On Oct 26, 1:25 am, Babloo <pruthviraj...@gmail.com> wrote:
> On Oct 26, 1:01 pm, Sean DiZazzo <half.ital...@gmail.com> wrote:
>
>
>
> > On Oct 25, 11:58 pm, Babloo <pruthviraj...@gmail.com> wrote:
>
> > > i have a small python application with GUI (frontend) which has
> > > various functions. I have a "RUN" button which runs python scripts in
> > > the background . It basically calls execfile() function internally
> > > which runs in a thread , to run the python script .
>
> > > I want to implement a "PAUSE" feature which would pause the running
> > > python script . So do that i have to either pause the thread in which
> > > execfile() runs or pause execfile itself .
>
> > > When the user presses "RUN" again then the python script should resume
> > > running .
>
> > > Any ideas how to pause the thread / pause execfile() . Any other ideas
> > > for the same would be helpful .
>
> > > Thanks
>
> > I think you can do that with a threading.event(). In the gui, create
> > a new threading.event() and pass it in to the worker thread. Set up
> > your code in the worker so that on every iteration of "work", it
> > checks to see if the event is set. If it finds it set, then it
> > sleeps, but keeps checking until the event is unset. When unset
> > again, it picks up and begins work again.
>
> > In the gui, your pause button just sets and unsets the event, and the
> > worker will find out and pause at the next iteration.
>
> > Depending on what kind of work your worker thread is doing, it might
> > be tough to structure the code so the event gets checked reasonably
> > often. Hope this helps.
>
> > ~Sean
>
> > PS. Not sure this idea will hold up when using execfile()
>
> Hi..
> Thanks for the reply . Yes tried doing exactly what you have
> suggested . i could show you the sample code .
> But some how it doesn't work and main reason could be i am using
> execfile() in the thread .
> I was trying to set the event on the press of a button . It doesnt
> pause the thread and instead keeps on executing .
> Dont know what the problem could be ???
>
> Sample code :-
>
> $$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$
> import threading
>
> class TestThread(threading.Thread):
> """
> A sample thread class
> """
>
> def __init__(self):
> """
> Constructor, setting initial variables
> """
> self._stopevent = threading.Event()
> self._sleepperiod = 1.0
>
> threading.Thread.__init__(self, name="TestThread")
>
> def run(self):
> """
> overload of threading.thread.run()
> main control loop
> """
> print "%s starts" % (self.getName(),)
>
> count = 0
> while not self._stopevent.isSet():
> count += 1
> print "loop %d" % (count,)
> self._stopevent.wait(self._sleepperiod)
>
> print "%s ends" % (self.getName(),)
>
> def join(self,timeout=None):
> """
> Stop the thread
> """
> self._stopevent.set()
> threading.Thread.join(self, timeout)
>
> if __name__ == "__main__":
> testthread = TestThread()
> testthread.start()
>
> import time
> time.sleep(10.0)
>
> testthread.join()
>
> $$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$
I was thinking along the lines of this. I'll bet you can find a more
efficient way of doing it, but this demonstrates what I was thinking.
import threading, time
class TestThread(threading.Thread):
def __init__(self):
self._stopevent = threading.Event()
threading.Thread.__init__(self)
def run(self):
count = 0
while 1:
if not self._stopevent.isSet():
count += 1
print count
time.sleep(1)
else:
print "paused"
time.sleep(1)
def pause(self):
self._stopevent.set()
def play(self):
self._stopevent.clear()
if __name__ == "__main__":
th = TestThread()
th.start()
time.sleep(5)
th.pause()
time.sleep(5)
th.play()
~Sean
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