Greenfoot

jam0037

2012/2/29

#

I'm new to greenfoot and I have a small dilemma. I'm having trouble trying to devise a way to get worms to move when approached by crabs. (I'm supposed to use getObjectsInRange) So far I have this:

public void act() {
          List f = getObjectsInRange(6, Crab.class);
         if (f.size() > 0) {
          move(5);
        }
    
        }

But it doesn't work

danpost

2012/2/29

#

try

public void act() {
    if (getObjectsInRange(6, Crab.class).size() > 0) {
        move(5);
    }
}

jam0037

2012/2/29

#

They won't budge. :(

danpost

2012/2/29

#

Curious! How about

 if (!getObjectsInRange(6, Crab.class).isEmpty())

jam0037

2012/2/29

#

no cigar. The worms must really just want to be eaten.

danpost

2012/2/29

#

That code is in the act() method of your Worm.class. Right?

jam0037

2012/2/29

#

Yeah. Here's all the code for my worm class. maybe something is wrong somewhere else

import greenfoot.*;
import java.util.List;

/**
 * Worm. A sand worm. Very yummy. Especially crabs really like it.
 * Author: Michael Kolling
 */
public class Worm extends Animal
{
  /**
   * modify the worm method such that the worm moves 5
   * times when it sees a crab. The implementation should be done 
   * using either "for" or "while" loop.
   */
    public void act() {  
        if (!getObjectsInRange(12, Crab.class).isEmpty()) { 
            move();  
        }  
    }  
}

jam0037

2012/2/29

#

it says to use a while loop. but I don't see how to work that in so I was just going for an if statement.

danpost

2012/2/29

#

change line 17 to read move(5); and see if they move then.

jam0037

2012/2/29

#

they won't move.

danpost

2012/2/29

#

OK, saw your last post about the for or while loop. Change line 17 to read

for (int i = 0; i < 5; i++) move(1);

EDITED: and they still will not move!

danpost

2012/2/29

#

What does the move() method of the Animal class look like? And there may be more than one.

jam0037

2012/2/29

#

these things are stubborn.

jam0037

2012/2/29

#

    /**
     * Move forward in the current direction.
     */
    public void move()
    {
        double angle = Math.toRadians( getRotation() );
        int x = (int) Math.round(getX() + Math.cos(angle) * WALKING_SPEED);
        int y = (int) Math.round(getY() + Math.sin(angle) * WALKING_SPEED);
        
        setLocation(x, y);
    }

danpost

2012/2/29

#

And what is WALKING_SPEED set at?

Activity

About

Documentation

Download

Discuss

Scenarios

Fleeing Worms