我正在为一个项目用Java制作一个格斗游戏,并试图让一张图片在面板上移动并重新绘制,以响应键盘(keyEvents)。我试图通过在 keyPressed 方法中进行开关来实现这一点,同时将 keyListener 添加到面板中。我一直在遵循我的 Java 书籍中的一个示例,并且我编写的代码几乎相同,但它只是无法工作。
我真正想知道的是为什么它似乎根本没有对 keyEvents 做出反应。该程序编译良好,但没有任何反应。我不知道出了什么问题。keyPressed()
如果我做一个,它不会到达方法中的断点,println()
如果我把它放在那里它也不会做。所以该keyPressed()
方法根本没有反应。我还测试并确保面板可聚焦,因此我确定它具有键盘焦点。
public class MovePanel extends JPanel implements KeyListener {
private ImageIcon currentImage, facingLeft, facingRight;
private int position;
private final int MOVEMENT;
private GameFrame gameFrame;
private URL lefturl, righturl;
public MovePanel(GameFrame gameFrame) {
// Taking in a gameFrame to be able to swap the active panel
// (not really relevant).
this.gameFrame = gameFrame;
// Adding the key listener here.
addKeyListener(this);
// These are just the Images I'm using to test.
// Trying to get it to swap from one to the other.
lefturl = getClass().getResource("/Images/facingLeft.jpg");
righturl = getClass().getResource("/Images/facingRight.jpg");
facingLeft = new ImageIcon(lefturl);
facingRight = new ImageIcon(righturl);
currentImage = facingLeft;
position = 50;
MOVEMENT = 30;
setBackground(Color.red);
setPreferredSize(new Dimension(600,300));
// Calling this method so that the panel will react
// to the keyboard without having to be clicked.
setFocusable(true);
}
// This is just the paintComponent method which works fine to paint the image
// when starting the game.
public void paintComponent(Graphics page) {
super.paintComponent(page);
currentImage.paintIcon(this, page, position, 170);
}
// No matter what I try to do inside the keyPressed method
// it doesnt seem to react at all.
public void keyPressed(KeyEvent e) {
// This switch is to make the method react accordingly to the keys pressed.
switch (e.getKeyCode()) {
case KeyEvent.VK_LEFT:
// Here I'm changing the "active" image and the position
// by changing the position variable which is used
// to determine the x placement of the image.
// This case is suppused to react if the left arrow key is pressed.
currentImage = facingRight;
position -= MOVEMENT;
break;
case KeyEvent.VK_RIGHT:
currentImage = facingRight;
position += MOVEMENT;
break;
// This case is to exit to the menu when escape is pressed.
case KeyEvent.VK_ESCAPE:
gameFrame.setMenuPanelActive();
break;
}
// After reacting to any of the proper keys pressed
// I'm trying to repaint which will use the
// paintComponent method to paint the new image in its new position.
repaint();
}
// I have empty definitions for the other
// implemented methods but won't be posting them.
}
有谁知道为什么这不起作用?为什么keyPressed()
方法不会反应?