【JAVA语言程序设计基础篇】--事件驱动程序设计--setActionCommand()

setActionCommand()和getActionCommand()的使用

/**
 * 功能：事件处理机制
 *
 */

package com.test3;

import java.awt.BorderLayout;
import java.awt.Color;
import java.awt.Graphics;
import java.awt.event.ActionEvent;
import java.awt.event.ActionListener;

import javax.swing.JButton;
import javax.swing.JFrame;
import javax.swing.JPanel;

@SuppressWarnings("serial")
public class Demo9_3 extends JFrame{

	MyPanel p1 = new MyPanel();

	JButton button1 = new JButton("黑色");
	JButton button2 = new JButton("红色");
	public Demo9_3(){
		add(button1,BorderLayout.NORTH);
		add(button2,BorderLayout.SOUTH);
		add(p1);
		p1.setBackground(Color.black);

		button1.addActionListener(new ActionListener(){//匿名內部类

			@Override
			public void actionPerformed(ActionEvent e) {
				p1.setBackground(Color.black);
				repaint();
			}
		}); 

		button2.addActionListener(new ActionListener() {//匿名内部类

			@Override
			public void actionPerformed(ActionEvent e) {
				if(e.getActionCommand().equals("red")){//51行setActionCommand方法中 的字符串如果等于 该行equal()中的字符串 就handle it
					 p1.setBackground(Color.red);
					 System.out.println("getActionCommand method is uesd successful");
				}
				repaint();
			}
		});
		button2.setActionCommand("red");

		setSize(400, 300);
		setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
		setVisible(true);
	}
	public static void main(String[] args) {
			new Demo9_3();
	}

	class MyPanel extends JPanel{
		public void paintComponent(Graphics g){
			super.paintComponent(g);

		}
	}
}