Re: Learning Tkinter
- From: "Eric Brunel" <see.signature@xxxxxxx>
- Date: Thu, 17 Apr 2008 13:48:38 +0200
On Wed, 16 Apr 2008 14:46:13 +0200, Doran, Harold <HDoran@xxxxxxx> wrote:
[snip]
Second, I am trying to work through a couple of the examples and make
some small tweaks as I go to see how new things can work. In the first
case, I have copied the code in the book to see how the menu works and
are created as in the example menu.py below. I see how menus are created
and how the command option is used to call the function callback.
# menu.py
from Tkinter import *
def callback():
print "called the callback!"
root = Tk()
# create a menu
menu = Menu(root)
root.config(menu=menu)
filemenu = Menu(menu)
menu.add_cascade(label="File", menu=filemenu)
filemenu.add_command(label="New", command=harold)
filemenu.add_command(label="Open...", command=callback)
filemenu.add_separator()
filemenu.add_command(label="Exit", command=callback)
helpmenu = Menu(menu)
menu.add_cascade(label="Help", menu=helpmenu)
helpmenu.add_command(label="About...", command=callback)
mainloop()
However, I now want to incorporate a basic python program with a
command. Say I have a simple program called test.py
# test.py
filename = raw_input("Please enter the file you want to open: ")
new_file = raw_input("Save the output file as: ")
f = open(new_file, 'w')
new = open(filename, 'r')
for line in new:
x = line.split('\t')
print >> f, x[0],':', x[1]
f.close()
To make this example complete assume I have a text file like this
# data.txt
1 one
2 two
3 three
4 four
So, the user currently just follows directions on the screen, enters the
file names, and I get what I want. I'd like to try experimenting with
gui programming to see if the python programs I have written can be made
even more user friendly. I currently use py2exe to create executables so
that others in my organization can use these programs.
In that spirit, say I want to have a menu option that allows the user to
search their computer for this file, execute the python code and then
save the result as a user-defined filename. So, I guess my questions are
how do I associate the portion of code in menu.py
"filemenu.add_command(label="Open...", command=callback)" with an
operation that gives the user the ability to search the drives on their
machine and then once they do let python execute the code in test.py?
The way it's written, you'll have a hard time doing it... Since test.py already includes a "user interface" via the raw_input calls, executing test.py will always ask the user for the file names, and there's no simple way to pass them otherwise as the module is written.
Considering how you asked the question, I'll assume you don't know Python very much; my apologies in advance if it's not the case...
So, what I would do is rewrite the test.py script as follows:
--- test.py -----------------------------------
def convert_file(filename, new_file):
f = open(new_file, 'w')
new = open(filename, 'r')
for line in new:
x = line.split('\t')
print >> f, x[0],':', x[1]
f.close()
if __name__ == '__main__':
filename = raw_input("Please enter the file you want to open: ")
new_file = raw_input("Save the output file as: ")
convert_file(filename, new_file)
-----------------------------------------------
This is basically the same as yours in another order, and defining a function that actually does the 'functional' part without asking the user anything. The last block - starting with this weird 'if __name__ == '__main__':' - ensures the script will work as you expect when you run it alone on the command line (with 'python test.py'). This is the meaning of the test on __name__: this magical variable is set to the string '__main__' if and only if the current script is the top-most one, i.e the one you ran python on. So basically, the script now defines a function, then asks for the function parameters and calls it _only if run as the main script_. Try it; it should have the same behaviour as the script you've written.
But the test on __name__ also allows to *import* this script as a module in another script without nasty side effects. This is done via the statement:
import test
in the other script. If test.py is written as above, this will execute the function definition, but not the body of the 'if', since test.py is no more run from the command line, but used in an import. If you didn't have this test, the module would have been *executed* by the import, and is would have asked the file names immediatly.
Once you've done the import, you can then use the function it defines by calling test.convert_file. So now, in your GUI part, you can now write something like:
--- menu.py ----------------------------------
## NEW! the next line gets the 'convert_file' function
import test
from Tkinter import *
## NEW! the next line gets the functions used to get file names via a Tkinter GUI
from tkFileDialog import askopenfilename, asksaveasfilename
## NEW! the following function is the callback for the 'Open' menu entry
def open_callback():
## Get name of the input file
input_file_name = askopenfilename()
if not input_file_name:
## Dialog has been cancelled
return
## Get name for output file
output_file_name = asksaveasfilename()
if not output_file_name:
## Dialog has been cancelled
return
## Do the job
test.convert_file(input_file_name, output_file_name)
def callback():
print "called the callback!"
root = Tk()
# create a menu
menu = Menu(root)
root.config(menu=menu)
filemenu = Menu(menu)
menu.add_cascade(label="File", menu=filemenu)
filemenu.add_command(label="New", command=harold)
## CHANGED! put the callback function defined above here
filemenu.add_command(label="Open...", command=open_callback)
filemenu.add_separator()
filemenu.add_command(label="Exit", command=callback)
helpmenu = Menu(menu)
menu.add_cascade(label="Help", menu=helpmenu)
helpmenu.add_command(label="About...", command=callback)
mainloop()
----------------------------------------------
Try it: it should basically do what you were asking for.
HTH
--
python -c "print ''.join([chr(154 - ord(c)) for c in 'U(17zX(%,5.zmz5(17l8(%,5.Z*(93-965$l7+-'])"
.
- References:
- Learning Tkinter
- From: Doran, Harold
- Learning Tkinter
- Prev by Date: #####SOUTH INDIAN SEX GIRLS SEX######
- Next by Date: Re: Metaprogramming Example
- Previous by thread: Re: Learning Tkinter
- Next by thread: is file open in system ? - other than lsof
- Index(es):
Relevant Pages
|
|
