线程实例：一个钟表的实现

最近在学习JAVA线程，照着书上例子写的钟表图形程序，对线程有一定的理解，但是发觉对图形编程的掌握不够很多函数还不能掌握~~

以下是钟表例子的代码

package hello;

import java.awt.*; import java.applet.*; import java.awt.event.*; import java.util.*; import java.awt.geom.*;

public class T extends Applet implements Runnable{ Thread tHour = null,tMinute = null,tSecond = null;//表示时针，分针和秒针的线程 int hour_a,hour_b,minute_a,minute_b,second_a,second_b;//表示时针，分针，秒针端点的整型变量 int hour = 0,minute = 0,second = 0;//获取当前时间的整型变量 //绘制时针，分针和秒针的Graphics对象 Graphics g_second = null,g_minute = null,g_hour =null; //存放表盘刻度的数组，供指针走动时使用 double point_x[] = new double[61],point_y[] = new double[61]; //存放表盘刻度的数组，供绘制表盘使用 double scaled_x[] = new double[61],scaled_y[] = new double[61]; //判断小程序是否重新开始的变量 int start_count = 0; public void init(){ g_hour = this.getGraphics(); g_hour.setColor(Color.CYAN); g_second = this.getGraphics(); g_second.setColor(Color.RED); g_minute = this.getGraphics(); g_minute.setColor(Color.blue); g_second.translate(200,200);//进行坐标系统变换，将新坐标系原点设在（200，200）处 g_minute.translate(200,200); g_hour.translate(200,200); point_x[0] = 0; point_y[0] = -120;//各个时针12点处的位置坐标（按新坐标系的坐标） scaled_x[0] = 0;scaled_y[0] = -140;//12点处的刻度位置坐标（按新坐标系的坐标） double jiaodu = 6*Math.PI/180; //表盘分割成60分，将分割点的坐标存放在数组中 for(int i = 0; i < 60; i++){ point_x[i+1] = point_x[i]*Math.cos(jiaodu)-Math.sin(jiaodu)*point_y[i]; point_y[i+1] = point_y[i]*Math.cos(jiaodu) + point_x[i]*Math.sin(jiaodu); } point_x[60] = 0; point_y[60] = -120; for(int i = 0; i < 60; i++){ scaled_x[i+1] = scaled_x[i]*Math.cos(jiaodu)-Math.sin(jiaodu)*scaled_y[i]; scaled_y[i+1] = scaled_y[i]*Math.cos(jiaodu) + Math.sin(jiaodu)*scaled_x[i]; } scaled_x[60]= 0; scaled_y[60] = -140; } public void start(){ //每当小程序重新开始时，首先消灭线程，然后重新开始创建线程 if(start_count >= 1){ tSecond.interrupt(); tMinute.interrupt(); tHour.interrupt(); } tSecond = new Thread(this); tMinute = new Thread(this); tHour = new Thread(this); tSecond.start(); tMinute.start(); tHour.start(); start_count++; if(start_count >= 2) start_count = 1; } public void stop() { tSecond.interrupt(); tMinute.interrupt(); tHour.interrupt(); } public void paint(Graphics g){ this.start(); g.drawOval(50,50,300,300);//表盘的外圈 g.translate(200,200); //绘制表盘的小刻度和大刻度 for(int i = 0 ; i < 60; i++){ if(i%5 == 0){ g.setColor(Color.BLACK); g.fillOval((int) scaled_x[i],(int) scaled_y[i],10,10); } else g.fillOval((int)scaled_x[i],(int)scaled_y[i],5,5); } } public void run(){ //获取本地时间 Date date = new Date(); String s=date.toString(); hour=Integer.parseInt(s.substring(11,13)); minute = Integer.parseInt(s.substring(14,16)); second = Integer.parseInt(s.substring(17,19)); if(Thread.currentThread() == tSecond){ second_a =(int)point_x[second]; second_b = (int)point_x[second]; g_second.drawLine(0,0,second_a,second_b);//秒针的初始位置 g_second.drawString("秒",second_a,second_b); int i = second; while(true){ try{ tSecond.sleep(1000); Color c = getBackground(); g_second.setColor(c); g_second.drawLine(0,0,second_a,second_b);//用背景色清除前一秒时的秒针 g_second.drawString("秒",second_a,second_b); //如果秒针与分针重合，恢复分针的显示 if((second_a == minute_a)&&(second_b == minute_b)){ g_minute.drawLine(0,0,minute_a,minute_b); g_minute.drawString("分",minute_a,minute_b); } //如果秒针与时针重合，恢复时针的显示 if((second_a == hour_a)&&(second_b == hour_b)){ g_hour.drawLine(0,0,hour_a,hour_b); g_hour.drawString("时",hour_a,hour_b); } } catch(InterruptedException e){ Color c = getBackground(); g_second.setColor(c); g_second.drawLine(0,0,second_a,second_b);//用背景色清除秒针 g_second.drawString("秒",second_a,second_b); return; } //秒针向前走一个单位 second_a=(int)point_x[(i+1)%60]; second_b = (int)point_y[(i+1)%60]; //每一秒走6度（一个单位格） g_second.setColor(Color.red); g_second.drawLine(0,0,second_a,second_b); g_second.drawString("秒",second_a,second_b); i++; } } if(Thread.currentThread() == tMinute){ minute_a = (int)point_x[minute]; minute_b = (int)point_y[minute]; g_minute.drawLine(0,0,minute_a,minute_b); int i = minute; while(true){ //第一次过60-second秒就前进一分钟，以后每过60秒前进一分钟 try{ tMinute.sleep(1000*60 - second*1000); second = 0; Color c = getBackground(); g_minute.setColor(c); g_minute.drawLine(0,0,minute_a,minute_b); g_minute.drawString("分",minute_a,minute_b); if((hour_a == minute_a)&&(hour_b== minute_b)){ g_hour.drawLine(0,0,minute_a,minute_b); g_hour.drawString("时",hour_a,hour_b); } } catch(InterruptedException e){ return; } minute_a = (int)point_x[(i+1)%60]; minute_b = (int)point_y[(i+1)%60]; g_minute.setColor(Color.BLUE); g_minute.drawLine(0,0,minute_a,minute_b); g_minute.drawString("分",minute_a,minute_b); i++; second = 0; } } if(Thread.currentThread() == tHour){ int h = hour%12; hour_a = (int)point_x[h*5 + minute/12]; hour_b = (int)point_y[h*5 + minute/12]; int i = h*5 + minute/12; g_hour.drawLine(0,0,hour_a,hour_b); g_hour.drawString("时",hour_a,hour_b); while(true){ //第一次过12-minute%12分钟就前进一个刻度，以后每过12分钟前进一个刻度 try{ tHour.sleep(1000*60*12 - 1000*60*(minute%12) - second *1000); minute = 0; Color c = getBackground(); g_hour.setColor(c); g_hour.drawLine(0,0,hour_a,hour_b); g_hour.drawString("时",hour_a,hour_b); } catch(InterruptedException e){ return; } hour_a = (int)point_x[(i+1)%60]; hour_b = (int)point_y[(i+1)%60]; g_hour.setColor(Color.CYAN); g_hour.drawLine(0,0,hour_a,hour_b); g_hour.drawString("时",hour_a,hour_b); i++;minute = 0; } } }}

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