neon.java

面向对象技术

import java.awt.Graphics;
import java.awt.Image;
import java.lang.Math;
//定义一个Neon类
public class Neon extends java.applet.Applet implements Runnable {
        Image mAge[];
        int iMagNdx=0;
        Thread endit;//声明一个拥有Thread对象的变量
	//初始化
        public void init() {
                resize(300,70);
                }
	//paint方法
        public void Paint(Graphics g) {
                update(g);
                }
	//update方法
        public void update(Graphics g) {
                if(mAge[iMagNdx]==null)
                        g.drawString("Error loading pic", 0, 170);
                g.drawImage(mAge[iMagNdx],0,0, this);
                }
	//start方法，开始执行线程
        public void start() {
                if(endit == null) {
                        endit=new Thread(this);
                        endit.start();
                        }
                }
//取得参数信息 
  public String[][] getParameterInfo() {
    String[][] info = {
      {"picture1",    "String",  "First image to be displayed." },
      {"picture2",    "String",  "Second image to be displayed"},
    };
    return info;
  }
 //取得Applet相关信息
  public String getAppletInfo() {
    return "Neon.java, V 1.2";
  }    
	//停止线程
        public void stop() {
        	endit.stop();
                endit=null;
                }
	//run方法，线程的核心
        public void run() {
                mAge=new Image[2];
                String m1 = getParameter( "picture1" );
                String m2 = getParameter( "picture2" );
                mAge[0]=getImage(getDocumentBase(), m1);
                mAge[1]=getImage(getDocumentBase(), m2);
                for(;;) {
                        repaint();
                        iMagNdx=iMagNdx==0 ? 1 : 0;

try {Thread.sleep( (int) (Math.random()*500));
} catch (InterruptedException e){}
                        }
                }
        }