Let’s Build A Calculator – Object Oriented Tkinter 4

In this video we’ll start to build out a Calculator using Object Oriented Tkinter and Python.

I’ve created calculators in the past using functional calculator, but in this video we’ll use OOP.

We’ll take what we’ve learned in the last few videos with class based code.

Python Code: class_calc.py
(Github Code)

from tkinter import *

class App(Tk):
	def __init__(self):
		super().__init__()

		# Title, icon, size
		self.title("Tkinter.com - OOP Calculator")
		self.iconbitmap('images/codemy.ico')
		self.geometry('500x850')

		# Create Widgets
		self.my_entry = Entry(self, width=25, font=("Helvetica", 24))
		self.my_entry.pack(pady=20)

		# Create a new frame to hold the button
		My_frame(self)

	# Clear the entry box
	def clear(self):
		self.my_entry.delete(0, END)

	# Flip numbers positive or negative
	def pos_neg(self):
		if self.my_entry.get():
			# Get whatever is in the entry box
			number = int(self.my_entry.get())
			# Delete Entry Box
			self.my_entry.delete(0, END)
			# Flip the number sign -/+
			self.my_entry.insert(0, (-1) * number)



# Button Frame Class
class My_frame(Frame):
	def __init__(self, parent):
		super().__init__(parent)
		# Pack the frame
		self.pack()
		# Define the buttons
		self.button_1 = Button(self, text="1", font=("Helvetica", 24))
		self.button_2 = Button(self, text="2", font=("Helvetica", 24))
		self.button_3 = Button(self, text="3", font=("Helvetica", 24))

		self.button_4 = Button(self, text="4", font=("Helvetica", 24))
		self.button_5 = Button(self, text="5", font=("Helvetica", 24))
		self.button_6 = Button(self, text="6", font=("Helvetica", 24))

		self.button_7 = Button(self, text="7", font=("Helvetica", 24))
		self.button_8 = Button(self, text="8", font=("Helvetica", 24))
		self.button_9 = Button(self, text="9", font=("Helvetica", 24))

		self.button_0 = Button(self, text="0", font=("Helvetica", 24))
		self.button_negative = Button(self, text="+/-", font=("Helvetica", 24), command=parent.pos_neg)
		self.button_equal = Button(self, text="=", font=("Helvetica", 24))

		self.button_plus = Button(self, text="+", font=("Helvetica", 24))
		self.button_minus = Button(self, text="-", font=("Helvetica", 24))
		self.button_multiply = Button(self, text="*", font=("Helvetica", 24))

		self.button_divide = Button(self, text="/", font=("Helvetica", 24))
		self.button_clear = Button(self, text="Clear", font=("Helvetica", 24), command=parent.clear)

		# Grid the buttons to the screen
		self.button_1.grid(row=0, column=0, ipadx=40, ipady=20, padx=(0, 10))
		self.button_2.grid(row=0, column=1, ipadx=40, ipady=20)
		self.button_3.grid(row=0, column=2, ipadx=40, ipady=20, padx=(10, 0))

		self.button_4.grid(row=1, column=0, ipadx=40, ipady=20, padx=(0, 10), pady=10)
		self.button_5.grid(row=1, column=1, ipadx=40, ipady=20, pady=10)
		self.button_6.grid(row=1, column=2, ipadx=40, ipady=20, padx=(10, 0), pady=10)

		self.button_7.grid(row=2, column=0, ipadx=40, ipady=20, padx=(0, 10), pady=10)
		self.button_8.grid(row=2, column=1, ipadx=40, ipady=20, pady=10)
		self.button_9.grid(row=2, column=2, ipadx=40, ipady=20, padx=(10, 0), pady=10)

		self.button_0.grid(row=3, column=0, ipadx=40, ipady=20, padx=(0, 10), pady=10)
		self.button_negative.grid(row=3, column=1, ipadx=31, ipady=20, pady=10)
		self.button_equal.grid(row=3, column=2, ipadx=40, ipady=20, padx=(10, 0), pady=10)

		self.button_plus.grid(row=4, column=0, ipadx=40, ipady=20, padx=(0, 10), pady=10)
		self.button_minus.grid(row=4, column=1, ipadx=40, ipady=20, pady=10)
		self.button_multiply.grid(row=4, column=2, ipadx=40, ipady=20, padx=(10, 0), pady=10)

		self.button_divide.grid(row=5, column=0, ipadx=42, ipady=20, padx=(0, 10), pady=10)
		self.button_clear.grid(row=5, column=1, columnspan=2, ipadx=84, ipady=20, padx=(10, 0), pady=10)

	
# Define and instantiate our app
app = App()
app.mainloop()