Java.Canvas

Java.Canvas"/>

Java.Canvas

计时器

//TestStopWatch.javapackage myprojects.teststopwatch;import java.awt.*; import java.awt.event.*;class TestStopWatch extends Frame {public TestStopWatch() {this.add(new StopWatch());addWindowListener(new WindowAdapter() {public void windowClosing(WindowEvent e) {dispose();System.exit(0);}});}public static void main(String args[]) {System.out.println("Starting TestStopWatch...");TestStopWatch mainFrame = new TestStopWatch();mainFrame.setSize(400, 400);mainFrame.setTitle("TestStopWatch");mainFrame.setVisible(true);} }

//StopWatch.javapackage myprojects.teststopwatch;import java.text.SimpleDateFormat; import java.util.Date; import java.awt.*; import java.awt.event.*;public class StopWatch extends Canvas implements Runnable { //StopWatch继承了Canvas组件类 //实现Runnable接口，实现实时刷新long startTime=0; //鼠标按下时的时间long endTime=0; //鼠标松开时的时间boolean bStart=false;public StopWatch(){enableEvents(AWTEvent.MOUSE_EVENT_MASK);}protected void processMouseEvent(MouseEvent e){if(e.getID()==MouseEvent.MOUSE_PRESSED){bStart=true;new Thread(this).start(); //启动 重绘刷 新线程startTime=endTime=System.currentTimeMillis(); //获取按下鼠标时的当前时间repaint(); //按下鼠标时重绘组件，实现计时器归零}else if(e.getID()==MouseEvent.MOUSE_RELEASED){endTime=System.currentTimeMillis(); //获取放开鼠标时的当前时间repaint(); //并且重绘组件bStart=false;}}public void paint(Graphics g){ //覆盖Component类的paint()方法SimpleDateFormat sdf=new SimpleDateFormat("HH:mm:ss");//注意HH:mm:ss几个字母的大小写Date elapsedTime=null; //定义鼠标按下和松开之间的时间差try{elapsedTime=sdf.parse("00:00:00");//设置elapsedTime初始值为00:00:00，编译时提示可能出现异常，要try一下}catch(Exception e){e.printStackTrace();}elapsedTime.setTime(elapsedTime.getTime()+endTime-startTime);String strTime=sdf.format(elapsedTime); //时间差elapsedTime格式化后的字符串就是要在计时器上显示的内容g.fill3DRect(0,0,78,28,true); //设置背景g.setColor(Color.WHITE); //设置字体颜色g.drawString(strTime,10,20); //绘制字符串}public void run() {// TODO: Add your code herewhile(bStart){ //循环刷新try{Thread.sleep(500); //500毫秒刷新一次}catch(Exception e){e.printStackTrace();}endTime=System.currentTimeMillis();repaint();}} }