java学习笔记_GUI(5)

demo如何为不同的button创建对应的响应函数

 import javax.swing.*;
 import java.awt.event.*;
 import java.awt.*;
 
 class MyPanel_2 extends JPanel {
     public void paintComponent( Graphics g ) {
         g.fillRect(0, 0, this.getWidth(), this.getHeight());
         int red = (int) (Math.random() * 255);
         int green = (int) (Math.random() * 255);
         int blue = (int) (Math.random() * 255);
         Color randomColor = new Color(red, green, blue);
         g.setColor(randomColor);
         g.fillOval(70, 40, 100, 100);
     }
 }
 
 class Gui{
 
     JButton button = new JButton("change color");
     JButton button_change_label = new JButton("change label");
     JLabel label = new JLabel("I'm a label");
     JFrame frame = new JFrame();
 
     private void set_frame() {
         frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
         frame.setSize(800, 600);
         frame.setVisible(true);
     }
 
     public void show_my_panel() {
         set_frame();
         frame.getContentPane().add(BorderLayout.SOUTH, button);
         button.addActionListener(new ColorButtonActionListener());
 
         frame.getContentPane().add(BorderLayout.EAST, button_change_label);
         button_change_label.addActionListener(new LabelButtonActionListener() );
 
         frame.getContentPane().add(BorderLayout.WEST, label);
 
         frame.getContentPane().add(BorderLayout.CENTER,new MyPanel_2());
     }
 
     class ColorButtonActionListener implements ActionListener {
         public void actionPerformed( ActionEvent event ) {
             frame.repaint();
         }
     }
 
     class LabelButtonActionListener implements ActionListener {
         public void actionPerformed( ActionEvent event ) {
             label.setText("That hurt!");
         }
     }
 }
 
 class GuiTest {
     public static void main( String[] args ) {
         Gui gui = new Gui();
         gui.show_my_panel();
     }
 }