How to register a broadcast receiver Programmatically in Android using Kotlin?

This example demonstrates how to register a broadcast receiver Programmatically 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.

<?xml version="1.0" encoding="utf-8"?>
<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"
   tools:context=".MainActivity">
   <TextView
      android:layout_width="wrap_content"
      android:layout_height="wrap_content"
      android:layout_centerHorizontal="true"
      android:layout_marginTop="50dp"
      android:text="Tutorials Point"
      android:textAlignment="center"
      android:textColor="@android:color/holo_green_dark"
      android:textSize="32sp"
      android:textStyle="bold" />
   <TextView
      android:layout_width="wrap_content"
      android:layout_height="wrap_content"
      android:layout_centerInParent="true"
      android:text="BroadCastReceiver"
      android:textColor="@android:color/holo_blue_dark"
      android:textSize="24sp" />
</RelativeLayout>

Step 3 − Add the following code to src/MainActivity.kt

import android.content.BroadcastReceiver
import android.content.Context
import android.content.Intent
import android.content.IntentFilter
import android.net.ConnectivityManager
import android.os.Bundle
import android.widget.Toast
import androidx.appcompat.app.AppCompatActivity
class MainActivity : AppCompatActivity() {
   private val myBroadCastReceiver: BroadcastReceiver = MyBroadCastReceiver()
   override fun onCreate(savedInstanceState: Bundle?) {
      super.onCreate(savedInstanceState)
      setContentView(R.layout.activity_main)
      title = "KotlinApp"
   }
   override fun onStart() {
      super.onStart()
      val filter = IntentFilter(ConnectivityManager.CONNECTIVITY_ACTION)
      registerReceiver(myBroadCastReceiver, filter)
   }
   override fun onStop() {
      super.onStop()
      unregisterReceiver(myBroadCastReceiver)
   }
}
class MyBroadCastReceiver : BroadcastReceiver() {
   override fun onReceive(context: Context?, intent: Intent?) {
      if (ConnectivityManager.CONNECTIVITY_ACTION == intent!!.action) {
         val noConnectivity: Boolean = intent.getBooleanExtra(ConnectivityManager.EXTRA_NO_CONNECTIVITY, false)
         if (noConnectivity) {
            Toast.makeText(context, "Disconnected", Toast.LENGTH_SHORT).show()
         } else {
               Toast.makeText(context, "Connected", Toast.LENGTH_SHORT).show()
         }
      }
   }
}

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="com.example.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>
</manifest>

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