How to "delay" the return of a function when its return value depends on an event ?

jalmince · June 2014

My function here below uses UrlLoader, but returns before the Event.complete strikes....

function GetHighScores()
 
	local url = "<a href="http://www.jalmince-lab.com/BallTrip/high_scores.php&quot" rel="nofollow">http://www.jalmince-lab.com/BallTrip/high_scores.php&quot</a>;
	local headers = { ["Content-Type"] = "application/x-www-form-urlencoded"}	
 
	local result = "" 
 
	local 	function onComplete(event)
				result = event.data
                        end			
	local loader = UrlLoader.new(url, UrlLoader.POST )
	loader:addEventListener(Event.COMPLETE, onComplete)	
 
	--- Need a "delay" here !!
	return(result)
end

Tried with a dummy loop " while not finished do end" before the return, setting finished=true in the event handler. But that freezes the player.

thanks for your help !
Jp

vitalitymobile · June 2014

Hi @jalmince,
You should call drawGUI function inside onComplete function

local 	function onComplete(event)
				result = event.data
drawGUI(result)
 
 
end

And then in code, you only need to call : GetHighScores()

jalmince · June 2014

thanks Vitalitymobile, but It doesn' t work.

vitalitymobile · June 2014

Hi @jalmince, maybe you can refer to Weather example (in Gideros setup folder ) to find out more...
onComplete is callback function, so when url load done, it's return result, and then you can pass it to other method to execute next ( that why you don't have to return in GetHighScores function)

jalmince · June 2014

thanks Vitality, but that is not the answer to my issue.
The weather example processes the xml result INSIDE the onComplete function.
Imagine now that you want to create a function, say "get_weather()", that returns the xml from yahoo, and that you want to call that fonction from another function; for example:

...
xml = get_weather()
"process" xml
....

How do you write the function to return the xml ONLY when the event has been processed ? yor function will look like that :

function get_weather()
....
   local xml
...  
   local function onComplete(event)	
      xml = XmlParser:ParseXmlText(event.data)
   end
...  
local loader = UrlLoader.new("<a href="http://xml.weather.yahoo.com/forecastrss/USCA0987.xml&quot" rel="nofollow">http://xml.weather.yahoo.com/forecastrss/USCA0987.xml&quot</a><img class="emoji" src="http://forum.gideros.rocks/resources/emoji/wink.png" title=";)" alt=";)" height="20" />
loader:addEventListener(Event.COMPLETE, onComplete)
...
return xml

and the bottom return is always reached before the event is processed, returning nil.

vitalitymobile · June 2014

I think loader and onComplete is async callback. If you really want get result when the event has been processed, you can show a loading dialog in the end of get_weather function and then in onComplete function, dispose dialog and process result?

Something like this will work

 
local function get_weather()
 
---- detail
end
 
local function process(xml)
 
---detail
 
end
 
local xml  = get_weather();
process(xml)
 
--->> change to async callback style
 
local function process(xml)
 
---detail
 
end
 
local function get_weather()
 
---- detail
  local function onComplete(event)	
     local xml = event.result;      
    process(xml)
   end
end
 
--- main entry
get_weather(); --- no need return here, when urlloader query data done, it is automatic call process

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How to "delay" the return of a function when its return value depends on an event ?

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How to "delay" the return of a function when its return value depends on an event ?

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