Dear Yann,
You can load data to tree store from a worker thread. I have done this
once where I am populating a tree store form a jumbo XML file and
showing percentage of loading on the UI. I suppose you are also looking
for the same.
For cooking this dish you'll need the following.
1. A UI thread (which you already have),
2. A worker thread to parse the file and add data to tree store
3. a Glib::Dispatcher to send completion status updates from worker
thread to UI thread
4. A member variable in your class where the worker thread shares the
completion status and
5. a Glib::Mutex to protect to shared resource.
And this is how you cook it.
1. Create a member function and connect it to the Glib::Dispatcher
object. This function starts with a Glib::Mutex::Lock and displays
the percentage completion.
2. Disconnect the tree view from the tree store. Leaving it connected
brings you serious speed issues and additionally its not a good idea
to control any UI element from within a thread other than the main
thread (gdk_threads_enter and leave never helped me! may be I was
doing something wrong altogether).
3. Start a worker thread (implemented as a private member function of
the same class) passing it the file from which to load.
4. Update the completion variable from the worker thread and trigger
the Glib::Dispatcher object as you progress (don't forget about
Glib::Mutex::Lock). I would do this once in 250 milliseconds.
5. Once your loading is complete, connect the tree store back to the
tree view.
This should get you started.
regards
*Mohith Manoj*,
Asst. Manager (R&D),
Skanray Technologies PVT.LTD
Web:www.skanray.com <http://www.skanray.com>
On 8/2/2013 6:47 PM, Yann Leydier wrote:
Thanks Kevin.
I know of the dispatcher but the problem is that I need to fill a
TreeStore: the data is very complex and hard to send through a dispatcher.
Does anyone know if filing a store that is not bound to any TreeView
would be ok (out of the main thread, I mean)? Is so, I could just swap
the TreeView's store with the new one.
Thanks
yann
On 02/08/13 15:10, Kevin Brightwell wrote:
I'm not entirely sure of your problem, but I do know that GTK does
not guarantee *any* thread safety for it's components. You should not
be modifying the TreeView outside the UI thread. If this is how GTK
manifests this problem, so be it. There is a Glib::Dispatcher() [1]
[2] which would allow you to spawn the dispatcher in the UI thread,
then push things from a worker thread and make sure the value gets
updated on the UI.
I hope I'm actually helping the problem and not just being critical
on style. :(
Cheers,
Kevin
[1] https://developer.gnome.org/glibmm/2.35/classGlib_1_1Dispatcher.html
[2]
https://developer.gnome.org/gtkmm-tutorial/3.8/sec-using-glib-dispatcher.html.en
On Fri, Aug 2, 2013 at 8:51 AM, Yann Leydier <[email protected]
<mailto:[email protected]>> wrote:
Hi,
my application fills some TreeStrores and ListStores at runtime
but the data is read from large files and the computation of some
values takes time. Therefore I put a progress bar in a splash
window and fill the store in another thread.
The TreeView fills oddly: once the lines do not fit anymore on
the display, the scollbar is not updated. I tried to add
gdk_threads_entrer() and gdk_threads_leave() before and after the
calls to XXXStore::append() but it did not change anything.
First question: are the stores really thread unsafe? I tend to
consider them as non-UI classes, so TreeView should be the one
handling the thread-safety...
Second question: how do I make sure I do not mess up with the
thread safety when filling my stores?
Thanks a lot,
yann
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/BESc. and BSc. Candidate 2015/
Western University www.westernu.ca <http://www.uwo.ca>
e. [email protected] <mailto:[email protected]>
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