java学习笔记_GUI(3)

 1 import javax.swing.*;
 2 import java.awt.event.*;
 3 import java.awt.*;
 4 
 5 class MyPanel extends JPanel {
 6     public void paintComponent( Graphics g ) {
 7         g.setColor( Color.orange );
 8         g.fillRect(20, 50, 100, 100);
 9     }
10 }
11 
12 
13 class Gui implements ActionListener{
14     
15     JButton button = new JButton("click me");
16     JFrame frame = new JFrame();
17     
18     private void set_frame() {
19         frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
20         frame.setSize(300, 200);
21         frame.setVisible(true);
22     }
23 
24     public void show_button() {
25         set_frame();
26         frame.getContentPane().add(button);
27         button.addActionListener(this);
28     }
29     
30     public void show_my_panel() {
31         set_frame();
32         frame.getContentPane().add(new MyPanel());
33     }
34     
35     public void actionPerformed( ActionEvent event ) {
36         button.setText("I‘ve been clicked!");
37     }
38 }
39 
40 class GuiTest {
41     public static void main( String[] args ) {
42         Gui gui = new Gui();
43         if ( args.length > 0 ) {
44             gui.show_my_panel();
45         }
46         else {
47             gui.show_button();
48         }
49     }
50 }