Wait for threads to finish before creating a new thread-CodePudding

I have this small block of code where the goal is to basically wait for monitoring_function while it's still running.

monitoring_function = threading.Thread(target=start_monitoring, args=( cycles, window), daemon=True)
 if (monitoring_function.is_alive()):
   print("Still Running, Please wait!")
 else:
   print("Starting new Thread")
   monitoring_function.start()

But every time I try to run this code alongside my GUI, the code basically creates a new thread without ever hitting monitoring_function.is_alive() method. I have called on my method multiple times and it'll keep creating threads non-stop. Is it possible to run this sequentially, where it waits until the thread has been completed? I know one of the solutions is to use join() but using that method causes the entire PySimpleGUI to freeze and wait for the function to finish.

CodePudding user response：

You always create a new thread before checking if necessary. Do this instead:

# Execute following two lines only once

monitoring_function = threading.Thread(target=start_monitoring, args=( cycles, window), daemon=True)
monitoring_function.start()

... # Do other things

# Check thread periodically like so:

if monitoring_function.is_alive():
   print("Still Running, Please wait!")
else:
   print("Starting new Thread")
   monitoring_function = threading.Thread(target=start_monitoring, args=( cycles, window), daemon=True)
   monitoring_function.start()