Your code is incorrect. You must widgetShowAll (passing the parent of the
affected widget) after creating a widget in order for it to be shown. You
don't show the label after creating it on a button press event so therefor
it does not get shown.
Timothy
---------- Původní zpráva ----------
Od: Rouan van Dalen <rvda...@yahoo.co.uk>
Datum: 5. 10. 2012
Předmět: [Gtk2hs-devel] Possible bug in gtk2hs?
"
Hi everyone,
(I am using GHC 7.4.1 x86, Gtk2hs 0.12.3, on win7 x64)
I am trying to add a Label with some text to the contentArea of an InfoBar,
but I am not getting the results I expect. If I use code to add the label
to the
InfoBar outside of a button-activate signal, the label is added fine.
If I use the exact same code as part of a button-activate signal, the label
is NOT
added.
Is this a bug in Gtk2hs? Or am I doing something wrong here?
Here is an isolated sample program that can be used to reproduce the error:
================================================
{-# LANGUAGE RecordWildCards #-}
module Main where
import Control.Concurrent
import Graphics.UI.Gtk(http://Graphics.UI.Gtk)
main = do
-- init GTK+ engine
initGUI
-- Every so often, we try to run other threads.
timeoutAddFull (yield >> return True) priorityDefaultIdle 100
-- show the main app window
widgetShowAll =<< mkWindow
-- Run the GTK+ main loop; exits after GUI is done
mainGUI
-- constructor for new window
mkWindow :: IO Window
mkWindow = do
(window, btnSave, btnCancel, ibarAlert) <- createAndConfigureWindow
-- add a default Label to the InfoBar
contentArea2 <- infoBarGetContentArea ibarAlert
lbl2 <- labelNew $! Just "Unsaved Changes"
boxPackStart (castToHBox contentArea2) lbl2 PackNatural 5
----------------------------------------------------------------
-- EVENTS
----------------------------------------------------------------
onDestroy window mainQuit
-- hook up the btnSave_onClick event handler
--btnSave `on` buttonActivated $! btnSave_onClick window ibarAlert
btnSave `on` buttonActivated $
do putStrLn "saving ..."
-- try to add another label to the InfoBar, BUT THIS DOES NOT
SEEM TO WORK
contentArea <- infoBarGetContentArea ibarAlert
lbl <- labelNew $! Just "Saving Completed"
boxPackStart (castToHBox contentArea) lbl PackNatural 5
-- hook up the btnCancel_onClick event handler
btnCancel `on` buttonActivated $! btnCancel_onClick window
return window
{------------------------------------------------------------------------
--------------------------------------
-- EVENT HANDLERS
-------------------------------------------------------------------------
-------------------------------------}
-- | event handler that fires when user clicks the Save button
btnSave_onClick :: Window -> InfoBar -> IO ()
btnSave_onClick _ ibarAlert = do
putStrLn "saving ..."
contentArea <- infoBarGetContentArea ibarAlert
lbl <- labelNew $! Just "Saving Completed"
boxPackStart (castToHBox contentArea) lbl PackNatural 5
return ()
-- | event handler that fires when user clicks the Cancel button
btnCancel_onClick :: Window -> IO ()
btnCancel_onClick window = do
widgetDestroy window
return ()
-- creates a new window and adds all the necessary controls to the window
createAndConfigureWindow = do
-----------------------------------------------
-- set up window
-----------------------------------------------
window <- windowNew
set window [windowDefaultWidth := 800
,windowDefaultHeight := 400
,containerBorderWidth := 5]
vb <- vBoxNew False 0
containerAdd window vb
-----------------------------------------------
-- set up info-panel
-----------------------------------------------
infoBarAlert <- infoBarNew
set infoBarAlert [infoBarMessageType := MessageOther]
-----------------------------------------------
-- set up buttons
-----------------------------------------------
hbButtons <- hBoxNew False 0
btnSave <- buttonNewWithLabel "Save"
btnCancel <- buttonNewWithLabel "Cancel"
boxPackStart hbButtons infoBarAlert PackGrow 5
boxPackStart hbButtons btnSave PackNatural 5
boxPackStart hbButtons btnCancel PackNatural 5
-----------------------------------------------
-- PACK WINDOW
-----------------------------------------------
boxPackStart vb hbButtons PackNatural 5
return (window, btnSave, btnCancel, infoBarAlert)
================================================
The code in the mkWindow function is the main thing to look at. I add a
label to the InfoBar
and use the same code for the btnSave-activate signal, but the 2nd label
does not get added.
Regards
Rouan
"------------------------------------------------------------------------------
Don't let slow site performance ruin your business. Deploy New Relic APM
Deploy New Relic app performance management and know exactly
what is happening inside your Ruby, Python, PHP, Java, and .NET app
Try New Relic at no cost today and get our sweet Data Nerd shirt too!
http://p.sf.net/sfu/newrelic-dev2dev
_______________________________________________
Gtk2hs-devel mailing list
Gtk2hs-devel@lists.sourceforge.net
https://lists.sourceforge.net/lists/listinfo/gtk2hs-devel
