To: lablgtk at math.nagoya-u.ac.jp
Subject: How to make column headers in a tree view clickable for sorting?
From: David MENTRE <dmentre at linux-france.org>
Organization: none
Date: Tue, 14 Jun 2005 23:21:00 +0200
Message-ID: <87vf4gy6rn.fsf at linux-france.org>
MIME-Version: 1.0
Content-Type: text/plain; charset=us-ascii

Hello,

In my program, I'm following sortable.ml example as found in Lablgtk2
Tree View Tutorial to make sortable columns. However, in the example,
one can't change sort order by clicking on column headers. How can I do
that?

Here is sortable.ml as found in the tutorial:

(* $Id: sortable.ml,v 1.1 2004/09/18 00:44:44 shoh Exp $ *)
(* file: sortable.ml *)

open GTree

let cols = new GTree.column_list
let col_name = cols#add Gobject.Data.string
let col_year_born = cols#add Gobject.Data.uint

let create_and_fill_model () =
  let liststore = GTree.list_store cols in

  (* Append a row, and fill it with some data *)
  let append (name, year_born) =
    let row = liststore#append () in
    liststore#set ~row ~column:col_name name;
    liststore#set ~row ~column:col_year_born year_born
  in
  List.iter append [
    ("Abel", 1963);
    ("Park", 1971);
    ("Lee", 1930);
  ];

  liststore

let compare a b =
  if a < b then -1
  else if a > b then 1
  else 0

let sort_by_name (model:#GTree.model) row1 row2 =
  let name1 = model#get ~row:row1 ~column:col_name in
  let name2 = model#get ~row:row2 ~column:col_name in
  compare name1 name2

let sort_by_year_born (model:#GTree.model) row1 row2 =
  let year1 = model#get ~row:row1 ~column:col_year_born in
  let year2 = model#get ~row:row2 ~column:col_year_born in
  compare year1 year2
  
let create_list_and_view ~packing () =
  let liststore = create_and_fill_model () in

  liststore#set_sort_func col_name.index sort_by_name;
  liststore#set_sort_func col_year_born.index sort_by_year_born;

  (* set initial sort order *)
  liststore#set_sort_column_id col_name.index `ASCENDING;

  let view = GTree.view ~model:liststore ~packing () in

  let renderer_text = GTree.cell_renderer_text [] in
  (* create tree view column and pack cell renderer into tree view column *)
  let col = GTree.view_column ~title:"Name"
      ~renderer:(renderer_text, [("text", col_name)]) () in
  (* pack tree view column into tree view *)
  view#append_column col;

  (* Column #2 *)
  let renderer_text = GTree.cell_renderer_text [] in
  (* create tree view column and pack cell renderer into tree view column *)
  let col = GTree.view_column ~title:"Year Born"
      ~renderer:(renderer_text, [("text", col_year_born)]) () in
  (* pack tree view column into tree view *)
  view#append_column col;

  view

let main () =
  let window = GWindow.window ~title:"Sortable" ~border_width:10 () in
  window#connect#destroy ~callback:GMain.Main.quit;
  create_list_and_view ~packing:window#add ();
  window#show ();
  GMain.Main.main ()

let _ = Printexc.print main ()

-- 
pub  1024D/A3AD7A2A 2004-10-03 David MENTRE <dmentre@linux-france.org>
 5996 CC46 4612 9CA4 3562  D7AC 6C67 9E96 A3AD 7A2A