Games smooth response problem

Question

Hi! I am working on a tile based rpg and I have noticed that when I run the game in a fast pc, everything speeds up and it doesn't work properly.
Other problem happens when I hold a key down. The game waits a few seconds before responding and when it does it does it very quickly like doing the same operation a hundred times. I need to smooth that kind of responses and to slow down the game when running in fast PCs.
Thanks and sorry about my English :P

Answer 1

Here's a little demo for you:
import java.awt.Color;
import java.awt.Dimension;
import java.awt.event.ActionEvent;
import java.awt.event.ActionListener;
import java.awt.Graphics;
import java.awt.image.BufferedImage;
import javax.swing.JFrame;
import javax.swing.JPanel;
import javax.swing.Timer;
class Junk{
  Junk(){
    JFrame f = new JFrame("Color Test 1.0");
    f.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
    myPanel p = new myPanel();
    f.add(p);
    f.pack();
    f.setVisible(true);
  public static void main(String[] args){
    new Junk();
  class myPanel extends JPanel implements ActionListener{
    BufferedImage bi;
    Color[] c = {Color.BLACK, Color.BLUE, Color.CYAN,
                 Color.DARK_GRAY, Color.GRAY, Color.GREEN,
                 Color.LIGHT_GRAY, Color.MAGENTA, Color.ORANGE,
                 Color.PINK, Color.RED, Color.WHITE,
                 Color.YELLOW};
    Graphics biG;
    int myDelay; //controls period of change for timer
    int iColor;
    Timer t;
    public myPanel(){
      myDelay = 500;
      t = new Timer(myDelay, this);
      iColor = 1; //start other than Black
      setPreferredSize(new Dimension(300, 300));
      bi = new BufferedImage(300, 300, BufferedImage.TYPE_INT_RGB);
      biG = bi.getGraphics();
      t.start();
    public void paintComponent(Graphics g){
      g.drawImage(bi, 0, 0, this);
    public void actionPerformed(ActionEvent e){
      if(iColor>(c.length - 1)) iColor = 0;
      biG.setColor(c[iColor]);
      biG.fillRect(50,50,200,200);
      repaint();
      iColor++;
}Play with myDelay and try it on various speed machines, I think you'll see it's the same on each.