Question

I’m having a lot of trouble trying to make my code move a player (Ship) around a screen. I can get the planets to draw on the screen and the the player ship but I can not figure out how to implement the keyListener to at least print out something. Thank you in advance for all the help!

    import javax.swing.JFrame;
    import javax.swing.JPanel;
    import java.awt.Canvas;
    import java.awt.Color;
    import java.awt.Dimension;
    import java.awt.Graphics;
    import java.awt.Point;
    import java.awt.Toolkit;
    import java.awt.event.KeyAdapter;
    import java.awt.event.KeyEvent;
    import java.awt.event.KeyListener;


    public class MapPanel extends JPanel {
public static final int WIDTH = 25;
 public static final int HEIGHT = 20;
 int zone = 0;
 private int xValue;
 private int yValue;
 private Color color;
 public Planet[][] planetGrid = new Planet[WIDTH][HEIGHT];
 static Player currPlayer = new Player("h");
 static Universe universe = new Universe(currPlayer);

 /**
 * Create the panel.
 */
 public MapPanel(Universe univ, Player p) {
    this.universe = univ;
    currPlayer = p;
    int i = 0;
    this.setSize(new Dimension(450,450));
    setVisible( true );
    //this.addKeyListener(new KeyController());
     KeyController kc = new KeyController();
     this.addKeyListener(kc);
    repaint();


 }


 /**
  * Draw method to draw the playing field
  * @param g Graphics object
  * @param tileDimension dimension of the tile
  */
 public void draw(Graphics g)
 {
 universe.draw(g);

    //    KeyController key = new KeyController();
 }
 public void paintComponent(Graphics g) {
     super.paintComponent(g);
     draw(g);
 }
 public static void main(String[] args)
 {
     MapPanel mp = new MapPanel(universe, currPlayer);
     JFrame f = new JFrame();
     f.add(mp);
     f.setSize(new Dimension(450,450));
     f.setVisible(true);
     f.setFocusable(true);


 }
 private class KeyController implements KeyListener {
     public KeyController()
     {
         System.out.println("ghgh");
         setFocusable(true);
        // addKeyListener(this);
     }
        @Override
        public void keyPressed(final KeyEvent key) {
            System.out.println("fgfgf");
            if (currPlayer != null) {

                int oldX = currPlayer.getPosition().x;
                int oldY = currPlayer.getPosition().y;

                switch (key.getKeyCode()) {
                    case KeyEvent.VK_RIGHT:
                      currPlayer.setPosition(new Point(oldX+1, oldY)); //move right
                      System.out.println("RIGHT");
                        break;
                    case KeyEvent.VK_LEFT:
                          currPlayer.setPosition(new Point(oldX-1, oldY));         //move left
                        break;
                    case KeyEvent.VK_DOWN:
                          currPlayer.setPosition(new Point(oldX, oldY+1));         //move down
                        break;
                    case KeyEvent.VK_UP:
                          currPlayer.setPosition(new Point(oldX, oldY-1));         //move up
                        break;
                }

            }
            repaint();
        }
        @Override
        public void keyReleased(KeyEvent e) {
            System.out.println("ggg");
        }
        @Override
        public void keyTyped(KeyEvent e) {
            System.out.println("typeeeddd");
        }
    }





    }

Answer 1

KeyListener is not the most appropriate method to achieve your results.

It would be better to use the key bindings API.

Apart from simplifying the code, it will also allow you to provide better focus control over when the keys should triggered.