API:ChangeTrade

UI Lua API · Trade functions
Version: WAR 1.4.8

Changes the player's side of the current trade (items or money) and sends the update to the server.

ChangeTrade(tradeSlot, inventorySlot, backpackType, money)

Arguments

tradeSlot: number – What to change. 0 updates the money offer only. 1–9 adds or removes an item (see Details).
inventorySlot: number – Slot of the item to add, inside its backpack. 0 removes the item in trade slot tradeSlot instead.
backpackType: number – Backpack that inventorySlot belongs to (the EA_Window_Backpack.TYPE_* values: 1 quest, 2 inventory, 3 currency, 4 crafting).
money: number – Money offered. Only read when tradeSlot is 0.

Returns

Nothing.

Details

The client keeps a list of the items the player offers (up to 9) and the money amount. After changing that list it sends a trade update with the full list and money to the current trade partner.
tradeSlot = 0: stores money as the money offer and sends the update. The item list is unchanged.
tradeSlot 1–9 and inventorySlot = 0: removes the item in that trade slot. Later items move up one slot.
tradeSlot 1–9 and inventorySlot not 0: appends the item to the end of the list. The actual value of tradeSlot does not matter here; the stock UI always passes 1. inventorySlot and backpackType are turned into the item's absolute inventory slot before it is stored.
Any other tradeSlot value sends the update without changing anything.
The money value is only stored when tradeSlot is 0; in the other cases the last stored amount is sent again.
The stock UI calls ChangeTrade(0, 0, 0, money) to take back an acceptance (EA_Window_Trade.UnacceptTrade).
The client does not check for duplicate items or for more than 9 items, and removing an empty trade slot still shortens the list by one. Keep track of the offer in Lua, as the stock trade window does.
Does nothing if the player object does not exist yet.
The function needs at least four arguments and only reads the last four. All must be numbers.

Errors

None besides the generic Invalid Parameters message when an argument is not a number.

Example

From default/ea_tradewindow/source/tradewindow.lua:

-- which trade slot we're requesting doesn't matter so just hardcoding 1,
--   since server is just putting it in first available slot
ChangeTrade( 1, invSlotNum, backpackType, EA_Window_Trade.myOfferMoney )

-- tell server we're removing item from trade
ChangeTrade( slot, 0, 0, EA_Window_Trade.myOfferMoney )

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