"if" Statement?!!!

Yes. The statement above would not make sense, however, but concatenating ANDs and ORs and using ! (the NOT symbol) can all be used in conjunction within the 'if' phrase. The statement where 'gettingString' is a boolean instance variable could be statement in some code.. Each (main, taking into account parenthesis) condition is checked in succession (from left to right) until a value (true or false) can be determined without going to the condition. In other words, in the case above: if 'gettingString' was 'false', processing of the 'if' will immediately return 'false', because it does not matter what results come from the rest of the conditions. If it were 'true', then the second check would be checked. The check to see if 'aString' was NOT an empty string will only be checked if both 'gettingString' were 'true' AND 'aString' was NOT null. Getting back to the 'if' statement you provided in the start of the discussion: Two 'mouseClicked' checks on different objects, ANDed together would never occur (how can you click on two objects at the same time). Unforntunately, even ORing them may not work (this has something to do with how the 'mouseClicked' method is written; you should only use it once per act cycle or on successive calls it will always return 'false').

I actually want to purchase a chocolate, so I need to enter the item number, which is two digits. For instance, Hobby is number 78, and the price is £6.75. I didn't use code, because I think keeping numbers as is much better than decimal, which doesn't make mess. However, the other thing which makes me confused sometimes, is String. Could you explain to me what is it and how to use it? What I know, it's not a clear picture of it. Many thanks.

That is where you need to check out the Java tutorials I mentioned in the other discussion. I could explain it, but the documentation is already written (and probably double-checked), plus there are diagrams to help explain there.

I just send the picture for the vender machine, which you can there see the keypad. all the buttons are as a class like Class NO 7. https://www.dropbox.com/s/guiopfwqtmjiyz3/Screen%20Shot%202012-09-05%20at%2016.06.58.png

Thanks ever so much for guidance. :-)

Dear Danpost, for purchasing a chocolate, user has to click on the numbers on the keypad, which every chocolate has got a two digits code. Therefore, user has to click on to number. As you said if statement doesn't work like the way I did. What about using the clickOn() method inside every single Key Class, then I invoke the methods from Keypad's Subclass in Screen Class, by interaction method. what do you think?

I think that since each click can be picked up on individually, that you can still have the method in the Keypad class. You will need a 'static String' variable to collect the characters. A static variable is a 'class' variable (not an object or instance one). All the classes will have access to that same individual variable. The Keypad method would look something like this: In your ChocolateBar class (if that is what you named it, in its act method, you can say Correct me if I am wrong, but did you say that the Counter object is created but not placed into the world? I think I recall you saying that it did not have an image. Please elaborate.