Greenfoot

2017/5/30

#

I am making a game where I need to access all of the Labels on the screen from my World (called Arena)

ArrayList<Label> kfls = getObjects(Label.class);

There is one error that I cannot expel, which is: incompatible types: no instances(s) of type variable(s) A exist so that java.util.List<A> conforms to java.util.ArrayList<Label>. If you could fix my error and also tell me why exactly this is happening that would be fantastic!

davmac

2017/5/31

#

I suspect that means that "Label" is not a subclass of Actor? In that case, you are asking for a list of objects in the world of a type of object which cannot be in the world. (However, I'm not sure. The error message is certainly confusing...)

HoperAndDreemurr

2017/5/31

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I tried adding a couple of them into the World (via addObject() ) but the error still persists. I am going to go to sleep now. Maybe the answer will come by next morning.

danpost

2017/5/31

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HoperAndDreemurr wrote...

I tried adding a couple of them into the World (via addObject() ) but the error still persists.

You might try this instead:

List<Label> kfls = getObjects(Label.class);

I do not know if it will help; but, it is worth a try.

HoperAndDreemurr

2017/5/31

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Wow!!! Thanks, after changing ArrayList to List, I got another error instead relating to my imported java.awt.* extension for another unknown reason, then I changed java.awt.* to java.awt.Color, and everything worked fine. Thank you again. It would be cool to know what happened exactly, although I don't care about it that much. Maybe I will see this again when I am a programmer with more experience.

davmac

2017/5/31

#

It would be cool to know what happened exactly

If you were importing java.awt.*, then you were implicitly importing java.awt.Label. That is what caused the error; Label in your code was referring to java.awt.Label, which is not an actor and therefore can't be in the world.

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World.getObject() strange error