Movement with timers.

Question

i have a game in which my character moves when one of the direction keys is pressed.
when a key is pressed, a timer is created, along with a timertask the changes the characters location every couple of miliseconds depending on what direction is pressed.
when the key is released, the timertask and timers are cancelled.
the problem with this, is that the timer can malfuntion, causing the character to uncontrollably run away.
this is due (i theorize) to the timers adding up, when more than one key is pressed at the same time.
is there a better way to get the character to move? (rather than timers)
just pressing the key isnt an option, since there is a pause if you depress it for a couple of milliseconds before it starts running smoothly.

Answer 1

import java.awt.*;
import java.awt.event.*;
import java.io.*;
import java.net.*;
import javax.imageio.ImageIO;
import javax.swing.*;
import javax.swing.Timer;
public class KeyMotion
    public static void main(String[] args)
        JFrame f = new JFrame();
        f.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
        f.getContentPane().add(new MotionPanel());
        f.setSize(400,400);
        f.setLocation(200,200);
        f.setVisible(true);
class MotionPanel extends JPanel
    Image image;
    int x, y, xInc, yInc;
    Timer upTimer, leftTimer, downTimer, rightTimer;
    public MotionPanel()
        x = 150;
        y = 150;
        xInc = 2;
        yInc = 2;
        loadImage();
        initializeTimers();
        registerKeys();
        setBackground(Color.white);
    protected void paintComponent(Graphics g)
        super.paintComponent(g);
        g.drawImage(image, x, y, this);
    private void registerKeys()
        String[] keys = { "UP", "LEFT", "DOWN", "RIGHT" };
        Action[] actions = { up, left, down, right };
        for(int j = 0; j < keys.length; j++)
            getInputMap().put(KeyStroke.getKeyStroke(keys[j]), keys[j]);
            getActionMap().put(keys[j], actions[j]);
    private void initializeTimers()
        upTimer = new Timer(40, new ActionListener()
            public void actionPerformed(ActionEvent e)
                y -= yInc;
                repaint();
        leftTimer = new Timer(40, new ActionListener()
            public void actionPerformed(ActionEvent e)
                x -= xInc;
                repaint();
        downTimer = new Timer(40, new ActionListener()
            public void actionPerformed(ActionEvent e)
                y += yInc;
                repaint();
        rightTimer = new Timer(40, new ActionListener()
            public void actionPerformed(ActionEvent e)
                x += xInc;
                repaint();
    private void loadImage()
        String fileName = "images/dukeWaveRed.gif";
        try
            URL url = getClass().getResource(fileName);
            image = ImageIO.read(url);
        catch(MalformedURLException mue)
            System.out.println("URL help: " + mue.getMessage());
        catch(IOException ioe)
            System.out.println("io help: " + ioe.getMessage());
    private Action up = new AbstractAction()
        public void actionPerformed(ActionEvent e)
            if(upTimer.isRunning())
                return;
            if(downTimer.isRunning())
                downTimer.stop();
                return;
            upTimer.start();
    private Action left = new AbstractAction()
        public void actionPerformed(ActionEvent e)
            if(leftTimer.isRunning())
                return;
            if(rightTimer.isRunning())
                rightTimer.stop();
                return;
            leftTimer.start();
    private Action down = new AbstractAction()
        public void actionPerformed(ActionEvent e)
            if(downTimer.isRunning())
                return;
            if(upTimer.isRunning())
                upTimer.stop();
                return;
            downTimer.start();
    private Action right = new AbstractAction()
        public void actionPerformed(ActionEvent e)
            if(rightTimer.isRunning())
                return;
            if(leftTimer.isRunning())
                leftTimer.stop();
                return;
            rightTimer.start();
}