RosettaCodeData/Task/Simple-windowed-application/Haskell/simple-windowed-application.hs

31 lines
660 B
Haskell

import Graphics.UI.Gtk
import Data.IORef
main :: IO ()
main = do
initGUI
window <- windowNew
window `onDestroy` mainQuit
windowSetTitle window "Simple Windowed App"
set window [ containerBorderWidth := 10 ]
hbox <- hBoxNew True 5
set window [ containerChild := hbox ]
lab <- labelNew (Just "There have been no clicks yet")
button <- buttonNewWithLabel "Click me"
set hbox [ containerChild := lab ]
set hbox [ containerChild := button ]
m <- newIORef 0
onClicked button $ do
v <- readIORef m
writeIORef m (v+1)
set lab [ labelText := "There have been " ++ show (v+1) ++ " clicks" ]
widgetShowAll window
mainGUI