calculator.py

from kivy.app import App
from kivy.uix.widget import Widget
from kivy.core.window import Window
from kivy.lang.builder import Builder
import re

Builder.load_file('./calculator.kv')
Window.size = (350, 550)

class CalculatorWidget(Widget):
    def clear(self):
        self.ids.input_box.text = '0'

    def button_value(self, number):
        prev_number = self.ids.input_box.text

        if "Wrong Equation" in prev_number:
            prev_number = ''

        if prev_number == '0':
            self.ids.input_box.text = ''
            self.ids.input_box.text = f"{number}"
        else:
            self.ids.input_box.text = f"{prev_number}{number}"

    def signs(self, sign):
        prev_number = self.ids.input_box.text
        self.ids.input_box.text = f"{prev_number}{sign}"

    def remove_last(self):
        prev_number = self.ids.input_box.text
        prev_number = prev_number[:-1]
        self.ids.input_box.text = prev_number

    def results(self):
        prev_number = self.ids.input_box.text
        try:
            result = eval(prev_number)
            self.ids.input_box.text = str(result)
        except:
            self.ids.input_box.text = "Wrong Equation"

    def positive_negative(self):
        prev_number = self.ids.input_box.text

        if "-" in prev_number:
            self.ids.input_box.text = f"{prev_number.replace('-', '')}"
        else:
            self.ids.input_box.text = f"-{prev_number}"

    def dot(self):
        prev_number = self.ids.input_box.text
        num_list = re.split("\+|\*|-|/|%", prev_number)

        if ("+" in prev_number or "-" in prev_number or "/" in prev_number or "*" in prev_number or "%" in prev_number) and "." not in num_list[-1]:
            prev_number = f"{prev_number}."
            self.ids.input_box.text = prev_number

        elif "." in prev_number:
            pass
        else:
            prev_number = f"{prev_number}."
            self.ids.input_box.text = prev_number

class CalculatorApp(App):
    def build(self):
        return CalculatorWidget()

if __name__ == "__main__":
    CalculatorApp().run()