按键侦听器在按下时不起作用 [英] Key Listener not working when being pressed

问题描述

尝试使我的代码在屏幕上移动播放器(Ship)时遇到很多麻烦.我可以在屏幕上绘制行星并播放器飞船，但是我不知道如何实现keyListener至少打印出一些东西.预先感谢您提供的所有帮助！

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");
        }
    }





    }

推荐答案

KeyListener不是获得结果的最合适方法.

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

最好使用键绑定 API

除了简化代码外，它还使您可以更好地控制按键的触发时间.

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

这篇关于按键侦听器在按下时不起作用的文章就介绍到这了，希望我们推荐的答案对大家有所帮助，也希望大家多多支持IT屋！