My assignment is to find a way to alter the program so that when the world is populated the leaves and wombats won't spawn on top of each other. I am supposed to create two methods: findEmptyCell() and isOccupied(), the second of which returns a boolean value. Been working on it for a while now and I can't seem to get it to work right. Can anyone point me in the right direction? Thank you!
Here is my code:
import greenfoot.*; // imports Actor, World, Greenfoot, GreenfootImage
import java.util.Random;
import java.util.List;
/**
* A world where wombats live.
*
* @author
* @version
*/
public class WombatWorld extends World
{
//Private class member variables can be declared here
int x;
int y;
/**
* Create a new world with 8x8 cells & with a cell size of 60x60 px
* Set the background of the world to "cell.jpg" which is located in
* the scenario's image folder. Finally, populate the world.
*/
public WombatWorld()
{
super(8, 8, 60);
setBackground("cell.jpg");
populate();
}
/**
* Populates world with a random arrangement of wombats and leaves
*/
public void populate()
{
addObject(new Wombat(), 1, 7);
addObject(new Wombat(), newX(), newY());
randomLeaves(getNumLeaves());
}
/**
* Place a pre-determined number of leaves into the world in random
* cells. Each leaf can only be placed in an unoccupied cell.
* @param howMany Number of leaves to be placed randomly in cells.
*/
public void randomLeaves(int howMany)
{
for(int i=0; i<howMany; i++)
{
addObject(new Leaf(), newX(), newY());
if (isOccupied(x,y))
{
findEmptyCell();
}
}
}
/**
* Get a random coordinate value for x
* @return a random integer value to be used as a new x-coordinate
*/
public int newX()
{
return Greenfoot.getRandomNumber(getWidth());
// getWidth() is a method defined in the World class.
// Since WombatWorld "is a" World it has this method as well.
}
/**
* Get a random coordinate value for x
* @return a random integer value to be used as a new y-coordinate
*/
public int newY()
{
return Greenfoot.getRandomNumber(getHeight());
// getHeight() is a method defined in the World class.
// Since WombatWorld "is a" World it has this method as well.
}
/**
* Get a random number of leaves that will be placed in the world
* @return a random int; represents number of leaves to be placed
*/
public int getNumLeaves()
{
return Greenfoot.getRandomNumber(getHeight() * getWidth());
}
// -------- NEW METHODS TO BE CREATED ---------- //
/**
* findEmptyCell() - Randomly locate a currently unoccupied cell
* in the world. Use the class member variables to hold the x and y
* coordinates once an empty cell has been found. No parameters
* are needed, and the return type is void.
*/
public void findEmptyCell()
{
x = newX();
y = newY();
if (isOccupied(x, y)==true)
{
x = newX();
y = newY();
}
}
/**
* isOccupied - Used to determine if a space is occupied by another
* Actor object.
* @param x int for the x-coordinate of the target cell to inspect
* @param y int for the y-coordinate of the target cell to inspect
* @return boolean true if target cell has one or more Actor objects
*/
public boolean isOccupied(int x, int y)
{
if (getObjectsAt(x, y, null) != null)
{
return false;
} else {
return true;
}
}
}
