Python | Aplicación GUI ToDo usando Tkinter

Python3

# import all functions from the tkinter  
from tkinter import *
 
# import messagebox class from tkinter
from tkinter import messagebox
 
# global list is declare for storing all the task
tasks_list = []
 
# global variable is declare for counting the task
counter = 1
 
# Function for checking input error when
# empty input is given in task field
def inputError() :
     
    # check for enter task field is empty or not
    if enterTaskField.get() == "" :
         
        # show the error message
        messagebox.showerror("Input Error")
         
        return 0
     
    return 1
 
# Function for clearing the contents
# of task number text field
def clear_taskNumberField() :
     
    # clear the content of task number text field
    taskNumberField.delete(0.0, END)
 
# Function for clearing the contents
# of task entry field  
def clear_taskField() :
 
    # clear the content of task field entry box
    enterTaskField.delete(0, END)
     
# Function for inserting the contents
# from the task entry field to the text area
def insertTask():
 
    global counter
     
    # check for error
    value = inputError()
 
    # if error occur then return
    if value == 0 :
        return
 
    # get the task string concatenating
    # with new line character
    content = enterTaskField.get() + "\n"
 
    # store task in the list
    tasks_list.append(content)
 
    # insert content of task entry field to the text area
    # add task one by one in below one by one
    TextArea.insert('end -1 chars', "[ " + str(counter) + " ] " + content)
 
    # incremented
    counter += 1
 
    # function calling for deleting the content of task field
    clear_taskField()
 
# function for deleting the specified task
def delete() :
     
    global counter
     
    # handling the empty task error
    if len(tasks_list) == 0 :
        messagebox.showerror("No task")
        return
 
    # get the task number, which is required to delete
    number = taskNumberField.get(1.0, END)
 
    # checking for input error when
    # empty input in task number field
    if number == "\n" :
        messagebox.showerror("input error")
        return
     
    else :
        task_no = int(number)
 
    # function calling for deleting the
    # content of task number field
    clear_taskNumberField()
     
    # deleted specified task from the list
    tasks_list.pop(task_no - 1)
 
    # decremented
    counter -= 1
     
    # whole content of text area widget is deleted
    TextArea.delete(1.0, END)
 
    # rewriting the task after deleting one task at a time
    for i in range(len(tasks_list)) :
        TextArea.insert('end -1 chars', "[ " + str(i + 1) + " ] " + tasks_list[i])
     
 
# Driver code
if __name__ == "__main__" :
 
    # create a GUI window
    gui = Tk()
 
    # set the background colour of GUI window
    gui.configure(background = "light green")
 
    # set the title of GUI window
    gui.title("ToDo App")
 
    # set the configuration of GUI window
    gui.geometry("250x300")
 
    # create a label : Enter Your Task
    enterTask = Label(gui, text = "Enter Your Task", bg = "light green")
 
    # create a text entry box
    # for typing the task
    enterTaskField = Entry(gui)
 
    # create a Submit Button and place into the root window
    # when user press the button, the command or
    # function affiliated to that button is executed
    Submit = Button(gui, text = "Submit", fg = "Black", bg = "Red", command = insertTask)
 
    # create a text area for the root
    # with lunida 13 font
    # text area is for writing the content
    TextArea = Text(gui, height = 5, width = 25, font = "lucida 13")
 
    # create a label : Delete Task Number
    taskNumber = Label(gui, text = "Delete Task Number", bg = "blue")
                        
    taskNumberField = Text(gui, height = 1, width = 2, font = "lucida 13")
 
    # create a Delete Button and place into the root window
    # when user press the button, the command or
    # function affiliated to that button is executed .
    delete = Button(gui, text = "Delete", fg = "Black", bg = "Red", command = delete)
 
    # create a Exit Button and place into the root window
    # when user press the button, the command or
    # function affiliated to that button is executed .
    Exit = Button(gui, text = "Exit", fg = "Black", bg = "Red", command = exit)
 
    # grid method is used for placing
    # the widgets at respective positions
    # in table like structure.
    enterTask.grid(row = 0, column = 2)
 
    # ipadx attributed set the entry box horizontal size              
    enterTaskField.grid(row = 1, column = 2, ipadx = 50)
                        
    Submit.grid(row = 2, column = 2)
         
    # padx attributed provide x-axis margin
    # from the root window to the widget.
    TextArea.grid(row = 3, column = 2, padx = 10, sticky = W)
                        
    taskNumber.grid(row = 4, column = 2, pady = 5)
                        
    taskNumberField.grid(row = 5, column = 2)
 
    # pady attributed provide y-axis
    # margin from the widget.                 
    delete.grid(row = 6, column = 2, pady = 5)
                        
    Exit.grid(row = 7, column = 2)
 
    # start the GUI
    gui.mainloop()