Tkinter Spinbox

**bartonc** · May 5 '07, 06:30 PM

Originally posted by 5N1P3R

Hi

I need a spinbox which when created can read a variable (which is an integer) from another location and use that variable for the starting value. i also need to only allow integers be input into the text field by keyboard (and only has high as 999). lastly, whenever the spinbox value is changed (either by keyboard input or by clicking on the arrows) i need to be able to verify that it is an integer and then save its value into another location.

i have tried to do these things but without success. currently i have this (it has been cut out of my main program:

Code:

 resistanceEntry = Spinbox(resistorFrame, from_=1, to=999, width=10, wrap=True, validate=ALL, validatecommand=validate)

def validate():
    print "VALIDATE"

i noticed that even with validate set to ALL it only runs the command validate once and that is when the spinbox is first created.

any help would be greatly appreciated, but please try and keep it simple i am still very new to this

thanks

Electronics huh?
I'm guessing that you need to associate a Variable class object that gets changes. I'll have a look tonight. Got to go at the moment.

**bartonc** · May 5 '07, 06:35 PM

Originally posted by 5N1P3R

Hi

I need a spinbox which when created can read a variable (which is an integer) from another location and use that variable for the starting value. i also need to only allow integers be input into the text field by keyboard (and only has high as 999). lastly, whenever the spinbox value is changed (either by keyboard input or by clicking on the arrows) i need to be able to verify that it is an integer and then save its value into another location.

i have tried to do these things but without success. currently i have this (it has been cut out of my main program:

Code:

 resistanceEntry = Spinbox(resistorFrame, from_=1, to=999, width=10, wrap=True, validate=ALL, validatecommand=validate)

def validate():
    print "VALIDATE"

i noticed that even with validate set to ALL it only runs the command validate once and that is when the spinbox is first created.

any help would be greatly appreciated, but please try and keep it simple i am still very new to this

thanks

Nice job on the CODE tags. Thanks. I like you naming style, too.

Validators must return True or False:

Code:

 resistanceEntry = Spinbox(resistorFrame, from_=1, to=999, width=10, wrap=True, validate=ALL, validatecommand=validate)

def validate():
    print "VALIDATE" 
    return True

Perhaps returning None is causing the problem.

**5N1P3R** · May 6 '07, 01:25 AM

thank you so much :) when i return true then it validates every time, now all i need is get the spinbox value to start at a specific value, any ideas?

**5N1P3R** · May 6 '07, 05:05 AM

EDIT: also how would i write the validate function i had the idea of this (below) but it seems very inefficient there must be a better way

Code:

 
def validate(input)
   for i in range (1000):
      if i == input:
         return True
   (...etc...)

**bvdet** · May 6 '07, 01:31 PM

Originally posted by 5N1P3R

EDIT: also how would i write the validate function i had the idea of this (below) but it seems very inefficient there must be a better way

Code:

 
def validate(input)
   for i in range (1000):
      if i == input:
         return True
   (...etc...)

Something like this:

Code:

>>> def validate(v):
... 	if isinstance(v, int) and v > 0 and v < 1000:
... 		return True
... 	else:
... 		return False
... 	
>>> validate(6)
True
>>> validate(0)
False
>>> validate(999)
True
>>> validate(1000)
False
>>> if validate(v):
... 	print 'Do some stuff'
... 	
Do some stuff
>>>

**bartonc** · May 6 '07, 06:21 PM

Originally posted by 5N1P3R

thank you so much :) when i return true then it validates every time, now all i need is get the spinbox value to start at a specific value, any ideas?

In the Frame's __init__(), keep a reference:

Code:

self.resistanceEntry = Spinbox(resistorFrame, from_=1, to=999, width=10, wrap=True, validate=ALL, validatecommand=validate)

Then, any time you want to, the a Frame method can

Code:

resistanceEntry.set(value)

or you can might be able to

Code:

STARTVALUE = 100   # or whatever
resistanceEntry = Spinbox(resistorFrame, from_=1, to=999,
                          value=STARTVALUE, width=10, wrap=True,
                          validate=ALL, validatecommand=validate)

Of, course, you'll have to experiment because I have not tested this.

Do you know where to find/have the on-line Tkinter reference???

**bartonc** · May 6 '07, 06:29 PM

Originally posted by bartonc

In the Frame's __init__(), keep a reference:

Code:

self.resistanceEntry = Spinbox(resistorFrame, from_=1, to=999, width=10, wrap=True, validate=ALL, validatecommand=validate)

Then, any time you want to, the a Frame method can

Code:

resistanceEntry.set(value)

or you can might be able to

Code:

STARTVALUE = 100   # or whatever
resistanceEntry = Spinbox(resistorFrame, from_=1, to=999,
                          value=STARTVALUE, width=10, wrap=True,
                          validate=ALL, validatecommand=validate)

Of, course, you'll have to experiment because I have not tested this.

Do you know where to find/have the on-line Tkinter reference???

Actually, I think that the proper way to do this is with and IntVar. There is a discussion here.

The Tkinter (old and incomplete) reference is here.

We'll make a Pythoneer out of you, yet!

**5N1P3R** · May 7 '07, 04:30 AM

Originally posted by bvdet

Something like this:

Code:

>>> def validate(v):
... 	if isinstance(v, int) and v > 0 and v < 1000:
... 		return True
... 	else:
... 		return False
... 	
>>> validate(6)
True
>>> validate(0)
False
>>> validate(999)
True
>>> validate(1000)
False
>>> if validate(v):
... 	print 'Do some stuff'
... 	
Do some stuff
>>>

this is perfect except how would you write isinstance? (its not a built in is it?)

i have taken in all of the other things people have written and just have one more question: i noticed that if i use the validatecommand function as used below then the validation is always one step behind. ie if the spinbox contains 5 and i change it to 6 it will verify the old value of 5 and then change the spinbox value of 6, thus it is always one step behind. is there any way to fix this or is there a way around it?

Code:

resistorProperties.resistanceEntry = Spinbox(resistorProperties.resistorFrame, from_=1, to=999, width=10, wrap=True, validate="all", validatecommand=validate)  #use get() to find entry
    resistorProperties.resistanceEntry.grid(column=1, row=1, sticky=N+E)

def validate():
    print "VALIDATE"
    
    if resistorProperties.resistanceEntry == None:
        return True
    else:
        toValidate = resistorProperties.resistanceEntry.get()

    print toValidate   
    return True

**5N1P3R** · May 7 '07, 10:18 AM

Originally posted by 5N1P3R

this is perfect except how would you write isinstance? (its not a built in is it?)

worked that part out, only the second part applies :)

**bartonc** · May 7 '07, 06:34 PM

Originally posted by 5N1P3R

worked that part out, only the second part applies :)

I fixed the event-sequence problem using an IntVar and trace().
I will ask you to consider designing you resistor model as a subclass of Frame, as follows:

Code:

class ResistorModel(Frame):
    """A subclass of Tkinter.Frame for modeling a resistor using IntVar."""
    def __init__(self, root, powerRating, *args, **kwargs):
        Frame.__init__(self, root, *args, **kwargs)
        self.powerRating = powerRating
        self.Ohms = IntVar()
        self.Ohms.trace('w', self.validateOhms)

##        label = Label()

        self.resistanceEntry = Spinbox(self, from_=1, to=999, width=10, wrap=True,
                                       validate="all", textvariable=self.Ohms)  #use get() to find entry
##        self.resistanceEntry.config(validatecommand=self.validateOhms)
        self.resistanceEntry.grid(column=1, row=1, sticky=N+E)

    def validateOhms(self, *args):
        print "VALIDATE OHMS"
        toValidate = self.Ohms.get()

        print toValidate, type(toValidate)
        return True


if __name__ == "__main__":
    root = Tk()

    frame = ResistorModel(root, 10)
    frame.pack()

**5N1P3R** · May 18 '07, 07:03 AM

Originally posted by bartonc

I fixed the event-sequence problem using an IntVar and trace().
I will ask you to consider designing you resistor model as a subclass of Frame, as follows:

Code:

class ResistorModel(Frame):
    """A subclass of Tkinter.Frame for modeling a resistor using IntVar."""
    def __init__(self, root, powerRating, *args, **kwargs):
        Frame.__init__(self, root, *args, **kwargs)
        self.powerRating = powerRating
        self.Ohms = IntVar()
        self.Ohms.trace('w', self.validateOhms)

##        label = Label()

        self.resistanceEntry = Spinbox(self, from_=1, to=999, width=10, wrap=True,
                                       validate="all", textvariable=self.Ohms)  #use get() to find entry
##        self.resistanceEntry.config(validatecommand=self.validateOhms)
        self.resistanceEntry.grid(column=1, row=1, sticky=N+E)

    def validateOhms(self, *args):
        print "VALIDATE OHMS"
        toValidate = self.Ohms.get()

        print toValidate, type(toValidate)
        return True


if __name__ == "__main__":
    root = Tk()

    frame = ResistorModel(root, 10)
    frame.pack()

wow it works :) thank you so much your code is fantastic and with minimal modification this can easily be placed directly into my program.

i apologise for the late reply but i have been swamped over the last few weeks and have not had any time to work on my program

:)

**bartonc** · May 18 '07, 07:04 AM

Originally posted by 5N1P3R

wow it works :) thank you so much your code is fantastic and with minimal modification this can easily be placed directly into my program.

i apologise for the late reply but i have been swamped over the last few weeks and have not had any time to work on my program

:)

I was just wondering about you today. Thank you for the update.
Keep posting, (like some working code, maybe)
Barton

Tkinter Spinbox

Tkinter Spinbox

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