from tkinter import *
from math import *

window = Tk()
window.title('miles and km converter')
window.minsize('500', '300')
window.config(padx=20, pady=20)

input_user = Entry()
input_user.insert(END, string="0")
input_user.grid(row=0, column=1)

Label(text='is equal to').grid(row=1, column=0)

converted = Label(text='')
converted.grid(row=1, column=1)


def button_action(factor):
    saved_user_input = round(float(input_user.get()) * float(factor), 2)


mybutton = Button(text='calculate', command=button_action)
mybutton.grid(row=2, column=1)

from_point = Label(text='')
from_point.grid(row=0, column=2)

to_point = Label(text='')
to_point.grid(row=1, column=2)


def to_miles():
    from_point['text'] = 'km'
    to_point['text'] = 'miles'
    converted['text'] = button_action(factor=1)


def to_km():
    from_point['text'] = 'miles'
    to_point['text'] = 'km'
    converted['text'] = button_action(factor=2)


radio_state = IntVar()
radio_1 = Radiobutton(text="km to miles", value=1,
                      variable=radio_state, command=to_miles)
radio_2 = Radiobutton(text="miles to km", value=2,
                      variable=radio_state, command=to_km)
radio_1.grid(row=3, column=3)
radio_2.grid(row=3, column=4)

window.mainloop()

For some reason, I am getting the following error:

Exception in Tkinter callback
Traceback (most recent call last):
  File "C:\Users\Lenovo\AppData\Local\Programs\Python\Python39\lib\tkinter\__init__.py", line 1885, in __call__
    return self.func(*args)
TypeError: button_action() missing 1 required positional argument: 'factor'

Why is this happening? I already declared the argument 'factor' in my button_action(). I also provided parameters for the function too. Does this have something to do with the placement of my code?

CodePudding user response：

Your my_button variable is calling button_action function. However, the function requires an argument(named factor in your case).

You can fix it using the lambda function.

mybutton = Button(text='calculate', command=lambda: button_action(input_user.get())

You will also need the input_user.get(). Since this is one of the ways to get the data from an entry widget in tkinter.

CodePudding user response：

In tkinter parameter command dont recive any argument. For use that you want you can 1) use global variable 2) use default value into function 3) use functools.partial(function,default_value). Here is a sample where varible factor removed, becourse it is copy of radio_state. Also here used global variable, and you dont need call button_action with any parameter. Also here fix bug: on start dont set default mode and it calls errors.

from tkinter import *
from math import *

window = Tk()
window.title('miles and km converter')
window.minsize('500', '300')
window.config(padx=20, pady=20)

input_user = Entry()
input_user.insert(END, string="0")
input_user.grid(row=0, column=1)

Label(text='is equal to').grid(row=1, column=0)

converted = Label(text='')
converted.grid(row=1, column=1)

def button_action(): 
    saved_user_input = round(float(input_user.get()) * float(radio_state.get()), 2) #replace factor bcrse radio_state used now
    print(saved_user_input,radio_state.get()) #debug output

mybutton = Button(text='calculate', command=button_action)
mybutton.grid(row=2, column=1)

from_point = Label(text='')
from_point.grid(row=0, column=2)

to_point = Label(text='')
to_point.grid(row=1, column=2)


def to_miles():
    from_point['text'] = 'km'
    to_point['text'] = 'miles'
    radio_state.set(1) #set mode
    converted['text'] = button_action()


def to_km():
    from_point['text'] = 'miles'
    to_point['text'] = 'km'
    radio_state.set(2)
    converted['text'] = button_action()


radio_state = IntVar()
radio_state.set(1)#set default mode

radio_1 = Radiobutton(text="km to miles", value=1,
                      variable=radio_state, command=to_miles)
radio_2 = Radiobutton(text="miles to km", value=2,
                      variable=radio_state, command=to_km)
radio_1.grid(row=3, column=3)
radio_2.grid(row=3, column=4)

window.mainloop()