How do you make a msgbox that will return true/false if the player chooses yes/no?
--Module (In ReplicatedStorage) --
local module = {}
module.showMSG = function(msgGUI) --< Inside the msgGUI, there's a textbutton called yes and a textbutton called no.
msgGUI.Enabled = true
msgGUI.Yes.MouseButton1Click:Connect(function() return true end)
msgGUI.No.MouseButton1Click:Connect(function() return false end)
end
return module
---local script (Descendant of PlayerGui) --
local module = require(game:GetService("ReplicatedStorage").Module)
script.Parent.MouseButton1down:Connect(function()
local processedModule = module.showMSG(game.Players.localPlayer.PlayerGui:FindFirstChild("msgbox"))
if processedModule == true then
print("Yahoo!")
else
print("Oh Noes!")
end
end)
When I tested it out, it kept returning false when I called the module, when I did not even press any button. Is there a way to fix this?
Thank you.
1 answer
See this thread about returning values that do not yet exist.
The return on line 7 returns from the function on line 7, not the showMSG function.
You can't forcibly return from another function, because that function may no longer be running (or may be recursive, etc...)
There are roughly three broad options:
1. Blocking
Don't return until you have an answer.
This is a little awkward to do in ROBLOX for this particular case, but it's possible and not too bad with BindableEvents.
function showMSG(gui)
gui.Enabled = true
local event = Instance.new("BindableEvent")
-- Listen for clicks
local yesEvent = gui.Yes.MouseButton1Click:Connect(function()
event:Fire(true)
end
local noEvent = gui.No.MouseButton1Click:Connect(function()
event:Fire(false)
end
-- Await the first click
local answer = event.Event:Wait()
-- Stop caring about clicks to the buttons
yesEvent:Disconnect()
noEvent:Disconnect()
-- Return the answer (`true` for Yes, `false` for No)
return answer
end
local answer = showMSG(foo)
print("Player said", answer)
2. Promise / Future
Return an object that can be used to produce an answer.
The simplest way to do this is to return an event:
function showMSG(gui)
gui.Enabled = true
local event = Instance.new("BindableEvent")
-- Listen for clicks
local noEvent, yesEvent
yesEvent = gui.Yes.MouseButton1Click:Connect(function()
event:Fire(true)
yesEvent:Disconnect()
noEvent:Disconnect()
end
noEvent = gui.No.MouseButton1Click:Connect(function()
event:Fire(false)
yesEvent:Disconnect()
noEvent:Disconnect()
end
-- Return an event.
-- The caller of showMSG() must either :Wait() or :Connect()
-- to get the result
return event.Event
end
local answer = showMSG(foo):Wait()
print("Player said", answer)
3. Callback / Continuation
When you invoke showMSG, tell it to contact you later.
This is usually the least convenient way to write code because it leads to lots of functions nested into each other, but it is an option.
function showMSG(gui, callback)
gui.Enabled = true
local event = Instance.new("BindableEvent")
-- Listen for clicks
local noEvent, yesEvent
yesEvent = gui.Yes.MouseButton1Click:Connect(function()
yesEvent:Disconnect()
noEvent:Disconnect()
callback(true)
end
noEvent = gui.No.MouseButton1Click:Connect(function()
yesEvent:Disconnect()
noEvent:Disconnect()
callback(false)
end
end
showMSG(foo, function(answer)
print("Player said", answer)
end)