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bangtan
bangtan wrote ...

2020/3/15

how do I check if an actor still exists

bangtan bangtan

2020/3/15

#
I want to check if there's still an existing actor before running another method
danpost danpost

2020/3/15

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bangtan wrote...
I want to check if there's still an existing actor before running another method
?
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if (someActor.getWorld() != null)
where someActor references a specific actor instance. Or
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if ( ! getWorld().getObjects(SomeActor.class).isEmpty())
where SomeActor is the type of actor (for any instances of that type)
bangtan bangtan

2020/3/15

#
thank you so much!!!!1
bangtan bangtan

2020/3/15

#
danpost wrote...
bangtan wrote...
I want to check if there's still an existing actor before running another method
?
1
if (someActor.getWorld() != null)
where someActor references a specific actor instance. Or
?
1
if ( ! getWorld().getObjects(SomeActor.class).isEmpty())
where SomeActor is the type of actor (for any instances of that type)
is there a way in which if the actor was removed, it will not do a method
danpost danpost

2020/3/15

#
bangtan wrote...
is there a way in which if the actor was removed, it will not do a method
Place one of those condition on calling the method.
bangtan bangtan

2020/3/15

#
like this?
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public void exist(){
        if ( ! getWorld().getObjects(runner.class).isEmpty()){
            getWall();
        }
    }
danpost danpost

2020/3/15

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bangtan wrote...
like this? << Code Omitted >>
Need more context. Show entire class codes.
bangtan bangtan

2020/3/15

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boolean needs to work if there's the runner, but if the runner gets killed, getWall shouldn't run because it will be an error
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public class runner extends Actor
{ 
     
     
    int health = 5;
  
    public void exist(){
        if ( ! getWorld().getObjects(runner.class).isEmpty()){
            getWall();
             
        }
    }
    public void act()
    {
        exist();
        health();
        kill();
         
        if(getWall() == false)
        {
             move(5);
        } else {
            int turn = Greenfoot.getRandomNumber(3);
          
            if(turn == 0)
            {
                turn(90);
            } else if (turn == 1){
                turn(-90);
            } else if (turn == 2){
                turn(180);
            } else if (turn == 3){
                turn(-180);
            }
 
        }
 
    private boolean getWall(){
        {
            GreenfootImage myImage = getImage();
            int distance = myImage.getWidth()/2;
            int xOffset = (int)Math.ceil(distanceToFront*Math.cos(Math.toRadians(getRotation())));
            int yOffset = (int)Math.ceil(distanceToFront*Math.sin(Math.toRadians(getRotation())));
             
            Actor wall = getOneObjectAtOffset(xOffset, yOffset, wall.class);
            return(wall != null);
             
        }
    }
 
    
    public void health(){
      Actor shot = getOneIntersectingObject(bullet.class);
        if (bullet != null) {
            health = health - 1;
      }
    }
    public void kill(){
        if (health == 0){
            getWorld().removeObject(this);
        }
    }
}
  
danpost danpost

2020/3/15

#
Oh. You want the runner to check if it, itself, is in the world. Alright. Remove lines 7 thru 12 and also line 15. Then, put the following at line 18:
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if (getWorld() == null) return;
That will immediately exit the method (not letting any further code in the method to execute) if the actor was removed from the world.
bangtan bangtan

2020/3/16

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thank you!!
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