Run Android Service Always in the Background Using Kotlin

This example demonstrates how to run an Android service always in the background 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.

Example

<?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" />
<Button
   android:id="@+id/button"
   android:layout_width="wrap_content"
   android:layout_height="wrap_content"
   android:layout_centerInParent="true"
   android:text="Click here to start background Service"
   android:textSize="16sp"
   android:textStyle="bold" />
</RelativeLayout>

Step 3 − Create a new Kotlin class MyService.kt and add the following code

import android.app.Service
import android.content.Intent
import android.os.IBinder
import android.widget.Toast
class MyService : Service() {
   override fun onStartCommand(intent: Intent, flags: Int, startId: Int): Int {
      onTaskRemoved(intent)
      Toast.makeText(
      applicationContext, "This is a Service running in Background",
      Toast.LENGTH_SHORT
      ).show()
      return START_STICKY
   }
   override fun onBind(intent: Intent): IBinder? {
      // TODO: Return the communication channel to the service.
      throw UnsupportedOperationException("Not yet implemented")
   }
   override fun onTaskRemoved(rootIntent: Intent) {
      val restartServiceIntent = Intent(applicationContext, this.javaClass)
      restartServiceIntent.setPackage(packageName)
      startService(restartServiceIntent)
      super.onTaskRemoved(rootIntent)
   }
}

Step 4 − Add the following code to src/MainActivity.kt

import android.content.Intent
import android.os.Bundle
import android.widget.Button
import androidx.appcompat.app.AppCompatActivity
class MainActivity : AppCompatActivity() {
   override fun onCreate(savedInstanceState: Bundle?) {
      super.onCreate(savedInstanceState)
      setContentView(R.layout.activity_main)
      title = "KotlinApp"
      val button: Button = findViewById(R.id.button)
      button.setOnClickListener { startService(Intent(applicationContext, MyService::class.java)) }
   }
}

Step 5 − 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>
      <service
      android:name=".MyService"
      android:enabled="true"
      android:exported="true" />
   </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

Click here to download the project code.