Greenfoot

MRCampbell

2019/5/6

#

In my world I creates a number of objects randomly in the world. I am doing this for 2 different Actors in different ways, so i though a method would simplify things. However I am having trouble passing an actor as a parameter. Here is the method I have so far.

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public void createThingsRandLocal(int num, Actor object)
    {
        for (int i = 0; i < num; i = i + 1)
        {
            int xSpawn = Greenfoot.getRandomNumber(600);
            int ySpawn = Greenfoot.getRandomNumber(400);
            addObject(object, xSpawn, ySpawn); 
        }
    }

Here I call the method.

1	`createThingsRandLocal(100, Food)`

danpost

2019/5/6

#

Move the for loop outside the method so the method can add a single object at a time: Use:

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public void addRandomLocal(Actor object)
{
    int xSpawn = Greenfoot.getRandomNumber(600);
    int ySpawn = Greenfoot.getRandomNumber(400);
    addObject(object, xSpawn, ySpawn);
}

and call it with:

1	`for` `(int` `i=0; i<100; i++) addRandomLocal(new` `Food());`

MRCampbell

2019/5/6

#

Thanks. Is there any way to keep the loop inside the method? Or a reason why it should not?

danpost

2019/5/6

#

MRCampbell wrote...

Is there any way to keep the loop inside the method?

You could, if you made the method specifically for one type object:

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public void addRandomFood(int num)
{
    for (int i=0; i<num; i++)
    {
        int xSpawn = Greenfoot.getRandomNumber(600);
        int ySpawn = Greenfoot.getRandomNumber(400);
        addObject(new Food(), xSpawn, ySpawn);
    }
}

Also what if my object constructor has a parameter?

What is the parameter for and how is it used?

MRCampbell

2019/5/9

#

Thanks for your help. Can you explain what limitations in java won't allow me to add an object inside the loop with a parameter?

Super_Hippo

2019/5/9

#

If you have an actor as the parameter, then you would add this actor several times. An actor can only be in a world at one position at a time. You don't want to add one object several times, you want to add several objects of a class.

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Actors as parameters