Foreground Service: starting and biding

foregroundService

/** You should start the service by calling
 * [startForegroundService] for API >= [Build.VERSION_CODES.O] to be certain that the Android will
 * not try to kill your service so soon. */
class SomeService : Service() {
  private val serviceBinder = PrepareBackupBinder()

  override fun onCreate() {
      if (Build.VERSION.SDK_INT >= Build.VERSION_CODES.O) {
         createSomeNotificationChannel()

         val notificationBuilder = applicationContext.basicNotificationBuilder(
            notificationTitle, notificationChannelId
         ).apply {
            setOngoing(true)
            setAutoCancel(false)
         }
         startForeground(NOTIFICATION_ID, notificationBuilder.build())
      }
   }

   override fun onBind(intent: Intent?): IBinder? = serviceBinder

   override fun onStartCommand(intent: Intent?, flags: Int, startId: Int): Int {
      // do some work - remember that here is the Main Thread
      return START_NOT_STICKY // return what is more accurate to you
   }

   fun somePublicFunctionToBeCalledFromBinder() {}

   inner class SomeServiceBinder : Binder() {
      fun service() = this@SomeService
   }
}


// some place on your project
@RequiresApi(Build.VERSION_CODES.O)
fun Context.createSomeNotificationChannel() {
   createNotificationChannel(
      CHANNEL_ID,
      CHANNEL_NAME,
      CHANNEL_DESCRIPTION
   )
}

fun Context.basicNotificationBuilder(title: String, channelId: String): NotificationCompat.Builder {
   return NotificationCompat.Builder(applicationContext, channelId).apply {
      setSmallIcon(R.drawable.icon)
      setContentTitle(title)
   }
}

fun Context.createNotificationChannel(
   id: String, name: String, description: String
) {
   val notificationManager = getSystemService(Context.NOTIFICATION_SERVICE) as NotificationManager

   val channel = NotificationChannel(id, name, NotificationManager.IMPORTANCE_DEFAULT).apply {
      this.description = description
      setSound(null, null)
   }
   notificationManager.createNotificationChannel(channel)
}

//################## activity ##################

// starting and binding the service
val intent = Intent(this, SomeService::class.java)

if (Build.VERSION.SDK_INT >= Build.VERSION_CODES.O) startForegroundService(intent)
else startService(intent)
bindService(intent, someServiceConnection, 0)

// in this way you can communicate with the service
val someServiceConnection = object : ServiceConnection {

    override fun onServiceConnected(className: ComponentName, service: IBinder) {
      val binder = service as SomeService.SomeServiceBinder
      binder.service().somePublicFunctionToBeCalledFromBinder()
    }

    override fun onServiceDisconnected(arg0: ComponentName) {}
 }

//################## Manifest ##################
<!-- declaring the service as private -->
<service
   android:name="...SomeService"
   android:exported="false" />