[Solved][1.6.4]GUI Button doesn't update

[Gugu42]

Hello !

I have a problem with a GUI Button

 

I want it to change state ( enabled / disabled ) wether or not I put a certain item in a slot.

It works, but only if I put the item, close the GUI and reopen it.

 

The button doesn't update when the correct item is put in the slot, and I must close/reopen the GUI for it to update.

 

http://pastebin.com/pVnsNtTN

 

 

PS : I guess it's because it's in a method that doesn't get updated every tick, but then, I don't know where to put the condition

[Gugu42]

I solved it by putting the condition in updateScreen()

 

Thanks