[Haskell-beginners] wxHaskell: add an external event from another thread

[Tilmann]

Hi,
this post might be helpful. 
http://snipplr.com/view/17538/wxhaskell-multithread--custom-event-example/

I needed something similar and came up with this. As far as I know there 
is now wxhaskell internal way of doing this.

import Graphics.UI.WX
import Graphics.UI.WXCore
import Control.Concurrent

eventId :: Int
eventId = wxID_HIGHEST + 2

main :: IO ()
main = do
   chan <- newChan
   forkIO $ externalEventLoop chan
   start $ gui chan

externalEventLoop :: Chan String -> IO ()
externalEventLoop chan = do
   writeChan chan "foobar"
   threadDelay $ 10 ^ 6
   externalEventLoop chan

gui :: Chan String -> IO ()
gui chan = do
   vCmd <- newEmptyMVar
   f <- frame []
   st <- textCtrl f []
   forkIO $ eventLoop eventId chan vCmd f
   evtHandlerOnMenuCommand f eventId $ takeMVar vCmd >>= \text -> 
appendText st $ text ++ "\n"
   set f [layout := fill $ minsize (Size 100 100) $ widget st]

eventLoop :: Int -> Chan String -> MVar String -> Frame () -> IO ()
eventLoop eventId chan vCmd f = do
   content <- readChan chan
   putMVar vCmd content
   e <- commandEventCreate wxEVT_COMMAND_MENU_SELECTED eventId
   evtHandlerAddPendingEvent f e
   eventLoop eventId chan vCmd f





Am 07.01.16 um 22:27 schrieb Puck:
> Hello all,
>
> how is it possible to process external events, for example a
> succeeded getLine or a takeMVar with its values in the wxHaskell
> framework?
>
> The reason is, that I want to connect a erlang node to wxHaskell.
>
> I have found the functions
> Graphics.UI.WX.Events.newEvent :: String -> (w -> IO a) -> (w -> a ->
> IO ()) -> Event w a
> "Create a new event from a get and set function."
>
> Beside from, that I don't know what the get and set function shall do, I
> don't know, how I can add the new event to the event-loop of wx, and
> when it "fires".
>
> Do you know any possibilities?
>
> Thank you in advance
> _______________________________________________
> Beginners mailing list
> Beginners at haskell.org
> http://mail.haskell.org/cgi-bin/mailman/listinfo/beginners
>