线条作画.java

200多个自己编的java程序,大家可以学一下.

/*
 * 线条作画.java
 *
 * Created on 2004年9月24日, 上午11:56
 */

/**
 *
 * @author  litertiger
 */
import java.awt.*;
import java.awt.event.*;
public class 线条作画 extends java.applet.Applet implements ActionListener,MouseMotionListener {
    
    /** Initialization method that will be called after the applet is loaded
     *  into the browser.
     */
    int x=-1,y=-1;
    
    int 橡皮擦通知 = 0;
    
    int 清除通知 = 0;
    Color c=new Color(255,0,0);
    int con=3;Button b_red,b_green,清除,b_quit,b_blue;
    
    
    
    public void init() {
        addMouseMotionListener(this);
        b_red=new Button("花红色图形");
        b_green=new Button("画绿色图形");
        b_blue=new Button("蓝色图形");
        b_quit=new Button("橡皮");
        清除=new Button("清除");
        add(b_red);
        add(b_green);
        add(b_blue);
        add(b_quit);
        add(清除);
        b_red.addActionListener(this);
        b_blue.addActionListener(this);
        b_green.addActionListener(this);
        b_quit.addActionListener(this);
        清除.addActionListener(this);
        // TODO start asynchronous download of heavy resources
    }
    public void paint(Graphics g)
    {   
        if(x!=-1&&y!=-1&&橡皮擦通知 == 0&&清除通知 == 0)
        {   
            g.setColor(c);
            g.fillOval(x, y,con,con);
        }
        else if(橡皮擦通知==1&&清除通知==0)
        {
            g.clearRect(x, y,10,10);
        }
                else if(橡皮擦通知==0&&清除通知==1)
        {
            g.clearRect(0, 0,getSize().width,getSize().height);
            
        }
        
    }

    
    public void mouseDragged(MouseEvent e) {
        x=(int)e.getX();
        y=(int)e.getY();
        repaint();
    }
    public  void update(Graphics g)
    {

    paint(g);
    }
    
    public void mouseMoved(MouseEvent e) {
    }
    
        public void actionPerformed(ActionEvent e) {
        if(e.getSource()==b_red)
        {
            橡皮擦通知=0;
            清除通知=0;
            c=new Color(255,0,0);
        }
            if(e.getSource()==b_green)
        {
            橡皮擦通知=0;
            清除通知=0;
            c=new Color(0,255,0);
        }
          if(e.getSource()==b_blue)
        {
            橡皮擦通知=0;
            清除通知=0;
            c=new Color(0,0,255);
        }
           if(e.getSource()==b_quit)
        {
            橡皮擦通知=1;
            清除通知=0;
           
        }
          if(e.getSource()==清除)
        {
            橡皮擦通知=0;
            清除通知=1;
            repaint();
            
        }
    }
    
    // TODO overwrite start(), stop() and destroy() methods
}