CODEWITHSUNDEEP
pythontkinter
Labrosb
Labrosb

Reputation: 69

Update label content on click using Python

I'm trying to update the content of a label, in Python, by clicking a button. For each clicks a counter will be raised and the value of the label will be updated by the current value of the counter (j). Here is the code:

import time 
import random
import MySQLdb
from Tkinter import *
j=0

def PrintNumber():
    global j
    j+=1
    print j
    return      

mgui=Tk()
mgui.geometry('200x200')
mgui.title('Queue System')

st = Button(mgui, text="Next Customer", command = PrintNumber)
st.pack()
f = PrintNumber()
label = Label(mgui, text=f)
label.pack()

mgui.mainloop()

Please be kind, i'm new in Python. :)

Upvotes: 2

Views: 3189

Answers (3)

Armin
Armin

Reputation: 102

Here is another way you could do it

import time 
import random
import MySQLdb
from Tkinter import *


def PrintNumber(label):
    PrintNumber.counter += 1 #simulates a static variable
    print PrintNumber.counter
    label.configure(text=str(PrintNumber.counter)) #you update label here

mgui=Tk()
mgui.geometry('200x200')
mgui.title('Queue System')

PrintNumber.counter = 0 #add an attribute to a function and use it as a static variable

label = Label(mgui) #create label

#pass the label as parameter to your function using lambda notation
st = Button(mgui, text="Next Customer", command=lambda label=label:PrintNumber(label))
st.pack()
label.pack()

mgui.mainloop()

Upvotes: 0

atlasologist
atlasologist

Reputation: 3964

You can use a Tkinter variable class instance to hold a value. If you assign the textvariable option of the Label widget to the variable class instance, it will update automatically as the value of the instance changes. Here's an example:

from Tkinter import *


root = Tk()

var = IntVar() # instantiate the IntVar variable class
var.set(0)     # set it to 0 as the initial value

# the button command is a lambda expression that calls the set method on the var,
# with the var value (var.get) increased by 1 as the argument    
Button(root, text="Next Customer", command=lambda: var.set(var.get() + 1)).pack()

# the label's textvariable is set to the variable class instance
Label(root, textvariable=var).pack()

mainloop()

Upvotes: 3

Simon
Simon

Reputation: 10841

You can change the label text in the function that responds to the command (PrintNumber() in this case) using label.config(), e.g.:

from tkinter import *

def PrintNumber():
    global j,label
    j+=1
    label.config(text=str(j))
    return     

j = 0

mgui=Tk()
mgui.geometry('200x200')
mgui.title('Queue System')

st = Button(mgui, text="Next Customer", command = PrintNumber)
st.pack()
label = Label(mgui, text=str(j))
label.pack()
mgui.mainloop()

Upvotes: 1

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