showOptionDialog(frame,"Click OK to continue",
"Warning",JOptionPane.DEFAULT_OPTION,JOptionPane.WARNING_MESSAGE,
null,options,options[0]);
if (select == 0)
tf.setText("choose OK");
else if (select == 1)
tf.setText("choose CANCEL");
else if (select == -1)
tf.setText("Closed");
}
}
}