Thread: Code not working

Hi. I have made a code that should allowed me to move an object in a frame, using the arrow keys. But I don't know why, is not working. So I hope that you know what I did wrong.

package joc;
import java.awt.Color;
import java.awt.Graphics;
import java.awt.event.ActionEvent;
import java.awt.event.ActionListener;
import java.awt.event.KeyEvent;
import java.awt.event.KeyListener;
import javax.swing.ImageIcon;
import javax.swing.JPanel;
import javax.swing.Timer;
/**
 *
 * @author Paul
 */
public class obiect extends JPanel implements ActionListener, KeyListener
{
    Timer tm = new Timer(5,this);
    int x = 0, y = 0, velX = 0, velY = 0;
 
    public obiect()
    {
        tm.start();
        addKeyListener(this);
        setFocusable(true); // enable keylistener
        setFocusTraversalKeysEnabled(false);
    }
    @Override
public void paintComponent(Graphics g)
{
    super.paintComponent(g);
    g.setColor(Color.CYAN);
    g.fillRect(x,y,50,30);
    tm.start();
    /*
    ImageIcon i = new ImageIcon("car.png");
    i.paintIcon(this, g, 100, 100); 
      */
}
 
    @Override
    public void actionPerformed(ActionEvent e)
{
    if(x<0){
        velX = 0;
        x = 0;
    }
    if(x>500) {
        velX = 0;
        x = 530;
    }
    if(y<0){
        velY=0;
        y=0;
    }
    if(y>500) {
        velY=0;
        y=500;
    } 
x = x + velX; // dreapta sau stanga
y = y + velY; // sus sau jos
repaint();
}
@Override   
public void keyPressed(KeyEvent e) 
{
    int c = e.getKeyCode();
 
    if(c == KeyEvent.VK_LEFT)
        {
            velX= -1; 
            velY = 0;
        }
    if(c == KeyEvent.VK_UP)
        {
            velX=0;
            velY=-1; 
        }
    if(c == KeyEvent.VK_RIGHT)
        {
            velX=1;
            velY=0;
        }
    if(c == KeyEvent.VK_DOWN)
        {
            velX=0;
            velY=1;
        }
}
@Override
public void keyTyped(KeyEvent e) {}
@Override
public void keyReleased(KeyEvent e) 
{
    velX=0;
    velY=0;
}
 
}

The main program is:

package joc;
import javax.swing.JFrame;
/**
 *
 * @author paul
 */
public class Joc {
 
    public static void main(String[] args) {
        obiect o = new obiect();
        JFrame frame = new JFrame("Proiect Diacu Paul");
        frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
        frame.getContentPane().setLayout(null);
        frame.setSize(500,500);
        frame.setVisible(true);
        frame.add(o);
    }
 
}

Does your KeyListener get called? Have to added some debug statements to test this? If yes, the problem may lie in the logic. If no, the problem may lie in the component not having focus (in which case, I would recommend using KeyBindings)

The code shows the current contents of the JFrame with: setVisible(true)
and then adds another component to the JFrame hoping that the JFrame will redo the display to show the newly added component.
Move the call to setVisible

No, I was talking about frame.

Try doing some debugging. Add some println statements to the methods that are being called that print out some values. I find the value from getBounds() is useful to see what is happening.
Some methods to add it in: paintComponent() and actionPerformed().

The output will show you which methods are being called and what the size of the component is and where it is located.

Can you post the updated version of the code and the print out from the debug println statements so we can see what the print out is telling you about the code when it executes.