我是新的Java，我目前正在为CS106A开展突破性游戏（不是为了获得信用）。我试图让用户点击球时开始游戏。当这个条件不存在时，游戏运行正常，但当我尝试实现这个条件时根本不起作用。任何帮助深表感谢！这是我的代码：
/*
* File: Breakout.java
* -------------------
* Name:
* Section Leader:
*
* This file will eventually implement the game of Breakout.
*/
import acm.graphics.*;
import acm.program.*;
import acm.util.*;
import java.applet.*;
import java.awt.*;
import java.awt.event.*;
public class Breakout extends GraphicsProgram {
/** Width and height of application window in pixels */
public static final int APPLICATION_WIDTH = 400;
public static final int APPLICATION_HEIGHT = 600;
/** Dimensions of game board (usually the same) */
private static final int WIDTH = APPLICATION_WIDTH;
private static final int HEIGHT = APPLICATION_HEIGHT;
/** Dimensions of the paddle */
private static final int PADDLE_WIDTH = 60;
private static final int PADDLE_HEIGHT = 10;
/** Offset of the paddle up from the bottom */
private static final int PADDLE_Y_OFFSET = 30;
/** Number of bricks per row */
private static final int NBRICKS_PER_ROW = 10;
/** Number of rows of bricks */
private static final int NBRICK_ROWS = 10;
/** Separation between bricks */
private static final int BRICK_SEP = 4;
/** Width of a brick */
private static final int BRICK_WIDTH =
(WIDTH - (NBRICKS_PER_ROW - 1) * BRICK_SEP) / NBRICKS_PER_ROW;
/** Height of a brick */
private static final int BRICK_HEIGHT = 8;
/** Radius of the ball in pixels */
private static final int BALL_RADIUS = 10;
/** Offset of the top brick row from the top */
private static final int BRICK_Y_OFFSET = 70;
/** Number of turns */
private static final int NTURNS = 3;
private static final int DELAY = 20;
/* Method: run() */
/** Runs the Breakout program. */
public void run() {
setup();
play();
}
private void setup(){
brickWall();
paddle();
initialization();
ball();
}
private void play(){
if(ballClicked()){
while(!gameOver()){
moveBall();
checkForCollisionWithWall();
bounceOffObject();
pause(DELAY);
}
playerFeedback();
}
}
private void brickWall(){
for (int i=0; i<NBRICK_ROWS; i++){
for (int k=0; k<NBRICKS_PER_ROW; k++){
double x = getWidth()/2-(BRICK_WIDTH*NBRICKS_PER_ROW/2)-((NBRICKS_PER_ROW-1)*BRICK_SEP)/2+BRICK_WIDTH*k+BRICK_SEP*k;
double y = BRICK_Y_OFFSET+BRICK_HEIGHT*i+BRICK_SEP*i;
brick = new GRect (x, y, BRICK_WIDTH, BRICK_HEIGHT);
if (i<2) brick.setColor(Color.RED);
if(i>1 && i<4) brick.setColor(Color.ORANGE);
if(i>3 && i<6) brick.setColor(Color.YELLOW);
if(i>5 && i<8) brick.setColor(Color.GREEN);
if(i>7 && i<NBRICK_ROWS) brick.setColor(Color.CYAN);
brick.setFilled(true);
add(brick);
}
}
}
private void paddle(){
paddle = new GRect(PADDLE_WIDTH,PADDLE_HEIGHT);
paddle.setFilled(true);
add(paddle, getWidth()/2-PADDLE_WIDTH/2, getHeight()-PADDLE_Y_OFFSET);
addMouseListeners();
}
public void mousePressed(MouseEvent e){
lastX = e.getX();
lastY = e.getY();
gobj = getElementAt(lastX,lastY);
}
public void mouseDragged(MouseEvent e){
if (gobj == paddle){
if(((gobj.getX()+(e.getX()-lastX))>=0) && (gobj.getX()+(e.getX()-lastX)<=(getWidth()-PADDLE_WIDTH))){
gobj.move(e.getX()-lastX, 0);
lastX=e.getX();
}
}
}
private void initialization(){
GLabel label = new GLabel ("Click the ball to start the game.");
double x = (getWidth() - label.getWidth()) / 2;
double y = (getHeight() + label.getAscent()) / 2 + 25;
label.setFont(new Font("Serif", Font.BOLD, 18));
label.setColor(Color.GREEN);
add(label, x, y);
}
private void ball(){
ball= new GOval(getWidth()/2-BALL_RADIUS,getHeight()/2-BALL_RADIUS, BALL_RADIUS*2, BALL_RADIUS*2);
add(ball);
ball.setFilled(true);
ball.sendToBack();
vy= +3.0;
vx=rgen.nextDouble(1.0, 3.0);
if (rgen.nextBoolean(0.5)) vx=-vx; // makes the velocity negative half of the time.
addMouseListeners();
}
public void mouseClicked(MouseEvent e){
clickedX=e.getX();
clickedY=e.getY();
firstClickedObject = getElementAt(clickedX, clickedY);
ballClicked();
}
private boolean ballClicked(){
return (firstClickedObject == ball);
}
private void moveBall(){
ball.move(vx, vy);
}
private void checkForCollisionWithWall(){
//determine whether there is a wall present
if (wallPresent()){
if(ball.getY()<0) {
vy = -vy;
bounceClip.play();
moveBall();
} else {
vx = -vx; //launch the ball right or left by reversing its velocity
bounceClip.play();
moveBall();
}
}
}
private boolean wallPresent(){
return((ball.getX()+BALL_RADIUS*2)>getWidth()) || (ball.getX()<0) || (ball.getY()<0) ;
}
private GObject getCollidingObject(){
if (getElementAt(ball.getX(), ball.getY()) != null){
return (getElementAt(ball.getX(), ball.getY()));
} else if (getElementAt(ball.getX()+2*BALL_RADIUS, ball.getY()) != null){
return (getElementAt(ball.getX()+2*BALL_RADIUS, ball.getY()));
} else if ((getElementAt(ball.getX(), ball.getY()+2*BALL_RADIUS) !=null)){
return (getElementAt(ball.getX(), ball.getY()+2*BALL_RADIUS));
} else if (getElementAt(ball.getX()+2*BALL_RADIUS, ball.getY()+2*BALL_RADIUS)!=null){
return (getElementAt(ball.getX()+2*BALL_RADIUS, ball.getY()+2*BALL_RADIUS));
} else {
return (null);
}
}
private void bounceOffObject(){
GObject collider = getCollidingObject();
if (collider != null){
if(collider == paddle){
if ((ball.getY()<=((getHeight()-PADDLE_Y_OFFSET)+(1/3)*(getHeight()- PADDLE_Y_OFFSET)))){
vy = - vy;
bounceClip.play();
moveBall();
}
} else { // meaning the ball collided with a brick;
vy = -vy;
bounceClip.play();
moveBall();
remove(collider);
bricksRemaining--;
}
}
}
private boolean collisionWithObjectOccured(){
return (getElementAt(ball.getX(), ball.getY()) != null) ||
(getElementAt(ball.getX()+2*BALL_RADIUS, ball.getY()) != null) ||
(getElementAt(ball.getX(), ball.getY()+2*BALL_RADIUS) !=null) ||
(getElementAt(ball.getX()+2*BALL_RADIUS, ball.getY()+2*BALL_RADIUS)!=null);
}
private boolean gameOver(){
return ((ball.getY()+BALL_RADIUS*2)>getHeight()) || (bricksRemaining == 0);
}
private void playerFeedback(){
if ((ball.getY()+BALL_RADIUS*2)>getHeight()){
GLabel label = new GLabel ("HAHA! YOU LOST! GAME OVER.");
double x = (getWidth() - label.getWidth()) / 2;
double y = (getHeight() + label.getAscent()) / 2;
label.setFont(new Font("Serif", Font.BOLD, 18));
label.setColor(Color.MAGENTA);
add(label, x, y);
} else {
GLabel label = new GLabel ("You won! Pop that champagne! It's time to celebrate.");
double x = (getWidth() - label.getWidth()) / 2;
double y = (getHeight() + label.getAscent()) / 2;
label.setFont(new Font("Serif", Font.BOLD, 18));
label.setColor(Color.GREEN);
add(label, x, y);
}
}
AudioClip bounceClip = MediaTools.loadAudioClip("bounce.au");
private RandomGenerator rgen = RandomGenerator.getInstance();
private GRect brick;
private GRect paddle;
private GObject gobj;
private GOval ball;
private double lastX;
private double lastY;
private double clickedX;
private double clickedY;
private double vx, vy; // velocity of the ball
private int bricksRemaining = NBRICKS_PER_ROW *NBRICK_ROWS;
GObject firstClickedObject;
}
当我通过(firstClickedObject == ball)测试System.out.println(firstClickedObject == ball)时，它会显示为真，所以我不确定问题是什么。
答案 0 :(得分：0)
在您的代码中，您有：
firstClickedObject = getElementAt(clickedX, clickedY);
ballClicked();
ballClicked()返回一个布尔值，所以基本上它返回true或false，而你没有处理返回值。
你可能意味着做一些事情：
firstClickedObject = getElementAt(clickedX, clickedY);
if(ballClicked() && !gameStarted){
//Start Game Sequence Code Goes Here
}
注意：我没有查看gameStarted是否是变量。如果不是，那么我的意思是它只是一个布尔说明游戏是否正在运行。如果你不像这样保护它，那就开始游戏代码＆＃39;将反复运行。
您的变量firstClickedObject也可以重新考虑它的名称。虽然它可能对你有意义，但像lastClickedObject这样的东西会更有意义吗？