Attempt To Index Nil With 'WaitForChild`

Help and Feedback Scripting Support
#1

Hi, I’m trying to make a shop system. I have a script in ServerScriptService, but I don’t know how to address the players gui. The script is shown below.

local gui = game.Players.LocalPlayer:WaitForChild("PlayerGui"):WaitForChild("ScreenGui")

local player = game.Players.LocalPlayer

local playerStats = player:WaitForChild("leaderstats")

local playerGold = playerStats:WaitForChild("Gold")

local ReplicatedStorage = game:GetService("ReplicatedStorage")

local remoteEvent = ReplicatedStorage:WaitForChild("RemoteEvent1")

local Owned = gui.Shop.Stats.Frame.LongStick.Owned

Owned.Value = false

local function purchasFunc(player, item)

if playerGold.Value >= 100 and Owned.Vlaue == false then

playerGold.Value = playerGold.Value - 100

Owned.Value = true

end

end

remoteEvent.OnServerEvent:Connect(purchasFunc)

If I did local gui = game.StarterGui.ScreenGui etc. then it would change the gui for everyone. (I think)

Please correct me if I’m wrong.

2 Likes
#2

You can’t access LocalPlayer from the server. This only works in LocalScripts. That’s going to be the cause of your error.

More specifically (not the cause of your error, but still a concern), you shouldn’t be trying to update user interfaces from the server anyway. It makes for slow, unresponsive user interfaces and is poor practice. Read more about best practice on this article about the Client-Server Model

5 Likes
#3

When the player buys the thing from the shop I want a boolValue to be set to true. Would I send a remote function back to the player to change the boolValue to true?

#4

The recommended way to do something like that is through a client-server model (what I linked). I’d read it to get a good impression of how to do this kind of thing in the future.

Example pseudocode:

-- PirateServer.lua (Server Script)

local ReplicatedStorage = game:GetService("ReplicatedStorage")

local RemoteEvent = ReplicatedStorage:WaitForChild("RemoteEvent")

RemoteEvent.OnServerEvent:Connect(function(Player, Type, Item)
    if Type == "Buy" then
        if Item == "Vitamin C" and Player.Coins.Value >= VitaminCPrice then
            -- Set Values
            Player.HasScurvy.Value = false
            Player.Coins.Value = math.max(Player.Coins.Value - VitaminCPrice, 0)
            RemoteEvent:FireClient(Player, Player.Coins.Value)
        end
    end
end)

-- PirateClient.lua (LocalScript)

local ReplicatedStorage = game:GetService("ReplicatedStorage")

local RemoteEvent = ReplicatedStorage:WaitForChild("RemoteEvent")

RemoteEvent.OnClientEvent:Connect(function(Coins)
    print(("Arr! I now have %i coins!"):format(Coins))
    CoinsValue.Text = ("$%i"):format(Coins)
end)

BuyButton.MouseButton1Click:Connect(function()
    RemoteEvent:FireServer("Buy", "Vitamin C")
end)

Here, the Client runs the interface, and the server handles the security & processing :slight_smile:

2 Likes
#5

I’m trying to update the player’s value in the ServerScript but it says I’m trying to index nil with 'WaitForChild`

local player = game.Players.LocalPlayer

local ReplicatedStorage = game:GetService("ReplicatedStorage")
local remoteEvent = ReplicatedStorage:WaitForChild("RemoteEvent1")
local playerStats = player:WaitForChild("leaderstats")
local playerGold = playerStats:WaitForChild("Gold")



local function purchasFunc(player, item)
	if playerGold.Value >= 100 and player.Owned.Value == false then 
		playerGold.Value = playerGold.Value - 100 
 
	end
end

remoteEvent.OnServerEvent:Connect(purchasFunc)
#6

Is it in a LocalScript? 30 chars

#7

No

This text will be blurred

#8

To answer this:
No. The StarterGui is copied to every player and will not affect the PlayerGui.

#9

I would use a LocalScript for that.

#10

But it’s in server script storage and I want all the players to see that the player’s coins was reduced after buying it

#11

Then you could fire a RemoteEvent to the server when a player buys an item, and then, when that event is fired, fire another RemoteEvent to all clients by using the RemoteEvent:FireAllClients() function.

You can’t call LocalPlayer on ServerScripts

I assume you already make use of a datastore system, you could create a table system in a ModuleScript in ServerScripts/ServerStorage and create a function with the player and amount argument to add/reduce money from their balance.

#12

Spelling error there
Just if you didn’t know. It couldve affected your script!

#13

As I stated in my original post, you can’t reference “LocalPlayer” on the server. Think about it - the Server doesn’t have a “Local Player” - only the client.

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