Kotlin Hello World App

Let?s develop a first hello word application on Android studio using Kotlin programming language. To develop android application launch Android Studio and select option 'Start a new Android Studio project'.

Provide a application name ('Hello World' in my case) and check 'Include Kotlin support' and proceed.

Select API level for android application and click next.

Select Activity type and click next.

activity_main.xml

Create an activity_main.xml file in layout folder and add the following code.

<?xml version="1.0" encoding="utf-8"?>
<android.support.constraint.ConstraintLayout 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:layout_height="match_parent"
    tools:context="example.app.javatpoint.helloworld.MainActivity">

    <TextView
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:text="Hello World!"
        app:layout_constraintBottom_toBottomOf="parent"
        app:layout_constraintLeft_toLeftOf="parent"
        app:layout_constraintRight_toRightOf="parent"
        app:layout_constraintTop_toTopOf="parent" />

</android.support.constraint.ConstraintLayout>

MainActivity.kt

Create MainActivity.kt file in example.app.javatpoint.helloworld package add the following code.

package example.app.javatpoint.helloworld

import android.support.v7.app.AppCompatActivity
import android.os.Bundle

class MainActivity : AppCompatActivity() {

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

Now run your app.