Inventory system

[cerulean blade]

I have spent around 10 hours debugging an inventory system, specifically the drag and drop. If anybody could tell me where the problem is, that would be very much appreciated.

Problem: Drag and drop, nothing happening when I drag

Code below ⬇️

Most likely part of the code that's causing problems (I think):

[lofty steppe]

** You are now Level 24! **

[cerulean blade]

Entire code ⬇️

Intended behaviour when dragging: Just move the item name and data from the original slot to the target slot

[cerulean blade]

(So far not happening)

[cloud sail]

Too much work to download that ngl just send it in different parts

[cerulean blade]

which one

[cloud sail]

Idk just send full code in different parts

[cerulean blade]

ok

-- Services
local Players            = game:GetService("Players")
local UserInputService   = game:GetService("UserInputService")
local ReplicatedStorage  = game:GetService("ReplicatedStorage")

-- Remote events
local RE_Equip = ReplicatedStorage:WaitForChild("RequestEquip")

-- Player & character
local player = Players.LocalPlayer
player.CharacterAdded:Wait()
local backpack = player:WaitForChild("Backpack")

-- Get GUIs
local screenGui       = player:WaitForChild("PlayerGui"):WaitForChild("InventoryUI")
local inventoryFrame  = screenGui:WaitForChild("InventoryFrame")
local hotbarContainer = screenGui:WaitForChild("HotbarContainer")
local scrollingFrame  = inventoryFrame:WaitForChild("Container")

local hotbarSlotTemplate    = hotbarContainer:WaitForChild("HotbarSlotTemplate")
local inventorySlotTemplate = scrollingFrame:WaitForChild("InventorySlotTemplate")
local maxHotbarSlots, maxInventorySlots = 5, 25

hotbarSlotTemplate.Visible    = false
inventorySlotTemplate.Visible = false

local lastDropUIIndex = nil

local dragging
local dragData = {}  

local hotbarSlots, inventorySlots = {}, {}
for i = 1, maxHotbarSlots do
    local slot = hotbarSlotTemplate:Clone()
    slot.SlotNumber.Text = i
    slot.Visible         = true
    slot.Parent          = hotbarContainer
    hotbarSlots[i]       = slot
end
for i = 1, maxInventorySlots do
    local slot = inventorySlotTemplate:Clone()
    slot.Visible       = true
    slot.Parent        = scrollingFrame
    inventorySlots[i]  = slot
end

local hotbarTools   = {}  
local inventoryOrder = {}
local uiInventory = {}

local function buildStackList()
    local stacks = {}
    for _, container in ipairs({ backpack, player.Character }) do
        for _, tool in ipairs(container:GetChildren()) do
            if tool:IsA("Tool") then
                local name = tool.Name
                if not stacks[name] then
                    stacks[name] = { name = name, tool = tool, count = 1 }
                else
                    stacks[name].count += 1
                end
            end
        end
    end

    local t = {}
    for _, data in pairs(stacks) do
        table.insert(t, { name = data.name, tool = data.tool })
    end
    table.sort(t, function(a, b)
        return a.name < b.name
    end)
    return t
end

local function makeGhost(slotFrame)
    
    local ghost = slotFrame:Clone()
    
    local absSize = slotFrame.AbsoluteSize
    ghost.Size        = UDim2.fromOffset(absSize.X, absSize.Y)
    ghost.AnchorPoint = Vector2.new(0, 0)
    
    ghost.BackgroundTransparency = 0.5
    ghost.Active = false
    
    ghost.ZIndex = 100
    ghost.Parent = screenGui
    return ghost
end

local function isOverSlot(x, y, slot)
    local pos, size = slot.AbsolutePosition, slot.AbsoluteSize
    return x >= pos.X and x <= pos.X + size.X
        and y >= pos.Y and y <= pos.Y + size.Y
end

do
    local initial = buildStackList()
    for _, entry in ipairs(initial) do
        table.insert(inventoryOrder, entry)
    end
end

local function refreshSlots()

    
    local stackCounts = {} 
    for _, container in ipairs({ backpack, player.Character }) do
        for _, tool in ipairs(container:GetChildren()) do
            if tool:IsA("Tool") then
                local name = tool.Name
                if not stackCounts[name] then
                    stackCounts[name] = { count = 1, prototype = tool }
                else
                    stackCounts[name].count += 1
                end
            end
        end
    end

    for i = 1, maxHotbarSlots do
        local slot = hotbarSlots[i]
        slot.ItemName.Text      = ""
        slot.StackLabel.Text    = ""
        local tool = hotbarTools[i]
        if tool then
            
            local name = tool.Name
            local data = stackCounts[name]
            if data then
                slot.ItemName.Text   = name
                slot.StackLabel.Text = (data.count > 1) and ("x "..data.count) or ""
                stackCounts[name] = nil
            else
                hotbarTools[i] = nil
            end
        else

else
            
            for _, entry in ipairs(inventoryOrder) do
                if stackCounts[entry.name] and not table.find(hotbarTools, entry.tool) then
                    hotbarTools[i]       = entry.tool
                    slot.ItemName.Text   = entry.name
                    local count = stackCounts[entry.name].count
                    slot.StackLabel.Text = (count > 1) and ("x "..count) or ""
                    stackCounts[entry.name] = nil
                    break
                end
            end
        end
    end

    
    local filtered, map = {}, {}
    for orderIdx, entry in ipairs(inventoryOrder) do
        if not table.find(hotbarTools, entry.tool) then
            table.insert(filtered, entry)
            map[#filtered] = orderIdx
        end
    end

    visibleInventory = {}
    for _, entry in ipairs(inventoryOrder) do
        if not table.find(hotbarTools, entry.tool) then
            table.insert(visibleInventory, entry)
        end
    end

    
    for uiIdx = 1, maxInventorySlots do
        local slot   = inventorySlots[uiIdx]
        local entry  = visibleInventory[uiIdx]

        if entry then
            
            local count = stackCounts[entry.name].count
            slot.ItemName.Text   = entry.name
            slot.StackLabel.Text = (count > 1) and ("x "..count) or ""
            slot:SetAttribute("hasEntry",  true)
            
            -- Making the slot red (for testing) (Not making it red)
            if uiIdx == lastDropUIIndex then
                slot.BackgroundColor3 = Color3.fromRGB(255, 0, 0)
            else
                
                slot.BackgroundColor3 = Color3.fromRGB( 50,  50, 50)  
            end
        else
            slot.ItemName.Text   = ""
            slot.StackLabel.Text = ""
            slot:SetAttribute("hasEntry",  false)
        end
        
        slot:SetAttribute("uiIdx", uiIdx)
    end
end

refreshSlots()
UserInputService.InputBegan:Connect(function(input, gameProcessed)
    if not gameProcessed and input.KeyCode == Enum.KeyCode.B then
        inventoryFrame.Visible = not inventoryFrame.Visible
    end
end)
for _, event in ipairs({ backpack.ChildAdded, backpack.ChildRemoved,
    player.Character.ChildAdded, player.Character.ChildRemoved }) do
    event:Connect(function() task.wait(); refreshSlots() end)
end


local function toggleEquip(slotIndex)
    local tool = hotbarTools[slotIndex]
    if not tool then return end

    RE_Equip:FireServer(tool)
    
    task.delay(0.1, refreshSlots)
end


local SlotsContainer = scrollingFrame 


local function GetSlotUnderMouse()
    local mousePos = UserInputService:GetMouseLocation()
    local guiInset = game:GetService("GuiService"):GetGuiInset() 
    local adjustedPos = mousePos - guiInset

    for _, slot in ipairs(SlotsContainer:GetChildren()) do
        if slot:IsA("GuiObject") then
            local pos = slot.AbsolutePosition
            local size = slot.AbsoluteSize

            local within =
                adjustedPos.X >= pos.X and adjustedPos.X <= pos.X + size.X and
                adjustedPos.Y >= pos.Y and adjustedPos.Y <= pos.Y + size.Y

            if within then
                print(slot.Name)
                slot.BackgroundColor3 = Color3.new(255, 0, 0)
                return slot
            end
        end
    end

    return nil
end

local function onSlotInput(slotFrame, containerType, slotIndex)

    
    local function getFilteredInventory()
        local filtered, map = {}, {}
        for orderIdx, entry in ipairs(inventoryOrder) do
            
            if not table.find(hotbarTools, entry.tool) then
                table.insert(filtered, entry)
                map[#filtered] = orderIdx
            end
        end
        return filtered, map
    end

    slotFrame.InputBegan:Connect(function(input)
        if input.UserInputType ~= Enum.UserInputType.MouseButton1 then
            return
        end

        local filteredStart, mapStart = getFilteredInventory()

        if containerType == "inventory" then
            -- exit if empty slot
            if not slotFrame:GetAttribute("hasEntry") then
                print("Empty slot")
                return
            end

            
            dragData.originContainer = "inventory"
            dragData.originUIIndex   = slotIndex
            dragData.entry           = visibleInventory[slotIndex]
            dragData.tool            = dragData.entry.tool
        end


        local startPos    = UserInputService:GetMouseLocation()
        local dragging    = false
        local moveConn, stateConn

        
        moveConn = UserInputService.InputChanged:Connect(function(rbxInput)
            if rbxInput.UserInputType ~= Enum.UserInputType.MouseMovement then
                return
            end

local curPos = UserInputService:GetMouseLocation()
            if not dragging and (curPos - startPos).Magnitude > 5 then
                dragging = true

                
                local filtered, map = getFilteredInventory()
                dragData.originContainer = containerType

                if containerType == "inventory" then
                    
                    local invEntry = filteredStart[slotIndex]
                    dragData.entry           = invEntry
                    dragData.tool            = invEntry.tool
                    dragData.originOrderIndex = mapStart[slotIndex]
                else
                    
                    local tool = hotbarTools[slotIndex]
                    if not tool then
                        
                        moveConn:Disconnect()
                        stateConn:Disconnect()
                        return
                    end
                    dragData.tool      = tool
                    dragData.entry     = { name = tool.Name, tool = tool }
                    dragData.originIndex = slotIndex
                end

                dragData.ghostFrame = makeGhost(slotFrame)
            end

            if dragging and dragData.ghostFrame then
                
                dragData.ghostFrame.Position = UDim2.fromOffset(curPos.X, curPos.Y)
            end
        end)

fuck

discord won't let me send anymore

[cerulean blade]

just download it, discord is being a bitch

oh

or I can send it on pastebin

[terse hazel]

ask gpt ya hurr

[cerulean blade]

full code:

https://pastebin.com/3Kzhcyxh

[cerulean blade]

my guy gpt exploded

[terse hazel]

lol

mine said ts

[cerulean blade]

what model is that?

[terse hazel]

im too lazy to read the code tbh so idk if gpt is being ahh

[terse hazel]

idk the premium one i had one more free message 💀

[cerulean blade]

lemme clarify: The drag icon appears and follows my mouse, but when I drop it onto another slot, nothing happens

[cloud sail]

Yeah this shit do not make sense to me I’m too low level

Add prints and find what it’s doing and not doing

[glacial hawk]

have you used the debugger?

[hidden ember]

dear god fix your nesting bruh lua end end end end) end) end

[hidden ember]

it's probably not working because this doesn't ever fire stateConn = input:GetPropertyChangedSignal("UserInputState"):Connect(function() you are connecting to nothing because the input variable never changes: slotFrame.InputBegan:Connect(function(input).
use inputended like a normal person?

[cerulean blade]

hi srry for the late response

[cerulean blade]

no it's firing

stateConn = input:GetPropertyChangedSignal("UserInputState"):Connect(function()
            print("HI")

it's printing HI when I drop onto a slot

[cerulean blade]

[cerulean blade]

Bump

[hidden ember]

fix your nesting bruh

[cerulean blade]

Po

I'll do that later

I just need to implement dragging and dropping so that I can complete my inventory system

[hidden ember]

add more prints and/or breakpoint and step into to find where it's halting?

i'd put the breakpoint on that print

[cerulean blade]

It's not halting

But it's just not swapping slot items when dragging and dropping

[hidden ember]

i dont see any swapping code in there

maybe i missed it but i can't spot any a,b=b,a or a temporary variable used in swapping

there's a bunch of these that kind-of look like swapping elseif dragData.originContainer == "inventory" and targetContainer == "inventory" then

but it's using table.remove then table.insert from the same table? much weird

oh there's a swap hotbarTools[dragData.originIndex], hotbarTools[targetIndex] =hotbarTools[targetIndex], hotbarTools[dragData.originIndex]

bruh this nesting is so bad

[cerulean blade]

I know 😭

[hidden ember]

you doing really weird things to this table ```lua
local function getFilteredInventory()
local filtered, map = {}, {}
for orderIdx, entry in ipairs(inventoryOrder) do

        if not table.find(hotbarTools, entry.tool) then
            table.insert(filtered, entry)
            map[#filtered] = orderIdx
        end
    end
    return filtered, map
end```

poor thing local inventoryOrder = {}

[hidden ember]

anyway looks like a bunch of stuff in there that looks like it should be swapping. the halt is where it is not doing that.

your nesting too stronk to properly trace this, breakpoint is your best bet

as you step through the code keep watch of the watch variables tab and find where the swap code is getting skipped over then check why

then just go from there 👍

[cerulean blade]

Alright will try that, thank you