其实这个程序并不难,主要是用Java 2D画图,弄一个线程,每隔一秒,依照时针分针秒针各自的速度重新计算它们走过的角度(相对12点方向顺时针偏离的角度),利用这个角度算出它们各自端点的坐标,重绘一次表针,达到刷新的目的,最后时限走动的效果,思路很简单,清晰明了。但是关键是这个画图呀,想着很容易,重写继承过来的JFrame里的paint函数就行,最后发现效果并不是期待的那样,而是一闪一闪的,于是去寻找原因,结果,尼玛,原来水这么深,一下子触到了知识盲区,什么repaint的实现细节,先调用update,再调用paint,update函数又是如何工作的,慢慢弄懂了它为什么会一闪一闪的原因,然后寻找解决办法,然后就看到了什么双缓冲原理,WTF!什么玩意呀,根本没听过,然后乖乖地去看那东西的实现原理,又看到有人建议不要去重写paint方法,说是会遇到诸多意想不到的问题,建议去重写paintComponent方法,可是书本上画图的例子都是重写paint方法呀,况且我也没听过paintComponent,无奈,又去看了一下paint的工作原理,原来它会调用paintComponent,最后放弃了自己实现双缓冲,乖乖改用了paintComponent。。。
其实我还遇到了几个脑残的问题,比如在画秒针时,直接把画时针的部分代码复制下来,最后忘了改掉走动的速度,结果运行时还在想秒针怎么走不动呢?原谅我是个逗逼,还有什么秒针逆时针走动,最后才发现算坐标时误把y轴正方向当成了向上,哎。。。
Anyway,最后运行的效果还是挺好的
-----------------------------------以下是代码-----------------------------------
import java.awt.*;
import java.util.Date;
import javax.swing.*;
public class Clock extends JComponent{
/**
*
*/
private static final long serialVersionUID = -5379472973578609775L;
private Font f = new Font("微软雅黑",Font.PLAIN,15);
private Font f2 = new Font("微软雅黑",Font.BOLD,15);
private JLabel l = new JLabel("当前时间:");
private JLabel display = new JLabel();
private JLabel display2 = new JLabel("");
private int hour = 0;
private int min = 0;
private int sec = 0;
private Date now = new Date();
private Graphics2D g;
final double PI = Math.PI;
private String strTime = "" ;
@SuppressWarnings("deprecation")
public Clock(){
add(l);
l.setBounds(120, 320, 80, 20);
l.setFont(f);
add(display);
display.setBounds(195, 320, 80, 20);
display.setFont(f);
display.setBorder(BorderFactory.createLineBorder(Color.black));
add(display2);
display2.setBounds(90, 350, 250, 20);
display2.setFont(f);
hour = now.getHours();
min = now.getMinutes();
sec = now.getSeconds();
setVisible(true);
}
public void paintComponent(Graphics g1){
double x,y;
super.paintComponent(g1);
g = (Graphics2D) g1;
//反锯齿开关开
g.setRenderingHint(RenderingHints.KEY_ANTIALIASING, RenderingHints.VALUE_ANTIALIAS_ON);
//画表盘
g.setPaint(new GradientPaint(5,40,Color.blue,15,50,Color.yellow,true));
g.setStroke( new BasicStroke(3,BasicStroke.CAP_BUTT,BasicStroke.JOIN_BEVEL));
g.drawOval(75, 40, 250, 250);
g.fillOval(195, 160, 10, 10);
g.setColor(Color.black);
//画60个点
for(int i = 0;i < 60;i++)
{
double[] co = new double[2];
co = paint_Dot(i * 2 * PI / 60);
x = co[0];
y = co[1];
if(i == 0 || i == 15 || i == 30 || i == 45)//画3,6,9,12四个大点
{
g.fillOval((int)(x - 5 + 200),(int)(y - 5 + 165),10,10);
}
else//其他小点
{
g.fillOval((int)(x - 2.5 + 200),(int)(y - 2.5 + 165),5,5);
}
}
//画四个数字
g.setFont(f2);
g.drawString("3", 300, 171);
g.drawString("6", 195, 273);
g.drawString("9", 91, 171);
g.drawString("12", 190, 68);
//画时针,分针,秒针
paint_HourPointer(hour*3600 + min*60 + sec,g);//时针走过的秒数
paint_MinutePointer(min*60 + sec,g);//分针走过的秒数
paint_SecondPointer(sec,g);//秒针走过的秒数
}
public void showUI(){
new Thread() {
@SuppressWarnings("deprecation")
public void run() {
while (true)
{
now = new Date();
hour = now.getHours();
min = now.getMinutes();
sec = now.getSeconds();
try {
Thread.sleep(1000);
} catch (InterruptedException ex) {
ex.printStackTrace();
}
showTime();
repaint();
}
}
}.start();
}
public void paint_HourPointer(int second,Graphics2D g){//second表示当前时间的时针相对00:00:00走了多少秒
double x,y,angle;
angle = second * PI / 21600;//时针的速度为PI/21600 (rad/s)
x = 200 + 60 * Math.sin(angle);
y = 165 - 60 * Math.cos(angle);
g.setStroke( new BasicStroke(5,BasicStroke.CAP_BUTT,BasicStroke.JOIN_ROUND));
g.setPaint(new GradientPaint(200,165,Color.red,260,165,Color.blue,true));
g.drawLine(200, 165, (int)x, (int)y);
}
public void paint_MinutePointer(int second,Graphics2D g){//second表示当前时间的分针相对00:00:00走了多少秒
double x,y,angle;
angle = second * PI / 1800;//分针的速度为PI/1800 (rad/s)
x = 200 + 80 * Math.sin(angle);
y = 165 - 80 * Math.cos(angle);
g.setStroke( new BasicStroke(3,BasicStroke.CAP_BUTT,BasicStroke.JOIN_ROUND));
g.setPaint(new GradientPaint(200,165,Color.magenta,280,165,Color.blue,true));
g.drawLine(200, 165, (int)x, (int)y);
}
public void paint_SecondPointer(int second,Graphics2D g){//second表示当前时间的秒针相对00:00:00走了多少秒
double x,y,x1,y1,x2,y2,x3,y3,angle;
double cos = 90 / Math.sqrt(8125);//90*90+5*5
double sin = 5 / Math.sqrt(8125);
angle = second * PI / 30;//时针的速度为PI/30 (rad/s)
x = 200 + 95 * Math.sin(angle);
y = 165 - 95 * Math.cos(angle);
x1 = 200 + 20 * Math.sin(angle + PI);
y1 = 165 - 20 * Math.cos(angle + PI);
x2 = 200 + Math.sqrt(8125)* ( Math.sin(angle)*cos - Math.cos(angle)*sin ); //sin(a-b)
y2 = 165 - Math.sqrt(8125)* ( Math.cos(angle)*cos + Math.sin(angle)*sin ); //cos(a-b)
x3 = 200 + Math.sqrt(8125)* ( Math.sin(angle)*cos + Math.cos(angle)*sin ); //sin(a+b)
y3 = 165 - Math.sqrt(8125)* ( Math.cos(angle)*cos - Math.sin(angle)*sin ); //cos(a+b)
g.setStroke( new BasicStroke(2,BasicStroke.CAP_BUTT,BasicStroke.JOIN_BEVEL));
g.setPaint(new GradientPaint(180,165,Color.CYAN,295,165,Color.MAGENTA,true));
g.drawLine((int)x1, (int)y1, (int)x, (int)y);
g.drawLine((int)x2, (int)y2, (int)x, (int)y);
g.drawLine((int)x3, (int)y3, (int)x, (int)y);
}
public double[] paint_Dot(double angle){
double[] co = new double[2];
co[0] = 115 * Math.cos(angle);//横坐标
co[1] = 115 * Math.sin(angle);//纵坐标
return co;
}
@SuppressWarnings("deprecation")
private void showTime(){
String date;
int hour_temp = hour,min_temp = min,sec_temp = sec;
sec_temp += 1 ;
if(sec_temp >= 60)
{
sec_temp = 0;
min_temp += 1 ;
}
if(min_temp>=60){
min_temp=0;
hour_temp+=1;
}
if(hour_temp < 10)
strTime = "0" + hour_temp + ":";
else
strTime = "" + hour_temp + ":";
if(min_temp < 10)
strTime = strTime + "0" + min_temp + ":";
else
strTime = strTime + "" + min_temp + ":";
if(sec < 10)
strTime = strTime + "0" + sec_temp;
else
strTime = strTime + "" + sec_temp;
//在窗体上设置显示时间
date = " " + (now.getYear()+1900) + "年" + (now.getMonth()+1) + "月" + now.getDate() + "日 " + "星期" ;
switch (now.getDay()) {
case 1:
date += "一";
break;
case 2:
date += "二";
break;
case 3:
date += "三";
break;
case 4:
date += "四";
break;
case 5:
date += "五";
break;
case 6:
date += "六";
break;
case 7:
date += "日";
break;
}
date += " CST";
strTime = " " + strTime;
display.setText(strTime);
display2.setText(date);
}
public static void main(String args[]){
Clock c = new Clock();
c.showUI();
JFrame f = new JFrame("Clock By XJX");
Image img=Toolkit.getDefaultToolkit().getImage("title.gif");//窗口图标
f.setIconImage(img);
f.setSize(400,400);
f.setResizable(false);
f.add(c, BorderLayout.CENTER);
f.setLocationRelativeTo(null);
f.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
f.setVisible(true);
}
}