Update label text after pressing a button in Tkinter

Question

I was wondering how to change the label text after clicking a button. For example:

from Tkinter import *
import tkMessageBox

def onclick():
    pass

root = Tk()

root.title("Pantai Hospital")

L1 = Label(root, text='Welcome to Pantai Hospital!')
L1.pack() 
L2 = Label(root, text='Login')
L2.pack() 

L3 = Label(root, text = "Username:")
L3.pack( side = LEFT, padx = 5, pady = 10)
username = StringVar()
E1 = Entry(root, textvariable = username, width = 40)
E1.pack ( side = LEFT)

L4 = Label(root, text = "Password:")
L4.pack( side = LEFT, padx = 5, pady = 10)
password = StringVar() 
E2 = Entry(root, textvariable = password, show = "*", width = 40)    
E2.pack( side = LEFT)'`

I want to change those labels username and password and the entry field into another different label after clicking a button. How do I do that?

Photoluminescence

Split the task in two: 1. how to do anything (e.g., print("something")) on pressing a button? 2. how to change label text? – Pruritus

first create button ;) – Cloudless

Answer 1

Answer for "how to do anything on pressing button" should be in any tutorial.
For example in effbot book: Button

Use command= to assign function name to button.

(btw: function name (or callback) means name without parenthesis and arguments)

btn = Button(root, text="OK", command=onclick)

---

Answer for "how to change label text" should be in any tutorial too.

lbl = Label(root, text="Old text")

# change text

lbl.config(text="New text")

# or

lbl["text"] = "New text"

---

If you want to change Entry into Label then remove/hide Entry (widget.pack_forget()) or destroy it (widget.destroy()) and create Label.

btw: you can disable Entry instead of making Label (ent.config(state='disabled'))

---

EDIT: I removed dot in lbl.["text"]

Cloudless

Thanks! it's very helpful. – Photoluminescence

lbl.["text"] needs to be lbl["text"] Thanks. – Carincarina

Answer 2

write lbl.pack() after you write the button.pack() A small snippet of code to display change in value on clicking a button. This is done so that the changes made in the label will be shown after you perform the button click.

    from tkinter import *

    root = Tk(className = "button_click_label")
    root.geometry("200x200")

    message = StringVar()
    message.set('hi')

    l1 = Label(root, text="hi")


    def press():
        l1.config(text="hello")

    b1 = Button(root, text = "clickhere", command = press).pack()

    l1.pack()

    root.mainloop()

---

Im just an entry level python programmer. Forgive , and do correct me if I'm wrong! Cheers!

Tepper

Answer 3

Another way to alter a label dynamically. here we use lambda to show multiple adjustments to a label display. if you want to go with one label change simply disregard lambda and call the function without a parameter (in this case the 1 and 2). remember to ensure you separate .pack method when creating a label for this use or you'll get an error when the function attempts to config a line with the .pack method.

from tkinter import *  

root = Tk(className = "button_click_label")  
root.geometry("200x200")
  
def press(x):  
    if x == 1:  
        l1.config(text='hello')    
    else:    
        l1.config(text='hi')  

b1 = Button(root, text = "click me", command = lambda:press(1)).pack()  
b2 = Button(root, text = 'click me', command = lambda:press(2)).pack()

l1 = Label(root, text="waiting for click")  
l1.pack()

root.mainloop()

Dowie

Answer 4

Here is an example where I created a basic gui with a label. Then I changed the label text.

import tkinter as tk
from tkinter import *
app = tk.Tk()
#creating a Label
label = Label(app,  text="unchanged")
label.pack()
#updating text 
label.config(text="changed")
app.mainloop()

Philina

Answer 5

This should work:

from tkinter import *

root = Tk(className = "button_click_label")
root.geometry("200x200")

message = StringVar()
message.set('hi')

l1 = Label(root, text="hi")
l1.pack()

def press():
    l1.config(text="hello")

b1 = Button(root, text = "clickhere", command = press).pack()

root.mainloop()

Jazzy

Answer 6

Here is a simple dice roller. In the on_click function you will see that label5 text is being changed to whatever dice was rolled, you can click the button many many times and get the label to change each and every time. I know this question has been answered multiple times but no one has suggested label["text"] = "some text". So i am adding it as an answer because it works:

from tkinter import *
import random

root = Tk()
root.title("Die Roller")

entry1 = Entry(root, width = 5)
entry2 = Entry(root, width = 5)

def on_click():
    r = 0
    for z in range(0, int(entry1.get())):
        r += random.randint(1, int(entry2.get()))
    label5["text"] = r

label1 = Label(root, text = "Die Roller!")
label2 = Label(root, text = "Number of Die")
label3 = Label(root, text = "Number of Sides")
label4 = Label(root, text = "Total")
label5 = Label(root, text = " ")
button = Button(root, text = "Roll", command = on_click)

label1.grid(column = 1, row = 0)
label2.grid(column = 0, row = 1)
label3.grid(column = 0, row = 2)
entry1.grid(column = 2, row = 1)
entry2.grid(column = 2, row = 2)
label4.grid(column = 0, row = 4)
label5.grid(column = 2, row = 4)
button.grid(column = 1, row = 3)

root.mainloop()

Isomer