threads with gtk gui problem

Discussion in 'Python' started by Andy Baxter, May 14, 2011.

  1. Andy Baxter

    Andy Baxter Guest

    Hi,

    I'm working on adding a Gtk GUI to a python program. Its main function
    is to read raw data from an arduino board over USB, and convert it to
    MIDI note/controller events to be sent to another program. I've had it
    working fine with just a command line interface, but when I replaced the
    command line with a Gtk interface, I started having problems getting the
    thread that reads the USB port to run.

    I'm not sure what the custom is on this list for pasting code - It's a
    long program so I don't want to paste the whole thing.

    The sequence of events I've coded is:

    - the program starts.
    - the port reader thread (which is a threading.Thread subclass) is
    initialised.
    - the object which controls the interface is initialised (i.e. the glade
    file is loaded.)
    - the port reader is started (i.e. the 'start' method is called, which
    calls the 'run' method in a thread).
    - then the gtk main loop is run.

    The behaviour I'm getting is that the port reader either fails to start,
    or stops running at the point where it tries to initialise the serial
    port. It then does nothing until I close the main window, at which point
    it starts running again.

    The port reader's run method begins like this:

    # the method called by the thread superclass to run the main loop of
    the thread.
    def run(self):
    # main loop of thread.
    print "Starting port reader."
    fhan=serial.Serial(port=keeper.config['usbPort'],
    baudrate=keeper.config['usbBaud'], timeout=0.1)
    print "1"
    fhan.open()
    print "2"
    seq=PySeq() # the sequencer library object
    port=seq.createOutPort(keeper.config['midiPortName']) # make a
    midi out port.
    midich=keeper.config['midich']
    print "3"
    while True:
    inbuf=[]
    print ".",
    char=fhan.read(1)
    if self.quit:
    fhan.close()
    return
    if len(char)==0: continue
    ... (code to process the character read in)

    ('keeper' is a global object which stores the config data and references
    to a few key objects).

    When you start the program, the thread stops either before the first
    print statement, or on the line which initialises the serial port (
    fhan=serial.Serial(...) ). '1', '2', and '3' only get printed /after/
    you close the gtk main window.

    Can anyone help with this?

    cheers,

    andy baxter



    --

    http://highfellow.org
     
    Andy Baxter, May 14, 2011
    #1
    1. Advertising

Want to reply to this thread or ask your own question?

It takes just 2 minutes to sign up (and it's free!). Just click the sign up button to choose a username and then you can ask your own questions on the forum.
Similar Threads
  1. Replies:
    2
    Views:
    544
  2. DreiJane
    Replies:
    0
    Views:
    346
    DreiJane
    Nov 23, 2009
  3. andy baxter

    Re: threads with gtk gui problem

    andy baxter, May 14, 2011, in forum: Python
    Replies:
    0
    Views:
    378
    andy baxter
    May 14, 2011
  4. Gergely Kontra
    Replies:
    2
    Views:
    271
    Joao Pedrosa
    Jun 18, 2004
  5. Alex Shulgin
    Replies:
    1
    Views:
    194
    thefed
    Nov 21, 2007
Loading...

Share This Page