RosettaCodeData/Task/GUI-component-interaction/Haskell/gui-component-interaction-1.hs

27 lines
1.0 KiB
Haskell

import Graphics.UI.WX
import System.Random
main :: IO ()
main = start $ do
frm <- frame [text := "Interact"]
fld <- textEntry frm [text := "0", on keyboard := checkKeys]
inc <- button frm [text := "increment", on command := increment fld]
ran <- button frm [text := "random", on command := (randReplace fld frm)]
set frm [layout := margin 5 $ floatCentre $ column 2
[centre $ widget fld, row 2 [widget inc, widget ran]]]
increment :: Textual w => w -> IO ()
increment field = do
val <- get field text
when ((not . null) val) $ set field [text := show $ 1 + read val]
checkKeys :: EventKey -> IO ()
checkKeys (EventKey key _ _) =
when (elem (show key) $ "Backspace" : map show [0..9]) propagateEvent
randReplace :: Textual w => w -> Window a -> IO ()
randReplace field frame = do
answer <- confirmDialog frame "Random" "Generate a random number?" True
when answer $ getStdRandom (randomR (1,100)) >>= \num ->
set field [text := show (num :: Int)]