topic Re: python add-in hanging due to while loop in Python Questions

python add-in hanging due to while loop

JelmerOosthoek — Tue, 05 May 2015 09:59:01 GMT

I'm building a python add-in for ArcGIS desktop with a button which runs a while loop. Another button should close the while loop. In the while loop there is a continuous process going on which is important for the functionality of the add-in. But unfortunately the while loop causes the add-in, and therefore ArcGIS desktop, to hang.

I have tried time.sleep(.1) in the while loop. And I have tried the threading library. But nothing seems to work.

I was hoping someone maybe had a suggestion? Thanks in advance!

Re: python add-in hanging due to while loop

JaiSiva1 — Sun, 12 Dec 2021 04:04:00 GMT

Hi Jelmer,

Can you please elaborate on this issue with the snippet that you have coded.

From the information provided, i can suggest you to use event listeners to achieve the trigger ,

  #function that keeps checking if the second button is pressed.
def IsButtonPressed():
    if (<your condition for the event>):
          return True
    else :
          return False


  #function that keeps looping after the first button is pressed.
def Loop():
   while (IsButtonPressed()):
        <do some action>

If you can specify which GUI framework you are using , i can help with the events trigger part.

Best,

Jai

Re: python add-in hanging due to while loop

JelmerOosthoek — Sun, 12 Dec 2021 04:04:02 GMT

Hi Jai, thanks for your reply.

I'm currently not using any other GUI framework than ArcGIS itself, using the python add-in wizard: https://www.arcgis.com/home/item.html?id=5f3aefe77f6b4f61ad3e4c62f30bff3b

And by using a while loop in the code the tool and ArcGIS hangs. Here is a simple snippet example:

import arcpy
import pythonaddins


class ButtonClass1(object):
    """Implementation for tryaddin_addin.button (Button)"""
    def __init__(self):
        self.enabled = True
        self.checked = False
    def onClick(self):
        # the while loop
        global switch
        while switch == 0:
            print 1
            global switch


class ButtonClass2(object):
    """Implementation for tryaddin_addin.button_2 (Button)"""
    def __init__(self):
        self.enabled = True
        self.checked = False
    def onClick(self):
        # turn off the while loop
        global switch
        switch = 1        
        
switch = 0

Re: python add-in hanging due to while loop

JaiSiva1 — Wed, 06 May 2015 13:23:26 GMT

Hi Jelmer ,

I think you got to change the logic that you have written in your program.

I have a similar kind of case which uses Tkinter package , using which you can modify your code.

python - How do you create a Tkinter GUI stop button to break an infinite loop? - Stack Overflow

Hope this is useful.

Re: python add-in hanging due to while loop

JelmerOosthoek — Wed, 06 May 2015 14:38:09 GMT

Hi Jai,

That did the trick! Thanks very much, it works like a charm, and doesn't even need threading.

All the best, Jelmer