Personal tools


From HaskellWiki

< Gtk2Hs | Tutorials
Revision as of 09:11, 1 September 2009 by Andrewufrank (Talk | contribs)

(diff) ← Older revision | Latest revision (diff) | Newer revision → (diff)
Jump to: navigation, search

I had much trouble with creating a simple selection from a list, lacking examples on the web i could find. Therefore i post here the solution I have working - it is not optimal and I would appreciate comments. I shows a simple list with four names and after clicking on one it says which one you selected. i hope it is useful for others!

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 Char

import Control.Monad

import Data.IORef

import Graphics.UI.Gtk

import Graphics.UI.Gtk.Gdk.Events

import Graphics.UI.Gtk.ModelView as Model

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!
   col <- Model.treeViewColumnNew
   Model.treeViewColumnSetTitle col "colTitle"
   renderer <- Model.cellRendererTextNew
   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  SelectionSingle
   Model.onSelectionChanged tree (oneSelection list tree)
   set window [ windowDefaultWidth := 100
               , windowDefaultHeight := 200
               , containerChild := treeview
   onDestroy window mainQuit
   widgetShowAll window
   return ()

oneSelection :: ListStore String -> Model.TreeSelection -> IO ()

oneSelection list tree = do

   sel <- Model.treeSelectionGetSelectedRows tree
   let s = head  (head sel)
   tree <- Model.treeSelectionGetTreeView tree
   v <- Model.listStoreGetValue list s
   putStrLn $ "selected " ++ v