EventDispatcher:addEventListener(type, listener, data)

GregBUG

Sorry but i can't find a solution...

but a function defined as "listener" can be part of a class function and can call another class function?

... yes i'm not very clear ...

try to explain with some "stripped" code example:

-- my class CTNTVirtualPad = Core.class(Sprite)   -- called by listener functions... but got and error function CTNTVirtualPad:checkPad(event) print(event) end     --- LISTENER FUNCTIONS ---- ----------------------- -- Touches begin event -- ----------------------- function CTNTVirtualPad:onTouchesBegin(event) self:checkPad(Event.TOUCHES_BEGIN) end   ----------------------- -- Touches move event -- ----------------------- function CTNTVirtualPad:onTouchesMove(event) self:checkPad(Event.TOUCHES_MOVE) end   ----------------------- -- Touches end event -- ----------------------- function CTNTVirtualPad:onTouchesEnd(event) self:checkPad(Event.TOUCHES_END) end   --- DEFINE EVENT LISTENER ----------------------- -- start Virutal Pad and events -- ----------------------- function CTNTVirtualPad:start() stage:addEventListener(Event.TOUCHES_BEGIN, self.onTouchesBegin) stage:addEventListener(Event.TOUCHES_MOVE, self.onTouchesMove) stage:addEventListener(Event.TOUCHES_END, self.onTouchesEnd) end

when you try to touch the screen of device you get this error:

tntvirtualpad.lua:204: attempt to call method 'checkPad' (a nil value)
stack traceback:
tntvirtualpad.lua:204: in function

but checkPad is not null!!

ahhhhrrrrgggg!

the event is raised correctly but seems that my function checkPad is not defined (nil)

why? (

EDIT:

obviously if checkPad is defined as "local function" the code works fine...

ex:

local function checkPad(event) print(event) end

:-?

chipster123

I think you need the additional argument 'self' to the addEventListener() call.

--- DEFINE EVENT LISTENER ----------------------- -- start Virutal Pad and events -- ----------------------- function CTNTVirtualPad:start() stage:addEventListener(Event.TOUCHES_BEGIN, self.onTouchesBegin, self) stage:addEventListener(Event.TOUCHES_MOVE, self.onTouchesMove, self) stage:addEventListener(Event.TOUCHES_END, self.onTouchesEnd, self) end

GregBUG

doh! yes!

thanks chipster123!!!

i lost some hours around this error...

but my eyes not see this *BIG* and *stupid* code error...

mmm it's better i go to sleep!! doh!!!

thanks again chipster!

Magnusviri

I keep making the mistake of typing stage:addEventListener(Event.TOUCHES_BEGIN, Object:onTouchesBegin) and produce similar errors.  Very aggravating but after doing it enough times I think I've learned to not do it anymore.

GregBUG

:P

petec

I spent most of yesterday doing exactly the same with self.world:addEventListener(Event.BEGIN_CONTACT,self.onBeginContact)
and driving myself crazy. I was very glad to see @chipster123's post above (thanks!).

I just hope I remember next time I need it. Note to self....