I want to a keystone like item but I don't have any idea how to make a item have an inventory.

This tutorial adds an inventory to an item: http://www.minecraftforum.net/topic/1949352-creating-an-item-that-stores-an-inventory/

 

It's for 1.6.2, but most of the concepts should be the same. Basically you need to store the inventory in the itemstack's NBT.

 

There's a good tutorial specifically about Item NBT on the Forge wiki:

http://www.minecraftforge.net/wiki/Item_nbt

Your common proxy doesn't work with 1.5.2.

Thanks, I already knew that. That's why I explicitly told you it was for 1.6.2. I didn't give you exact code to copy, I gave you information on how to implement your idea conceptually with a fully functional example in 1.6.2. You'll have to work backwards from that to make it 1.5.2 compatible.

 

What about it doesn't work? What errors are you getting? Is there any output in the console that might help you? Posting this kind of error information as well as your code will get you help. Simply stating that it 'doesn't work' will not get you anywhere.

New problem.  I've updated my mcp to 1.6.2, but now I get an error in your ItemStore class.

 

 

Keyboard.isKeyDown(Component.Identifier.Key.K)

I changed the arguments so it works, but now eclipse says "Cannot make a static reference to the non-static method isKeyDown(Component.Identifier.Key) from the type Keyboard"

 

 

That error is your own. Use Keyboard.isKeyDown(Keyboard.KEY_K), like I did in the tutorial, and it should work fine. If it gives you an error, then you've done something wrong. What is the error it gave you?

 

It won't be multiplayer compatible - for that, see the note at the top of the tutorial.