timeclock.java

一个Java时钟程序

import java.awt.*;
import java.applet.*;
import java.util.Date;   
public class TimeClock extends Applet implements Runnable   
{
	public void init()
	{
		setBackground(Color.pink);
	}
	Date timenow;     
	Clock myClock;    
	Thread clockthread=null;   
	public void start()     
	{
		if (clockthread==null) 
		{
			clockthread=new Thread (this);  
			clockthread.start();            
		}
	}
	
	public void stop()            
	{
		clockthread.stop();   
		clockthread=null;     
	}
	
	public void run()             
	{
		while(true)           
		{
			repaint();        
			try
			{
				Thread.sleep(1000);
			}    
			catch(InterruptedException e)
			{
			} 
		}
	}
		
	public void paint(Graphics g)
	{
		g.setFont(new Font("TimesRoman",Font.PLAIN,18));
		timenow=new Date();     
		myClock=new Clock(timenow.getHours (),timenow.getMinutes (),
		timenow.getSeconds ());
		g.drawString(timenow.toString(),48,260);
		myClock.show(g,180,120,100);
		
	}
}

class Clock        
{
	Clock(int hrs,int min,int sec)  
	{
		hour=hrs%12;            
		minute=min;             
		second=sec;             
	}
	void show(Graphics g,int cx,int cy,int rad)  
	{
		int hrs_len=(int)(rad*0.5),       
			min_len=(int)(rad*0.6),   
			sec_len=(int)(rad*0.9);   
		double theta;
		g.drawOval(cx-rad,cy-rad,rad*2,rad*2);  
		theta=(double)(hour*60*60+minute*60+second)/43200.0*2.0*Math.PI ;
		drawNiddle(g,Color.blue,cx,cy,hrs_len,theta);  
		theta=(double)(minute*60+second)/3600.0*2.0*Math.PI ;
		drawNiddle(g,Color.red,cx,cy,sec_len,theta);  
		theta=(double)(second)/60.0*2.0*Math.PI ;
		drawNiddle(g,Color.green ,cx,cy,sec_len,theta);
		g.setColor(Color.darkGray);
		g.drawString("9",cx-98,cy+3);
		g.drawString("3",cx+90,cy+1);
		g.drawString("12",cx-10,cy-84);
		g.drawString("6",cx-3,cy+98);
	}
	private void drawNiddle(Graphics g,Color c,int x,int y,int len,double theta)
	{
		int ex=(int)(x+len*Math.sin(theta));
		int ey=(int)(y-len*Math.cos(theta));
		g.setColor (c);
		g.drawLine(x,y,ex,ey);
	}
	int hour,minute,second;
}