I didn't change anything except adding spin() to the end of the act() method. And that's when it started crashing
tallyaka wrote ...
2012/3/5
Collision
I can't see why that would be the case. What is the stack trace you get in the terminal?
java.lang.IllegalStateException: Actor not in world. An attempt was made to use the actor's location while it is not in the world. Either it has not yet been inserted, or it has been removed.
at greenfoot.Actor.failIfNotInWorld(Actor.java:656)
at greenfoot.Actor.getX(Actor.java:157)
at Mover.move(Mover.java:55)
at Mover.move(Mover.java:46)
at Bone.<init>(Bone.java:16)
at Polyphemus.fire(Polyphemus.java:93)
at Polyphemus.shoot(Polyphemus.java:102)
at Polyphemus.act(Polyphemus.java:31)
at greenfoot.core.Simulation.actActor(Simulation.java:507)
at greenfoot.core.Simulation.runOneLoop(Simulation.java:470)
at greenfoot.core.Simulation.runContent(Simulation.java:204)
at greenfoot.core.Simulation.run(Simulation.java:194)
That's the terminal I got.
In your Bone class constructor, line 6 (move()) tries to 'move' the object, but it is still being constructed, and not yet in the world. Remove that line and see what happens then.
From the terminal output, it is probably line 16 now (see if you can figure out where I saw that).
line 16 is public void spin()... what's wrong with that?
also,removing move() in the constructor fixed the problem.
Also also, can anyone get me the initial help that I needed? About collision? Like I said, what I have works, it's just that once I touch a block.class, it can't move in any direction.
tallyaka wrote...
line 16 is public void spin()... what's wrong with that?
tallyaka wrote...
About collision?Absoloutely nothing. And also, it's in the first code I posted and it's mixed in the the walk() method. Here it is again just for you danpost :P
public void walk()
{
Block b = (Block)getOneIntersectingObject(Block.class);
if(Greenfoot.isKeyDown("down"))
{
if(b == null){
setLocation(getX(), getY() + 3);
setDirection(WEST);
}
}
if(Greenfoot.isKeyDown("right"))
{
if(b == null){
setLocation(getX() + 3, getY());
setDirection(SOUTH);
}
}
if(Greenfoot.isKeyDown("left"))
{
if(b == null){
setLocation(getX() - 3, getY());
setDirection(NORTH);
}
}
if(Greenfoot.isKeyDown("up"))
{
if(b == null){
setLocation(getX(), getY() - 3);
setDirection(EAST);
}
}
} Also, here is my current bone code...
public class Bone extends Mover
{
private int rotation;
public Bone()
{
rotation = getRotation();
}
public void act()
{
setRotation(rotation);
move(5);
spin();
disappear();
}
private int rotation2;
public void spin()
{
rotation2 = rotation2 + 10;
setRotation(rotation2);
}
public void disappear()
{
if(atWorldEdge())
{
getWorld().removeObject(this);
}
}
}
Please, please, fix the indentation for the walk() method and re-post it. It's so hard to read without proper indentation. Use the 'auto-layout' function in the editor.
And: you can't move when you're touching a block, because that's how it's coded. Line 3 finds an intersecting block, and all the movement is surrounded with "if (b == null) { ... }" and so can only happen if you're not touching a block.
If you want to prevent walking into a block, you need to look ahead in the direction of movement - use getOneObjectAtOffset(...), with a different offset depending on the direction (i.e. depending on which key is pressed) - instead of getOneIntersectingObject(...). OR, check for an intersecting object after moving, and if there is a collision, move back to the original position immediately.
Ok, I get what your saying. I'm sorry about the walk indentation, it was an accident. Usually I like it indented correctly it's just that when I copied it it messed up. Sorry
This is my new Walk() method...
This is the terminal that I got. I have no idea what I did wrong but this came up as soon as I tried to run the Scenario.
public void walk()
{
Block b1 = (Block)getObjectsAtOffset(0, -2, Block.class);
if(Greenfoot.isKeyDown("down"))
{
if(b1 == null){
setLocation(getX(), getY() + 3);
setDirection(WEST);
}
}
Block b2 = (Block)getObjectsAtOffset(2, 0, Block.class);
if(Greenfoot.isKeyDown("right"))
{
if(b2 == null){
setLocation(getX() + 3, getY());
setDirection(SOUTH);
}
}
Block b3 = (Block)getObjectsAtOffset(-2, 0, Block.class);
if(Greenfoot.isKeyDown("left"))
{
if(b3 == null){
setLocation(getX() - 3, getY());
setDirection(NORTH);
}
}
Block b4 = (Block)getObjectsAtOffset(0, 2, Block.class);
if(Greenfoot.isKeyDown("up"))
{
if(b4 == null){
setLocation(getX(), getY() - 3);
setDirection(EAST);
}
}
}java.lang.ClassCastException: java.util.ArrayList cannot be cast to Block at Odysseus.walk(Odysseus.java:107) at Odysseus.act(Odysseus.java:37) at greenfoot.core.Simulation.actActor(Simulation.java:507) at greenfoot.core.Simulation.runOneLoop(Simulation.java:470) at greenfoot.core.Simulation.runContent(Simulation.java:204) at greenfoot.core.Simulation.run(Simulation.java:194)
My suggestion from previous post:
... use getOneObjectAtOffset(...) ...
versus your code:
Block b1 = (Block)getObjectsAtOffset(0, -2, Block.class);
The exception actually gives you a good hint in this case. "ArrayList cannot be cast to Block" - you are taking a List (which is what getObjectsAt(...) returns) and casting it to a Block, which isn't possible.
Ok, I implemented this and now I just walk up to a Block and when I get close enough to the point at which I stop moving, I can't move in any direction. This is the same result as before.
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