from kivy.app import App
from kivy.uix.gridlayout import GridLayout
from kivy.uix.button import Button
from kivy.uix.widget import Widget
from kivy.uix.label import Label
from kivy.uix.boxlayout import BoxLayout
from kivy.config import Config
Config.set('graphics', 'resizable', '0')
Config.set('graphics', 'width', '400')
Config.set('graphics', 'height', '500')


class CalculatorApp(App):
    def update_label(self):
        self.lbl.text = self.formula
    def add_number(self,instance):
        if self.formula == '0':
            self.formula = ''
        self.formula += str(instance.text)
        self.update_label()
    def add_operation(self,instance):
        if str(instance.text).lower() == 'x':
            self.formula += '*'
        else:
            self.formula += str(instance.text)
        self.update_label()
    def calc_result(self,instance):
        self.lbl.text = str(eval(self.lbl.text))
        self.formula = '0'
    def build(self):
        self.formula = '0'
        bl = BoxLayout(orientation = 'vertical',padding = 10)
        self.lbl = Label(text = '0', font_size = 40, size_hint = (1,.4),halign = 'right',valign = 'center', text_size = (400-20,500 * .4 - 20)) # font_size - размер текста
        # text_size задает размеры текстуры текста. 1 - ширина, 2 - высота
        bl.add_widget(self.lbl)
        gl = GridLayout(cols = 4, spacing = 1, size_hint = (1,.6))
        gl.add_widget(Button(text = '7', on_press = self.add_number))
        gl.add_widget(Button(text='8', on_press = self.add_number))
        gl.add_widget(Button(text='9', on_press = self.add_number))
        gl.add_widget(Button(text='X',on_press = self.add_operation))

        gl.add_widget(Button(text='4', on_press = self.add_number))
        gl.add_widget(Button(text='5', on_press = self.add_number))
        gl.add_widget(Button(text='6', on_press = self.add_number))
        gl.add_widget(Button(text='-',on_press = self.add_operation))

        gl.add_widget(Button(text='1', on_press = self.add_number))
        gl.add_widget(Button(text='2', on_press = self.add_number))
        gl.add_widget(Button(text='3', on_press = self.add_number))
        gl.add_widget(Button(text='+',on_press = self.add_operation))

        gl.add_widget(Button(text='/', on_press = self.add_operation))
        gl.add_widget(Button(text='0', on_press = self.add_number))
        gl.add_widget(Button(text='.', on_press = self.add_number))
        gl.add_widget(Button(text='=',on_press = self.calc_result))
        bl.add_widget(gl)
        return bl

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