Java - JPanel and KeyListener Problem.

Question

I have a JFrame with 3 panels. I extend an App class, and then add three panels to it, like so:

JPanel controlButtonsPanel = new GameControlButtons();
        controlButtonsPanel.setPreferredSize(new Dimension(801,60));
        controlButtonsPanel.setBorder(new LineBorder(Color.white, 1));
        constraints.anchor = GridBagConstraints.NORTHWEST;
        constraints.weightx = 2;
        constraints.weighty = 0.3;
        this.add(controlButtonsPanel, constraints);

        JPanel tempP = new JPanel();     
/`/ *** I'm going to create a Jpanel subclass for this, too, I just haven't yet.`
        tempP.setPreferredSize(new Dimension(500,838));
        tempP.setBorder(new LineBorder(Color.white, 2));
        constraints.anchor = GridBagConstraints.NORTHEAST;
        constraints.weightx = 1;
        constraints.weighty = 2;
        this.add(tempP, constraints);

        JPanel graphicsPanel = new RoofRunnerGame("Ken");
        constraints.anchor = GridBagConstraints.SOUTHWEST;
        constraints.weightx = 2;
        constraints.weighty = 1;
        graphicsPanel.setBorder(new LineBorder(Color.white, 1));
        graphicsPanel.setPreferredSize(new Dimension(800,800));
        graphicsPanel.requestFocus();
        this.add(graphicsPanel, constraints);       

I've extended JPanel for the GameControlButtons and RoofRunnerGame classes. I've added a mouselistener to the former. And I've add a mouse listener and a key listener to the latter.

** The problem: the mouse listeners work fine for both, but the key listener does't seem to listen in my RoofRunnerGame panel.**

I found two possible fixes online, but wanted to ask first.

1) One was calling requestFocus() in the RoofRunnerGame subclass. The problem with this is that once I clicked a different panel, it loses focus. (It's a short term fix.)

2) Another thing mentioned was to use keyBindings. I have never used them before. I will if you recommend it, but would prefer to keep using keyListener if that's possible.

So, what do you think? Is there some way I can keep the RoofRunnerGame panel to KEY listen throughout?

Answer 1

You can make other panels not focusable, but it might also require making every component on those panels not focusable.

See this, and this examples about adding a key listener through ActionMap. JComponent.WHEN_IN_FOCUSED_WINDOW flag in getInputMap() method should allow your panel to receive input events even when it's not focused.