How do I change a variable's value with the command from a Tkinter button?-CodePudding

The command I set for a Tkinter button was a function that changed the text of a label. Yet the text does not seem to change!

The variable I attempted to change using the function "textChange()" is called "text", and the purpose of its value is to be the text of a label called "finalText". But, the text of the label "finalText" didn't change!

#Imports
from tkinter import *

#Variables
wn = Tk()
text = 'Button Commands'


#Change Text
def textChange():
  global variable
  text = 'Can do THIS!'
  finalText = Label(wn, text=text)


finalText = Label(wn, text=text)
finalText.place(x=0, y=0)

#Button
btn = Button(wn, command=(textChange()))

btn.place(x=5, y=20)

CodePudding user response：

You actually create a new label and assign to a local variable finalText inside textChange(). So the global finalText is not changed.

You need to use finalText.config(text=text) to update the text of the global finalText.

Also command=(textChange()) will execute textChange() immediately without clicking the button. Use command=textChange instead.

Below is the updated code:

#Imports
from tkinter import *

#Variables
wn = Tk()
text = 'Button Commands'

#Change Text
def textChange():
    text = 'Can do THIS!'
    # update the text of the global label finalText
    finalText.config(text=text)

finalText = Label(wn, text=text)
finalText.place(x=0, y=0)

#Button
btn = Button(wn, command=textChange)
btn.place(x=5, y=20)

wn.mainloop()