[MetalZelda]

Yes, use another savegame variable for the amounts, otherwise the engine would be confused

[dpro_games]

With this code, if I take two keys, I just can open one door after... 

How can I and where I need to inizialize a other variable for the amouts ?

I really sorry because I am a real beginners   ...

[MetalZelda]

I don't remember if you need to use item:add_amount(item:get_amount() + 1) in on_obtaining() or if the engine does it automatically. I'm sure that this would fix your problem.

[Diarandor]

I don't know because I have never used the key-door system. But what MetalZelda says is surely the correct thing to do.

[dpro_games]

Oh thank !!! It works !!! It's the first time than I do something which works with solarus ! Thank you ! 

[MetalZelda]

Also if you are a true begginer (we all passed this step), I recommand you to watch all of Solarus Tutorial videoes by Christopho

https://www.youtube.com/watch?v=DKLrGyMqvaU

These are a bit old and would be replaced by the new ones, but the engine is a bit similar and it would help you to understand the basics of the engine and the map editor.

If you want to make a game with Solarus (which I guess is what you're here for), I recommand you to learn the basics of lua
https://www.lua.org/pil/contents.html#P1

[Diarandor]

You can also use the function "item:add_amount(amount)",
which should be equivalent to "item:add_amount(item:get_amount() + 1)".

[MetalZelda]

You can also use the function "item:add_amount(amount)",
which should be equivalent to "item:add_amount(item:get_amount() + 1)".

Yes that works too, I just didn't remember how it worked  (It's been a long time since I didn't look at items)

[dpro_games]

But there is an eroor in the consol with that : Error: In on_obtaining: [string "items/small_key.lua"]:16: bad argument #1 to add_amount (integer expected, got nil))

[Diarandor]

As the error says "integer expected, got nil",
so write something like "item:add_amount(1)".

EDIT: when I wrote above:

You can also use the function "item:add_amount(amount)",
which should be equivalent to "item:add_amount(item:get_amount() + 1)".

I wanted to say:
You can also use the function "item:add_amount(amount)",
which should be equivalent to "item:set_amount(item:get_amount() + 1)".

Sorry for the mistakes, it's quite late and we are all tired... 

[MetalZelda]

But there is an eroor in the consol with that : Error: In on_obtaining: [string "items/small_key.lua"]:16: bad argument #1 to add_amount (integer expected, got nil))

integer expected means that eigher tou enterred a letter and not a number in add_amount()

In Diarandor's example, what he means is

Code: (lua) [Select]

item:add_amount(amount)
amount can be replaced by a number, 1

So, it is

Code: (lua) [Select]

item:add_amount(1)

[dpro_games]

Realy thanks ! I can sleeping well now ! Bye ! Maybe later... to help me pass the beginner steps !