Question

I’m new to graphics programming and am having some difficluties with using a KeyListener to move and image left or right. Currently my code does not even register that a key is being pressed. If someone could help me out with just getting it to register this then I can do the rest myself.

Here is the frame code:

import java.awt.CardLayout;
import java.awt.event.ActionEvent;
import java.awt.event.ActionListener;
import java.awt.event.KeyEvent;
import java.awt.event.KeyListener;
import javax.swing.JFrame;
import javax.swing.JPanel;

public class FrameMain extends JFrame {

    final JPanel pnlShow;
    PanelHome pnlHome = new PanelHome();
    PanelPlayerInfo pnlPlayerInfo = new PanelPlayerInfo();
    PanelPlay pnlPlay = new PanelPlay(pnlPlayerInfo);
    PanelInstruction pnlInstructions = new PanelInstruction();
    PanelStore pnlStore = new PanelStore();
    PanelHighscores pnlHighscores = new PanelHighscores();
    ControlActionListenter CAL = new ControlActionListenter();

    public FrameMain() {
        pnlShow = new JPanel(new CardLayout());
        pnlShow.add(pnlHome, "Home");
        pnlShow.add(pnlPlay, "Play");
        pnlShow.add(pnlInstructions, "Instructions");
        pnlShow.add(pnlStore, "Store");
        pnlShow.add(pnlHighscores, "Highscores");
        pnlShow.add(pnlPlayerInfo, "PlayerInfo");

        this.setDefaultCloseOperation(EXIT_ON_CLOSE);
        this.setTitle("TANKS");
        this.setVisible(true);
        this.setSize(806, 628);
        this.setResizable(false);
        this.add(pnlShow);
        this.addKeyListener(new Move());

        pnlHome.btnExit.addActionListener(CAL);
        pnlHome.btnExit.setActionCommand("Exit");
        pnlHome.btnPlay.addActionListener(CAL);
        pnlHome.btnPlay.setActionCommand("PlayerInfo");
        pnlHome.btnInst.addActionListener(CAL);
        pnlHome.btnInst.setActionCommand("Instructions");
        pnlHome.btnHigh.addActionListener(CAL);
        pnlHome.btnHigh.setActionCommand("Highscores");
        pnlInstructions.btnBack.addActionListener(CAL);
        pnlInstructions.btnBack.setActionCommand("Main");
        pnlPlay.pnlToolbar.btnHome.addActionListener(CAL);
        pnlPlay.pnlToolbar.btnHome.setActionCommand("Main");
        pnlHighscores.btnBack.addActionListener(CAL);
        pnlHighscores.btnBack.setActionCommand("Main");
        pnlPlayerInfo.btnPlay.addActionListener(CAL);
        pnlPlayerInfo.btnPlay.setActionCommand("Play");
        pnlPlayerInfo.btnBack.addActionListener(CAL);
        pnlPlayerInfo.btnBack.setActionCommand("Main");

    }

    class ControlActionListenter implements ActionListener {

        public void actionPerformed(ActionEvent e) {
            CardLayout cl = (CardLayout) (pnlShow.getLayout());
            String cmd = e.getActionCommand();

            if (cmd.equals("Main")) {
                cl.show(pnlShow, "Home");
            } else if (cmd.equals("Exit")) {
                System.exit(0);
            } else if (cmd.equals("Play")) {
                pnlPlay.arpPlayer[0].populateName(pnlPlayerInfo.txtPlayer1.getText());
                pnlPlay.arpPlayer[1].populateName(pnlPlayerInfo.txtPlayer2.getText());
                pnlPlay.pnlPlayer.lblPlayer1.setText(pnlPlay.arpPlayer[0].sPlayer);
                pnlPlay.pnlPlayer.lblPlayer2.setText(pnlPlay.arpPlayer[1].sPlayer);
                cl.show(pnlShow, "Play");
            } else if (cmd.equals("PlayerInfo")) {
                cl.show(pnlShow, "PlayerInfo");
            } else if (cmd.equals("Instructions")) {
                cl.show(pnlShow, "Instructions");
            } else if (cmd.equals("Highscores")) {
                cl.show(pnlShow, "Highscores");
            }
        }
    }

    class Move implements KeyListener {

        public void keyPressed(KeyEvent e) {
            System.out.println("rp");
        }

        public void keyTyped(KeyEvent e) {
            System.out.println("rp");
        }

        public void keyReleased(KeyEvent e) {
            System.out.println("rp");
        }
    }
}

I have added a keylistener to the frame and made a class that implements this keylistener. Like I said, all I want to do is have the program output something when I hit a key on the keyboard. If I need to show you anything else let me know and I will post it.

Answer 1

Try adding KeyListener to the components you need, not the whole JFrame. And make sure they are focused.

Also you may find How to Use Key Bindings useful, as an alternative to key listeners.