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aa124
aa124 wrote ...

2019/1/5

class issue in greenfoot for score counter

aa124 aa124

2019/1/5

#
m trying to add a score counter in greenfoot. The following code is in my bullets class. Each time a bullet hits the rocket, the score is supposed to increase by one. I've added the necessary code to the counter class and it works normally, however when I try to add the code to my bullet class, greenfoot says that it cant find myWorld. public void act() { if(!toRemove) { setLocation(getX()+vx,getY()); Actor actor=getOneIntersectingObject(Enemy.class); if(actor!=null) { ((Enemy)actor).destroyed(); GameScreen gameScreen = (GameScreen)myWorld; Counter counter = gameScreen.getCounter(); counter.addScore(); } if(getX()>getWorld().getWidth()+200) { toRemove=true; } } else { getWorld().removeObject(this); } } The part that doesn't work is GameScreen gameScreen = (GameScreen)myWorld; if(actor!=null) { ((Enemy)actor).destroyed(); GameScreen gameScreen = (GameScreen)myWorld; Counter counter = gameScreen.getCounter(); counter.addScore(); } This is in my counter method public class Counter extends Actor { int score = 0; /** * Act - do whatever the Counter wants to do. This method is called whenever * the 'Act' or 'Run' button gets pressed in the environment. */ public void act() { setImage(new GreenfootImage("Score : " + score, 24, greenfoot.Color.RED, greenfoot.Color.BLACK)); } public void addScore() { score++; } } Pls help
Zamoht Zamoht

2019/1/5

#
myWorld is probably not a declared reference in your class. You could try to replace "myWorld" with "getWorld()".
aa124 aa124

2019/1/5

#
I tried that and the code compiles however the score is not adding each time the bullet hits the other actors. What should I do?
Zamoht Zamoht

2019/1/5

#
Can you show me the GameScreen code? Seems like gameScreen.getCounter(); doesn't return the right counter.
aa124 aa124

2019/1/6

#
public class GameScreen extends World { private int delay = 0; Counter counter = new Counter(); /** * Constructor for objects of class GameScreen. * */ public GameScreen() { // Create a new world with 600x400 cells with a cell size of 1x1 pixels. super(600, 400, 1, false); prepare(); } public Counter getCounter() { return counter; } public void act() { if(delay>0) { delay--; } else { delay=20; } if(delay==1) { int py=Greenfoot.getRandomNumber(getHeight()); addObject(new Enemy(-(2+Greenfoot.getRandomNumber(3))),getWidth()+200,py); } } /** * Prepare the world for the start of the program. * That is: create the initial objects and add them to the world. */ private void prepare() { addObject(new Rocket(), 100, 200); Counter counter = new Counter(); addObject(counter,300,30); }
aa124 aa124

2019/1/6

#
this is the counter code public class Counter extends Actor { int score = 0; /** * Act - do whatever the Counter wants to do. This method is called whenever * the 'Act' or 'Run' button gets pressed in the environment. */ public void act() { setImage(new GreenfootImage("Score : " + score, 24, greenfoot.Color.RED, greenfoot.Color.BLACK)); } public void addScore() { score++; } }
Zamoht Zamoht

2019/1/6

#
Please use the embedded code feature when listing code. Okay so the problem seems to be that you are declaring a new Counter in the prepare method "Counter counter = new Counter();". This is then different from the one in the top "private int delay = 0; Counter counter = new Counter();". In your getCounter() method you return the one in the top, which is not in the world, because you declare a new and place that in the world instead. To solve this change "Counter counter = new Counter();" to "counter = new Counter();" or remove the line completely. Hope this works and makes sense.
danpost danpost

2019/1/6

#
Remove the middle line in your prepare method: 
Counter counter = new Counter();
You have already declared a Counter field called counter with a Counter object assigned to it (line 4 above). The line to be removed declares a local Counter variable called counter, whose name over-shadows that of the field. For the rest of the method "counter" refers to the local variable and to refer to the field you would need to use "this.counter".
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