importjava.awt.*;importjava.awt.event.*;importjavax.swing.*;publicclassX10{publicstaticvoidmain(String[]args){Winwin=newWin();win.setTitle("下拉框的事件");}}classWinexten...
import java.awt.*;
import java.awt.event.*;
import javax.swing.*;
public class X10
{
public static void main(String[]args){
Win win=new Win();
win.setTitle("下拉框的事件");
}
}
class Win extends JFrame implements ItemListener,ActionListener
{
JComboBox choice;
JTextField text;
JTextArea area;
JButton add,del,exi;
Win(){
init();
setBounds(300,400,300,300);
setVisible(true);
setDefaultCloseOperation(EXIT_ON_CLOSE);
}
void init(){
setLayout(new FlowLayout());
choice=new JComboBox();
text=new JTextField(8);
area=new JTextArea(6,25);
choice.addItem("音乐天地");
choice.addItem("武术天地");
choice.addItem("象棋乐园");
choice.addItem("交友聊天");
add=new JButton("添加");
del=new JButton("删除");
exi=new JButton("退出");
add.addActionListener(this);
del.addActionListener(this);
text.addActionListener(this);
choice.addItemListener(this);
exi.addActionListener(this);
add(choice);
add(add);
add(del);
add(text);
add(exi);
add(new JScrollPane(area));
}
//public void actionPerformed(ActionEvent e){
public void itemStateChanged(ItemEvent e){
String name=choice.getSelectedItem().toString();
int index=choice.getSelectedIndex();
area.setText("\n"+index+":"+name);
}
public void actionPerformed(ActionEvent e){
if(e.getSource()==add||e.getSource()==text){
String name=text.getText();
if(name.length()>0){
choice.addItem(name);
choice.setSelectedItem(name);
area.append("\n列表添加:"+name);
}
}
else if(e.getSource()==del){
area.append("\n列表删除:"+choice.getSelectedItem());
choice.removeItemAt(choice.getSelectedIndex());
}
}
}请看上面的代码，按钮exi该怎么添加监视器，能让点击“退出”关闭窗口
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