Simple Counting App Using Kotlin

 XML Code: 

 

<?xml version="1.0" encoding="utf-8"?>
<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
    xmlns:app="http://schemas.android.com/apk/res-auto"
    xmlns:tools="http://schemas.android.com/tools"
    android:layout_width="match_parent"
    android:orientation="vertical"
    android:gravity="center"
    android:layout_height="match_parent"
    tools:context=".MainActivity">

<TextView
    android:id="@+id/textCount"
    android:layout_width="wrap_content"
    android:layout_height="wrap_content"
  android:text="24"
    android:layout_marginBottom="50dp"
  android:textSize="80sp"/>

  <LinearLayout
      android:layout_width="wrap_content"
      android:orientation="horizontal"
      android:layout_height="wrap_content">

    <Button
        android:id="@+id/btnMinus"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:layout_marginEnd="20dp"
        android:text="Minus(-)"/>
  <Button
    android:id="@+id/btnAdd"
      android:layout_width="wrap_content"
      android:layout_height="wrap_content"
      android:layout_marginStart="20dp"
    android:text="Add(+)"/>


  </LinearLayout>
  <Button
      android:id="@+id/btnReset"
      android:layout_width="wrap_content"
      android:layout_height="wrap_content"
      android:text="Reset(0)"/>


</LinearLayout>

 

 GRADLE :App (plugin):

 

plugins {
    id 'com.android.application'
    id 'kotlin-android'
    id 'kotlin-android-extensions'
}

 

KOTLIN Code: 

 

package com.akhil.kotlintutorialapp

import androidx.appcompat.app.AppCompatActivity
import android.os.Bundle
import kotlinx.android.synthetic.main.activity_main.*

class MainActivity : AppCompatActivity() {
    override fun onCreate(savedInstanceState: Bundle?) {
        super.onCreate(savedInstanceState)
        setContentView(R.layout.activity_main)

        var count = 0
        textCount.text = count.toString()

        btnAdd.setOnClickListener {
            textCount.text = (count + 1).toString()
            count = count +1
        }

        btnMinus.setOnClickListener {
            textCount.text = (count - 1).toString()
            count = count -1
        }

        btnReset.setOnClickListener {
            textCount.text = 0.toString()
            count = 0
        }

    }
}