我试图用Java创建一个简单的乒乓球游戏，但我不知道如何让两个玩家同时使用键盘。游戏不完整，我正在为两位玩家进行划桨运动。问题是，当玩家按下他们的向上键并向上移动他们的牌时，但如果其他玩家击中他们的任何键，它会取消之前的玩家动作并导致击球板停止。我想我需要一种方法来同时处理多个键输入。这是我的代码，底部的KeyListeners是我需要帮助的地方。我只有一年的Java程序员，所以我可以轻松完成剩下的代码。
import java.awt.Color;
import java.awt.Graphics;
import java.awt.Graphics2D;
import javax.swing.*;
import java.awt.*;
import java.awt.event.ActionEvent;
import java.awt.event.ActionListener;
import java.awt.event.KeyEvent;
import java.awt.event.KeyListener;
import java.util.HashSet;
import java.util.Set;
public class DrawGame extends JPanel implements ActionListener{
public static final int XPOS = 0;
public static final int YPOS = 0;
public boolean xFlag = true; // true means ballx is going right
public boolean yFlag = true; // true means bally is going down
public int ballX = 300; // Ball starting point
public int ballY = 400; // Ball starting point
Timer ballTimer; // Starts balls animation
public int leftScore;
public int rightScore;
public int rightPadY; // Right players paddle position
public int leftPadY; // left players paddle position
// Constructor
public DrawGame(){
addKeyListener(new RightListener());
addKeyListener(new LeftListener());
leftScore = 0;
rightScore = 0;
rightPadY = YPOS + 230;
leftPadY = YPOS + 230;
setBackground(Color.BLACK);
setPreferredSize(new Dimension(800, 600));
setFocusable(true);
ballTimer = new Timer(10, this);
ballTimer.start();
}
// Draws game
public void paintComponent(Graphics g){
super.paintComponent(g);
Graphics2D g2d = (Graphics2D)g;
//Drawing Side Boards
g2d.setColor(Color.WHITE);
g2d.fillRect(XPOS + 5, YPOS + 20, 775, 25); // Top Board
g2d.fillRect(XPOS + 5, YPOS + 517, 775, 25); // Bottom board
//Drawing the center line
g2d.fillRect(XPOS + 377, YPOS + 45 * 1, 25, 25);
g2d.fillRect(XPOS + 377, YPOS + 45 * 2, 25, 25);
g2d.fillRect(XPOS + 377, YPOS + 45 * 3, 25, 25);
g2d.fillRect(XPOS + 377, YPOS + 45 * 4, 25, 25);
g2d.fillRect(XPOS + 377, YPOS + 45 * 5, 25, 25);
g2d.fillRect(XPOS + 377, YPOS + 45 * 6, 25, 25);
g2d.fillRect(XPOS + 377, YPOS + 45 * 7, 25, 25);
g2d.fillRect(XPOS + 377, YPOS + 45 * 8, 25, 25);
g2d.fillRect(XPOS + 377, YPOS + 45 * 9, 25, 25);
g2d.fillRect(XPOS + 377, YPOS + 45 * 10, 25, 25);
g2d.fillRect(XPOS + 377, YPOS + 45 * 11, 25, 25);
//Drawing the paddles
g2d.fillRect(XPOS + 10, leftPadY, 20, 100);// Left
g2d.fillRect(XPOS + 755, rightPadY, 20, 100); // Right
//Drawing the ball
g2d.fillRect(ballX, ballY, 23, 23);
//Drawing the score
switch(leftScore){
case 0:
g2d.fillRect(XPOS + 305, YPOS + 50, 7, 30);
g2d.fillRect(XPOS + 325, YPOS + 50, 7, 30);
g2d.fillRect(XPOS + 305, YPOS + 50, 25, 7);
g2d.fillRect(XPOS + 305, YPOS + 80, 27, 7);
break;
case 1:
g2d.fillRect(XPOS + 325, YPOS + 50, 7, 30);
}
switch(rightScore){
case 0:
g2d.fillRect(XPOS + 450, YPOS + 50, 7, 30);
g2d.fillRect(XPOS + 470, YPOS + 50, 7, 30);
g2d.fillRect(XPOS + 450, YPOS + 50, 25, 7);
g2d.fillRect(XPOS + 450, YPOS + 80, 27, 7);
break;
case 1:
g2d.fillRect(XPOS + 450, YPOS + 50, 7, 30);
}
}
// Controls the animation of the ball
public void actionPerformed(ActionEvent e){
if(xFlag == true && ballX >= 735){
ballX += 2;
xFlag = false;
} else if(xFlag == true){
ballX += 2;
}
if(xFlag == false && ballX <= 25){
ballX -= 2;
xFlag = true;
} else if(xFlag == false){
ballX -= 2;
}
if(yFlag == true && ballY >= 500){
ballY += 2;
yFlag = false;
} else if(yFlag == true){
ballY += 2;
}
if(yFlag == false && ballY <= 45){
ballY -= 2;
yFlag = true;
} else if(yFlag == false){
ballY -= 2;
}
repaint();
ballTimer.restart();
}
// Keylistener for right player
private class RightListener implements KeyListener{
@Override
public synchronized void keyPressed(KeyEvent event) {
if(event.getKeyCode() == KeyEvent.VK_UP){
rightPadY -= 5;
}else if(event.getKeyCode() == KeyEvent.VK_DOWN){
rightPadY += 5;
}
repaint();
}
@Override
public synchronized void keyReleased(KeyEvent e) {
// TODO Auto-generated method stub
}
@Override
public synchronized void keyTyped(KeyEvent e) {
// TODO Auto-generated method stub
}
}
// Keylistener for left player
private class LeftListener implements KeyListener{
@Override
public synchronized void keyPressed(KeyEvent event) {
if(event.getKeyCode() == KeyEvent.VK_W){
leftPadY -= 5;
} else if(event.getKeyCode() == KeyEvent.VK_S){
leftPadY += 5;
}
repaint();
}
@Override
public synchronized void keyReleased(KeyEvent e) {
// TODO Auto-generated method stub
}
@Override
public synchronized void keyTyped(KeyEvent e) {
// TODO Auto-generated method stub
}
}
}
答案 0 :(得分：6)
不要使用KeyListener。您应该使用Key Bindings。
有关详细信息，请参阅Motion Using the Keyboard。
我将以下代码添加到上述链接中的KeyboardAnimation示例中，这样您就可以执行所需操作：
JLabel label2 = new JLabel( new ColorIcon(Color.GREEN, 40, 40) );
label2.setSize( label2.getPreferredSize() );
label2.setLocation(500, 500);
contentPane.add( label2 );
KeyboardAnimation animation2 = new KeyboardAnimation(label2, 24);
animation2.addAction("A", -3, 0);
animation2.addAction("D", 3, 0);
animation2.addAction("W", 0, -3);
animation2.addAction("S", 0, 3);
答案 1 :(得分：0)
最好使用线程进行动画制作。当您keyPressed时，我们会告诉程序密钥已关闭。在keyReleased我们将告诉程序密钥已启动。在线程中，我们将读取此值并确定是否要移动。这也会更加顺畅。
首先，您需要在某个类中实现Runnable。您甚至可以在那里的主要课程中完成。
添加public void run方法。
它将是：
while(true)
{
if(player1.upkeyIsDown() && player1.downKeyIsUp())
{
//move Player1 Up
}
else if(player1.downKeyIsDown() && player1.upKeyIsUp())
{
//move Player1 Down
}
//do similar for player 2
try{
Thread.sleep(50);
}
catch(InterruptedException ie)
{
ie.printStackTrace();
}
}
这是半伪代码，你必须实现如何保存密钥。在KeyListeners中，你需要在主类中调用一些东西来改变这些值，然后这个线程将处理其余的。
此线程也需要启动。在你的main / constructor中的某处写new Thread(this).start();