使用KeyListener的Pong控件
栾英资
问题内容：
问题答案：
我在打乒乓球游戏时遇到了麻烦，这个项目只是从制作具有物理性的球开始，但后来我决定做更多的工作
我有那个球来回弹跳，除了键W和S之外，其他所有键都不控制玩家1，上下箭头键不控制玩家2
public void keyPressed(KeyEvent e){
if(e.getKeyCode() == e.VK_UP){
p2Y -= 3;
System.out.println("UP");
}
if(e.getKeyCode() == e.VK_DOWN){
p2Y += 3;
System.out.println("Down");
}
if(e.getKeyCode() == e.VK_W){
p1Y -= 3;
System.out.println("Up");
}
if(e.getKeyCode() == e.VK_S){
p1Y += 3;
System.out.println("down");
}
repaint();
}
它甚至不会显示系统打印消息
我不知道这只是问题的代码的这一部分还是其他地方
如果在其他位置，请访问此文件其余部分的链接
http://pastebin.com/TJbLBxL7
整个代码：
import javax.swing.*;
import java.awt.*;
import java.awt.event.*;
import java.util.ArrayList;
public class Pong extends JPanel
{
Circle circle1;
javax.swing.Timer timer;
ArrayList<Point> points = new ArrayList<Point>();
int p1X=10, p1Y=320;
int p2X=760, p2Y = 320;
int y, y1;
int p1Score, p2Score;
boolean playing = true;
public Pong(Color backcolor, int Width, int Height)
{
setBackground(backcolor);
setPreferredSize(new Dimension(Width, Height));
//first circle
circle1 = new Circle(Width / 2, 360, 15, Color.white);
circle1.setVelocity(4);
circle1.setDirection(180);
timer = new javax.swing.Timer(5, new MoveListener());
addKeyListener(new KeyWatcher());
timer.start();
}
public void paintComponent(Graphics g)
{
super.paintComponent(g);
//first circle
circle1.draw(g);
circle1.fill(g);
// Draw Players
g.setColor(Color.red);
g.fillRect(p1X, p1Y, 10, 75);
g.setColor(Color.blue);
g.fillRect(p2X, p2Y, 10, 75);
//Draw Scores
g.setColor(Color.white);
g.drawString("Player 1's Score: " + p1Score, 10, 10);
g.drawString("Player 2's Score: " + p2Score, getWidth() - 120, 10);
repaint();
if(!playing)
{
g.setColor(Color.red);
g.drawString("GAMEOVER!!!", (getWidth() / 2) - 15, 10);
}
else
{
}
}
private class MoveListener extends MouseAdapter implements ActionListener
{
public void actionPerformed(ActionEvent arg0)
{
int x1 = circle1.getX();
int y1 = circle1.getY();
int width = getWidth();
int height = getHeight();
int radius1 = circle1.getRadius();
//first circle
if(x1 - radius1 <= 0)
{
p2Score++;
circle1.setX(getWidth()/2);
circle1.setY(getHeight()/2);
}
if(x1 + radius1 >= width)
{
p1Score++;
circle1.setX(getWidth()/2);
circle1.setY(getHeight()/2);
}
if(y1 - radius1 <= 0 || y1 + radius1 >= height )
{
circle1.turnY();
}
if((x1 - radius1 == p1X) || (x1 + radius1 == p2X))
{
circle1.turnX();
}
circle1.move();
repaint();
}
public void GameOver()
{
playing = false;
}
}
private class KeyWatcher implements KeyListener
{
@Override
public void keyPressed(KeyEvent e){
if(e.getKeyCode() == e.VK_UP){
p2Y -= 3;
System.out.println("UP");
}
if(e.getKeyCode() == e.VK_DOWN){
p2Y += 3;
System.out.println("Down");
}
if(e.getKeyCode() == e.VK_W){
p1Y -= 3;
System.out.println("Up");
}
if(e.getKeyCode() == e.VK_S){
p1Y += 3;
System.out.println("down");
}
repaint();
}
@Override
public void keyReleased(KeyEvent e){
//if(e.getKeyCode() == e.VK_UP){
// y1 = p2Y;
// repaint();
// }
// if(e.getKeyCode() == e.VK_DOWN){
// y1 = p2Y;
// repaint();
// }
//if(e.getKeyCode() == e.VK_W){
// y = p1Y;
// repaint();
// }
// if(e.getKeyCode() == e.VK_S){
// y = p1Y;
// repaint();
// }
}
@Override
public void keyTyped(KeyEvent arg0) {
// TODO Auto-generated method stub
}
}
}
我的新代码这个问题是每次只能控制一个玩家
它也有我愚蠢的尝试，通过制作2 MyKeyAction来解决它，但是它并没有改变它
package Bouncy;
import javax.swing.*;
import java.awt.*;
import java.awt.event.*;
import java.util.ArrayList;
public class Pong extends JPanel
{
Circle circle1;
javax.swing.Timer timer;
ArrayList<Point> points = new ArrayList<Point>();
int p1X=10, p1Y=320;
int p2X=760, p2Y = 320;
int y, y1;
int p1Score, p2Score;
boolean playing = true;
public Pong(Color backcolor, int Width, int Height)
{
setBackground(backcolor);
setPreferredSize(new Dimension(Width, Height));
//first circle
circle1 = new Circle(Width / 2, 360, 15, Color.white);
circle1.setVelocity(4);
circle1.setDirection(180);
timer = new javax.swing.Timer(5, new MoveListener());
setupKeyBinding();
setupKeyBinding2();
timer.start();
}
private void setupKeyBinding() {
int condition = JComponent.WHEN_IN_FOCUSED_WINDOW;
InputMap inMap = getInputMap(condition);
ActionMap actMap = getActionMap();
// this uses an enum of Direction that holds ints for the arrow keys
for (DirectionP1 direction : DirectionP1.values()) {
int key = direction.getKey();
String name = direction.name();
// add the key bindings for arrow key and shift-arrow key
inMap.put(KeyStroke.getKeyStroke(key, 0), name);
inMap.put(KeyStroke.getKeyStroke(key, InputEvent.SHIFT_DOWN_MASK), name);
actMap.put(name, new MyKeyAction(direction));
}
}
private void setupKeyBinding2() {
int condition = JComponent.WHEN_IN_FOCUSED_WINDOW;
InputMap inMap = getInputMap(condition);
ActionMap actMap = getActionMap();
// this uses an enum of Direction that holds ints for the arrow keys
for (DirectionP2 direction : DirectionP2.values()) {
int key = direction.getKey();
String name = direction.name();
// add the key bindings for arrow key and shift-arrow key
inMap.put(KeyStroke.getKeyStroke(key, 0), name);
inMap.put(KeyStroke.getKeyStroke(key, InputEvent.SHIFT_DOWN_MASK), name);
actMap.put(name, new MyKeyAction2(direction));
}
}
public void paintComponent(Graphics g)
{
super.paintComponent(g);
//first circle
circle1.draw(g);
circle1.fill(g);
// Draw Players
g.setColor(Color.red);
g.fillRect(p1X, p1Y, 10, 75);
g.setColor(Color.blue);
g.fillRect(p2X, p2Y, 10, 75);
//Draw Scores
g.setColor(Color.white);
g.drawString("Player 1's Score: " + p1Score, 10, 10);
g.drawString("Player 2's Score: " + p2Score, getWidth() - 120, 10);
repaint();
if(!playing)
{
g.setColor(Color.red);
g.drawString("GAMEOVER!!!", (getWidth() / 2) - 15, 10);
}
else
{
}
}
private class MoveListener extends MouseAdapter implements ActionListener
{
public void actionPerformed(ActionEvent arg0)
{
int x1 = circle1.getX();
int y1 = circle1.getY();
int width = getWidth();
int height = getHeight();
int radius1 = circle1.getRadius();
//first circle
if(x1 - radius1 <= 0)
{
p2Score++;
circle1.setX(getWidth()/2);
circle1.setY(getHeight()/2);
}
if(x1 + radius1 >= width)
{
p1Score++;
circle1.setX(getWidth()/2);
circle1.setY(getHeight()/2);
}
if(y1 - radius1 <= 0 || y1 + radius1 >= height )
{
circle1.turnY();
}
if((x1 - radius1 <= p1X) || (x1 + radius1 >= p2X))
{
circle1.turnX();
}
circle1.move();
repaint();
}
public void GameOver()
{
playing = false;
}
}
enum DirectionP1 {
W(KeyEvent.VK_W), S(KeyEvent.VK_S);
private int key;
private DirectionP1(int key) {
this.key = key;
}
public int getKey() {
return key;
}
}
enum DirectionP2 {
UP(KeyEvent.VK_UP), DOWN(KeyEvent.VK_DOWN);
private int key;
private DirectionP2(int key) {
this.key = key;
}
public int getKey() {
return key;
}
}
class MyKeyAction extends AbstractAction {
private DirectionP1 direction;
public MyKeyAction(DirectionP1 direction) {
this.direction = direction;
}
@Override
public void actionPerformed(ActionEvent e) {
switch (direction) {
case W:
p1Y -= 6;
break;
case S:
p1Y += 6;
break;
default:
break;
}
}
}
class MyKeyAction2 extends AbstractAction {
private DirectionP2 direction2;
public MyKeyAction2(DirectionP2 direction2) {
this.direction2 = direction2;
}
@Override
public void actionPerformed(ActionEvent e) {
switch (direction2) {
case UP:
p2Y -= 6;
break;
case DOWN:
p2Y += 6;
break;
default:
break;
}
}
}
}
问题答案：
您有一个重点问题。您正在向JPanel添加KeyListener：但是JPanel永远不会具有焦点，因此KeyListener将无法工作：
public class Pong extends JPanel
{
//...
public Pong(Color backcolor, int Width, int Height)
{
// ...
timer = new javax.swing.Timer(5, new MoveListener());
addKeyListener(new KeyWatcher());
但是JPanel永远不会获得焦点，并且KeyListeners仅在被侦听的组件具有焦点时才起作用。
更好的解决方案不是中继KeyListener，而是使用Swing Timer和Key
Bindings。请参阅[此链接](http://codingdict.com/questions/2408以获取此示例。
编辑 ：或者甚至更好的链接-JavaKeyListener不注册箭头键。
编辑2
也许更好的解决方案是使用按键绑定，但是使用它们在按键或释放按键时设置类的字段，然后使用Swing Timer作为游戏循环来轮询这些字段。
例如，这不会显示动画（由您决定），但是表明此技术将允许对同时按下的键做出响应：
import java.awt.event.ActionEvent;
import java.awt.event.ActionListener;
import java.awt.event.KeyEvent;
import java.util.EnumMap;
import javax.swing.*;
public class NewArrowTest extends JPanel {
private static final String PRESSED = "pressed";
private static final String RELEASED = "released";
private static final int TIMER_DELAY = 20;
private EnumMap<Key, Boolean> keyMap = new EnumMap<NewArrowTest.Key, Boolean>(Key.class);
public NewArrowTest() {
keyMap.put(Key.W, false);
keyMap.put(Key.S, false);
keyMap.put(Key.UP, false);
keyMap.put(Key.DOWN, false);
// set up key binding
ActionMap actionMap = getActionMap();
int condition = JComponent.WHEN_IN_FOCUSED_WINDOW;
InputMap inputMap = getInputMap(condition);
for (Key key : Key.values()) {
KeyStroke pressedKeyStroke = KeyStroke.getKeyStroke(key.getKeyCode(), 0, false);
KeyStroke releasedKeyStroke = KeyStroke.getKeyStroke(key.getKeyCode(), 0, true);
inputMap.put(pressedKeyStroke, key.getText() + PRESSED);
inputMap.put(releasedKeyStroke, key.getText() + RELEASED);
actionMap.put(key.getText() + PRESSED, new MyArrowBinding(key, false));
actionMap.put(key.getText() + RELEASED, new MyArrowBinding(key, true));
}
// start polling timer or game loop
new Timer(TIMER_DELAY, new TimerListener()).start();
}
private static void createAndShowGui() {
NewArrowTest mainPanel = new NewArrowTest();
JFrame frame = new JFrame("NewArrowTest");
frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
frame.getContentPane().add(mainPanel);
frame.pack();
frame.setLocationByPlatform(true);
frame.setVisible(true);
}
public static void main(String[] args) {
SwingUtilities.invokeLater(new Runnable() {
public void run() {
createAndShowGui();
}
});
}
private class TimerListener implements ActionListener {
public void actionPerformed(java.awt.event.ActionEvent e) {
for (Key key : keyMap.keySet()) {
System.out.printf("%6s %b%n", key, keyMap.get(key));
// here we'd move things based on which key is true
}
System.out.println();
};
}
private class MyArrowBinding extends AbstractAction {
private Key key;
private boolean released;
public MyArrowBinding(Key key, boolean released) {
this.key = key;
this.released = released;
}
@Override
public void actionPerformed(ActionEvent aEvt) {
keyMap.put(key, !released);
}
}
enum Direction {
UP("Up"), DOWN("Down"), NEUTRAL("Neutral");
private String text;
private Direction(String text) {
this.text = text;
}
public String getText() {
return text;
}
}
enum Key {
W("W", Direction.UP, KeyEvent.VK_W), S("S", Direction.DOWN, KeyEvent.VK_S),
UP("Up", Direction.UP, KeyEvent.VK_UP), DOWN("Down", Direction.DOWN, KeyEvent.VK_DOWN);
private String text;
private Direction direction;
private int keyCode;
private Key(String text, Direction direction, int keyCode) {
this.text = text;
this.direction = direction;
this.keyCode = keyCode;
}
public String getText() {
return text;
}
public Direction getDirection() {
return direction;
}
public int getKeyCode() {
return keyCode;
}
}
}
类似资料：
-
问题内容： 我目前正在尝试在程序中实现一个键侦听器，以便当我按下箭头键时它会执行一个操作，程序中的对象向左或向右移动。 这是我程序中的移动方法 我想知道程序应该如何读入（KeyEvent）e。我真的不能输入箭头键。 请帮忙！ 编辑：我还需要知道我需要添加到代码中的内容，以便我的程序在继续使用另一种方法之前要等待大约700毫秒的时间才能进行键输入 问题答案： http://docs.oracle.c
-
问题内容： 我正在计划在Windows下运行的Java程序的计划制定工作，该程序可以在背景的不同键runnig上映射不同的“宏”。问题是- 如何使Java在应用程序未聚焦时监听按键。 我发现很多观点认为这是不可能的。但是我也发现Stefano在SO上写的这本书。这种解决方案对我来说还不够好，至少没有一个重要的信息。如果没有按下该键，该函数将返回一个值。按键后，它会返回不同的值…如果函数在按键事件后
-
Pong! 是一个完全用 JavaScript 实现的 pong 游戏，基于 Socket.io 和 Canvas 技术实现。 特性： 服务器 socket.io 集成 支持两个在线玩家 响应式和自适应 UI 支持移动设备 支持手势操作 tokenized lobby entry page
-
一个在设置了Keylistener或Keyadapter类并重写了keyPressed之后，另两个在程序中如何获得键盘响应呢？例如，假设我已经设置了Keyadapter类： 我将如何从那里开始，使它能够实际检测到它，并在我按w时显示字符串？没有任何方法，我可以在main方法中调用，使它开始检查，是吗？如果没有，JVM如何知道开始检查main中是否没有方法告诉它？ 谢谢你抽出时间。
-
ms （数值型） 自ping到pong经历的毫秒数 socket.on('pong', (timeout) => { // ... });
-
ms （数值型） 自ping至pong经过的毫秒数 当接受到服务器端的pong时触发。