在我的帮助下，我应该修改一个greenfoot项目，通过创建私有数据类型并使用setter和getter来展示对数据封装的理解，以及在游戏中触摸和遗漏的病毒和细菌的值，以及修改评分系统。我能够让得分系统起作用，但是当我运行游戏时，它只会将setter的值递增1并且不会计算通过它。
public class Bloodstream extends World
{
private int score;
private int time;
/**New Private variables **/
private int numberOfBacteriaTouched;
private int numberOfBacteriaMissed;
private int numberOfVirusTouched;
private int numberOfVirusMissed;
/**
* Constructor: Set up the staring objects.
*/
public Bloodstream()
{
super(780, 360, 1);
setPaintOrder(Border.class);
prepare();
score = 0;
time = 2000;
this.numberOfBacteriaTouched= 0;
this.numberOfBacteriaMissed = numberOfBacteriaMissed;
this.numberOfVirusTouched = 0;
this.numberOfVirusMissed = numberOfVirusMissed;
showScore();
showTime();
}
/**
* Create new floating objects at irregular intervals.
*/
public void act()
{
if (Greenfoot.getRandomNumber(100) < 3)
{
addObject(new Bacteria(), 779, Greenfoot.getRandomNumber(360));
}
if (Greenfoot.getRandomNumber(100) < 1)
{
addObject(new Lining(), 779, 0);
}
if (Greenfoot.getRandomNumber(100) < 1)
{
addObject(new Lining(), 779, 359);
}
if (Greenfoot.getRandomNumber(100) < 1)
{
addObject(new Virus(), 779, Greenfoot.getRandomNumber(360));
}
if (Greenfoot.getRandomNumber(100) < 6)
{
addObject(new RedCell(), 779, Greenfoot.getRandomNumber(360));
}
countTime();
}
/** Getters for new variables **/
public int getNumberOfBacteriaTouched()
{
return numberOfBacteriaTouched;
}
public int getNumberBacteriaMissed()
{
return numberOfBacteriaMissed;
}
public int getNumberOfVirusTouched()
{
return numberOfVirusTouched;
}
public int getNumberOfVirusMissed()
{
return numberOfVirusMissed;
}
/** Setters for new variables **/
public void setNumberOfBacteriaTouched(int numberOfBacteriaTouched)
{
this.numberOfBacteriaTouched = numberOfBacteriaTouched;
}
public void setNumberOfBacteriaMissed(int numberOfBacteriaMissed)
{
this.numberOfBacteriaMissed= numberOfBacteriaMissed;
}
public void setNumberOfVirusTouched(int numberOfVirusTouched)
{
this.numberOfVirusTouched= numberOfVirusTouched;
}
public void setNumberOfVirusMissed(int numberOfVirusMissed)
{
this.numberOfVirusMissed= numberOfVirusMissed;
}
/**
* Add some points to our current score. (May be negative.)
* If the score falls below 0, game's up.
*/
public void addScore(int points)
{
score = score + points;
showScore();
if (score < 0)
{
Greenfoot.playSound("game-over.wav");
Greenfoot.stop();
}
}
/**
* Show our current score on screen.
*/
private void showScore()
{
showText("Score: " + score, 80, 25);
showText("Bacteria Eaten: " + getNumberOfBacteriaTouched(), 80, 325);
showText("Virus Missed: " + getNumberOfVirusMissed(), 80, 300);
}
/**
* Count down the game time and display it. Stop the game
* with a winning message when time is up.
*/
private void countTime()
{
time--;
showTime();
if (time == 0)
{
showEndMessage();
Greenfoot.stop();
}
}
/**
* Show the remaining game time on screen.
*/
private void showTime()
{
showText("Time: " + time, 700, 25);
}
/**
* Show the end-of-game message on screen.
*/
private void showEndMessage()
{
showText("Time is up - you win!", 390, 150);
showText("Your final score: " + score + " points", 390, 170);
}
/**
* Prepare the world for the start of the program. In this case: Create
* a white blood cell and the lining at the edge of the blood stream.
*/
private void prepare()
{
WhiteCell whitecell = new WhiteCell();
addObject(whitecell, 128, 179);
Lining lining = new Lining();
addObject(lining, 126, 1);
Lining lining2 = new Lining();
addObject(lining2, 342, 5);
Lining lining3 = new Lining();
addObject(lining3, 589, 2);
Lining lining4 = new Lining();
addObject(lining4, 695, 5);
Lining lining5 = new Lining();
addObject(lining5, 114, 359);
Lining lining6 = new Lining();
Lining lining7 = new Lining();
addObject(lining7, 295, 353);
Lining lining8 = new Lining();
Lining lining9 = new Lining();
Lining lining10 = new Lining();
addObject(lining10, 480, 358);
Lining lining11 = new Lining();
addObject(lining11, 596, 359);
Lining lining12 = new Lining();
addObject(lining12, 740, 354);
Border border = new Border();
addObject(border, 0, 180);
Border border2 = new Border();
addObject(border2, 770, 180);
}
}
这是主类的副本，这里是计数器的子类吗？
import greenfoot.*; // (World, Actor, GreenfootImage, Greenfoot and MouseInfo)
public class WhiteCell extends Actor
{
/**
* Act: move up and down when cursor keys are pressed.
*/
public void act()
{
checkKeyPress();
checkCollision();
}
/**
* Check whether a keyboard key has been pressed and react if it has.
*/
private void checkKeyPress()
{
if (Greenfoot.isKeyDown("up"))
{
setLocation(getX(), getY()-8);
}
if (Greenfoot.isKeyDown("down"))
{
setLocation(getX(), getY()+8);
}
if (Greenfoot.isKeyDown("right"))
{
setLocation(getX()+4, getY());
}
if (Greenfoot.isKeyDown("left"))
{
setLocation(getX()-4, getY());
}
}
/**
* Check whether we are touching a bacterium or virus. Remove bacteria.
* Game over if we hit a virus.
*/
private void checkCollision()
{
if (isTouching(Bacteria.class))
{
Greenfoot.playSound("slurp.wav");
removeTouching(Bacteria.class);
Bloodstream bloodstream = (Bloodstream)getWorld();
bloodstream.addScore(1);
bloodstream.setNumberOfBacteriaTouched(+1);
}
if (isTouching(Virus.class))
{
removeTouching(Virus.class);
Bloodstream bloodstream = (Bloodstream)getWorld();
bloodstream.addScore(-2);
bloodstream.setNumberOfVirusTouched(+1);
}
}
}
感谢您的帮助！
答案 0 :(得分：1)
如果查看setter代码，则意味着设置值，而不是增量。每次执行时，它都会将numberOfBacteriaTouched的值设置为1。这就是为什么你的计数器第一次工作，但不计算第一次。
public void setNumberOfBacteriaTouched(int numberOfBacteriaTouched)
{
this.numberOfBacteriaTouched = numberOfBacteriaTouched;
}
增加值的正确方法是使用getter获取值，将值加1并使用setter设置它。
bloodstream.setNumberOfBacteriaTouched(bloodstream.getNumberOfBacteriaTouched()+1);
bloodstream.setNumberOfVirusTouched(bloodstream.getNumberOfVirusTouched()+1);
或者，您也可以编写一个不同的方法，将变量递增1.
public void incrementNumberOfBacteriaTouched()
{
this.numberOfBacteriaTouched++;
}
答案 1 :(得分：0)
public void setNumberOfBacteriaTouched(int numberOfBacteriaTouched)
{
this.numberOfBacteriaTouched = numberOfBacteriaTouched;
}
看一下该方法正在做什么。它将触摸的数字设置为您传入的任何值。您没有添加该值，而是设置一个全新的值。
答案 2 :(得分：0)
每次调用checkCollision（）时，您都会重新初始化Bloodstream类。尝试将实例化移出checkCollision（）方法
private Bloodstream bloodstream;
onCreate(){
bloodstream = (Bloodstream)getWorld();
}
private void checkCollision(){
if (isTouching(Bacteria.class))
{
Greenfoot.playSound("slurp.wav");
removeTouching(Bacteria.class);
bloodstream.addScore(1);
bloodstream.setNumberOfBacteriaTouched(+1);
}
if (isTouching(Virus.class))
{
removeTouching(Virus.class);
bloodstream.addScore(-2);
bloodstream.setNumberOfVirusTouched(+1);
}
}