jcomboboxdemo.java

来自「这是一个用java编写的复选框演示程序」· Java 代码 · 共 55 行

import java.awt.Color;
import java.awt.Container;
import java.awt.FlowLayout;
import java.awt.event.ItemEvent;
import java.awt.event.ItemListener;

import javax.swing.JComboBox;
import javax.swing.JFrame;
import javax.swing.JLabel;


public class JComboBoxDemo extends JFrame{

	/**
	 * @param args
	 */
	private JComboBox comboBox;
	private JLabel label;
	private String names[]={"beijing","nanjing","wuhan"};

	public JComboBoxDemo()
	{
		super("下拉列表");
		setSize(200,150);
		Container container=getContentPane();
		container.setLayout(new FlowLayout());
		container.setBackground(Color.YELLOW);
		comboBox =new JComboBox(names);
		comboBox.setMaximumRowCount(3);
		comboBox.setSelectedIndex(0);
		comboBox.addItemListener(new ComboBoxHandler());
		label=new JLabel("you select: beijing");
		container.add(comboBox);
		container.add(label);
		setVisible(true);
		setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
	}
	public static void main(String[] args) {
		// TODO Auto-generated method stub
		JComboBoxDemo application =new JComboBoxDemo();

	}
	private class ComboBoxHandler implements ItemListener
	{
		public void itemStateChanged(ItemEvent event)
		{
			if(event.getStateChange()==event.SELECTED)
			{
				label.setText("you select: "+names[comboBox.getSelectedIndex()]);
			}
		}
	}

}