Remove line 2 from both classes given above -- you are not using any ArrayList object in your Simon class and you are not using any Date object in the RedButton class (or the other buttton classes). Right now, you have each button reacting to any clicks on them. Although that is what might be needed to detect a step in the response to a given sequence, it is not something that you would want to happen at any time. There are two main phases in a Simon type game -- the phase where a sequence is given (not requiring mouse clicks) and the phase where the user tries to reproduce the sequence (requiring mouse clicks or user input of some type). You start with an empty sequence (no sequence, really). The first phase involves adding one of the four buttons to the sequence and then running the sequence. This is not something that an individual button can do -- it needs to be done by the world. The world needs to retain the sequence to play it and to check against the input given by the user. One question that comes to mind is how to represent a sequence of buttons. One possible idea might by to use an ArrayList (as you have implicitly indicated went through your mind or was an idea provided to you from some other source). Actually, a more "clever" way, or at least a way I would consider to be better, is to use a simple String object, representing the buttons by the first letter in their colors, "R", 'G", "B", and "Y". So, a sequence might end up to be something like "YRBBGBYRRGYGRBY". Now, since the world will have to perform the sequence before the user can reproduce it, the world would need to keep references to the buttons so it will not have to segregate them from other actors in the world every act cycle. So an array of length four can be created and loaded with the buttons. Then, so the array does not have to be iterated through every act for a specific button, a String object can be created and the first letter of the colors of the buttons as they appear in the list can be concatenated to build this string. The world will now be able to take a character, say "G", get the index of it in the four-character string, say "RGYB" and use that index to get the appropriate button from the button list. Finally, the world class act method is ready to control the buttons (setting the images for both pressed and normal) and also check for clicks on those buttons (all in one place). The button classes can be basically empty of added codes -- for example, the RedButton class can be simply this: and similar for the other buttons. The Simon class act method can control the entire game. You will need a strategy for controlling the phases -- probably using a boolean and a counter.

Hi Dan! This already helped a lot, thank you! I've now added a ArrayList (I hope, that I did it right^^) in my Simon World. I also know that I need a "Sequence"-method, where I can let the first phase run through. I also understand that I need to represent the buttons with String objects, however that's where I'm stuck now. I thought, maybe I have to put it like that: However, this also doesn't work. Again, thank you for helping :)

First, it is not an ArrayList -- it is an Array (line 6 in Simon class). Second, a major issue is that the button actors you add into the world are not the same actors that you placed into the array (lines 11 through 14 must not use the "new" keyword, but must reference the actors in your array. Well, I myself would refrain from using Greenfoot.delay; so, a sequence method would be kind of out the window. I would use timer and sequence index fields to perform the sequence through the act method of the class. There are multiple issues with this one line of code. In a line of code that assigns a value (or reference) to a new variable, the parts are labelled as follows: varType is either a primitive type, like int, boolean or double, or an Object type, like World, Actor or String. It declares what type of value the new variable will hold. varName is the name you give the new variable and there are limitations as to what names you can declare for variables. expression is everything to the right of the equal sign and must evaluate to the type declared for the variable. Your line of code has the following errors (1) string is an invalid type (should be String); (2) "R" is not a valid variable name (quotes are illegal); and (3) an Actor reference cannot be assigned to a variable that is supposed to hold a String object. Along with your array, you can add this line: Later, in your code, you will be able to use something like this: with this method

Ok, I get what you mean. However, I don't know how I can refer to the Actors in my Array. What are timer and sequence index fields? Sorry to bother you. (1) Ok, so I changed the varType to String. (2) I deleted the quotes (3) Ok, I understand, still I don't understand how I can "equal" my Actor to a String object so that the program just needs to use the String object. Again, thank you for helping me :)

There is an example in the getButton method. Line 12 could simply be the following (and lines 13 through 15 similarly): They are int fields you add to the class to act (1) as an act counter to help regulate actions over time; and (2) as a pointer to indicate which character in the sequence string is currently being acted on (in phase one, that character's respective button image is being illuminated; in phase two, the button is tested as the next correctly clicked button). I believe the answer to this was given earlier in this posting (see code line).

Perfect, thanks :) Ok great, thank you :) Is this what you mean? I understand that the varType needs to be String and the varName can be R (without quotes), but I don't know what expression means in this case. I tried but both don't seem to work. I know that String can't be equal to an Actor, so that's why I'm asking :) Thank you again for helping :)

All that stuff about varType, varName and expression was just general information on how to create and assign a value to a new variable. The RHS, expression , could be a simple value, another variable name, a mix of method calls and math operations -- any expression that results to something of the type that the variable can hold. For example, since a RedButton object is an Actor object, the line in your act method above works. The method called on the RHS is the expression that provides an Actor object which is then assigned to the variable button which can only hold objects of type Actor. As far as a String representing a button, you can see by that line in your act method that by calling the getButton method with the String as the argument, the appropriate button actor is returned. You should drop your attempts to assign R a value, mainly because you want the button actor -- not a String object.

So, I'm now at this point: Example button: If it's ok to ask, in your eyes, what should be the next step for me to focus on? :)

Here, there is a mismatching. The order must be the same in both lines. Those lines are legitimate, but are not necessary. When you build your act method, you will use the getButton method when needed. Line one is not needed here. You should probably create methods to perform some of the actions needed for the game (for example, one to detect clicks on the buttons, one to run the act counter and control the playing out of the sequence -- things like that).

Thank you very much! I'll now try to create those methods and will post again later :)

I wish to remind you that pretty much everything will go in your Simon class.

Ok, so after a short break I'm now trying to get the detectClick method to work. My question is: Should I create a detectClick method for every individual button, so that they can individually swap out the images or should I put it like in the code i posted. Also: I already tried using this method: However, if I put it like that, Greenfoot just gives out "File saved", without compiling and I can't use the interface, because it is greyed out.