java学习笔记_GUI(4)

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

 class MyPanel_0 extends JPanel {
     public void paintComponent( Graphics g ) {
         g.setColor( Color.orange );
         g.fillRect(20, 50, 100, 100);
     }
 }

 class MyPanel_1 extends JPanel {
     public void paintComponent( Graphics g ) {
         Image image = new ImageIcon("Winter.jpg").getImage();
         g.drawImage(image, 3, 4, this);
     }
 }

 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 MyPanel_3 extends JPanel {
     public void paintComponent( Graphics g ) {
         Graphics2D g2d = (Graphics2D) g;
         GradientPaint gradient = new GradientPaint(70, 70, Color.blue, 150, 150, Color.orange);
         g2d.setPaint( gradient );
         g2d.fillOval(70, 70, 100, 100);
     }
 }

 class Gui implements ActionListener{

     JButton button = new JButton("click me");
     JFrame frame = new JFrame();

     private void set_frame() {
         frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
         frame.setSize(300, 200);
         frame.setVisible(true);
     }

     public void show_button() {
         set_frame();
         frame.getContentPane().add(button);
         button.addActionListener(this);
     }

     public void show_my_panel( String index) {
         set_frame();
         if ( index.equals("0") ) {
             frame.getContentPane().add(new MyPanel_0());
         }
         else if ( index.equals("1") ) {
             frame.getContentPane().add(new MyPanel_1());
         }
         else if ( index.equals("2") ) {
             frame.getContentPane().add(new MyPanel_2());
         }
         else if ( index.equals("3") ) {
             frame.getContentPane().add(new MyPanel_3());
         }
     }

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

 class GuiTest {
     public static void main( String[] args ) {
         Gui gui = new Gui();
         if ( args.length > 0 ) {
             gui.show_my_panel( args[0] );
         }
         else {
             gui.show_button();
         }
     }
 }

这个程序演示了几种不同的绘图等方法