From massimo.pozzoni at st.com  Tue Sep 20 04:05:36 2022
From: massimo.pozzoni at st.com (Massimo POZZONI)
Date: Tue, 20 Sep 2022 08:05:36 +0000
Subject: [Tkinter-discuss] TKinter ttk combobox Focusout event
Message-ID: <PAXPR10MB49779BF5A9209312AE6C711D8C4C9@PAXPR10MB4977.EURPRD10.PROD.OUTLOOK.COM>

I find an issue with the Combobox events:

The <FocusOut> event is triggered also when the drop-down menu list is opened. (Basically it works as the FocusOut of the associated Entry, not of the ComboBox)
The <<ComboboxSelected>> event is triggered only when a selection is done from the list, but not if something is written inside the associated Entry.

My problem is that I need an event that is triggered when the overall combox widget is left,
which is not the FocusOut, because when I open the drop-down menu I am still using the widget,
and it is not the <<ComboboxSelected>> because if I left the widget after writing inside the associated Entry, the event is not triggered because no selection from list happens.

Is there any way to have an event that is triggered when the overall combobox is left, but not when the drop-down list is opened?

Thanks

Massimo




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From klappnase at web.de  Wed Sep 21 19:26:10 2022
From: klappnase at web.de (Michael Lange)
Date: Thu, 22 Sep 2022 01:26:10 +0200
Subject: [Tkinter-discuss] TKinter ttk combobox Focusout event
In-Reply-To: <PAXPR10MB49779BF5A9209312AE6C711D8C4C9@PAXPR10MB4977.EURPRD10.PROD.OUTLOOK.COM>
References: <PAXPR10MB49779BF5A9209312AE6C711D8C4C9@PAXPR10MB4977.EURPRD10.PROD.OUTLOOK.COM>
Message-ID: <20220922012610.98822950f6d0aaed271d5429@web.de>

Hi,

On Tue, 20 Sep 2022 08:05:36 +0000
Massimo POZZONI via Tkinter-discuss <tkinter-discuss at python.org> wrote:

(...)
> My problem is that I need an event that is triggered when the overall
> combox widget is left, which is not the FocusOut, because when I open
> the drop-down menu I am still using the widget, and it is not the
> <<ComboboxSelected>> because if I left the widget after writing inside
> the associated Entry, the event is not triggered because no selection
> from list happens.
>
> Is there any way to have an event that is triggered when the overall
> combobox is left, but not when the drop-down list is opened?

maybe a workaround might help.
As far as I know there is no simple way to directly access ttk subwidgets
from tkinter, but with a simple trick you could check if the focus went
from the combobox's entry to the drop down list, as in this example:

####################################################

from tkinter import *
from tkinter import ttk

root = Tk()
b = Button(root, text='Hi')
b.pack(padx=100, pady=30)

v = StringVar(value='foo')
# define a unique widget name for the combobox
c = ttk.Combobox(root, name='unique_name',
                    textvariable=v, values=('foo', 'bar', 'bla'))
c.pack(pady=30)

def do_something():
    print('Doing something...')

def on_focus_out(event):
    # check if the drop-down list has keyboard focus
    if 'unique_name.popdown' in str(root.tk.call('focus')):
        print('Drop-down list opened.')
    else:
        do_something()

c.bind('<FocusOut>', on_focus_out)
root.mainloop()

####################################################

Alternatively one could skip that uinque-name thing and use the fact that
focus_get() crashes when the drop down list has focus, with a modified
event callback:

def on_focus_out(event):
    try:
        c.focus_get()
        do_something()
    except KeyError:
        pass

Not sure about this one, maybe it might fail if the focus goes from the
combobox directly to some other ttk subwidget? In the
simplified example program above both versions seem to work.

Have a nice day,

Michael


.-.. .. ...- .   .-.. --- -. --.   .- -. -..   .--. .-. --- ... .--. . .-.

Every living thing wants to survive.
		-- Spock, "The Ultimate Computer", stardate 4731.3

From massimo.pozzoni at st.com  Thu Sep 22 12:17:50 2022
From: massimo.pozzoni at st.com (Massimo POZZONI)
Date: Thu, 22 Sep 2022 16:17:50 +0000
Subject: [Tkinter-discuss] Program continuing execution while tkinter window
 is open
In-Reply-To: <PAXPR10MB49779BF5A9209312AE6C711D8C4C9@PAXPR10MB4977.EURPRD10.PROD.OUTLOOK.COM>
References: <PAXPR10MB49779BF5A9209312AE6C711D8C4C9@PAXPR10MB4977.EURPRD10.PROD.OUTLOOK.COM>
Message-ID: <PAXPR10MB4977B130FAB4C2ED0EFB56F98C4E9@PAXPR10MB4977.EURPRD10.PROD.OUTLOOK.COM>


I'm wondering if there is any way to have a tkinter window running, while the main program is continuing its execution.
I tried with threading but with no success.

So far I always got the program to wait until the tkinter window is closed.

Is there any way to have the python main program to continue the execution while a tkinter window is open?

Massimo




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From klappnase at web.de  Thu Sep 22 19:03:31 2022
From: klappnase at web.de (Michael Lange)
Date: Fri, 23 Sep 2022 01:03:31 +0200
Subject: [Tkinter-discuss] Program continuing execution while tkinter
 window is open
In-Reply-To: <PAXPR10MB4977B130FAB4C2ED0EFB56F98C4E9@PAXPR10MB4977.EURPRD10.PROD.OUTLOOK.COM>
References: <PAXPR10MB49779BF5A9209312AE6C711D8C4C9@PAXPR10MB4977.EURPRD10.PROD.OUTLOOK.COM>
 <PAXPR10MB4977B130FAB4C2ED0EFB56F98C4E9@PAXPR10MB4977.EURPRD10.PROD.OUTLOOK.COM>
Message-ID: <20220923010331.c4835954c64ab2660ce979c0@web.de>

Hi,

On Thu, 22 Sep 2022 16:17:50 +0000
Massimo POZZONI via Tkinter-discuss <tkinter-discuss at python.org> wrote:

>
> I'm wondering if there is any way to have a tkinter window running,
> while the main program is continuing its execution. I tried with
> threading but with no success.
>
> So far I always got the program to wait until the tkinter window is
> closed.
>
> Is there any way to have the python main program to continue the
> execution while a tkinter window is open?

I am not sure what you actually want to achieve; when using threads you
need to make sure that the Tcl interpreter (inside which the tkinter
window is running) runs in the main program thread and that you must
*never* do any calls to tkinter from within any of the child threads. For
interaction between tkinter and the child threads you can for example use
Lock or Condition objects to safely update some variable value from the
child thread and an after() loop to query the variable value on the Tk
side.

Below a primitive example:

##########################################

from tkinter import *
from threading import Thread, Lock
from time import sleep
from signal import signal

root = Tk()
s = IntVar()
s.set(0)
Label(root, textvariable=s).pack(pady=30, padx=70)

x = 0
run = True
lock = Lock()

def quit(*args):
    global run
    # make sure the child stops before we quit
    run = False
    root.quit()
root.protocol('WM_DELETE_WINDOW', quit)
# make sure keyboard interrupt is handled properly
signal(2, quit)

def poll():
    lock.acquire()
    s.set(x)
    print('current value ->', x)
    lock.release()
    root.after(500, poll)
poll()

def incr():
    global x
    while run:
        lock.acquire()
        x += 1
        lock.release()
        sleep(1)
    print('child thread done')

t = Thread(target=incr)
t.start()

root.mainloop()

##########################################

Have a nice day,

Michael

.-.. .. ...- .   .-.. --- -. --.   .- -. -..   .--. .-. --- ... .--. . .-.

Without facts, the decision cannot be made logically.  You must rely on
your human intuition.
		-- Spock, "Assignment: Earth", stardate unknown