File handle not being released by close

B

bg_ie

Hi,

I'm in the process of writing some code and noticed a strange problem
while doing so. I'm working with PythonWin 210 built for Python 2.5. I
noticed the problem for the last py file processed by this script,
where the concerned tmp file is only actually written to when
PythonWin is closed. In other words, after I run this script, one of
the generated tmp files has a size of 0kB. I then close PythonWin and
it is then written to.

I'm guessing the garbage collector is causing the file to be written,
but shouldn't close do this?

/Barry

import os, time, string

dir = 'c:\\temp1'

def listAllFile(fileNames,dir,files):
def f1(a,dir=dir): return os.path.join(dir,a)
files2 = map(f1, files)
fileNames.extend(files2)

fileNames = []
os.path.walk(dir,listAllFile,fileNames)

for fileName in fileNames:
fileBeginning = os.path.splitext(fileName)[0]
fileEnd = os.path.splitext(fileName)[1]

if fileEnd == ".py":
print fileName
f=open(fileBeginning+".tmp", 'w')
f.write("Hello")
f.close
 
P

Peter Otten

I'm in the process of writing some code and noticed a strange problem
while doing so. I'm working with PythonWin 210 built for Python 2.5. I
noticed the problem for the last py file processed by this script,
where the concerned tmp file is only actually written to when
PythonWin is closed. In other words, after I run this script, one of
the generated tmp files has a size of 0kB. I then close PythonWin and
it is then written to.

I'm guessing the garbage collector is causing the file to be written,
but shouldn't close do this?
Yes.

f=open(fileBeginning+".tmp", 'w')
f.write("Hello")
f.close

In Python () is nessary to call a parameterless function or method:
Hi Barry

This allows it to treat functions as variables consistently:
.... write("Hello")
....Hello>>>

Peter
 
E

Eric Brunel

Hi,

I'm in the process of writing some code and noticed a strange problem
while doing so. I'm working with PythonWin 210 built for Python 2.5. I
noticed the problem for the last py file processed by this script,
where the concerned tmp file is only actually written to when
PythonWin is closed. In other words, after I run this script, one of
the generated tmp files has a size of 0kB. I then close PythonWin and
it is then written to.

I'm guessing the garbage collector is causing the file to be written,
but shouldn't close do this?

/Barry

import os, time, string

dir = 'c:\\temp1'

def listAllFile(fileNames,dir,files):
def f1(a,dir=dir): return os.path.join(dir,a)
files2 = map(f1, files)
fileNames.extend(files2)

fileNames = []
os.path.walk(dir,listAllFile,fileNames)

for fileName in fileNames:
fileBeginning = os.path.splitext(fileName)[0]
fileEnd = os.path.splitext(fileName)[1]

if fileEnd == ".py":
print fileName
f=open(fileBeginning+".tmp", 'w')
f.write("Hello")
f.close

f.close()

HTH...
 
G

Gary Duzan

[ ... ]

for fileName in fileNames:
fileBeginning = os.path.splitext(fileName)[0]
fileEnd = os.path.splitext(fileName)[1]

if fileEnd == ".py":
print fileName
f=open(fileBeginning+".tmp", 'w')
f.write("Hello")
f.close
f.close()

Gary Duzan
Motorola CHS
 
G

Glenn Hutchings

I want to build a GUI to execut python script. I found TKinter and
wxpython. Which one is easier for a newbie? and which one is better?

Well, Tkinter comes with Python, so newbies can get up and running
straight away without having to download and install anything else.
And there are probably lots more examples out there that a newbie can
look at and learn from. As for *better*, wxPython has a lot more
kinds of widgets in it, which will make writing GUIs less tedious in
the long run, and the widgets look a lot nicer too.

Glenn
 
K

kyosohma

Hi,

I want to build a GUI to execut python script. I found TKinter and
wxpython. Which one is easier for a newbie? and which one is better?

Thanks

Frank

_________________________________________________________________

http://clk.atdmt.com/GBL/go/msnjpqjl0060000010gbl/direct/01/

I've read that Tkinter doesn't scale well if you're writing complex
GUIs. I haven't been able to test this hypothesis though. However,
since I had to rewrite VBA apps into Python, to get the right "look
and feel" I needed the widgets that wxPython provided. Since I started
out with C++, I find wxPython better than Tkinter, but it's all pretty
subjective. Try them both!

Mike
 
P

Paul Rubin

I've read that Tkinter doesn't scale well if you're writing complex
GUIs. I haven't been able to test this hypothesis though. However,
since I had to rewrite VBA apps into Python, to get the right "look
and feel" I needed the widgets that wxPython provided. Since I started
out with C++, I find wxPython better than Tkinter, but it's all pretty
subjective. Try them both!

Tkinteger (dang, I always end up typing it that way, I won't even
bother fixing the error) is easy to use for simple gui's, and it's
part of the standard python distro which for me is a big advantage (no
extra crap to download). However, the widget set is rather ugly and
doesn't blend in well with anyone's native widgets; the widget
selection itself is rather narrow, and I think kyosohma may be right
that it doesn't scale well to complex gui's. I've looked at the code
for IDLE's gui and it's terrifying.

At this point I think nobody should write desktop gui apps without a
good reason. There is a fairly flexible and easy to program gui
already running on almost every desktop, namely the web browser.
Before you write a gui using some client side toolkit, ask yourself
whether you can instead embed a web server in your application and
write an HTML gui. That approach is not always the answer, but it has
considerable advantages when you can do it that way.
 
K

kyosohma

Tkinteger (dang, I always end up typing it that way, I won't even
bother fixing the error) is easy to use for simple gui's, and it's
part of the standard python distro which for me is a big advantage (no
extra crap to download). However, the widget set is rather ugly and
doesn't blend in well with anyone's native widgets; the widget
selection itself is rather narrow, and I think kyosohma may be right
that it doesn't scale well to complex gui's. I've looked at the code
for IDLE's gui and it's terrifying.

At this point I think nobody should write desktop gui apps without a
good reason. There is a fairly flexible and easy to program gui
already running on almost every desktop, namely the web browser.
Before you write a gui using some client side toolkit, ask yourself
whether you can instead embed a web server in your application and
write an HTML gui. That approach is not always the answer, but it has
considerable advantages when you can do it that way.

I agree that making web apps is probably the way of the future.
However, there are lots of security risks involved with it that need
to be understood. One of the problems that raging is about AJAX, see
here: http://arstechnica.com/news.ars/pos...bout-the-risks-of-premature-ajax-ulation.html

Desktop apps have security issues too, of course.

Mike
 
C

Chris Mellon

Tkinteger (dang, I always end up typing it that way, I won't even
bother fixing the error) is easy to use for simple gui's, and it's
part of the standard python distro which for me is a big advantage (no
extra crap to download). However, the widget set is rather ugly and
doesn't blend in well with anyone's native widgets; the widget
selection itself is rather narrow, and I think kyosohma may be right
that it doesn't scale well to complex gui's. I've looked at the code
for IDLE's gui and it's terrifying.

At this point I think nobody should write desktop gui apps without a
good reason. There is a fairly flexible and easy to program gui
already running on almost every desktop, namely the web browser.
Before you write a gui using some client side toolkit, ask yourself
whether you can instead embed a web server in your application and
write an HTML gui. That approach is not always the answer, but it has
considerable advantages when you can do it that way.

Some disadvantages of the web based platform:

No native look and feel - constrained by the browser.
No control over browser UI idioms. I had to write this post twice
because the text control lost focus and I hit backspace, going back in
the history and losing my work.
No native integration - no "open file", no "browse the filesystem", no
rich drag and drop, no copy/paste.
No or poor dialogs. Poor multiple window support.
More platforms to develop on and test with.
Limited to CSS box model for layout.


You can mitigate some of these constraints if you *require* the local
web browser technique, rather than supporting local or remote access.
You can mitigate more if you write your own browser host (along the
lines of the dashboard in OS X), but then you get to write 3
applications instead of one.

The web is a terrible application platform. There is not a single web
application in existence which has even half the UI functionality of a
rich client application. There are some (even many) applications for
which the benefit of global access and easy deployment makes up for
the lack in functionality, but statements like "At this point I think
nobody should write desktop gui apps without a good reason" are simply
ludicrously misguided.
 
P

Paul Rubin

I agree that making web apps is probably the way of the future.
However, there are lots of security risks involved with it that need
to be understood. One of the problems that raging is about AJAX, see
here: http://arstechnica.com/news.ars/pos...bout-the-risks-of-premature-ajax-ulation.html

Yes, do be careful of ajax, and of internet programming in general.
However, the usual use of a desktop app is deployment within one
company, so if you write it as a web app you can ease the security
issue by firewalling the server so that it can't be accessed through
the outside internet. That still makes deployment a lot easier, since
there are zero desktop installations required, and you can upgrade the
software whenever you want at the server side.
 
P

Paul Rubin

Chris Mellon said:
No native look and feel - constrained by the browser.

Might or might not matter for the application, especially considering
that tkinter is part of the discussion.
No control over browser UI idioms. I had to write this post twice
because the text control lost focus and I hit backspace, going back in
the history and losing my work.

Sounds weird, I'm used to having stuff in text boxes stay in the
browser, and why did backspace have that effect anyway?
No native integration - no "open file", no "browse the filesystem", no
rich drag and drop, no copy/paste.

File i/o and file system browsing are available from javascript if the
user grants permission. File system browsing for the limited purpose
of file upload is available in regular html. Copy/paste of ordinary
text is always available. However, this type of requirement is what I
mean by a "good reason" to write a desktop gui. It applies to some
applications, not all.
No or poor dialogs. Poor multiple window support.

Might or might not matter depending on the application. Most dialogs
can be done with html. Multiple windows are evil most of the time,
and should instead by done with multiple panes or cells in a single
window.
More platforms to develop on and test with.

Compared to a desktop app? I don't think so.
Limited to CSS box model for layout.

Might or might not matter depending on the application. If you're
doing a consumer app that has to look slick, you have no choice but to
use something like wxwidgets (tkinter won't cut it either). If you're
doing a special purpose office or industrial app, slickness isn't
important.
The web is a terrible application platform. There is not a single web
application in existence which has even half the UI functionality of a
rich client application.

Some of us consider simple interfaces with consistent, familiar
(i.e. web) elements to be a good thing. Fancy client interfaces are
ok if you feel you need to make a style statement, but are often
unnecessary if you just want to get something done.
There are some (even many) applications for which the benefit of
global access and easy deployment makes up for the lack in
functionality, but statements like "At this point I think nobody
should write desktop gui apps without a good reason" are simply
ludicrously misguided.

Well, I don't say that good reasons don't exist, I just see a lot of
desktop apps that could be done just as well as web apps, i.e. for
those, the good reason didn't exist.
 
K

kyosohma

Some disadvantages of the web based platform:

No native look and feel - constrained by the browser.
No control over browser UI idioms. I had to write this post twice
because the text control lost focus and I hit backspace, going back in
the history and losing my work.
No native integration - no "open file", no "browse the filesystem", no
rich drag and drop, no copy/paste.
No or poor dialogs. Poor multiple window support.
More platforms to develop on and test with.
Limited to CSS box model for layout.

You can mitigate some of these constraints if you *require* the local
web browser technique, rather than supporting local or remote access.
You can mitigate more if you write your own browser host (along the
lines of the dashboard in OS X), but then you get to write 3
applications instead of one.

The web is a terrible application platform. There is not a single web
application in existence which has even half the UI functionality of a
rich client application. There are some (even many) applications for
which the benefit of global access and easy deployment makes up for
the lack in functionality, but statements like "At this point I think
nobody should write desktop gui apps without a good reason" are simply
ludicrously misguided.

If you could use Python's antiquated Grail web browser and write
plugin applications, then that would be awesome! There are trade offs
with anything though.

Mike
 
K

Kevin Walzer

Paul said:
Tkinteger (dang, I always end up typing it that way, I won't even
bother fixing the error) is easy to use for simple gui's, and it's
part of the standard python distro which for me is a big advantage (no
extra crap to download). However, the widget set is rather ugly and
doesn't blend in well with anyone's native widgets; the widget
selection itself is rather narrow, and I think kyosohma may be right
that it doesn't scale well to complex gui's. I've looked at the code
for IDLE's gui and it's terrifying.

It's entirely possible to make sophisticated GUI's in Tkinter, but you
are right, most people don't. Part of the issue is that Tkinter
developers haven't kept up with what's going on in Tk and instead use
outdated, ugly widget sets like Tix, PMW, and so on. Making use of the
available wrappers for current Tk libraries such as BWidgets, Tile,
Tablelist, TkTreeCtrl, and so on allows you to make UI's every bit as
polished as what comes with wxPython: tree views, multi-column lists,
notebook tabs, comboboxes, etc., with platform-specific theming
(XP/Vista, Aqua/OS X, and X11).

For more references, see:

http://tkinter.unpythonic.net/wiki/TileWrapper
http://tkinter.unpythonic.net/wiki/TableListWrapper
http://tkinter.unpythonic.net/wiki/TableListTileWrapper
http://tkinter.unpythonic.net/wiki/PyLocate
http://tkinter.unpythonic.net/wiki/PyLocateTile
http://tkinter.unpy.net/bwidget/
http://tkinter.unpy.net/wiki/NoteBook
http://klappnase.zexxo.net/TkinterTreectrl/index.html
At this point I think nobody should write desktop gui apps without a
good reason. There is a fairly flexible and easy to program gui
already running on almost every desktop, namely the web browser.
Before you write a gui using some client side toolkit, ask yourself
whether you can instead embed a web server in your application and
write an HTML gui. That approach is not always the answer, but it has
considerable advantages when you can do it that way.

Given a choice between a rich desktop client and a web app, I'd choose
the desktop client in most cases. It's just much more pleasant to work
with .
 
C

Chris Mellon

Might or might not matter for the application, especially considering
that tkinter is part of the discussion.

The point is that you have no option with the browser - even Tkinter
has platform theming support now.
Sounds weird, I'm used to having stuff in text boxes stay in the
browser, and why did backspace have that effect anyway?

On Windows, backspace is a browser global hotkey that means "go back
once in the history". When the text box lost focus, hitting backspace
navigated back. Gmail uses ajax instead of a page load when you start
typing a reply, and the fragile tricks it uses to try to keep the
browser history and the ajax state in sync don't work in this case.
It's a specific example of the general problems of the browser as
application platform.
File i/o and file system browsing are available from javascript if the
user grants permission.

Which they won't (I don't even know how, from Firefox), so you can't
rely on it working. You can mitigate with your own browser host, or if
you write all your own file browsing in HTML and move it into your
local browser. Poor solutions all around.
File system browsing for the limited purpose
of file upload is available in regular html.
Copy/paste of ordinary
text is always available.

But not of anything else. I've often wanted to drag & drop a file onto
the file upload box in gmail, for example.
However, this type of requirement is what I
mean by a "good reason" to write a desktop gui. It applies to some
applications, not all.

How about something as simple as context menus? You can't reliably
override the browser context menu from a web page unless, again, you
provide your own browser host. This is a good thing, because a browser
needs to be wary of arbitrary malicious web pages. They aren't good
application hosts.

Keyboard shortcuts that happen to conflict with whatever the browser
or any of its plugins happen to use, too. Although I notice that
Firefox now allows web pages to override that, which is a little sad.
Might or might not matter depending on the application. Most dialogs
can be done with html. Multiple windows are evil most of the time,
and should instead by done with multiple panes or cells in a single
window.

Multiple windows are the common case on the mac. They're not rare on
other platforms as well. The fact that your windows are constrained to
the browser and can't be torn off is a large limitation. No toolbars,
no palettes, no modal dialogs (except on IE, or if you constrain them
to the browser). Lots of unnecessary chrome on your extra windows, too
(see below).
Compared to a desktop app? I don't think so.

Did you ever try counting? X browsers * Y browser versions * Z
platforms. There are javascript and CSS bugs and differences between
all of these. From my own professional experience, it's not any easier
to account for browser differences than it is for platform
differences. It's getting better as more people jump on the web
bandwagon and CSS and JS abstraction libraries show up, but it's not
even good as the available platform abstraction libraries like
wxWidgets or Qt.
Might or might not matter depending on the application. If you're
doing a consumer app that has to look slick, you have no choice but to
use something like wxwidgets (tkinter won't cut it either). If you're
doing a special purpose office or industrial app, slickness isn't
important.

I'm not talking about chrome and slickness. I'm talking about basic
usability concerns like "will this work with a higher font size" and
"will it reflow in a sensible way if I change the window size". The
CSS box model works okay for text, it's not so good for widgets. More
than a few web apps end up writing their own layout engines in dynamic
javascript. This is sad. While I'm talking about chrome, add "wasted
screenspace due to browser chrome" to a limitation of web apps, again
unless you write your own browser host. This is another example of a
feature that makes a good browser (don't let arbitrary web pages mess
with my web browser functionality) clashing with the desires of a good
application (don't waste screen space with irrelevant functionality).
Some of us consider simple interfaces with consistent, familiar
(i.e. web) elements to be a good thing. Fancy client interfaces are
ok if you feel you need to make a style statement, but are often
unnecessary if you just want to get something done.

Man, you should be in PR with the way you spin things. You can't
implement anything except the most trivial of applications using only
the simple, familiar web elements like HTML forms. Anything more
complicated than that needs to be done with DHTML and probably AJAX,
and those UI elements don't look anything like the familiar ones. You
go in one breath from saying that you can implement dialogs in HTML to
saying that the rich client is the *less* familiar of the interfaces?
Well, I don't say that good reasons don't exist, I just see a lot of
desktop apps that could be done just as well as web apps, i.e. for
those, the good reason didn't exist.
--

If you'd said "if you're making something really simple that has
limited rich UI or data entry needs, consider a web application
instead" I wouldn't have posted. A web application is something you
make because the deployment and access benefits outweigh the UI and
integration limitations, not as your default "go to" whenever you
create an application.

I'd like an example you have of a desktop application that could have
just as easily been a web application. Bonus points if it's not a CRUD
screen, and double bonus if you don't just handwave away things like
file browsing. Although there are benefits even for the crud screen -
I've written screens and applications for data entry professionals and
they almost always prefer the speed optimizations you can make in a
client application.
 
P

Paul Rubin

Paul Rubin said:
File i/o and file system browsing are available from javascript if the
user grants permission. File system browsing for the limited purpose
of file upload is available in regular html. Copy/paste of ordinary
text is always available. However, this type of requirement is what I
mean by a "good reason" to write a desktop gui. It applies to some
applications, not all.

I should also add: there is also the possibility of running a Python
program with an embedded http server on the same desktop as the
browser, using the browser purely as a gui, but with the Python
program having complete access to the file system and so forth. This
could be seen as combining the disadvantages of both the remote web
server approach (i.e. gui elements constrained by the browser) and the
all-desktop approach (deployment issues). However, a lot of the time
it's still just plain easier to do. Whenever I've written a desktop
gui app I've always just been shocked at how much time goes into
making the gui look decent and do the right stuff, even though none of
mine have been even slightly slick (they've all been for industrial
applications). When I do a web gui, it's been just a matter of
tossing some html into a file or into some print statements, viewing
it in a browser, and tweaking it a little as needed. Maybe that's
mostly a matter of the lousy state of gui toolkits, and we actually
need a toolkit that's more like an embedded browser. But we don't
have that at the moment.
 
P

Paul Rubin

Chris Mellon said:
The point is that you have no option with the browser - even Tkinter
has platform theming support now.

Hmm, I don't know anything about that. I'm taking the view that for a
lot of apps, the requirement is to just put some functionality on the
screen, with slick visual appearance having little value or even
negative value.
...Gmail uses ajax instead of a page load when you start
typing a reply,

I see, the answer to what caused your problem is approximately "ajax
is evil", or alternatively, the gmail app attempts slickness with a
tool that doesn't support slickness that well. OK, I can accept that
using browsers for slick interfaces has its problems, but the answer
(a lot of the time, not always) is to just decide you don't need
slickness.
Which they won't (I don't even know how, from Firefox), so you can't
rely on it working.

The application javascript pops a dialog asking for permission and the
user clicks yes or no. If you can get them to install a desktop app
(gah!!) then you can certainly get them to click yes in a browser.
The permission mechanism is admittedly browser dependent.
But not of anything else. I've often wanted to drag & drop a file onto
the file upload box in gmail, for example.

Well, ok, that's a slick feature that your app might need. None of
mine have needed it so far.
How about something as simple as context menus?

Unnecessary slickness for many apps. I've never needed it.
Multiple windows are the common case on the mac. They're not rare on
other platforms as well. The fact that your windows are constrained to
the browser and can't be torn off is a large limitation. No toolbars,
no palettes, no modal dialogs (except on IE, or if you constrain them
to the browser). Lots of unnecessary chrome on your extra windows, too
(see below).

You can get rid of the chrome with javascript, but the extra windows
are still usually evil and unnecessary. Just because they get used a
lot doesn't change that. A heck of a lot of deployed interfaces, web
or desktop, simply suck.
Did you ever try counting? X browsers * Y browser versions * Z
platforms. There are javascript and CSS bugs and differences between
all of these.

If you can tell them to install a desktop app, you can alternatively
tell them what browser to use. For example we use a complicated
firefox-only browser app where I work, that relies heavily on canvas
objects. But if you write your application with straightforward html
you tend to have very few platform problems.
From my own professional experience, it's not any easier
to account for browser differences than it is for platform
differences. It's getting better as more people jump on the web
bandwagon and CSS and JS abstraction libraries show up,

I guess I see that stuff as mostly-evil and prefer straightforward
html.
I'm not talking about chrome and slickness. I'm talking about basic
usability concerns like "will this work with a higher font size" and
"will it reflow in a sensible way if I change the window size". The
CSS box model works okay for text, it's not so good for widgets.

I just haven't had this problem with HTML interfaces. I've never even
used CSS, though that makes me a bit of a lamer. An interface that
needs to fill the whole screen with widgets is probably too
complicated.
More than a few web apps end up writing their own layout engines in
dynamic javascript. This is sad. While I'm talking about chrome, add
"wasted screenspace due to browser chrome" to a limitation of web
apps, again unless you write your own browser host. This is another
example of a feature that makes a good browser (don't let arbitrary
web pages mess with my web browser functionality) clashing with the
desires of a good application (don't waste screen space with
irrelevant functionality).

I guess the term I'd use to describe all these effects is "slick" and
a heck of a lot of the time it's just not needed. Anyway you can pop
a chromeless browser window with a simple javascript call.
Man, you should be in PR with the way you spin things. You can't
implement anything except the most trivial of applications using only
the simple, familiar web elements like HTML forms. Anything more
complicated than that needs to be done with DHTML and probably AJAX,
and those UI elements don't look anything like the familiar ones. You
go in one breath from saying that you can implement dialogs in HTML to
saying that the rich client is the *less* familiar of the interfaces?

I don't see the contradiction--with HTML you have just a few widgets
that everyone understands and you get an interface that's almost
always self-explanatory. Yes you could call those interfaces trivial,
but the little secret that I'm trying to convey is that very often,
trivial is all that's needed.
If you'd said "if you're making something really simple that has
limited rich UI or data entry needs, consider a web application
instead" I wouldn't have posted. A web application is something you
make because the deployment and access benefits outweigh the UI and
integration limitations, not as your default "go to" whenever you
create an application.

Well, I could back off to somewhere between the two. Like, "ask
yourself whether your application really needs a rich gui or complex
data entry features. If you can get by with a simple HTML interface,
and a lot of the time you can, you'll probably have an easier time
doing it that way and that should be the default".
I'd like an example you have of a desktop application that could have
just as easily been a web application. Bonus points if it's not a CRUD
screen, and double bonus if you don't just handwave away things like
file browsing. Although there are benefits even for the crud screen -
I've written screens and applications for data entry professionals and
they almost always prefer the speed optimizations you can make in a
client application.

I guess I've written 4 or 5 nontrivial desktop gui apps and ZERO of
them had file browsing. One of them did need access to the pc's
serial port, which means there had to be application code on the
desktop, but the gui could have been a browser (talking to an
application-embedded http server) if browsers were available in those
days. Another one of them saved some state to a local file but it did
that without file browsing, and could have instead saved the state on
a remote server if it were written as a remote app.

I'm not saying file browsing is never needed, just that from
experimental observation, it's quite often not needed.

Again, it all depends on what you're trying to do. For data entry
stuff you probably want the data on a remote server anyway, and you
can do basic CRUD validation with fairly simple javascript. Maybe
that departs from pure HTML but it's nothing like the ajax/dhtml
madness that causes the problems you've described.
 
K

kyosohma

It's entirely possible to make sophisticated GUI's in Tkinter, but you
are right, most people don't. Part of the issue is that Tkinter
developers haven't kept up with what's going on in Tk and instead use
outdated, ugly widget sets like Tix, PMW, and so on. Making use of the
available wrappers for current Tk libraries such as BWidgets, Tile,
Tablelist, TkTreeCtrl, and so on allows you to make UI's every bit as
polished as what comes with wxPython: tree views, multi-column lists,
notebook tabs, comboboxes, etc., with platform-specific theming
(XP/Vista, Aqua/OS X, and X11).

For more references, see:

http://tkinter.unpythonic.net/wiki/...lappnase.zexxo.net/TkinterTreectrl/index.html

I tried the PMW widget toolkit. It was ok, but it seemed kind of
buggy. I found out about Tix on a forum of some sort. When I tried to
find out how to get it and use it, all I found was conflicting
information. I finally got it downloaded only to find I had to compile
it and I didn't have the right version of TCL. So I switched to
wxPython then. Months later I found out that Tix is now included with
Python.

I still don't know how to use it though. As with most external Tkinter
widget sets, Tix doesn't have examples. The docs look less inviting
than man pages...but I realize that's probably just me. I just don't
like man pages much.

Thanks for the info though. You never know when you might need another
toolkit for a specialized job.

Mike
 
C

Chris Mellon

Hmm, I don't know anything about that. I'm taking the view that for a
lot of apps, the requirement is to just put some functionality on the
screen, with slick visual appearance having little value or even
negative value.

Define "functionality". From the rest of your posts, that seems to be
limited to "press buttons" and "type small amounts of non-formatted
text" on the interaction side and "display small amounts of simply
formatted text" on the output side. I'm not denying that you can get
by with this functionality in a large number of cases, but it's
certainly not optimal in general. If it were, we'd all still be using
VT100 terminals.
I see, the answer to what caused your problem is approximately "ajax
is evil", or alternatively, the gmail app attempts slickness with a
tool that doesn't support slickness that well. OK, I can accept that
using browsers for slick interfaces has its problems, but the answer
(a lot of the time, not always) is to just decide you don't need
slickness.

What you're calling "slickness" is what other people call "usable".
Obviously it could be done without the ajax, but you lose features and
usability. It's slower, because it takes a full page load, and I lose
the context of the discussion.
The application javascript pops a dialog asking for permission and the
user clicks yes or no. If you can get them to install a desktop app
(gah!!) then you can certainly get them to click yes in a browser.
The permission mechanism is admittedly browser dependent.

My out of the box firefox install simply denies the operation and
raises a javascript error.
Well, ok, that's a slick feature that your app might need. None of
mine have needed it so far.


Unnecessary slickness for many apps. I've never needed it.

How have you decided that you've never needed it? Have you ever worked
with a UI designer or workflow expert? Or have you just never bothered
to implement it and you never heard anything from your users? How
closely have you worked with the users of your applications?
You can get rid of the chrome with javascript, but the extra windows
are still usually evil and unnecessary. Just because they get used a
lot doesn't change that. A heck of a lot of deployed interfaces, web
or desktop, simply suck.

As phishing attacks become more common, browsing are restricting the
ability to remove or modify chrome. Again, a good feature for a
browser, not so much for an application platform.
If you can tell them to install a desktop app, you can alternatively
tell them what browser to use. For example we use a complicated
firefox-only browser app where I work, that relies heavily on canvas
objects. But if you write your application with straightforward html
you tend to have very few platform problems.

It depends on your target audience and deployment arena. The context
is cross platform applications, so at least 2 browsers and at least 2
platforms are required. Don't forget browser versioning, too - IE 5 is
different than IE 6 is different than IE 7. Even "straightforward"
HTML has non-trivial cross browser differences.
I guess I see that stuff as mostly-evil and prefer straightforward
html.

You simply can't do much of anything beyond display text and basic
crud with straightforward HTML without stying. If that is the sole
limit of your UI needs, then bully for you but that's hardly the
common case and I'd venture that you don't have the experience to
support the rather sweeping claim you made.
I just haven't had this problem with HTML interfaces. I've never even
used CSS, though that makes me a bit of a lamer. An interface that
needs to fill the whole screen with widgets is probably too
complicated.

An application is not a book. Of course you fill the whole "screen"
with widgets - your application is defined by the widgets that it has,
and the amount of space those widgets take up is your screen space.
I guess the term I'd use to describe all these effects is "slick" and
a heck of a lot of the time it's just not needed. Anyway you can pop
a chromeless browser window with a simple javascript call.


I don't see the contradiction--with HTML you have just a few widgets
that everyone understands and you get an interface that's almost
always self-explanatory. Yes you could call those interfaces trivial,
but the little secret that I'm trying to convey is that very often,
trivial is all that's needed.

That's simply not true, and I don't think you can objectively justify
it. Besides, you specifically claimed HTML dialogs as being a
replacement for "real" ones, and that can't be done using trivial
interfaces. It requires DHTML, sometimes ajax, and/or browser support.
Well, I could back off to somewhere between the two. Like, "ask
yourself whether your application really needs a rich gui or complex
data entry features. If you can get by with a simple HTML interface,
and a lot of the time you can, you'll probably have an easier time
doing it that way and that should be the default".

I would challenge the assumption that, starting from zero, it is less
complicated to write a web application, much less a "pretend" web app
using a local web server, than a desktop application using Tkinter
(ick) or wxPython or pyQt. I would also challenge the assumption that
'a lot of the time' you can get away with a simple HTML interface, at
least by my personal definition of 'get away with'. I've worked a lot
with data entry people, where the actual requirements in terms of
slickness and flash are quite small. But "basic html" simply does not
fit the bill. There is a real cost in terms of how fast and how
accurately they can enter data in this environment.

Moreover, if you *don't* need global access or zero-deployment
(zero-deployment is always nice but most environments where you can
reasonably force a specific browser and version also have IT
infrastructure), then you should ask yourself if forcing your
application in the web app model (I haven't even touched on the whole
stateless HTTP being mapped to a stateful environment issue, or the
need to manage the local web server) actually buys you anything. I
simply do not buy the claim that HTML interfaces are necessarily
simpler in any but the most trivial of cases, and even in those
super-trivial applications there are often hidden concerns that don't
filter up to management.
I guess I've written 4 or 5 nontrivial desktop gui apps and ZERO of
them had file browsing. One of them did need access to the pc's
serial port, which means there had to be application code on the
desktop, but the gui could have been a browser (talking to an
application-embedded http server) if browsers were available in those
days. Another one of them saved some state to a local file but it did
that without file browsing, and could have instead saved the state on
a remote server if it were written as a remote app.

Exactly how much time do you think using an HTML interface with an
embedded server would have saved you, especially considering the
careful care you have to take with access to the serial port? For the
record, I've written over a dozen client applications, many of which I
would consider trivial (but used features that would be expensive or
impossible to implement in the browser) and probably twice that many
web apps.
I'm not saying file browsing is never needed, just that from
experimental observation, it's quite often not needed.

Plural of anecdote and all that. Make a survey of every application
that you interact with and see how many of them need to interact with
arbitrary files from the filesystem.
Again, it all depends on what you're trying to do. For data entry
stuff you probably want the data on a remote server anyway, and you
can do basic CRUD validation with fairly simple javascript. Maybe
that departs from pure HTML but it's nothing like the ajax/dhtml
madness that causes the problems you've described.
--

CRUD with javascript is something I actually have a lot of experience
with. Deficiencies in the data entry UI have real consequences because
you get invalid data and slow data entry speeds. The auto-completing
combo-box, for example, is simply impossible in a browser without
quite complicated (and slow) DHTML and is a huge boon for data entry.

I'm not trying to claim that there are no benefits to web
applications. But I often see people touting the web as a *superior
application platform*, which is simply false, and as innately simpler
to develop for, which is also false.
 
K

Kevin Walzer

I tried the PMW widget toolkit. It was ok, but it seemed kind of
buggy. I found out about Tix on a forum of some sort. When I tried to
find out how to get it and use it, all I found was conflicting
information. I finally got it downloaded only to find I had to compile
it and I didn't have the right version of TCL. So I switched to
wxPython then. Months later I found out that Tix is now included with
Python.

I still don't know how to use it though. As with most external Tkinter
widget sets, Tix doesn't have examples. The docs look less inviting
than man pages...but I realize that's probably just me. I just don't
like man pages much.

Tkinter comes more naturally to me than other toolkits because I'm also
a Tcl developer. I just haven't felt the need to learn wxPython because
I can get what I need from Tkinter, even the more complicated GUI layouts.
 

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