java JComboBox



JComboBox.

JComboBox(组合框)
下拉列表,用来提供多项内容供用户选择
组合框从JComponent继承的JComboBox类来实现
JcomboBox产生ItemEvent事件
setMaximumRowCount方法可以设置用户点击JComboBox时显示的最大条目数n
当前条目数大于n时,将自动提供滚动条
import java.awt.*;
import java.awt.event.*;

import javax.swing.*;
public class ComboBoxTest extends JFrame
{

/**
*
*/
private static final long serialVersionUID = 0L;
/**
* @param args
*/
private JComboBox imageComboBox;
private JLabel label;
private String names[]={“1.gif”,”2.gif”,”3.gif”,”4.gif”};
private Icon icons[]={new ImageIcon(names[0]),new ImageIcon(names[1]),new ImageIcon(names[2]),new ImageIcon(names[3])};
public ComboBoxTest()
{
super(“Testing JcomboBox”);
Container container=getContentPane();
container.setLayout(new FlowLayout());
imageComboBox=new JComboBox(names);
imageComboBox.setMaximumRowCount(3);
imageComboBox.addItemListener(new ItemListener()
{

public void itemStateChanged(ItemEvent e) {
if(e.getStateChange()==ItemEvent.SELECTED)
label.setIcon(icons[imageComboBox.getSelectedIndex()]);

}

});
container.add(imageComboBox);
label=new JLabel(icons[0]);
container.add(label);
setSize(350,100);
setVisible(true);
}
public static void main(String[] args) {
ComboBoxTest application=new ComboBoxTest();
application.setDefaultCloseOperation(JFrame.DISPOSE_ON_CLOSE);

}

}