KeyListener事件显然没有在java applet中触发

我刚刚开始学习编程applet和java GUI，我试图制作一个简单的游戏。 目前，我有主要类（游戏）和玩家类（玩家）我让玩家绘制到屏幕上，但我正在努力让关键事件发挥作用，任何帮助赞赏！

玩家图像显示完美，但是当我完全按下按键时位置不会改变。

编辑：为播放器发布错误代码，更新

Game.java：

public class Game extends Applet { Player player; @Override public void init() { player = new Player(this); this.setSize(800, 600); addKeyListener(player); } @Override public void paint(Graphics g) { player.paint(g); } } 

Player.java：

 public class Player implements KeyListener { Game game; Image image; int x; int y; public Player(Game game) { this.game = game; x = 0; y = 0; image = game.getImage(game.getCodeBase(), "images/Player.png"); } public void paint(Graphics g) { g.drawImage(image, x, y, game); } @Override public void keyTyped(KeyEvent e) { return; } @Override public void keyPressed(KeyEvent e) { switch (e.getKeyCode()) { case KeyEvent.VK_A: x -= 1; break; case KeyEvent.VK_D: x += 1; break; case KeyEvent.VK_S: y += 1; break; case KeyEvent.VK_W: y -= 1; break; } game.repaint(); } @Override public void keyReleased(KeyEvent e) { return; } } 

Answer 1

面板可能要么没有焦点，要么没有焦点。

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试试这个代码。 我将键更改为左/右/上/下箭头。 为简单起见，我把它留作了基于AWT的applet。

 //  import java.applet.*; import java.awt.*; import java.awt.event.*; public class Game extends Applet implements KeyListener { Player player; @Override public void init() { player = new Player(getImage(32)); addKeyListener(this); setFocusable(true); requestFocusInWindow(); } @Override public void paint(Graphics g) { player.paint(g); } public Image getImage(int size) { Image img = createImage(size,size); Graphics g = img.getGraphics(); g.setColor(Color.RED); g.fillRect(0,0,size,size); g.dispose(); return img; } @Override public void keyTyped(KeyEvent e) { return; } @Override public void keyPressed(KeyEvent e) { switch (e.getKeyCode()) { case KeyEvent.VK_LEFT: player.x -= 1; break; case KeyEvent.VK_RIGHT: player.x += 1; break; case KeyEvent.VK_DOWN: player.y += 1; break; case KeyEvent.VK_UP: player.y -= 1; break; } repaint(); } @Override public void keyReleased(KeyEvent e) { return; } } class Player { Image image; int x; int y; public Player(Image image) { x = 0; y = 0; this.image = image; } public void paint(Graphics g) { g.drawImage(image, x, y, null); } }