Problem when running a ui program from shortcut.

[satsuki.kojima]

I put a home screen icon with shortcut to run a program I made. The program is with a ui view and the problem is that when I leave the view after using it without closing it (which we usually do when using a tablet,) and next time I run a program from the shortcut, a new view is invoked over the same view I opened last time. That seems natural because shortcut is only to open a program and run it, but I wonder if there is any way to avoid opening as many views as I click the icon. It seems difficult to manage a program running in a different thread, but as I believe we should mostly face the same problem when making a shortcut, does anyone have good idea on it?

[cvp]

@satsuki.kojima usually, we close the view before swapping to another app

[cvp]

@satsuki.kojima this seems to work, automatic close of the view if app goes in background:

import console
import ui
import threading
import time

class my_thread(threading.Thread):
	global main_view
	def __init__(self):
		threading.Thread.__init__(self)
	def run(self):
		while True:
			time.sleep(1)
			if console.is_in_background():
				main_view.close()
				break

main_view = ui.View()
main_view.background_color = 'white'
th = my_thread()
th.start()
main_view.present()

[JonB]

The discussion here might help with some ideas:

https://forum.omz-software.com/topic/5440/prevent-duplicate-launch-from-shortcut/17

[cvp]

@JonB Not sure he wants to prohibit a second launch. As I understood (perhaps erroneously), he wants to restart its script from scratch but the previous view is still there.

[satsuki.kojima]

@cvp

Yeah, this seems to work somehow, I mean I’m not quite sure why it works.
Anyway, adding your codes, I run my program by shortcut, leave it without closing it, once again I click the shortcut and now the previous view is closed. But this behavior is not stable, sometimes the view is still running behind the new view. I’m trying to find what makes this difference of behavior.

So far, by adding some print statement as follows:

class my_thread(threading.Thread):
global main_view

def __init__(self):
	self.timestamp = time.time()
	threading.Thread.__init__(self)
	
def run(self):
	while True:
		time.sleep(1)
		print(self.timestamp, console.is_in_background())
		if console.is_in_background():
			print('closing view')
			main_view.close()
			break

Seems like my_thraead closes the view only when the Pythonista itself is re-opened.
For example when I run this program on Pythonista (not from shortcut,) close the view and then again run the program, the output in the console shows like this:

1618751761.064212 False
1618751765.282424 False
1618751761.064212 False
1618751765.282424 False
1618751761.064212 False
1618751765.282424 False
;
;
(meaning two threads are still running)

and when I go back to the home screen and reopen Pythonista, the output shows like this:

1618751761.064212 True
closing view
1618751765.282424 True
closing view

I’m not sure but it may make sense. What do you think?
Still, I have some mysterious behavior so keep working on it. Thank you for your help. I didn’t think about using “console.is_in_background()”.

[cvp]

@satsuki.kojima do you see a difference if you have or not a tab with your script open?

[cvp]

@satsuki.kojima my solution is correct, I think, if you leave Pythonista by opening another app, like you asked.

[satsuki.kojima]

@cvp
I closed all the tab of my script, and now it works all fine so far.

[JonB]

@cvp I think the singleton view approach in that thread would work, with modification -- basically as part of the launch, it would close and reopen the view ( or reinitialize it). Haven't tried it myself.

[cvp]

@JonB good idea. @satsuki-kojima you could try

[satsuki.kojima]

@JonB
Excuse my slow response. I knew, advised by you, that the same discussion was held in this forum 2 years ago. There were many ideas in that discussion as well although I haven't been all through this yet.
I am very new to singleton approach and my understanding is that singleton pattern can be implemented in one running program. Am I right? If I run my program twice and create a thread in each program, then those threads have to be different threads(different instances,) I think.
Given many ideas, I'll keep posting for any update. Thank you so much.

@cvp
Your solution seems working. Mysterious behavior (which I described) may be caused by my impatient testing. (run a program, close Pythonista, run a program again with no break but only clicking the shortcut icon etc.)

[JonB]

Again, I'll caveat that I haven't run this, but @TPO's code could be modified to return lock_view from is_active, then you could simply close and relaunch the view. Or, if the view is already active, you could reuse the view, and just replace all the subviews.

I'll have to experiment with it.

[satsuki.kojima]

@JonB
Ah yes, so you mean the codes of @TPO, posted 2 years ago. Sorry, I did't get it and was misunderstanding your suggestion. Well, I think I need to try it. Will let you know how it works.

[satsuki.kojima]

This post is deleted!

[cvp]

@satsuki.kojima don't worry, this user has posted in the last 10 topics, everybody saw it.

[ruheladev40]

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