#command blocks

For Loka Minecraft I had to figure out a way of testing to see if an item within a hopper, and if a piece of leather armour on an armour stand matched specific characteristics for the completion of quests.

The first step in the process was to determine what value could be measured within the items NBT Data. The easiest way I have found to do this is use this command:

/minecraft:data get entity @s SelectedItem

^ this gives you the information unique to that item, so you can determine what value detect for within your command block.

If you want to use the same commands, with the same values, here is a command to get a potion that works with it.

/minecraft:give @s minecraft:potion{CustomPotionColor:16753920} 1

With the data visible, the easiest way of detecting the item in this case is to use the custom potion colour, as detecting for the name would be difficult due to its complexity. 

In a command block you can use the command:

/execute if block x y z minecraft:hopper{Items:[{tag:{CustomPotionColor:16753920}}]} run . . .

This will detect for the specific potion, and you can have the command run whatever else you desire.

The execution of a command based on leather armour is a slightly more complex command, but fundamentally works in the same way. I would recommend first creating leather with whatever colour you want first, and then using the first command to determine its colour.

^ an example item

/execute if entity @e[type=minecraft:armor_stand,sort=nearest,limit=1,nbt={ArmorItems:[{},{},{tag:{display:{"color":16351261}}},{}]}] run . . .