gtk2hs: ListStore and TreeView example

listtest.hs

module Main where
 {- an example how to select from a list
   not satisfactory yet:
       - there should be a simpler way to render a simple list
       - i could not convert the model i got back to a list 
           from which to get the value
       
       - the interface offers a great number of functions 
           and it is very difficult to find which ones are 
           really needed for simple tasks
  -}
import Graphics.UI.Gtk
import Graphics.UI.Gtk.ModelView as Model
import Control.Monad.Trans

main :: IO ()
main = do
   initGUI       -- is start
   window <- windowNew
   list <- listStoreNew ["Vince", "Jhen", "Chris", "Sharon"]
   treeview <- Model.treeViewNewWithModel list
   Model.treeViewSetHeadersVisible treeview True
           -- there should be a simpler way to render a list as the following!
   col <- Model.treeViewColumnNew
   Model.treeViewColumnSetTitle col "colTitle"
   renderer <- Model.cellRendererTextNew

   listStoreAppend list "dkdk"
 

   Model.cellLayoutPackStart col renderer False
   Model.cellLayoutSetAttributes col renderer list
           $ \ind -> [Model.cellText := ind]
   Model.treeViewAppendColumn treeview col
   tree <- Model.treeViewGetSelection treeview
   Model.treeSelectionSetMode tree  SelectionBrowse --Multiple
   Model.onSelectionChanged tree (oneSelection list tree)
   vbox <- vBoxNew False 0 
   buttonAppend <- buttonNewWithLabel "Append"
   boxPackStart vbox treeview PackGrow 0 
   boxPackStart vbox buttonAppend PackNatural 0
   containerAdd window vbox
   
   buttonAppend `on` buttonActivated $  do 
     putStrLn "button clicked"
     addToList list "123"


   set window [ windowDefaultWidth := 100
               , windowDefaultHeight := 200
--               , containerChild := treeview
              ]
   onDestroy window mainQuit
   widgetShowAll window
   mainGUI
   return ()


addToList :: ListStore String -> String -> IO ()
addToList list str  = do 
   listStoreAppend list str
   return () 

oneSelection :: ListStore String -> Model.TreeSelection ->  IO ()
oneSelection list tree = do
   sel <- Model.treeSelectionGetSelectedRows tree
   let s = head  (head sel)
   v <- Model.listStoreGetValue list s
   putStrLn $ "selected " ++ v