loop.java

Java 范例实战 光盘使用说明 ========================== 本光盘的文件结构如下所示： =====================================

import java.applet.Applet;
import java.awt.*;

public class Loop extends Applet implements Runnable
{

    String text ;
    Thread mover = null;
    int x, y, delay;
    Font font ;

    public Loop() {}

    int getParameter(String s1, int s2) 
    {
    
        String s = getParameter(s1) ;
        return (s != null) ? Integer.parseInt(s) : s2 ;
    
    }

    String getParameter(String s1, String s2) 
    {
    
        String s = getParameter(s1) ;
        return (s != null) ? s : s2 ;
    
    }

    public void init()
    {
    
        font = new Font("TimesRome", Font.PLAIN, 20) ;
        setBackground(Color.black);
        text = getParameter("text","Put your message in text parm");
        x = getSize().width;
        y = 10 ;
        delay = getParameter("delay", 50) ;
    
    }

    public void start()
    {
    
        if(mover == null)
        {
    
            mover = new Thread(this);
            mover.start();
    
        }
    
    }

    public void stop()
    {
    
        mover = null;
    
    }

    public void run()
    {
    
        while(mover != null)
        {
    
            try
            {
    
                Thread.sleep(delay);
    
            }
            catch(InterruptedException e) { }
            repaint();
        
        }
    
    }

    public void paint(Graphics g)
    {
    
        switch(x % 5)
        {
     
        case 0: g.setColor(Color.red);
                break;
        case 1: g.setColor(Color.pink);
                break;
        case 2: g.setColor(Color.orange);
                break;
        case 3: g.setColor(Color.magenta);
                break;
        case 4: g.setColor(Color.cyan);
                break;
     
        }
        g.setFont(font);
        g.drawString(text, x, y);
        if(--x <= 0) x = getSize().width ;
    
    }

}