Write a GUI-based program that allows the user to open, edit, and save text files. The GUI should include a labeled entry field for the filename and multi-line text widget for the text of the file. The user should be able to scroll through the text by manipulating a vertical scrollbar. Include command buttons labeled Open, Save, and New that allow the user to open, save and create new files. The New command should then clear the text widget and the entry widget.

to create a simple notepad in Python using Tkinter. This notepad GUI will consist of various menu like file and edit, using which all functionalities like saving the file, opening a file, editing, cut and paste can be done.

Now for creating this notepad, Python 3 and Tkinter should already be installed in your system. You can download suitable python package as per system requirement. After you have successfully installed python you need to install Tkinter (a Python’s GUI package).

Use this command to install Tkinter :

pip install python-tk

Importing Tkinter :

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import tkinter  

import os  

from tkinter import *

# To get the space above for message  

from tkinter.messagebox import *

# To get the dialog box to open when required  

from tkinter.filedialog import *

Note : messagebox is used to write the message in the white box called notepad and filedialog is used for the dialog box to appear when you are opening file from anywhere in your system or saving your file in a particular position or place.

Adding Menu :

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# Add controls(widget)  

self.__thisTextArea.grid(sticky = N + E + S + W)  

# To open new file  

self.__thisFileMenu.add_command(label = "New",  

                               command = self.__newFile)  

# To open a already existing file  

self.__thisFileMenu.add_command(label = "Open",  

                               command = self.__openFile)  

# To save current file  

self.__thisFileMenu.add_command(label = "Save",  

                               command = self.__saveFile)  

# To create a line in the dialog  

self.__thisFileMenu.add_separator()  

# To terminate  

self.__thisFileMenu.add_command(label = "Exit",  

                               command = self.__quitApplication)  

self.__thisMenuBar.add_cascade(label = "File",  

                              menu = self.__thisFileMenu)  

# To give a feature of cut  

self.__thisEditMenu.add_command(label = "Cut",  

                               command = self.__cut)  

# To give a feature of copy  

self.__thisEditMenu.add_command(label = "Copy",  

                               command = self.__copy)  

# To give a feature of paste  

self.__thisEditMenu.add_command(label = "Paste",  

                               command = self.__paste)  

# To give a feature of editing  

self.__thisMenuBar.add_cascade(label = "Edit",  

                              menu = self.__thisEditMenu)  

# To create a feature of description of the notepad  

self.__thisHelpMenu.add_command(label = "About Notepad",  

                               command = self.__showAbout)  

self.__thisMenuBar.add_cascade(label = "Help",  

                              menu = self.__thisHelpMenu)  

self.__root.config(menu = self.__thisMenuBar)  

self.__thisScrollBar.pack(side = RIGHT, fill = Y)  

# Scrollbar will adjust automatically  

# according to the content  

self.__thisScrollBar.config(command = self.__thisTextArea.yview)  

self.__thisTextArea.config(yscrollcommand = self.__thisScrollBar.set)  

With this code we will add the menu in the windows of our notepad and will add the things like copy, paste, save etc, to it.

Explanation: