How to Build a Text Editor with Python

Introduction
Prerequisites
Setting Up
Creating the GUI
Adding Functionality
Conclusion

Introduction

In this tutorial, we will learn how to build a simple text editor using Python. By the end of this tutorial, you will have created a basic text editor with a graphical user interface (GUI) and the ability to perform common text editing tasks.

Prerequisites

Before starting this tutorial, you should have a basic understanding of Python programming concepts. Familiarity with the Tkinter library, which is used for creating the GUI, will also be helpful. If you are new to Tkinter, you may want to refer to the official documentation for additional information.

Setting Up

To get started, make sure you have Python installed on your system. You can download the latest version of Python from the official website and follow the installation instructions for your operating system.

Once Python is installed, open your preferred code editor or IDE. We will be working with Python’s built-in IDLE for this tutorial, but you can use any code editor of your choice.

Creating the GUI

Begin by creating a new Python file and importing the necessary modules:

 from tkinter import Tk, Text, Scrollbar, Menu, messagebox, filedialog

Next, create a class called TextEditor that inherits from the Tk class:

 class TextEditor(Tk):
     def __init__(self):
         super().__init__()
         self.title("Text Editor")
	        
         # Initialize the text widget
         self.text = Text(self, wrap="word", undo=True)
         self.text.pack(expand=True, fill="both")
	        
         # Add a scrollbar
         scrollbar = Scrollbar(self.text)
         scrollbar.pack(side="right", fill="y")
         self.text.configure(yscrollcommand=scrollbar.set)
         scrollbar.configure(command=self.text.yview)
	        
         # Create the menu bar
         self.menu_bar = Menu(self)
         self.config(menu=self.menu_bar)
	        
         # Add File menu
         self.file_menu = Menu(self.menu_bar, tearoff=False)
         self.menu_bar.add_cascade(label="File", menu=self.file_menu)
	        
         # Add Edit menu
         self.edit_menu = Menu(self.menu_bar, tearoff=False)
         self.menu_bar.add_cascade(label="Edit", menu=self.edit_menu)

Now, let’s add the functionality to open and save files. Add the following code to the TextEditor class:

 def open_file(self):
     file = filedialog.askopenfile(mode="r")
     if file:
         self.text.delete("1.0", "end")
         self.text.insert("1.0", file.read())
	
 def save_file(self):
     file = filedialog.asksaveasfile(mode="w")
     if file:
         file.write(self.text.get("1.0", "end-1c"))
         file.close()

Next, let’s add the functionality to undo and redo changes. Add the following code to the TextEditor class:

 def undo(self):
     try:
         self.text.edit_undo()
     except:
         pass
	
 def redo(self):
     try:
         self.text.edit_redo()
     except:
         pass

Finally, let’s add a method to run the text editor. Add the following code to the TextEditor class:
```
 def run(self):
     self.mainloop()
```
To run the text editor, create an instance of the TextEditor class and call the run() method:
```
 if __name__ == "__main__":
     editor = TextEditor()
     editor.run()
```
Congratulations! You have successfully created a basic text editor using Python and Tkinter.

Adding Functionality

Now that we have a basic text editor, let’s add some additional functionality to enhance the user experience.

Let’s start by adding a “New” option to the File menu. Add the following code inside the __init__ method of the TextEditor class:
```
 self.file_menu.add_command(label="New", command=self.new_file)
```

Next, add the following method to the TextEditor class to handle the “New” option:

 def new_file(self):
     result = messagebox.askyesno("New File", "Are you sure you want to create a new file? Any unsaved changes will be lost.")
     if result:
         self.text.delete("1.0", "end")

Let’s also add a shortcut for the “Save” option. Update the following line inside the __init__ method of the TextEditor class:
```
 self.file_menu.add_command(label="Save", command=self.save_file, accelerator="(Ctrl+S)")
```
Next, bind the keyboard shortcut to the “Save” option by adding the following code inside the __init__ method of the TextEditor class:
```
 self.bind("<Control-s>", lambda event: self.save_file())
```
Let’s add a “Cut” option to the Edit menu. Add the following code inside the __init__ method of the TextEditor class:
```
 self.edit_menu.add_command(label="Cut", command=self.cut_text, accelerator="(Ctrl+X)")
```

Implement the cut_text method to handle the “Cut” option:

 def cut_text(self):
     self.clipboard_clear()
     self.clipboard_append(self.text.selection_get())
     self.text.delete("sel.first", "sel.last")

Repeat the above steps to add “Copy” and “Paste” options to the Edit menu. Use the following code for the “Copy” option:

 self.edit_menu.add_command(label="Copy", command=self.copy_text, accelerator="(Ctrl+C)")

And the following code for the “Paste” option:

 self.edit_menu.add_command(label="Paste", command=self.paste_text, accelerator="(Ctrl+V)")

Implement the methods copy_text and paste_text:
```
 def copy_text(self):
     self.clipboard_clear()
     self.clipboard_append(self.text.selection_get())
	
 def paste_text(self):
     self.text.insert("insert", self.clipboard_get())
```
That’s it! You have added some additional functionality to the text editor, including the ability to create a new file, save files with a shortcut, and perform basic text editing tasks like cut, copy, and paste.

Conclusion

In this tutorial, you learned how to build a text editor using Python and the Tkinter library. You started by creating a basic GUI with a text widget and a scrollbar. Then, you added functionality to open and save files, as well as undo and redo changes. Finally, you added additional options to the File and Edit menus to enhance the user experience.

With the knowledge and skills gained from this tutorial, you can further explore and improve your text editor by adding more features or customizing the interface. Happy coding!

Published: 17 December 2019