TKinter in Python - advanced notions

[Thomas Passin]

On 6/23/2023 4:16 AM, Andreas Heckel via Python-list wrote:
> Hi,
> 
> Apologies for potentially mis-using this thread. But I have been struggling recently making exactly this leap from simple GUI examples to a more elaborate MVVM concept. Mainly I have been struggling finding nice example python code bases, that allow some understanding to the beginner, which I certainly still am, but also show enough complexity to see the concept in action.
> Any hints / links to github or similar highly welcome. If the list is not the appropriate place, I am happy if you email me directly.
> 
> Cheers,
> Andreas
> 
>> -----Original Message-----
>> From: Python-list
>> On Behalf Of Diego Souza via Python-list
>> Sent: Friday, June 23, 2023 4:14 AM
>> To: aapost
>> Cc: python-list
>> Subject: Re: TKinter in Python - advanced notions
>>
>> Have you considered improving the architecture itself, not your GUI library
>> skills?
>>
>> I recommend you look at the Model View ViewModel (MVVM) concept and
>> implement something similar (this is largely used in the Android framework
>> nowadays). This would separate your program logic from the rendering and
>> visualization. It would also make your program more reactive, decoupled,
>> and easier to maintain. When you mentioned threads I immediately thought of
>> this because it is much easier to implement parallel jobs and present
>> results back in the GUI, as everything becomes reactive. This is overkill
>> for a small project such as the code you showed, but I recommend it for
>> larger projects.

As a general comment (and I have not done anything tricky or complex 
with Tk), MVC or the other approaches in a similar vein, though good, 
can lead you into more complexity than you need, because of the extra 
abstractions involved.  Yes, for sure the GUI should not be doing domain 
or business logic. Yes, it's good to keep database access separate from 
the other parts of your program. But you may not need all the classes 
and layers that you think you might.  It all depends on what you need to 
do, of course.

Another useful design thought is to try to keep as much of the GUI logic 
separate from Tk itself as possible.  Basically, you would write a more 
abstract (and simpler) GUI API, and then write an adapter that knows how 
to make Tk do those things.  One advantage is that this approach makes 
it easier to change to another GUI toolkit later (say PyQt, for 
example).  Another is that it helps you avoid getting sucked into too 
many Tk details that aren't needed for the program concept.

Here is a simple (or simple-minded :) ) example:

class AbstractApi:
     """An abstract class for standardizing access to a display widget."""
     def __init__(self, parent):
         self.parent = parent
         self.client = None

     def registerClient(self, client):
         self.client = client

     def loadPanel(self, panel_name, html):
         """Load html into display panel."""
         pass

     def focusPanel(self, panel_name):
         """Select a named display panel."""
         pass

     def handleSearchText(self):
         pass

     def writeStatusBar(self, msg):
         pass

     def handleLinkClicked(self, uri, source):
         """Handle a link clicked in the "source" display panel."""
         pass

These (let us say for the purposes of illustration) are the only things 
you need from the GUI.  You can write a Tk-specific version of this, and 
the rest of your program doesn't need to know that Tk is even involved. 
If you want to change to say GTK, this class is the only thing that 
would need to change.

Even if this approach turns out to be too simple for a really 
complicated UI, the closer you can come to realizing it the better.

>>
>> On Wed, Jun 21, 2023 at 7:20 PM aapost via Python-list <
>> python-list at python.org> wrote:
>>
>>> On 6/21/23 09:47, Dan Kolis wrote:
>>>> I've write a huge biotech program ( an IDE for synthetic biology ), and
>>> am slowly outgrowing TKINTER.
>>>>
>>>> Has anybody out there merged a little bit of TCL direct calls from
>>> Python 3.X to get more freedom then TKINTER for just some Windows ?
>>>
>>>> I wish it looked better, but its 'ok'. I believe X11 IO is considerably
>>> superior for serious work the HTML.  I mean 'serious' work. with lots of
>>> multi media windows. I am not talking about fb "Oh ! There is a window it
>>> opened inthe corner !"... trivial functionality.
>>>
>>>
>>> I don't know if it would help, but you can extend/add tcl/tk packages
>>>
>>> I don't remember the full instructions right off, but quickly reverse
>>> engineering my old stuff I think you just need to drop them in
>>> /usr/share/tcltk/ or equivalent.
>>>
>>> (I needed to do that to replace the terrible looking default file dialog
>>> for unix/linux with fsdialog.)
>>>
>>> then running something like the following from your Tk object
>>>
>>> self.eval('package require fsdialog')
>>>
>>> (reverse engineering the python tkinter source you can likely find other
>>> ways of doing more tcl direct stuff)
>>>
>>> I have not researched if there are some better, more featured
>>> (non-buggy) Text widgets implemented in tcl that can be dropped in, (I
>>> know several of the tcl drop in widgets I tried were lacking in
>>> refinement).
>>>
>>>   From what I can tell, once upon a time there were better, more
>>> interesting projects and tutorials on extending tkinter, such as WCK
>>> (tkinter3000), but the only remnants of those remain publicly available
>>> are outdated unmaintained archives.
>>>
>>> You might also consider looking at the Grail browser source for research
>>> purposes, as it does some interesting things with some of the widgets,
>>> (parsing html and such), even though it is 20 years old now (and written
>>> in python 1).
>>> The update attempts from 10+ years ago have disappeared. (it's license
>>> is considered questionable from what I understand, so not sure if that
>>> is an aspect of it, the other being one of it's main features, python
>>> applets, is unsafe and was not easily fixable)
>>>
>>> You might already be beyond some of these things though.
>>>
>>> I know what you mean as far is feeling like the little bit extra you
>>> need pushes beyond what tkinter can do / makes you feel like you have
>>> outgrown the module.
>>>
>>> (I had to take a break from one of my projects and send it to
>>> development hell until my UI knowledge/skills improve after I found
>>> myself considering using xml schema appinfo annotations to store json
>>> formatted widget specific information, lol.)
>>>
>>> I have felt that sense of lack with most of the UI modules I have tried
>>> though.
>>>
>>> I don't know of a clear better python-only solution though that fits my
>>> personal needs.
>>>
>>> So I have to lean toward improving my tcl / C in hopes that it might
>>> help steer me toward that extra (which seems to be in the spirit of what
>>> tcl/tk's intent is to begin with). That will be a while for me though if
>>> I get there.
>>>
>>>
>>>
>>>
>>> --
>>> https://mail.python.org/mailman/listinfo/python-list
>>>
>>
>>
>> --
>> Diego Souza
>> Wespa Intelligent Systems
>> Rio de Janeiro - Brasil
>> --
>> https://mail.python.org/mailman/listinfo/python-list
>