java - Keylistener not working for JPanel

Question

I am trying to do something when one of the arrow keys are pressed using the KeyListener in my JPanel class. Here is my code:

public class TestPanel extends JPanel implements KeyListener{

    public TestPanel(){
        this.addKeyListener(this);
        this.setFocusable(true);
        this.requestFocusInWindow();
    }

    public void keyPressed(KeyEvent e) {
        if (e.getKeyCode() == KeyEvent.VK_RIGHT) {
            System.out.println("Right");

        }

        if (e.getKeyCode() == KeyEvent.VK_LEFT) {
            System.out.println("Left");
        }

    }

    public void keyTyped(KeyEvent e) {}
    public void keyReleased(KeyEvent e) {}
}

My main method adds a new instance of this panel to a frame and displays it. Do I need to add the keylistener to the JFrame? In my case, this would be difficult and inefficient, so I would like to make it work with this JPanel if possible. Anyone know what I am doing wrong?

EDIT: Key Bindings code that does not work either:

public class GamePanel extends JPanel implements ActionListener{

//Constructor
public GamePanel(){

    setupKeyBinding();
    this.setFocusable(true);
    this.requestFocusInWindow();


}

private void setupKeyBinding() {
    int condition = JComponent.WHEN_IN_FOCUSED_WINDOW;
    InputMap inMap = getInputMap(condition);
    ActionMap actMap = getActionMap();

    inMap.put(KeyStroke.getKeyStroke(KeyEvent.VK_LEFT, 0), "Left");
    actMap.put("Left", new leftAction());
}

private class leftAction extends AbstractAction {

       public void actionPerformed(ActionEvent e) {
          System.out.println("test");
       }
}

public void actionPerformed(ActionEvent e) {
    //some other game info
}
} 

Can someone tell me why this doesnt work either? (my second action listener is for other stuff needed for my game)

Answer 1

If you search this problem, you'll see that it is asked and has been solved many times.

• KeyListeners need to be on the focused component to work. One solution is to give your component the focus after first making it focusable.
• Better by a long shot however is to use Key Bindings. Google the tutorial on this.

Please have a look at my answer to this question for more on this, including many of the gory details.