PYTHON FOR USER INTERFACE – TKINTER BASICS

Tkinter is a Graphical User Interface (GUI) package. It is used to create interactive user interface by adding widgets to the application.

INSTALLATION IN PYTHON(3.X)

The Tkinter package comes pre-installed in Python.

In the case that it is not installed open command prompt/terminal and type:

~pip install tkinter

MAIN METHODS OF TKINTER PACKAGE:

1. Tk(screenname = None, baseName =Name, class_ame = ‘Tk’ useTk=1)

To create a main window, Tkinter offers this method. To change the name of the window, you can change the class_name.

2. mainloop()

mainloop() is an infinite loop used to run the application infinitely and it waits for an event, such as closing the application, to stop the loop.

CREATING A SIMPLE WINDOW USING TKINTER.

1. Import tkinter

2. From Tkinter import everything (*).

3. Create a variable to store the body of the GUI.

4. To add the title use root.title(‘title’) function

5. To run the app and close the body use mainloop() function.

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import tkinter as tk
from tkinter
import *
root = tk.Tk()
root.title("First App")
#body of the GUI

root.mainloop()

ADDING GEOMETRY AND BACKGROUND COLOR

1. Import tkinter.

2. To specify the geometry use root.geometry(‘dimension’) function.

3. To give a background colour use

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root.config(bg = ’color_name / hex_color_code’)
root[‘background’] = ’color_name / hex_color_code’
root[‘bg’] = ’color_name / hex_color_code’

4. Close the body with root.mainloop().

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import tkinter as tk
root = tk.Tk()

root.title("First App")
root.geometry('300x300')
root.config(bg = 'gray')

root.mainloop()

ADDING BUTTON WIDGET AND ADD CLICK FUNCTION

The button widget is used to add a button. Buttons can display text or images and use the command function to call the function whenever the button is pressed.

1. Import tkinter

2. Import messagebox

3. Define a function, here dialogueBox().

4. Inside the function display a pop-up window use messagebox.showinfo()

5. Inside messagebox.showinfo() pass the title and the text of the pop-up.

6. To create a button widget use Button(‘text_of_button’,command = function_name).pack()

7. pack() is used to close the body of any widget.

8. We can show / ask various types of pop-messages like:

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showinfo()
showwaning()
showerror()
askquestion()
asktocancel()
askyesno()
askretrycancel()

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import tkinter
from tkinter
import messagebox

root = Tk()
root.geometry('100x100')

def box():
  messagebox.showinfo('Title', 'Hello World!')
tkinter.Button(root, text = "Click me", command = box)
  .pack()

root.mainloop()

Result:

ADDING LABEL AND ENTRY BOX WIDGET

1. Import tkinter.

2. From tkinter import Label and Text.

3. Create a window using mainloop().

4. To add a label widget use Label(window_name, options).

5. Options such as text, bg, height, width etc.

6. To place a widget to a specific place we use grid(row =row_value ,column= column_value).

7. Create an entry box using Entry(window_name) widget.

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import tkinter as tk
from tkinter
import *

root = tk.Tk()
root.geometry('200x200')

Label(root, text = 'Username ')
  .grid(row = 0, column = 0)
Entry(root)
  .grid(row = 0, column = 1)

root.mainloop()

FETCHING DATA FROM ENTRY BOX AND DISPLAYING IN A NEW DIALOGUE BOX

Creating a simple login app.

1. Import tkinter.

2. From tkinter import messagebox, Label, Button, Entry.

3. Create two labels and two entry boxes.

4. Create a function showData() to fetch and display the dialoguebox.

5. To fetch the data from the Entry field use get() function.

6. Pass get() function to showinfo() function.

7. Create a button login and set the command parameter to showData().

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import tkinter as tk
from tkinter
import Label, Entry, Button, messagebox

def showData():
  textName = name.get()
messagebox.showinfo('Logged in', textName + " logged in successful")

root = tk.Tk()
root.geometry('200x200')

Label(root, text = 'Username ')
  .grid(row = 0, column = 0)
Label(root, text = 'Password ')
  .grid(row = 1, column = 0)

name = Entry(root)
name.grid(row = 0, column = 1)
password = Entry(root, show = '*')
password.grid(row = 1, column = 1)

Button(root, text = "Login", command = showData)
  .grid(row = 2, column = 0, columnspan = 2)
root.mainloop()

Result: