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Gtk2Hs/Tutorials/TreeView

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Current revision (09:24, 1 September 2009) (edit) (undo)
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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!
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!
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module Main where
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module Main where
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{- an example how to select from a list
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{- an example how to select from a list
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not satisfactory yet:
not satisfactory yet:
- there should be a simpler way to render a simple list
- there should be a simpler way to render a simple list
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and it is very difficult to find which ones are
and it is very difficult to find which ones are
really needed for simple tasks
really needed for simple tasks
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-}
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import Graphics.UI.Gtk
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import Graphics.UI.Gtk.ModelView as Model
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-}
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main :: IO ()
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main = do
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import Char
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import Control.Monad
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import Data.IORef
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import Graphics.UI.Gtk
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-
 
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import Graphics.UI.Gtk.Gdk.Events
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import Graphics.UI.Gtk.ModelView as Model
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main :: IO ()
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main = do
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initGUI -- is start
initGUI -- is start
window <- windowNew
window <- windowNew
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list <- listStoreNew ["Vince", "Jhen", "Chris", "Sharon"]
list <- listStoreNew ["Vince", "Jhen", "Chris", "Sharon"]
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treeview <- Model.treeViewNewWithModel list
treeview <- Model.treeViewNewWithModel list
Model.treeViewSetHeadersVisible treeview True
Model.treeViewSetHeadersVisible treeview True
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-- there should be a simpler way to render a list!
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-- there should be a simpler way to render a list as the following!
col <- Model.treeViewColumnNew
col <- Model.treeViewColumnNew
Model.treeViewColumnSetTitle col "colTitle"
Model.treeViewColumnSetTitle col "colTitle"
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return ()
return ()
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oneSelection :: ListStore String -> Model.TreeSelection -> IO ()
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oneSelection :: ListStore String -> Model.TreeSelection -> IO ()
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oneSelection list tree = do
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oneSelection list tree = do
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sel <- Model.treeSelectionGetSelectedRows tree
sel <- Model.treeSelectionGetSelectedRows tree
let s = head (head sel)
let s = head (head sel)
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tree <- Model.treeSelectionGetTreeView tree
 
v <- Model.listStoreGetValue list s
v <- Model.listStoreGetValue list s
putStrLn $ "selected " ++ v
putStrLn $ "selected " ++ v

Current revision

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 Graphics.UI.Gtk
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 as the following!
   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
   mainGUI
   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
Retrieved from "http://www.haskell.org/haskellwiki/Gtk2Hs/Tutorials/TreeView"