Java Event listeners (mouse and keyboard)

Question

So everything in my program works, except for the mouse and the keyboard listeners. I've got a couple actionListeners working on Jbuttons that do exactly what I'm trying to do here, but the assignment says it has to work with all three. So I would like to know why it compiles, but doesn't work. Am I doing something wrong?

panel.addKeyListener(new KeyListener() {
        @Override
        public void keyTyped(KeyEvent e) {

        }

        @Override
        public void keyPressed(KeyEvent e) {
             if(e.getKeyCode() == KeyEvent.VK_UP){
                shape.addSides();
            }
            if(e.getKeyCode() == KeyEvent.VK_DOWN){
                shape.subSides();
            }
        }

        @Override
        public void keyReleased(KeyEvent e) {

        }

    }

    );
    panel.addMouseListener(new MouseListener(){
        @Override
        public void mouseEntered(MouseEvent e){
            if(e.getButton() == MouseEvent.BUTTON1){

                shape.addSides();
            }
            if(e.getButton() == MouseEvent.BUTTON3){

                shape.subSides();
            }

        }

        @Override
        public void mouseClicked(MouseEvent e) {

        }

        @Override
        public void mousePressed(MouseEvent e) {   
        }

        @Override
        public void mouseReleased(MouseEvent e) {
        }

        @Override
        public void mouseExited(MouseEvent e) {
        }

    }
    );

Answer 1

Regarding KeyListener: it won't work unless the listened-to component is focusable and has focus. So you will want to call setFocusable(true) and requestFocusInWindow() on your JPanel. As for the MouseListener -- something else may be taking the mouse event and preventing it from reaching your JPanel. To debug this you need to post a minimal, compilable, runnable example program.

Also regarding your MouseListener, you're checking getButton() in a mouseEntered event which makes no sense. The buttons are not involved in this type of event. Are you instead meaning to check mouseDragged(...) of a MouseMotionListener?