例8-13.java

医院无线局域网设计方案 医院无线局域网设计方案

//Example 8-13
import java.awt.*;
import java.applet.Applet;
public class tt extends Applet implements Runnable
{	
  Thread runThread;
  String s;
  int s_length,x_character=0,y_coord,textcolor,backcolor,delay;
  int appletWidth,appletHeight;
  String fontName;
  int fontSize;
  Font wordFont;
  FontMetrics wordMetrics;
  public void init()
  {
    String temp;
    appletWidth=getSize().width;appletHeight=getSize().height;
    temp=getParameter("font");
    fontName=(temp==null)?"TimesRoman":temp;
    temp=getParameter("fontsize");
    fontSize=(temp==null)?12:Integer.parseInt(temp);
    wordFont=new Font(fontName,Font.BOLD,fontSize);
    if(wordFont==null) wordFont=getFont();
    wordMetrics=getFontMetrics(wordFont);
    temp=getParameter("text");
    s=(temp==null)?"Message goes here....":temp;
    s_length=s.length();
    temp=getParameter("textcolor");
    textcolor=(temp==null)?0:Integer.parseInt(temp,16);
    setForeground(new Color(textcolor));//教材无此句
    temp=getParameter("backcolor");
    backcolor=(temp==null)?0xffffff:Integer.parseInt(temp,16);
    setBackground(new Color(backcolor));//教材无此句
    temp=getParameter("delay");
    delay=(temp==null)?100:Integer.parseInt(temp);
    y_coord=appletHeight/2+(wordMetrics.getHeight()-wordMetrics.getDescent())/2;
  }
  public void start()
  {
    if(runThread==null)
    {
      runThread=new Thread(this);
      runThread.start();
    } 
  }
  public void stop()
  {
    if(runThread!=null)
    {
      runThread.stop();
      runThread=null;
    }
  }
  public void run()
  {
    while(true)
    {
      if(++x_character>s_length)
        x_character=0;
      repaint();
      try{Thread.sleep(delay);}catch(InterruptedException e){}
    }
  }
  public void paint(Graphics g)
  {
    g.setFont(wordFont);
    g.setColor(getForeground());//教材有错
    g.drawString(s.substring(0,x_character),8,y_coord);
  }
  public void update(Graphics g)
  {
    if(x_character==0)
    {
      g.setColor(getBackground());
      g.fillRect(0,0,appletWidth,appletHeight);
      g.setColor(getForeground());
    }
    paint(g);
  }
}