15-7. Entry widget

An Entry widget is a rectangular area within a graphical user interface where users can input text. It serves as a means to collect user input in a GUI program. Typically, an Entry widget is accompanied by a button for submitting the entered data. The callback function attached to the button retrieves the data from the Entry widget(s) and performs necessary processing. To retrieve data from an Entry widget, the get() method is employed, which returns the entered text as a string.

Example 1

This example demonstrates how to input two numbers, add them together, and display the result using an Entry widget.

from tkinter import *
from tkinter import messagebox

class FirstGUI:

def __init__(self):
        self.main_window = Tk()
        self.main_window.geometry('400x200')

self.label1 = Label(self.main_window, text="Number 1")
        self.label1.grid(row=0, column=0)
        self.entry1 = Entry(self.main_window)
        self.entry1.grid(row=0, column=1)

self.label2 = Label(self.main_window, text="Number 2")
        self.label2.grid(row=1, column=0)
        self.entry2 = Entry(self.main_window)
        self.entry2.grid(row=1, column=1)

self.label3 = Label(self.main_window, text="Sum")
        self.label3.grid(row=2, column=0)
        self.entry3 = Entry(self.main_window)
        self.entry3.grid(row=2, column=1)

self.button = Button(self.main_window, text="Click to add", 
                             command=self.sum)
        self.button.grid(row=3, column=1)

self.main_window.title('My First GUI')

self.main_window.mainloop()

def sum(self):
        try:
            num1 = int(self.entry1.get())
            num2 = int(self.entry2.get())
            sum = num1 + num2
            self.entry3.delete(0, END)  # Clear any previous value
            self.entry3.insert(0, sum)
        except ValueError:
            messagebox.showerror("Error", "Please enter valid numbers")

if __name__ == '__main__':
    FirstGUI()

Output:

After entering two numbers, click Sum button.

Example 2: StringVar

To display data, initiate a StringVar object and then establish a Label widget, linking it to the StringVar object. Following this, any data stored within the StringVar object will be promptly showcased in the Label widget.

from tkinter import *
from tkinter import messagebox

class FirstGUI:

def __init__(self):
        self.main_window = Tk()
        self.main_window.geometry('400x200')

self.label1 = Label(self.main_window, text="Number 1")
        self.label1.grid(row=0, column=0)
        self.entry1 = Entry(self.main_window)
        self.entry1.grid(row=0, column=1)

self.label2 = Label(self.main_window, text="Number 2")
        self.label2.grid(row=1, column=0)
        self.entry2 = Entry(self.main_window)
        self.entry2.grid(row=1, column=1)

self.label3 = Label(self.main_window, text="Sum")
        self.label3.grid(row=2, column=0)

self.value = StringVar()
        self.label4 = Label(self.main_window, textvariable=self.value)
        self.label4.grid(row=2, column=1)

self.button = Button(self.main_window, text="Click to add", 
                             command=self.sum)
        self.button.grid(row=3, column=1)

self.main_window.title('My First GUI')

self.main_window.mainloop()

def sum(self):
        try:
            num1 = int(self.entry1.get())
            num2 = int(self.entry2.get())
            sum = num1 + num2
            self.value.set(sum)
        except ValueError:
            messagebox.showerror("Error", "Please enter valid numbers")

if __name__ == '__main__':
    FirstGUI()

Output:

Last updated: April 22, 2025

Python Programming

15-7. Entry widget