Never can get False if the store_true checkbox with a default value True

[wangw37]

parser.add_argument('--opt_arg', action='store_true', default=True)
if you want a checkbox widget, and set the default status on UI is checked, it can not work as expect, and it always return True no matter you select the checkbox or not.
and another issue about it: you can not uncheck it and run you app if it is not a optional parameter. because the ui tell you that you have not given a value to it...

[sbillinge]

Thanks for posting this @wangw37 .

It strikes me that the behavior you are describing is the expected behavior for action=store_true. The run-time options for this are that the optional argument is set or not set. If it is set you want the associated variable to be a bool with value True and if it is not set you want that variable to be bool with value False, so by setting default=True breaks that logic.

If I understand your challenge correctly, I think that to do what you want to do you can do with store_false for the action which has a default of True but can be set to False by setting the optional arg.

Please let me know if I didn't understand your issue correctly.

[wangw37]

Thank you very much for your detailed reply.
This is my first time using argParse, so my understanding of store_xxx may be off.
I understood it based on a UI behaviour, and I thought 'default' was the default value displayed on the UI (which it can), but in fact it is not only, that is why I was confused.
In the end, what you've said does solve the problem I'm having, although it's a bit convoluted, so thanks again.

[sbillinge]

Thanks for confirming @wangw37 . Closing this issue as not needed.