Discussions

I'm afraid that we can't really provide legal advice. There may be provisions such as "fair use" that allow for use of copyright-protected work, though these will vary from country to country; it may or may not be enough that the work is not used for profit and is used in an educational context. I would suggest that the safest course of action is to have your students produce their own artwork or use images from sources that expressly allow re-use. You can use CC search for example to find such images.

Thank you that did the trick.

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.

This forum isn't for random noise, please. Keep it to real discussion of Greenfoot/programming issues.

Can you show me the code to do that?

Oh, I see. You need to retain the base image (one without any dots) and make copies of that and add the dots to each copy to be set as the current image. So, <Code Omitted>

The getObjectsInRange method returns a list, not just an actor. You can use a for-each to go through the list. <Code Omitted>

Problem 1: For the Paddle to be removed you need the ball to be touching the paddle when s == 48. If you want to remove all the paddles from the world (which will remove the one that's there), then you can do the following: <Code Omitted> Problem 2: I can't help with what's happening with the Paddle2 with the code you gave, you need to show the full Paddle2 class code.

Aah, I completely forgot about the act method. Thank you so much :D.

Fact 1: an actor must be created prior to it being placed into a world Fact 2: the constructor of an object is executed at the time the object is created This being said, 'getWorld', when used in the constructor of an Actor subclass, must return a 'null' value. Line 15 of the Score class constructor sets 'null' as the value of the 'world' variable. Then, line 16 and 17 tries to call the 'getP!score' and 'getP2score' methods on that 'null' value. Hence, the 'NullPointerException' error you were getting. You could make use of the 'addedToWorld(World) method of the Actor class, which is

There is no code to add a ball into the world (nor created). So 'myBall' is never assigned any Ball object that can be removed.

I am not sure what 'Counter' would be, either. But, it sounds like all you need is the following for line 3 <Code Omitted>

Thank you danpost, it is working :)

Davin, Thanks for the feedback. I will use a Producer/Consumer model for the message pump approach. I always try to design and build solutions that can be used as a learning opportunity for my students. In the example above I have stripped away all of the unnecessary elements to focus on the pause between actions. I still need to ensure that the pause will work across multiple actors to solve the long running (aggregate of primitives actions) method calls. On another note: Any plans to change Actors from a class to an interface? ;)

Please check out my Value Display Tutorial scenario for information on adding a counter to your world.