Minecraft – ny way that I can track a villager trade and execute a command when an item is traded

minecraft-commandsminecraft-java-edition

I'm working on a minecraft map and basically what I want is to execute a command when a player trades an item with the villager. (This is a custom villager with custom items not a random villager). I haven't tried anything yet, but what I was thinking of is a scoreboard that counts how many times the trade got used. If someone could help me that would be great!

Best Answer

If you're OK with using command blocks, a quick search online revealed this thread, citing this wiki page; apparently solving your very issue.

Emphasis added:

i want to detect when i do a trade with a villager. there is maybe a way to do it if i use data when i do a trade there is an nbt that change called uses but and i try to write the command it doesn't work any idea's?

Oh, yea, easy peasy… There's an advancement trigger that's made for just this!
{
  "criteria": {
    "requirement": {
      "trigger": "minecraft:villager_trade",
      "conditions": {
        "item": {
          "item": "minecraft:diamond"
        }
      }
    }
  }
}
…

If you're just looking to detect just one villager and run some commands as that villager, (for some custom map NPC or something) it would be very easy to just have:
data modify storage temp NPC_1.uses set value []
data modify storage temp NPC_1.uses append from entity <NPC #1> Offers.Recipes[0].uses
data modify storage temp NPC_1.uses append from entity <NPC #1> Offers.Recipes[1].uses
data modify storage temp NPC_1.uses append from entity <NPC #1> Offers.Recipes[2].uses

... and so on...

execute store success score .changed int run data modify storage map NPC_1.uses set from storage temp NPC_1.uses
execute if score .changed matches 1 run tellraw @a {"text":"NPC #1 was traded with."}
execute if score .changed matches 1 as <NPC #1> run say "It's true, a player traded with me."

Related Solutions

Minecraft – How to detect if anyone stepped on block and then execute command toward that play

/execute @a ~ ~ ~ detect ~ ~-1 ~ minecraft:stonebrick 1 /tp @p @e{type=Villager]
When ANY player steps on mossy stonebrick (minecraft:stonebirck 1) it teleports the nearest player to the command block to the villager regardless if he step on the mossy cobble.

The /execute command modifies the sender of the command to that of its target. Any subsequent selectors in commands being run are going to use the executor as the sender.

This comes into play with sender bias, which forces a target selector to target the entity that ran the command. The command you've presented already uses it. The executing player will be the one to be teleported, so long as they are alive.

The @a selector is the only target selector capable of targeting dead players. If a player dies while on top of stonebrick, they will teleport the nearest living player to them rather than themselves, because @p cannot target dead players.

The fix for that in particular is to use the @a selector while reducing the count (via c parameter) to 1, which also enforces a sender bias. The command itself is still functional as you need it without having to have changed anything else.

/execute @a ~ ~ ~ detect ~ ~-1 ~ minecraft:stonebrick 1 /tp @a[c=1] @e[type=Villager,c=1]

/execute is used to change the sender and origin of commands to run. /tp is being run through the player, not by the command block. @p will be in reference to the executing player's location, and due to sender bias, @p will always target that player so long as that player is alive. Your command was originally working fine apart from the dead targeting flaw.

Minecraft – Custom Villager with potions as trade

In 1.9, potions no longer rely on the damage value of the potion item to determine what type of default potion it is. Instead, the Potion string tag holds a string-based default potion ID, which is stored in the tag compound:

sell:{id:"minecraft:potion",Count:1,tag:{Potion:"minecraft:strength"}}}

If instead you want to sell a potion with custom effects, you would use the old CustomPotionEffects list (using an effect ID):

sell:{id:"minecraft:potion",Count:1,tag:{CustomPotionEffects:[{Id:5,Duration:600}]}}}