How do I slow down a thread for a specific object

Newbie & Debugging Questions
#1

I have three images that I want to cycle through once a KeyEvent is hit. But, since the paint method is constantly repainting, my images get cycled through pretty fast. So far, the only thing that’s worked is if I make the thread sleep for a longer period. Which messes up everything else.
This code below isn’t what I’m working on but it has the basic principles. The colors get updated everytime the thread wakes up. How do I slow the colors down only. If you increase the number inside thread.sleep() to 300, you’ll get what I’m trying to do.


import java.applet.Applet;
import java.awt.Color;
import java.awt.Graphics;
import java.awt.event.KeyEvent;
import java.awt.event.KeyListener;
import java.util.Random;




public class TheApplet extends Applet implements KeyListener, Runnable{
    public int x = 20;
    public int y = 20;
    public int dx = 5;
    
    public Random r = new Random();
     
    public Random r2 = new Random();
     
    public Random r3 = new Random();
    
    
    boolean change = false;
    boolean keydown = false;
    
   public void init(){
        setSize(800, 600);
        setFocusable(true);
        addKeyListener(this);
     }
     
     public void start(){
    	 
        Thread thread = new Thread(this);
        thread.start();
     }
     
     public void run(){
       
        int counter = 0;
        
        while(true){
           
           if(keydown && counter <= 0) x+=dx;
           
           counter--;
           
           repaint();
           try {
            Thread.sleep(17);
         } catch (InterruptedException e) {
            e.printStackTrace();
         }
        }
     }
     
     public void paint(Graphics g){
         if(change){
        	 int RandomNum = r.nextInt(200); 
        	 int RandomNum2 = r2.nextInt(200);
        	 int RandomNum3 = r3.nextInt(200);
        	 
    	 g.setColor(new Color(RandomNum, RandomNum2, RandomNum3));}
    	 g.fillRect(x, y, 40, 40);
     }

   @Override
   public void keyPressed(KeyEvent e) {
      switch(e.getKeyCode()){
      case KeyEvent.VK_RIGHT:
         keydown=true;
         change = true;
      }
      
   }

   @Override
   public void keyReleased(KeyEvent e) {
      switch(e.getKeyCode()){
         case KeyEvent.VK_RIGHT:
            keydown=false;
            change = false;
         }         
   }

   @Override
   public void keyTyped(KeyEvent e) {
      // TODO Auto-generated method stub
      
   }
  
   
}
#2

Assuming i understand it right it is a very simple problem, ill do it in pseudo code



int timeElapsed = 0;
int sleeptime = 17;
while(true)
{
      if(timeElapsed >= 300)
      {
                repaint();
                timeElapsed = 0;
      }
      Thread.sleep(sleeptime);
      timeElapsed += sleeptime;
}
#3

Okay, this works, but how do I make it affect only the colors? The x position needs to be repainted as well and this way makes it lag.

Edit: Nevermind this does work :slight_smile: thanks.

#4

Have a look at this post, read down for my reply.

Ideally you shouldn’t be sleeping the thread unless you are making a game loop (a bad or good for one depends on how you code it) , which AFAIK you are not.