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) {
        }

    }
    );

Community · Accepted Answer · 2017-05-23 11:51:02Z

3

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?

edited May 23, 2017 at 11:51

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answered Feb 11, 2014 at 19:25

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2 Comments

dic19 Over a year ago

+1. Another way is set keybinding on JButton's using JComponent.WHEN_IN_FOCUSED_WINDOW condition, as described in this Q&A

Chris Over a year ago

Completely missed the setFocusable(true) and requestFocusInWindow() in my book. That fixed he keyboard for me. As for the placement of the mouseListener, I had it where it is placed above originally. When it didn't work I did a copypasta to all 4 to hope one would work, and it didn't. When I just put it in mouseClicked() it does work. Thank you for your help. I got the project completed on time.

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