banner.java

来自「Mcgraw-Hill - Java 2 - A Beginner S Guid」· Java 代码 · 共 64 行

/*  
   Project 12-1 
 
   A simple banner applet. 
 
   This applet creates a thread that scrolls 
   the message contained in msg right to left 
   across the applet's window. 
*/ 
import java.awt.*; 
import java.applet.*; 
/* 
<applet code="Banner" width=300 height=50> 
</applet> 
*/ 
 
public class Banner extends Applet implements Runnable { 
  String msg = " Java Rules the Web "; 
  Thread t; 
  boolean stopFlag; 
 
  // Initialize t to null.  
  public void init() { 
    t = null; 
  } 
 
  // Start thread 
  public void start() { 
    t = new Thread(this); 
    stopFlag = false; 
    t.start(); 
  } 
 
  // Entry point for the thread that runs the banner. 
  public void run() { 
    char ch; 
 
    // Display banner  
    for( ; ; ) { 
      try { 
        repaint(); 
        Thread.sleep(250); 
        ch = msg.charAt(0); 
        msg = msg.substring(1, msg.length()); 
        msg += ch; 
        if(stopFlag) 
          break; 
      } catch(InterruptedException exc) {} 
    } 
  } 
 
  // Pause the banner. 
  public void stop() { 
    stopFlag = true; 
    t = null; 
  } 
 
  // Display the banner. 
  public void paint(Graphics g) { 
    g.drawString(msg, 50, 30); 
  } 
}