Does GetAttributeChangedSignal() work for detecting if its children get changed?

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1

I want to detect if an instance’s children get changed. It is a folder named “Tower” that gets changed when a timer runs out. I have tried using Changed(), but it doesn’t work. I’m wondering if GetAttributeChangedSignal() would work for it.

This is what I tried doing but got an error:

game.Workspace.Tower:Changed(function()
	wait(1)
end)

If there is any other way to detect the change then please reply!

4 Likes
2

Changed is not a method, but rather, an event.

game.Workspace.Tower.Changed:Connect(function()
	wait(1)
end)
2 Likes
3

Something like this might work:

function setup_descendant_changed_listener(ancestor, callback)
    l
    local descendant_added_c
    
    local function setup_changed_listener(child)
        local changed_c = child.Changed:Connect(function(...)
            callback(child, ...)
        end)
        local ancestry_changed_c

        ancestry_changed_c = child.AncestryChanged:Connect(function()
            if not child:IsDescendantOf(ancestor) then
                ancestry_changed_c:Disconnect()
                if changed_c.Connected then
                   changed_c:Disconnect()
                end
            end
        end)
    end
    
    --Setup for existing descendants and any that are added later
    descendant_added_c = ancestor.DescendantAdded:Connect(setup_changed_listener)
    for _, d in pairs(ancestor:GetDescendants()) do
        setup_changed_listener(d)
    end
end

setup_descendant_changed_listener(game.Workspace.Tower, function(changed_child)
    print( ("%s was changed!"):format(changed_child.Name) )
end)

Can’t test it right now but let me know if it has problems

4

It works all right but since there are lots of descendants of the children of the folder, (there are models inside the folder, and the models and a lot more descendants.) I would make it look for just children that are changed/added.

2 Likes
5

I see, here’s a version that only listens for children changed events:

function setup_child_changed_listener(parent, callback)
	local changed_cs = {}

	local function setup_changed_listener(child)
		local changed_c = child.Changed:Connect(function(...)
			callback(child, ...)
		end)
		table.insert(changed_cs, changed_c)

		--Stop listening for Changed events if the child gets a different Parent
		local ancestry_changed_c
		ancestry_changed_c = child.AncestryChanged:Connect(function()
			if not child.Parent == parent then
				ancestry_changed_c:Disconnect()
				if changed_c.Connected then
					changed_c:Disconnect()
				end
			end
		end)
	end

	--Setup for existing children and any that are added later
	local child_added_c = parent.DescendantAdded:Connect(setup_changed_listener)
	for _, d in pairs(parent:GetDescendants()) do
		setup_changed_listener(d)
	end

	--Return a cleanup function that disconnects the callback from any Changed events
	return function()
		child_added_c:Disconnect() --Don't connect callback to any Changed event for future added children
		--Stop listening for Changed events for current children
		for _, c in pairs(changed_cs) do
			if c.Connected then
				c:Disconnect()
			end
		end
	end
end

It also returns a cleanup function so you can stop listening to these events again. Here’s a test script I used:

local cleanup
cleanup = setup_child_changed_listener(game.Workspace.Part, function(child, ...)
	print(child, ...)
	if child.Name == "Stop" then
		unbind()
	end
end)

It prints every time a child of workspace.A changes, but if a child is renamed to “Stop” (or if something called “Stop” is added as a child), it stops printing.