12图形用户接口

//创建frame
    JFrame frame = new JFrame();
    //创建widget
    JButton button = new JButton();
    //把widget加到frame上
    frame.getContentPane().add(button);
    //显示出来
    frame.setSize(300, 300);
    frame.setVisible(true);

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

//ActionListener是java.awt.event 包中的接口，只有一个方法void actionPerformed(ActionEvent e)
public class Test implements ActionListener{ 
    JButton button1;
    public static void main(String[] args) {
        Test t = new Test();
        t.play();
    }

    public void play() {
        JFrame frame = new JFrame();
        button1 = new JButton("Button1");
        button1.addActionListener(this);
        frame.getContentPane().add(button1);
        frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
        frame.setSize(300, 300);
        frame.setVisible(true);
    }

    public void actionPerformed(ActionEvent event){
        button1.setText("I'v been clicked!");
    }
}