How to create a Custom Ratingbar in Android using Kotlin?

This example demonstrates how to create a Custom Ratingbar in Android using Kotlin.
Step 1 − Create a new project in Android Studio, go to File ⇒ New Project and fill all required details to create a new project.
Step 2 − Add the following code to res/layout/activity_main.xml.
<RelativeLayout xmlns:android="http://schemas.android.com/apk/res/android"
xmlns:tools="http://schemas.android.com/tools"
   android:layout_width="match_parent"
   android:layout_height="match_parent"
   android:padding="16sp"
   tools:context=".MainActivity">
   <RatingBar
      android:id="@+id/ratingBar"
      android:layout_width="wrap_content"
      android:layout_height="wrap_content"
      android:layout_alignParentTop="true"
      android:layout_centerHorizontal="true"
      android:numStars="5"
      android:rating="2.0"
      android:stepSize="1.0" />
   <Button
      android:id="@+id/buttonCheck"
      android:layout_width="match_parent"
      android:layout_height="wrap_content"
      android:layout_below="@id/ratingBar"
      android:layout_centerHorizontal="true"
      android:text="CHECK" />
   <TextView
      android:id="@+id/textView"
      android:layout_width="wrap_content"
      android:layout_height="wrap_content"
      android:layout_centerInParent="true"
      android:textColor="@android:color/holo_red_dark"
      android:textSize="24sp" />
</RelativeLayout>
Step 3 − Add the following code to src/MainActivity.kt
import android.os.Bundle
import android.widget.Button
import android.widget.RatingBar
import android.widget.RatingBar.OnRatingBarChangeListener
import android.widget.TextView
import android.widget.Toast
import androidx.appcompat.app.AppCompatActivity
class MainActivity : AppCompatActivity() {
   lateinit var ratingBar: RatingBar
   lateinit var button: Button
   lateinit var textView: TextView
   override fun onCreate(savedInstanceState: Bundle?) {
      super.onCreate(savedInstanceState)
      setContentView(R.layout.activity_main)
      title = "KotlinApp"
      ratingBar = findViewById(R.id.ratingBar)
      ratingBar.numStars = 5
      button = findViewById(R.id.buttonCheck)
      textView = findViewById(R.id.textView)
      ratingBar.onRatingBarChangeListener =
      OnRatingBarChangeListener {
         _, rating, _ ->
         Toast.makeText(
         this@MainActivity, "Stars: " +
         rating.toInt(), Toast.LENGTH_SHORT
         ).show()
      }
      button.setOnClickListener {
         textView.text = "You have got " + ratingBar.rating.toInt()+ " stars"
      }
   }
}
Step 4 − Add the following code to androidManifest.xml
<?xml version="1.0" encoding="utf-8"?> 
<manifest xmlns:android="http://schemas.android.com/apk/res/android" package="app.com.q11">
   <application
      android:allowBackup="true"
      android:icon="@mipmap/ic_launcher"
      android:label="@string/app_name"
      android:roundIcon="@mipmap/ic_launcher_round"
      android:supportsRtl="true"
      android:theme="@style/AppTheme">
      <activity android:name=".MainActivity">
         <intent-filter>
            <action android:name="android.intent.action.MAIN" />
            <category android:name="android.intent.category.LAUNCHER" />
         </intent-filter>
      </activity>
</application>
Let's try to run your application. I assume you have connected your actual Android Mobile device with your computer. To run the app from android studio, open one of your project's activity files and click the Run icon from the toolbar. Select your mobile device as an option and then check your mobile device which will display your default screen