当gameover为true并且我从DOWN按钮KeyListener调用startGame方法时，它会破坏我的游戏，并且不允许我单击JFrame上的退出按钮并且paddle不再起作用。请帮忙。
import javax.swing.*;
import java.awt.event.*;
import java.awt.image.*;
import java.awt.Graphics2D;
import java.awt.Toolkit;
import java.awt.Color;
import java.awt.Rectangle;
import java.awt.Image;
public class AustinsBrickBreaker {
JFrame window;
DrawPanel panel;
public AustinsBrickBreaker() {
window = new JFrame("Brick Breaker");
panel = new DrawPanel();
window.setSize(800, 592);
window.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
window.getContentPane().add(panel);
window.setLocationRelativeTo(null);
window.setVisible(true);
window.setResizable(false);
}
public void go() {
panel.startGame();
}
public static void main(String[] args) {
AustinsBrickBreaker game = new AustinsBrickBreaker();
game.go();
}
}
@SuppressWarnings("serial")
class DrawPanel extends JPanel implements KeyListener {
final int WIDTH = 800, HEIGHT = 592;
BufferedImage buffer;
public static Brick[][] bricks = new Brick[3][5];
Paddle paddle;
Ball ball;
int score = 0;
int lives = 3;
boolean gameover = false;
Image brickImage = Toolkit.getDefaultToolkit().getImage("brick.png");
Image brickImage2 = Toolkit.getDefaultToolkit().getImage("brick2.png");
Image brickImage3 = Toolkit.getDefaultToolkit().getImage("brick3.png");
Image brickImage4 = Toolkit.getDefaultToolkit().getImage("brick4.png");
Image brickImage5 = Toolkit.getDefaultToolkit().getImage("brick5.png");
Image paddleImage = Toolkit.getDefaultToolkit().getImage("paddle.png");
Image background = Toolkit.getDefaultToolkit().getImage("background.jpg");
Image ballImage = Toolkit.getDefaultToolkit().getImage("ball.png");
Image heartImage = Toolkit.getDefaultToolkit().getImage("heart.png");
public DrawPanel() {
setIgnoreRepaint(true);
addKeyListener(this);
setFocusable(true);
}
public void keyTyped(KeyEvent e) {}
public void keyPressed(KeyEvent e) {
int key = e.getKeyCode();
if (key == KeyEvent.VK_LEFT) paddle.left = true;
if (key == KeyEvent.VK_RIGHT) paddle.right = true;
if (key == KeyEvent.VK_UP && gameover) {
gameover = false;
score = 0;
lives = 3;
startGame();
}
if (key == KeyEvent.VK_DOWN && gameover) System.exit(0);
}
public void keyReleased(KeyEvent e) {
int key = e.getKeyCode();
if (key == KeyEvent.VK_LEFT) paddle.left = false;
if (key == KeyEvent.VK_RIGHT) paddle.right = false;
}
public int count() {
int count = 0;
for (int r = 0; r < DrawPanel.bricks.length; r++)
for (int c = 0; c < DrawPanel.bricks[r].length; c++)
if (!bricks[r][c].visible) count++;
else
break;
int returner = 0;
if (count == 15) returner = 1;
return returner;
}
public void initialize() {
buffer = new BufferedImage(WIDTH, HEIGHT, BufferedImage.TYPE_INT_RGB);
for (int r = 0; r < DrawPanel.bricks.length; r++)
for (int c = 0; c < DrawPanel.bricks[r].length; c++)
DrawPanel.bricks[r][c] = new Brick(c * 150 + 50, r * 60 + 30, 100, 50);
ball = new Ball(390, 200, 20, 20, 10);
paddle = new Paddle(350, 510, 100, 20, 8);
}
public void updateMovement() {
paddle.move();
ball.move();
}
public void checkCollisions() {
if (paddle.x <= 20) paddle.x = 20;
if (paddle.x >= 679) paddle.x = 679;
if (ball.x < 21) {
ball.left = false;
ball.right = true;
}
if (ball.x > 761) {
ball.left = true;
ball.right = false;
}
if (ball.y < 21) {
ball.up = false;
ball.down = true;
}
if (paddle.getBounds().intersects(ball.getBounds())) ball.swap();
for (int r = 0; r < DrawPanel.bricks.length; r++)
for (int c = 0; c < DrawPanel.bricks[r].length; c++) {
if (ball.getBounds().intersects(DrawPanel.bricks[r][c].getBounds()) && !DrawPanel.bricks[r][c].collision) {
ball.swap();
bricks[r][c].collide();
score += 10;
}
}
}
public void drawBuffer() {
Graphics2D b = buffer.createGraphics();
b.drawImage(background, 0, 0, null);
if (!gameover) {
for (int l = 0; l < lives; l++)
b.drawImage(heartImage, 20 * l + 620, 535, null);
b.drawString("Score: " + score, 700, 550);
b.drawImage(paddleImage, paddle.getX(), paddle.getY(), null);
b.drawImage(ballImage, ball.getX(), ball.getY(), null);
for (int r = 0; r < DrawPanel.bricks.length; r++)
for (int c = 0; c < DrawPanel.bricks[r].length; c++) {
if (bricks[r][c].visible == true)
if (bricks[r][c].colour == 1)
b.drawImage(brickImage, DrawPanel.bricks[r][c].getX(), DrawPanel.bricks[r][c].getY(), null);
else if (bricks[r][c].colour == 2)
b.drawImage(brickImage2, DrawPanel.bricks[r][c].getX(), DrawPanel.bricks[r][c].getY(), null);
else if (bricks[r][c].colour == 3)
b.drawImage(brickImage3, DrawPanel.bricks[r][c].getX(), DrawPanel.bricks[r][c].getY(), null);
else if (bricks[r][c].colour == 4)
b.drawImage(brickImage4, DrawPanel.bricks[r][c].getX(), DrawPanel.bricks[r][c].getY(), null);
else if (bricks[r][c].colour == 5)
b.drawImage(brickImage5, DrawPanel.bricks[r][c].getX(), DrawPanel.bricks[r][c].getY(), null);
}
b.dispose();
} else {
b.drawString("G A M E O V E R !", 340, 300);
b.drawString("G A M E O V E R !", 341, 300);
b.drawString("G A M E O V E R !", 342, 300);
b.drawString("Press ↑ To Play Again!", 332, 320);
b.drawString("Press ↓ To Exit :(", 342, 340);
}
}
public void drawScreen() {
Graphics2D g = (Graphics2D) this.getGraphics();
g.drawImage(buffer, 0, 0, this);
Toolkit.getDefaultToolkit().sync();
g.dispose();
}
public void startGame() {
initialize();
while (!gameover) {
try {
updateMovement();
checkCollisions();
drawBuffer();
drawScreen();
Thread.sleep(15);
if (ball.y > 562 && lives != -1) {
Thread.sleep(500);
lives -= 1;
ball.x = 390;
ball.y = 200;
ball.left = false;
ball.right = false;
paddle.x = 350;
}
if (lives == -1) {
Thread.sleep(500);
gameover = true;
drawBuffer();
drawScreen();
}
//Replace Bricks
if (count() == 1) {
Thread.sleep(500);
startGame();
}
} catch (Exception e) {
e.printStackTrace();
}
}
}
}
/*--|--|--|--| GAME CLASSES |--|--|--|--*/
class Brick {
int x, y, width, height, colour;
boolean collision, visible;
public Brick(int x, int y, int w, int h) {
this.x = x;
this.y = y;
this.width = w;
this.height = h;
this.collision = false;
this.visible = true;
this.colour = (int) Math.ceil(Math.random() * 5);
}
public int getX() {
return x;
}
public int getY() {
return y;
}
public int getWidth() {
return width;
}
public int getHeight() {
return height;
}
public Rectangle getBounds() {
return new Rectangle(getX(), getY(), getWidth(), getHeight());
}
public void collide() {
if (collision == false) {
visible = false;
collision = true;
}
}
}
class Paddle {
int x, y, width, height, speed;
boolean left, right;
public Paddle(int x, int y, int w, int h, int s) {
this.x = x;
this.y = y;
this.width = w;
this.height = h;
this.speed = s;
}
public int getX() {
return x;
}
public int getY() {
return y;
}
public int getWidth() {
return width;
}
public int getHeight() {
return height;
}
public Rectangle getBounds() {
return new Rectangle(getX(), getY(), getWidth(), getHeight());
}
public void move() {
if (left) x -= speed;
if (right) x += speed;
}
}
class Ball {
int x, y, width, height, speed;
boolean up, down, left, right;
public Ball(int x, int y, int w, int h, int s) {
this.x = x;
this.y = y;
this.width = w;
this.height = h;
this.speed = s;
this.up = false;
this.down = true;
}
public int getX() {
return x;
}
public int getY() {
return y;
}
public int getWidth() {
return width;
}
public int getHeight() {
return height;
}
public Rectangle getBounds() {
return new Rectangle(getX(), getY(), getWidth(), getHeight());
}
public void move() {
if (up) y -= speed;
if (down) y += speed;
if (left) x -= (float) Math.ceil(Math.random() * 5);
if (right) x += (float) Math.ceil(Math.random() * 5);
}
public void swap() {
if (up) {
down = true;
up = false;
} else if (down) {
up = true;
down = false;
}
double r = Math.random();
if (r <= 0.5) {
left = false;
right = true;
} else if (r > 0.5) {
left = true;
right = false;
} else left = true;
}
}
答案 0 :(得分：2)
您的代码完全忽略了Swing线程规则，并且在首次运行时以某种方式允许这种情况，因为首次运行时，在Swing事件线程的主线程中调用startGame()方法。但是当第二次调用它时，它会在事件线程上调用，而这次，所有这些睡眠调用都会使Swing事件线程和您的应用程序进入休眠状态。解决方案：了解Swing线程规则，让应用程序遵守这些规则，包括不调用Thread.sleep，或者在事件线程上调用永久循环。
答案 1 :(得分：2)
首先，getGraphics不是自定义绘画在Swing中的工作原理，你永远不应该使用它。
首先查看Painting in AWT and Swing和Performing Custom Painting，了解有关绘画在Swing中如何运作的详细信息。
Swing使用被动渲染逼近，这意味着它的绘画过程可以在任何时间发生，出于任何原因，在没有您的交互或知识的情况下，在您当前的方法下，您最终可能会遇到中间闪烁几乎不可能诊断或重复。
如果您想控制绘画（主动绘画），请查看BufferStrategy和BufferStrategy and BufferCapabilities
其次，不要使用KeyListener，我可能会考虑使用KeyListener的情况非常有限，但这不是其中之一，当您发现自己想要回复时对于关键事件，您应该从the key bindings API
第三，不要使用Toolkit.getDefaultToolkit().getImage，而是使用ImageIO，它支持更多图像，它会在返回之前加载图像（而不是使用后台线程）并抛出{ {1}}无法加载图片时有关详细信息，请参阅Reading/Loading an Image
第四，你违反了Swing的单线程规则。基本上，因为系统的工作方式，IOException在所谓的＆＃34; main＆＃34;线程，但Swing在它自己的线程中运行（AKA The Event Dispatching Thread）。
所以当你第一次开始时，main正在＆＃34; main＆＃34;线程，但是当你从go拨打start时，你就在EDT中运行了，这意味着你在游戏循环中＃34;将阻止EDT并且没有任何东西会再次绘制，并且用户无法与您的程序进行交互。
有关详细信息，请参阅Concurrency in Swing;有关可能的解决方案，请参阅How to Use Swing Timers