如何使用JFrame完成动态模拟时钟

这篇文章介绍了使用jframe完成动态模拟时钟，在面板中绘制时钟并提取系统当前时刻，主方法中暂停线程1秒，刷新面板。

实现代码如下

import javax.swing.*;
import java.awt.*;
import java.util.*;
import java.lang.thread;
import java.text.decimalformat;
 
public class stillclock extends jpanel {
 
  /**
   * @param args
   */
  private int hour;
  private int minute;
  private int second;
   
  //构造函数
  public stillclock() {
    setcurrenttime();
  }
 
  //返回小时
  public int gethour() {
    return hour;
  }
   
   
  public int getminute() {
    return minute;
  }
   
   
   
  public int getsecond() {
    return second;
  }
   
   
  //绘制时钟
  protected void paintcomponent(graphics g) {
     
    super.paintcomponent(g);
    //初始化
    int clockradius = (int)(math.min(getwidth(), getheight()) * 0.8 * 0.5);
    int xcenter = getwidth() / 2;
    int ycenter = getheight() / 2;
    //画圆
    g.setcolor(color.black);
    g.drawoval(xcenter - clockradius, ycenter - clockradius, 2 * clockradius, 2 * clockradius);
    g.drawstring("12", xcenter - 5, ycenter - clockradius + 15);
    g.drawstring("9", xcenter - clockradius + 3, ycenter + 5);
    g.drawstring("3", xcenter + clockradius - 10, ycenter + 3);
    g.drawstring("6", xcenter - 3, ycenter + clockradius - 3);
    //画秒针
    int slength = (int)(clockradius * 0.8);
    int xsecond = (int)(xcenter + slength * math.sin(second * (2 * math.pi / 60)));
    int ysecond = (int)(ycenter - slength * math.cos(second * (2 * math.pi / 60)));
     
    g.setcolor(color.red);
    g.drawline(xcenter, ycenter, xsecond, ysecond);
     
    //画分针
    int mlenth = (int)(clockradius * 0.65);
    int xminute = (int)(xcenter + mlenth * math.sin(minute * (2 * math.pi / 60)));
    int yminute = (int)(xcenter - mlenth * math.cos(minute * (2 * math.pi / 60)));
    g.setcolor(color.blue);
    g.drawline(xcenter, ycenter, xminute, yminute);
     
    //画时针
    int hlength = (int)(clockradius * 0.5);
    int xhour = (int)(xcenter + hlength * math.sin((hour % 12 + minute / 60.0) * (2 * math.pi / 12)));
    int yhour = (int)(ycenter - hlength * math.cos((hour % 12 + minute / 60.0) * (2 * math.pi / 12)));
    g.setcolor(color.green);
    g.drawline(xcenter, ycenter, xhour, yhour);
     
    //画数字时钟
    g.setcolor(color.black);
    decimalformat s=new decimalformat("00");
    g.drawstring(s.format(gethour()) + ":" + s.format(getminute()) + ":" + s.format(getsecond()), xcenter - 22, ycenter - clockradius - 15);
     
  }
   
  public void setcurrenttime() {
    calendar calendar = new gregoriancalendar();
     
    this.hour = calendar.get(calendar.hour_of_day);
    this.minute = calendar.get(calendar.minute);
    this.second = calendar.get(calendar.second);
  }
   
   
  public static void main(string[] args) {
    // todo auto-generated method stub
    jframe frame = new jframe("diaplayclock");
        frame.setresizable(false);
    frame.settitle("diaplayclock");
    frame.setdefaultcloseoperation(jframe.exit_on_close);
    frame.setsize(300,350);
    frame.setvisible(true);
     
    while(true) {
      stillclock clock = new stillclock();
      frame.getcontentpane().add(clock);
      clock.setvisible(true);
      frame.validate();
      try {
        thread.sleep(1000);
         
      }
      catch (interruptedexception e) {
        e.printstacktrace(); 
      }
      clock.setvisible(false);
      frame.remove(clock);
      clock = null;
      frame.validate();
       
    }
 
  }
}

效果图：

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