Date: Fri, 20 Aug 2004 14:53:24 +0200 (CEST)
Message-Id: <20040820.145324.41627916.andrieu at ijm.jussieu.fr>
To: mike at halcrow.us
Cc: lablgtk at kaba.or.jp
Subject: Re: Combo entry_completion?
From: Olivier Andrieu <andrieu at ijm.jussieu.fr>
In-Reply-To: <20040819152938.GA6894 at halcrow.us>
References: <20040819152938.GA6894 at halcrow.us>
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 Michael Halcrow [Thu, 19 Aug 2004]:
 > I am just learning Objective Caml, so if you feel inclined to
 > critique my ocaml coding style, please do so.
 > 
 > I am working on a project where I view records in a database.  I would
 > like the user to be able to search the contents of the data set based
 > on a person's name and display the record.  Here is what I have so far:
 > 
 > http://cvs.sourceforge.net/viewcvs.py/ldsdps/src_ocaml/ldsdps_stage.ml?rev=1.15&view=auto
 > 
 > Basically, I want this behavior:
 > 
 > As the user types into the entry widget of the combo widget, the first
 > element in the combo list for which the text typed so far matches is
 > auto-completed and highlighted, so that the next character typed
 > replaces the auto-completed remainder and re-does the auto completion.
 > Let's do an example:
 > 
 > Combo list contents: [ "abc"; "123"; "abcdef"; "abcxyz"; "abcxyzw" ]
 > Entry widget contents: ""
 > 
 > User enters the entry widget and types "a".  "abc" gets automatically
 > put into the widget.  The cursor is after the "a" and before the "b",
 > and "bc" is highlighted.  User types "b".  Contents are still "abc",
 > with the cursor after the "b" and before the "c", with "c"
 > highlighted.  User types "c".  Contents are "abc", with the cursor
 > after the "c" and nothing highlighted.  User types "x".  Now the
 > contents are "abcxyz", with the cursor after the "x" and before the
 > "y", with "yz" highlighted.  User hits "enter", and the search is made
 > for the record with "abcxyz" as the key, etc., etc.
 > 
 > Alternatively, I would like the combo box to be dropped down for the
 > entire process, and the contents of the entry widget matched against
 > the list, with the closest matching element highlighted.  As it
 > stands, I am hooking the activate signal, which is sent when the user
 > hits ``enter'', but that also drops down the combo box, which I don't
 > really want at that point...
 > 
 > I tried referencing entry_completion in my code, but I got that
 > run-time error that one gets when linking against the wrong version
 > of gtk (although I checked carefully, and I think I am linking
 > against gtk 2.4).  In any case, I'm not sure how to use
 > entry_completion to get this functionality.

If you get a runtime error (Failure "unsupported in GTK+ < ...") this
means that lablGTK was not compiled against 2.4 but against a previous
version. If lablGTK was compiled with 2.4 but your program is linked
with a previous version, you will get a linker error.

To use completion with a combo box entry, it goes somehow like this:

,----
| let make_combo_box_entry_with_completion packing strings =
|   let (combo, (model, column)) = GEdit.combo_box_entry_text ~strings ~packing () in
|   let entry = combo#entry in
|   let completion = GEdit.entry_completion ~model ~entry () in
|   completion#set_text_column column ;
|   (combo, entry, completion)
`----

-- 
   Olivier