Question

java JComboBox 项触发事件问题

发这个帖子是想知道 触发项事件，监听接口里要怎么写代码呢？

例如我选择3，则输出3

看了下面的代码就知道我想问什么了
import java.awt.*;
import javax.swing.*;
import java.awt.event.*;

public class heqian extends JFrame
{
public heqian()
{
Container c=getContentPane();
//c.setLayout(new BoxLayout(c,BoxLayout.Y_AXIS));
c.setLayout(new FlowLayout());
String[] s={"1","2","3","4","5","6"};
JComboBox JL=new JComboBox (s);
JL.setMaximumRowCount(5);
JL.addItemListener(new J_ItemListener());
c.add(JL);
}
class J_ItemListener implements ItemListener
{

public void itemStateChanged(ItemEvent e)
{

//这里该怎么写，达到我上述的目的呢？？？？？

}
}

public static void main(String[] args)
{
heqian app=new heqian();
app.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
app.setSize(360,150);
app.setVisible(true);

}
}

Answer 1

package df;

import java.awt.*;
import javax.swing.*;
import java.awt.event.*;

public class heqian extends JFrame
{
//变量在其它地方用建议写这
String[] s={"1","2","3","4","5","6"};
JComboBox JL=new JComboBox (s);
public heqian()
{
Container c=getContentPane();
//c.setLayout(new BoxLayout(c,BoxLayout.Y_AXIS));
c.setLayout(new FlowLayout());

JL.setMaximumRowCount(5);
JL.addItemListener(new ItemListener() {
//处理部分如下
public void itemStateChanged(ItemEvent arg0) {
if(arg0.getStateChange()==ItemEvent.SELECTED)
{
System.out.println(JL.getSelectedItem());
}
}
});
c.add(JL);
}

public static void main(String[] args)
{
heqian app=new heqian();
app.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
app.setSize(360,150);
app.setVisible(true);

}
}

Answer 2

System.out.println(JL.getSelectedItem().toString);