如何每分钟执行一次方法

Question

我是Java编程的新手,正在制作一个有背景图像和太阳的项目.太阳根据现实生活中的时间改变颜色.

我的代码如下:

package demos;
import processing.core.*;

import java.time.LocalDateTime;
import java.util.TimerTask;


public class Trial extends PApplet{
String URL="http://cseweb.ucsd.edu/~minnes/palmTrees.jpg";
PImage backgroundImg;



public void setup(){
    size(200,200);
    backgroundImg = loadImage(URL,"jpg");
}

public void draw(){
      int hour = LocalDateTime.now().getHour();       
      int minute = LocalDateTime.now().getMinute();   

      switch(hour){
      case 13:
      {
          backgroundImg.resize(0    ,height);
          image( backgroundImg , 0,0);
          fill(238,238,0);
          ellipse(width/4,height/5,width/5,height/5);
          break;
      }
      case 14:
      {
          backgroundImg.resize(0    ,height);
          image( backgroundImg , 0,0);
          fill(205,205,0);
          ellipse(width/4,height/5,width/5,height/5);
          break;
      }
      case 15:
      {
          backgroundImg.resize(0    ,height);
          image( backgroundImg , 0,0);
          fill(255,215,0);
          ellipse(width/4,height/5,width/5,height/5);
          break;
      }
      case 16:
      {
          backgroundImg.resize(0    ,height);
          image( backgroundImg , 0,0);
          fill(238,201,0);
          ellipse(width/4,height/5,width/5,height/5);
          break;
      }
      case 17:
      {
          backgroundImg.resize(0    ,height);
          image( backgroundImg , 0,0);
          fill(255,193,37);
          ellipse(width/4,height/5,width/5,height/5);
          break;
      }
      case 18:
      {
          backgroundImg.resize(0    ,height);
          image( backgroundImg , 0,0);
          fill(205  ,133,0);
          ellipse(width/4,height/5,width/5,height/5);
          break;
      }
      case 19:
      {
          backgroundImg.resize(0    ,height);
          image( backgroundImg , 0,0);
          fill(255,0,0);
          ellipse(width/4,height/5,width/5,height/5); 
          break;
      }
      case 20:
      {
          backgroundImg.resize(0    ,height);
          image( backgroundImg , 0,0);
          fill(211,211,0);
          ellipse(width/4,height/5,width/5,height/5);
          break;
      }
      case 21:
      {
          backgroundImg.resize(0    ,height);
          image( backgroundImg , 0,0);
          fill(169,169,169);
          ellipse(width/4,height/5,width/5,height/5);
          break;
      }

      case 22:
      {
          backgroundImg.resize(0    ,height);
          image( backgroundImg , 0,0);
          fill(105,105,105);
          ellipse(width/4,height/5,width/5,height/5);
          break;
      }
      case 23:
      {
          backgroundImg.resize(0    ,height);
          image( backgroundImg , 0,0);
          fill(79,79,79);
          ellipse(width/4,height/5,width/5,height/5);
          break;
      }
      case 00:
      {
          backgroundImg.resize(0    ,height);
          image( backgroundImg , 0,0);
          fill(0,0,0);
          ellipse(width/4,height/5,width/5,height/5);
          break;
      }
      case 1:
      {
          backgroundImg.resize(0    ,height);
          image( backgroundImg , 0,0);
          fill(79,79,79);
          ellipse(width/4,height/5,width/5,height/5);
          break;
      }
      case 2:
      {
          backgroundImg.resize(0    ,height);
      image( backgroundImg , 0,0);
      fill(105,105,105);
      ellipse(width/4,height/5,width/5,height/5);
      break;
      }
      case 3:
      {
          backgroundImg.resize(0    ,height);
          image( backgroundImg , 0,0);
          fill(169,169,169);
          ellipse(width/4,height/5,width/5,height/5);
          break;
      }
      case 4:
      {
          backgroundImg.resize(0    ,height);
          image( backgroundImg , 0,0);
          fill(211,211,0);
          ellipse(width/4,height/5,width/5,height/5);
          break;
      }
      case 5:
      {
          backgroundImg.resize(0    ,height);
      image( backgroundImg , 0,0);
      fill(255,0,0);
      ellipse(width/4,height/5,width/5,height/5);
      break;
      }
      case 6:
      {
          backgroundImg.resize(0    ,height);
          image( backgroundImg , 0,0);
          fill(205,133,0);
          ellipse(width/4,height/5,width/5,height/5); 
          break;
      }
      case 7:
      {
          backgroundImg.resize(0    ,height);
          image( backgroundImg , 0,0);
          fill(255,193,37);
          ellipse(width/4,height/5,width/5,height/5);
          break;
      }
      case 8:
      {
          backgroundImg.resize(0    ,height);
          image( backgroundImg , 0,0);
          fill(121,29,121);
          ellipse(width/4,height/5,width/5,height/5);
          break;
      }
      case 9:
      {
          backgroundImg.resize(0    ,height);
          image( backgroundImg , 0,0);
          fill(111,209,0);
          ellipse(width/4,height/5,width/5,height/5);
          break;
      }
      case 10:
      {
          backgroundImg.resize(0    ,height);
          image( backgroundImg , 0,0);
          fill(230,209,0);
          ellipse(width/4,height/5,width/5,height/5);  
          break;
      }

      case 11:
      {
          backgroundImg.resize(0    ,height);
          image( backgroundImg , 0,0);
          fill(255,200,0);
          ellipse(width/4,height/5,width/5,height/5);  
          break;
      }

      case 12:
      {
          backgroundImg.resize(0    ,height);
          image( backgroundImg , 0,0);
          fill(255,209,0);
          ellipse(width/4,height/5,width/5,height/5);  
          break;
      }



      default:
      {  backgroundImg.resize(0 ,height);
          image( backgroundImg , 0,0);
          fill(255,209,0);
          ellipse(width/4,height/5,width/5,height/5);
          break;

      }
}
           }     
}

现在它只执行一次draw方法来改变太阳的颜色.如果小时改变,我需要绘制方法来执行每分钟以改变颜色.

Answer 1

你可以使用ScheduledExecutorService:

首先,您需要创建一个runnable并将您的方法放入其中:

Runnable drawRunnable = new Runnable() {
    public void run() {
        draw();
    }
};

然后安排执行者:

ScheduledExecutorService exec = Executors.newScheduledThreadPool(1);
exec.scheduleAtFixedRate(drawRunnable , 0, 1, TimeUnit.MINUTES);

这样它将每分钟执行一次.

只需更改时间或TimeUnit更改执行之间的时间即可.