MainActivity.kt - batooldshilleh/TrainingTasks GitHub Wiki

Introduction:

This is the Kotlin part.

What can we do within this file?

1. Package Declaration:

   • package com.example.myapplication: Declares the package name for the application.

2. Imports:

   • Import necessary classes from Android framework: AppCompatActivity, Bundle, View, Button, EditText, TextView.

3. MainActivity Class Declaration:

   • Declares a class named MainActivity which extends AppCompatActivity and implements View.OnClickListener interface.

4. Properties Declaration:

   • Private properties for various UI components:
     • btnAdd, btnSub, btnMultiply, btnDivision: Buttons for arithmetic operations.
     • etA, etB: EditText fields for inputting numbers.
     • resultTv: TextView for displaying the result.

5. onCreate() Method:

   • Override the onCreate() method from AppCompatActivity.
   • Call the superclass's onCreate() method and set the content view to the layout defined in activity_main.xml.
   • Initialize UI components by finding their views using findViewById().
   • Set OnClickListener to each button.

6. onClick() Method:

   • Override the onClick() method from View.OnClickListener.
   • Handle click events of buttons.
   • Retrieve the input values from etA and etB, convert them to double.
   • Perform the corresponding arithmetic operation based on the clicked button using a when expression.
   • Update the resultTv TextView with the computed result.