3rd party widgets with qtHaskell (Marble)
Hi, I know this isn't a qtHaskell list, but I don't think there is one. Was wondering if anyone has any ideas on the below. Basically I'm trying to control a Marble (Map software) Qt widget from qtHaskell. So I've mocked up a very simple user interface in Qt Designer (1 form, 1 Marble widget). I can load this up and display it fine in Haskell, but as soon as I try to interrogate the widget I get a seg fault (eg qObjectProperty) My guess is that the call to findChild, although it executes OK it is not producing a valid QObject - probably casting to Marble::MarbleWidget* it crux of the problem. I can get this working using standard Qt Widgets (just like the examples show from qtHaskell), so I know the method is sound - although calling 3rd party widgets like this may be ambitious or impossible. I recognise this is a fairly broad query! Has anyone tried anything similar? Is it even possible to do this in qtHaskell as I'm proposing? I'm a Qt novice, so it may well be that I've misunderstood qtHaskell. Cheers, Phil. Using: GHC 6.12.1 / QT4.5 / Marble 0.8 / Ubuntu 9.04 module Main where import Qtc main :: IO () main = do app <- qApplication () rok <- registerResource "marble.rcc" loader <- qUiLoader () uiFile <- qFile ":/marble.ui" open uiFile fReadOnly ui <- load loader uiFile close uiFile () ui_map <- findChild ui ("Marble::MarbleWidget*", "MarbleWidget") sc <- qObjectProperty ui_map "showCompass" qshow ui () ok <- qApplicationExec () return ()
This something you are afaik able to do. I'm cc'ing David (qthaskell's author). On Wed, Mar 10, 2010 at 1:59 AM, Philip Beadling < phil.beadling@googlemail.com> wrote:
Hi,
I know this isn't a qtHaskell list, but I don't think there is one.
Was wondering if anyone has any ideas on the below.
Basically I'm trying to control a Marble (Map software) Qt widget from qtHaskell.
So I've mocked up a very simple user interface in Qt Designer (1 form, 1 Marble widget).
I can load this up and display it fine in Haskell, but as soon as I try to interrogate the widget I get a seg fault (eg qObjectProperty)
My guess is that the call to findChild, although it executes OK it is not producing a valid QObject - probably casting to Marble::MarbleWidget* it crux of the problem.
I can get this working using standard Qt Widgets (just like the examples show from qtHaskell), so I know the method is sound - although calling 3rd party widgets like this may be ambitious or impossible.
I recognise this is a fairly broad query! Has anyone tried anything similar? Is it even possible to do this in qtHaskell as I'm proposing?
I'm a Qt novice, so it may well be that I've misunderstood qtHaskell.
Cheers,
Phil.
Using: GHC 6.12.1 / QT4.5 / Marble 0.8 / Ubuntu 9.04
module Main where
import Qtc
main :: IO () main = do app <- qApplication () rok <- registerResource "marble.rcc" loader <- qUiLoader () uiFile <- qFile ":/marble.ui" open uiFile fReadOnly ui <- load loader uiFile close uiFile ()
ui_map <- findChild ui ("Marble::MarbleWidget*", "MarbleWidget") sc <- qObjectProperty ui_map "showCompass"
qshow ui () ok <- qApplicationExec () return ()
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-- Alp Mestanogullari http://alpmestan.wordpress.com/ http://alp.developpez.com/
On Wed, 2010-03-10 at 11:22 +0100, Alp Mestanogullari wrote:
This something you are afaik able to do.
I'm cc'ing David (qthaskell's author).
Thanks for the reply. I've worked it out.
The below code demonstrates getting and setting a property from a marble
widget.
I'm a little surprised it worked. If my C++ is right what I've done
here is dynamically cast the Marble widget as it's Qt parent.
This of course is fine, but given that longitude() is not a virtual
function on the parent, I'd to have to cast as the child to access this
function - my code shouldn't have scope of Marble specific functions.
This doesn't follow C++ (or I need to brush up on my OO programming!).
I can live with this, after all I'm not writing a C++ program, but if
anyone can explain this I'd be interested to understand why.
One other peculiarity I noticed was that the qVariant "constructor" will
only take Double or Integer types if they are nested in a tuple. Again,
this is fine, but at odds with the documentation which implies
constructors can take:
() | p1 | (p1) | (p1,p2,...pn)
So I'm over the first hurdle; it is possible, now to think of something
interesting to do with it :-)
module Main where
import Qtc
main :: IO ()
main
= do
app <- qApplication ()
rok <- registerResource "marble.rcc"
loader <- qUiLoader ()
uiFile <- qFile ":/marble.ui"
open uiFile fReadOnly
ui <- load loader uiFile
close uiFile ()
ui_map <- findChild ui ("
participants (2)
-
Alp Mestanogullari -
Philip Beadling