How can l call one varible from one to other subclass ? and X and Y coordinate too?
( l mean how to get value of one variable from one to another edtior)
60sChallange wrote ...
2015/1/27
Problem
Documentation - tutorial #6
Be more specific. What exactly are you trying to do? How are the classes related? Show what you have tried.
actor- "ws" subclass;
public void act()
{
GreenfootImage image =getImage();
setLocation(getX() , getY() + WS_SPEED);
and
actor- "wb" subclass;
public void act()
{
setLocation(getX()+ dy,getY());
}
now l want to create if in "wb" subclass;
if (l don't know how to call x and y coordinate "ws" > x,y coordinate from "wb")
{ dy = 4
}
so can you write me a code that has to be between ()
and there is one more question beacouse l am finishing a game.. can greenfoot game be posted on google play? and can it be used on android?
If there is always exactly one "ws" object in the world, you can use:
then you can execute the 'getX' and 'getY' methods on 'actor'.
The line that gets the reference to the ws object gets the first ('0') element from the list returned by 'getObjects' of ws class objects in the world. The list returns the objects as Object type objects and the compiler needs to be told that the element extracted from the list is indeed an Actor before it will look in the Actor class for the 'getX' and 'getY' methods (or before it can store the reference in a field that holds an Actor type object).
Actor actor = (Actor)getWorld().getObjects(ws.class).get(0);
but l need to put that in "if"between () ... how can l call x and y then?
60sChallange wrote...
but l need to put that in "if"between () ... how can l call x and y then?if (actor.getX() > getX() && actor.getY() > getY())
java.lang.IndexOutOfBoundsException: Index: 0, Size: 0
at java.util.ArrayList.rangeCheck(ArrayList.java:635)
at java.util.ArrayList.get(ArrayList.java:411)
at WoodBall.act(WoodBall.java:43) (this line is marked red)
at greenfoot.core.Simulation.actActor(Simulation.java:583)
at greenfoot.core.Simulation.runOneLoop(Simulation.java:541)
at greenfoot.core.Simulation.runContent(Simulation.java:215)
at greenfoot.core.Simulation.run(Simulation.java:205)
that appears in terminal window and when l click red marked line, editor opens with marked "Actor actor = (Actor)getWorld().getObjects(ws.class).get(0);".....
tnx for help danpost
btw game starts just for second and stops
The error message is given because you do not always have a ws object in the world.
Since you may not have one in the world, you need to ensure that the list returned by 'getObjects' is not empty:
danpost wrote...
If there is always exactly one "ws" object in the world, you can use:
Actor actor = (Actor)getWorld().getObjects(ws.class).get(0);
if (! getWorld().getObjects(ws.class).isEmpty())
{
Actor actor = (Actor)getWorld().getObjects(ws.class).get(0);
if (actor.getX() > getX() && actor.getY() > getY())
{
/** whatever you do */
}
}ty
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