Nested loading

loves_oi

I'M using nested loading function and it confuses me . It worked for one loading .Then i put a loading function for putting image to screen. It should load both the text and picture and they should be visible on screen. But loading of picture doesn't work.Why doesn't it work?

results = Core.class(Sprite) function results:init(params)   local screen = Bitmap.new(Texture.new("resources/images/opt_back.png")) self:addChild(screen) screen:setPosition(0,0) p = 2 local a = 1 mySize = table.getn(params) k=1 tit = "" q = ""       function onComplete2(p, event) q = event.data   the[p] = TextField.new(nil, "hello") the[p]:setPosition(100,50 +a*50) the[p]:setTextColor(0x007B25) the[p]:setScaleX(3)the[p]:setScaleY(3)   ------------------------------------------ if ( tit == "xx") then   local picLoader = UrlLoader.new("<a href="http://localhost/bird.png&quot" rel="nofollow">http://localhost/bird.png&quot</a><img class="emoji" src="http://forum.giderosmobile.com/resources/emoji/wink.png" title=";)" alt=";)" height="20" />   local function onComplete3(event) local out = io.open("|D|image.png", "wb") out:write(event.data) out:close()   local b = Bitmap.new(Texture.new("|D|image.png")) b:setPosition(10,10) stage:addChild(b) -----HERE IS NOT OKAY.PNG FILE DOESN'T LOAD end   picLoader:addEventListener(Event.COMPLETE, onComplete3) picLoader:addEventListener(Event.ERROR, onError) picLoader:addEventListener(Event.PROGRESS, onProgress) ---------------------------------------------------------------   end the[p]:setText(params[p+1] .. q) print("q : " .. q)   stage:addChild(the[p]) -- HERE IS OKAY a = a + 1   end   while(k < mySize+1) do if (params[k] ==true) then p=k local loader2 = UrlLoader.new(params[k+2]) loader2:addEventListener(Event.COMPLETE, onComplete2, p) end k = k+3 end end

Thanks in advance

techdojo

The use of closures and nested functions is NOT easy to get your head round - especially for the beginning lua programmer. To be honest in this case there is NO need to add that level of complexity, also your actually wasting a LOT more memory and resources as each time round the loop your actually CREATING a whole new set of functions and retaining references to upvalues.

Remember K.I.S.S.

loves_oi

Actually,the code doesn't give any error and it works. But picture isn't visible bcs it isn't loaded.Only text is visible.
If i don't not use nested functions , what else can i do to perform it? Any idea?
Thanks a lot

techdojo

IF the code worked then you wouldn't have posted with a problem - it might work the first time but it's on the subsequent runs your getting an issue.

Move ALL of your onComplete functions OUTSIDE of (preferably before) the :init function and make them local like so

local function onComplete2(self,event) .... end

Then change your addEventListener to something like

loader2:addEventListener(Event.COMPLETE, onComplete2, self)

NOTE : the self at the end - then when onComplete is called the first parameter (self) will actually reference the correct instance of results - you can prove this by "print(self)" in both cases and you'll get a "table : xxxxxxxx" where xxxxxxxx is the address of the table in memory and will be the same in both functions.

You can then freely (and safely) access any variables defined in results:init() and you can be sure your looking at the correct instance.

loves_oi

Ok. I did it and it worked perfectly. Thanks.
local picLoader = UrlLoader.new(URL)
although i send two different values of URL , it will load the same URL for them.
But when i select two checkbox ,
Moskow MoskowPicture
Madrid MadridPicture
in screen , it will look like as:
Moskow MoskowPicture
Madrid MoskowPicture
in screen.
When i run the same code without changing anything ,it may look like :
Moskow MadridPicture
Madrid MadridPicture
However , in all attempts , the right url of the Moskow and Madrid comes .
This is the code:

results = Core.class(Sprite) function results:init(params)   local screen = Bitmap.new(Texture.new("resources/images/opt_back.png")) self:addChild(screen) screen:setPosition(0,0)   the = {} p = 2 local a = 1 mySize = table.getn(params) k=1 tit = "" q = ""   local function onComplete3(p,event) local out = io.open("|D|image.png", "wb") out:write(event.data) out:close()   local b = Bitmap.new(Texture.new("|D|image.png")) b:setPosition(50,50+p*40) stage:addChild(b) end     function onComplete2(p, event) q = event.data   the[p] = TextField.new(nil, "hello") the[p]:setPosition(100,50 +a*50) the[p]:setTextColor(0x007B25) the[p]:setScaleX(3)the[p]:setScaleY(3)   i=1 while (not(string.find(string.sub(q,i,i), "\t"))) -- take the tit do tit = tit .. string.sub(q,i,i) i = i + 1 end   if (string.find(string.sub(q,i,i), "\t")) then i = i + 1 end print("tit : " .. tit)     if ( tit == "xx") then   --TIT IS OBTAINED   print ("URL is :" .. tit) -------TİT is holding the url of the cities which will be loaded   local picLoader = UrlLoader.new(tit) ---This line works wrongly. It doesn't load the second URL. It loads the same photo although this line works two times and values of tit are different. tit="" picLoader:addEventListener(Event.COMPLETE, onComplete3,p) end stage:addChild(the[p]) a = a + 1 end   while(k < mySize+1) do if (params[k] ==true) then p=k local loader2 = UrlLoader.new(params[k+2]) loader2:addEventListener(Event.COMPLETE, onComplete2, p) end k = k+3 end end

output is :
URL is :http://localhost/moscow.png
URL is :http://localhost/madrid.png

However , in all attempts , when i checked moscow and madrid ,
in screen , it will look like as:
Moskow MoskowPicture
Madrid MoskowPicture

When i run the same code without changing anything ,it may look like :
Moskow MadridPicture
Madrid MadridPicture

zvardin

@loves_oi: I'm rather confused looking at the code in this conversation. Your response to @techdojo was you followed his advice, but the code you posted does not remove the nested functions from the init functions at all. I would also recommended better variable names for reading your code because it may become hard to maintain your code as it grows. It's great to use short variables when you're just using them quick and tossing them, but to persist so many shorthand variables can make it pretty hard to read the code.

There's also some things, I'm not sure why you would do the way you're doing and I wonder if maybe you should look over some general Lua material (I've used http://www.lua.org/pil/index.html quite a bit). I'm rather new to some of this myself and I realize there can be a lot to take in.

It's really hard to narrow down what's going on with what you've provided and some examples of what I feel like might be oddities are:

For instance your comment here:

---This line works wrongly. It doesn't load the second URL. It loads the same photo although this line works two times and values of tit are different.

This is inside an if statement checking tit=="xx", so your code block should be ensuring the value is the same.

Your 'the' table will have a lot of random holes because it looks like the parameter your passing is every 3rd parameter, but you're using the index from the params to pass into your 'the' table. (ie: you will have values at the[1], the[4] etc.)