I am trying to update information in tkinter labels and buttons without redrawing entire screens. I’m using Python 3, a Raspberry Pi, and Idle. I have a trivial example of what I am trying to do. I see comments here that suggest I need to learn to manipulate stringvariable or IntVar, etc. but my book is totally unhelpful in that regard. In this example, I would like the number between the buttons to track the value of the number as it changes with button pushes.
##MoreOrLess.01.py
from tkinter import *
global number
number = 5
root = Tk()
root.title("Test Buttons")
def Less():
global number
number -= 1
print ("The number is now ", number)
def More():
global number
number += 1
print("The number is now ", number)
def MakeLabel(number):
textvariable = number
label1 = Label(root, text = "Pick a button please.").pack(pady=10)
btnL = Button(root, text = "More", command = More).pack(side = LEFT)
btnR = Button(root, text = "Less", command = Less).pack(side = RIGHT)
label2 = Label(root, text = number).pack(pady = 20)
MakeLabel(number)
Answer
Not only do you base yourself in a book, check the official documentation of tkinter. in your case you must create a variable of type IntVar with its set() and get() method, and when you want to link that variable through textvariable.
from tkinter import *
root = Tk()
root.title("Test Buttons")
number = IntVar()
number.set(5)
def Less():
number.set(number.get() - 1)
print ("The number is now ", number.get())
def More():
number.set(number.get() + 1)
print("The number is now ", number.get())
def MakeLabel(number):
textvariable = number
label1 = Label(root, text = "Pick a button please.").pack(pady=10)
btnL = Button(root, text = "More", command = More).pack(side = LEFT)
btnR = Button(root, text = "Less", command = Less).pack(side = RIGHT)
label2 = Label(root, textvariable = number).pack(pady = 20)
MakeLabel(number)
root.mainloop()