[Tutor] help with Tkinter, please

[Michael Lange]

On Thu, 23 Nov 2006 02:07:17 -0800
Dick Moores <rdm at rcblue.com> wrote:

> I think I see how to make a simple GUI with Tkinter, but I still 
> don't see how to use one with even a simple, previously non-GUI 
> Python script. I'm wondering if someone could create an example for 
> me, using the 2 functions fact() and printFact() at 
> <http://www.rcblue.com/Python/fact.txt>. I'm thinking of something 
> really plain and simple. A frame widget, an entry widget, and a text 
> widget. The user enters an integer n (which can be very large), and 
> the text widget shows n! in 2 formats, as the output of a modified 
> printFact(). Maybe a button is also necessary?
> 

Hi Dick,

assuming the functions you want to use are in a separate module "fact.py",
a simple (and dirty) solution might look like

from Tkinter import *
import fact

root = Tk()
entry = Entry(root)
entry.pack(side='top')
text = Text(root)
text.pack(side='top')

# now you need a callback that calls fact() and inserts the result into the text widget
def compute_fact():
    value = int(entry_get())
    result = fact.fact(value)
    newtext = 'Result: %d\n' % result# change this to the output format you wish
    text.insert('end', result)

button = Button(root, text="Compute fact", command=compute_fact)
button.pack(side='top')
root.mainloop()

In case you do not want an extra button, you can bind the compute_fact() callback
to Key-Return events for the entry:

entry.bind('<Return>', compute_fact)

however you will have to change the callback's constructor to accept an event object
as argument:

def compute_fact(event):
    (...)

or :

def compute_fact(event=None):
    (...)

which allows both.

In case you want the output formatting done in the fact module, change the printFact() function,
so that it *returns* a string instead of printing it to stdout, so you can use a callback like:

def compute_fact(event=None):
    text.insert('end', fact.printFact(int(entry.get())))


I hope this helps

Michael