Gtk, Python, and Threading.

[Robert Park <rbpark exolucere ca>]

Hi hackers!

Does anybody have any experience with threading in python/pygobject?

Basically, I'm using json with urllib to download some information in
the background (I don't want this action to block the UI for the user,
as it's quite slow). So I have a simple class that inherits from
threading.Thread and does all the work of downloading, and once the
download is complete, it needs to insert it into a ListStore for
display to the user.

The code I have by and large works, but the problem I'm running into
is that in order to get the information to display in the liststore,
you have to click around a lot in the interface. What I mean is, if
you initiate the thread and then just sit there and wait, nothing will
appear to happen. but if I click around from one entry in the
liststore to the next rapidly, that causes the data to appear, but
slowly (it takes three to seven clicks to make each row display it's
data). It's almost as if the background thread is blocked by the GTK
main loop, and it requires clicking around to advance the loop and run
the thread.

However, if I comment out the call to ListStore.set_value(), it
doesn't stop this happening. Even with just print statements (and
absolutely no GTK code in the thread method), this behavior still
happens.

I also noticed that if I quit the program before the thread stops
running, the rest of the thread successfully executes quite quickly
just as the application window disappears.

Does anybody have any thoughts on this? Am I doing something wrong? Is
threading terrible? How can I do slow things in the background so the
UI can remain responsive?

Thanks.

-- 
http://exolucere.ca