Python Kivy: Build a standard calculator application – GUI part-1

In this tutorial, we will learn how to build a standard calculator application using Python Kivy. Kivy is an open-source Python library for developing multitouch applications. It is cross-platform and supports various operating systems such as Windows, macOS, Linux, Android, and iOS.

Getting Started with Kivy

Before we start building our calculator application, we need to install Kivy. You can install Kivy using pip by running the following command:

    
      pip install kivy
    
  

Once Kivy is installed, we can begin building our calculator application.

Building the GUI

First, we need to create a new Python file for our calculator application. We’ll start by importing the necessary modules and creating the main application class. We’ll also define the layout and add the necessary widgets for our calculator.

    
      import kivy
      from kivy.app import App
      from kivy.uix.gridlayout import GridLayout
      from kivy.uix.button import Button
      from kivy.uix.textinput import TextInput

      class CalculatorApp(App):
          def build(self):
              layout = GridLayout(cols=4)
              buttons = [
                  '7', '8', '9', '/',
                  '4', '5', '6', '*',
                  '1', '2', '3', '-',
                  'C', '0', '=', '+'
              ]
              for button in buttons:
                  if button == '=':
                      equals_button = Button(text=button)
                      equals_button.bind(on_press=self.calculate)
                      layout.add_widget(equals_button)
                  elif button == 'C':
                      clear_button = Button(text=button)
                      clear_button.bind(on_press=self.clear)
                      layout.add_widget(clear_button)
                  else:
                      layout.add_widget(Button(text=button))

              self.text_input = TextInput(multiline=False)
              layout.add_widget(self.text_input)

              return layout

          def calculate(self, instance):
              # logic for calculating and displaying the result

          def clear(self, instance):
              # logic for clearing the input

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

In the code above, we create a GridLayout with 4 columns to arrange the buttons in a grid format. We then create buttons for the numbers, arithmetic operators, and the equals and clear buttons. We also add a TextInput widget for displaying the input and output of the calculator.

Conclusion

In this part of the tutorial, we learned how to build the GUI for a standard calculator application using Python Kivy. In the next part, we will implement the logic for calculating the input and displaying the result.