Scene Manager and function calls. self.<variable> is nil but shouldn't be!

joelghill

I'm trying to display scores retrieved from an online leaderboard. The scoreboard is a scene within the scene manager. The relevant code snippets are below:

scores = Core.class(Sprite)     function scores:init() --setup format self.online = online self.scores = false -- a boolean value. false when score boards not retreived self.count = 0 -- arbitrary counter self.y = 0-- important variable I need later   self.scoreBoard = Sprite.new()     self:addEventListener("enterEnd", self.onEnterEnd, self) self:addEventListener("exitBegin", self.onExitBegin, self) self:addEventListener("enterBegin", self.onEnterBegin, self) self:addEventListener("exitEnd", self.onExitEnd, self) end

Early in scene I create the class and declare variables. Notice self.y is set to zero and self.scoreBoard is a Sprite

Later, in

function scores:onEnterBegin()

I call this function:

function scores:getScores(gm, leaderboard, a) --   local leader = leaderboard -- test board local format = "json" -- xml, json local auth = a     local method = "UrlLoader.GET" local headers = gm.headers local body = "auth_token="..auth local url = "<a href="https://api.gameminion.com/leaderboards/"..leader.."/scores."..format.."?"..body" rel="nofollow">https://api.gameminion.com/leaderboards/"..leader.."/scores."..format.."?"..body</a>   print(body)   self.info = TextField.new(nil, "loading...") self.info:setPosition(380, 240) self.info:setScale(3) --self:addChild(self.info)   function self.onComplete(event) --self:removeChild(info) print("data retrieved") local t = Json.Decode(event.data) print(t[1].username) --> joelghill -- ADD SCORES TO SCREEN print(#t) for i = 1, #t, 1 do   --adds a new textfield as a child local newText = TextField.new(nil, string.format("%i.", i)) --, self.highScore:getName(i) newText:setScale(3) newText:setTextColor(0xffffff) newText:setY(y) newText:setX(10) --y = y + newText:getHeight() + 10 self.scores.scoreBoard:addChild(newText)   newText = TextField.new(nil, string.format( "%.1fm", t[i].value)) newText:setScale(3) newText:setTextColor(0xffffff) newText:setY(self.y) newText:setX(200 + self.x - newText:getWidth() ) --y = y + newText:getHeight() + 10 self.scoreBoard:addChild(newText)   newText = TextField.new(nil, string.format("%s",t[i].username )) newText:setScale(3) newText:setTextColor(0xffffff) newText:setY(scores.y) newText:setX(600 - newText:getWidth() ) scores.y = scores.y + 40 --print(y) self.scoreBoard:addChild(newText) print(self.scoreBoard:getHeight()) end   end   function self.onError() --info:setText("error") print("error in getting scoress") --add error message to leaderboard end   function self.onProgress(event) print("progress: " .. event.bytesLoaded .. " of " .. event.bytesTotal) end   self.loader = UrlLoader.new(url, UrlLoader.GET, headers, body) -- , body   self.loader:addEventListener(Event.COMPLETE, self.onComplete) self.loader:addEventListener(Event.ERROR, self.onError) self.loader:addEventListener(Event.PROGRESS, self.onProgress)     end

I get an error indicating that self.y is a nil value (the one used in the for-loop) , and if I replace that with an actual number, I get an error saying that self.scoreBoard is nil (also the one within the for-loop) even though I have it declared previously.

I believe this has something to do with the naming conventions I am using. I have no idea on how to go about using "self.y" within a function that is within a function, that is within a scene :S

Where did I go wrong here?

joelghill

Update:

This entire block of code now magically works. I'm not exactly sure what I did to make it work though :S (I think I changed a variable from scores. to self.)

I suppose if anyone has anything to add on the subject, feel free to bring it up, but I've solved my problem... somehow.

zaniar

self.scores.scoreBoard:addChild(newText)

should be

self.scoreBoard:addChild(newText)

,

newText:setY(scores.y)

should be

newText:setY(self.y)

and

scores.y = scores.y + 40

should be

self.y = self.y + 40

you are working inside "scores" class. So if you want to refer to this class' instance, use "self" instead of "scores". "scores" is global variable