Question

I have some simple wxpython GUI, and when I click a button click, I want to run some io task in a another thread(in order not to block the GUI) and update the GUI accordingly while the io thread is running (for example updating a label to:”[io task percentage completed]%”) from the io thread.

However sometimes this works, and sometimes an exception is thrown:

The program 'python2.7' received an X Window System error.
This probably reflects a bug in the program.
The error was 'RenderBadPicture (invalid Picture parameter)'.
  (Details: serial 14127 error_code 163 request_code 149 minor_code 7)
  (Note to programmers: normally, X errors are reported asynchronously;
   that is, you will receive the error a while after causing it.
   To debug your program, run it with the --sync command line
   option to change this behavior. You can then get a meaningful
   backtrace from your debugger if you break on the gdk_x_error() function.)

Running the program with –sync command yields the following error :

[xcb] Unknown request in queue while dequeuing
[xcb] Most likely this is a multi-threaded client and XInitThreads has not been called

I have read that it is not allowed to update the GUI thread from another thread than the one which created the GUI, but if this is the case, how to accomplish this simple task? updating the GUI from another thread.

Thanks

Answer 1

There are already tons of threads on this topic here, and it’s well covered on the wxpython wiki. Look up wx.CallAfter.