Roberto O R

An Android Service, is an application component that can perform long-running operations in the background, and it doesn’t provide a user interface.

A few example uses for a service could be:

• Network transactions
• Play music
• Perform file I/O operations
• Interact with content providers
• Background operations

I’ve recently implemented a service in one of my applications to start a sound triggered by a BroadcastReceiver when an alarm expires and here is how I implemented it with Kotlin.

AlarmService.kt

	package com.isscroberto.powernap.util
	import android.app.Service
	import android.content.Context
	import android.content.Intent
	import android.media.Ringtone
	import android.media.RingtoneManager
	import android.os.IBinder
	class AlarmService : Service() {
	private lateinit var ringtone: Ringtone
	override fun onBind(p0: Intent?): IBinder? {
	return null
	}
	override fun onStartCommand(intent: Intent?, flags: Int, startId: Int): Int {
	playAlarm()
	return super.onStartCommand(intent, flags, startId)
	}
	override fun onDestroy() {
	super.onDestroy()
	ringtone.stop()
	}
	fun playAlarm() {
	val notification = RingtoneManager.getDefaultUri(RingtoneManager.TYPE_ALARM)
	ringtone = RingtoneManager.getRingtone(this, notification)
	if(!ringtone.isPlaying()) {
	ringtone.play()
	}
	}
	}

view raw AlarmService.kt hosted with ❤ by GitHub

Then, this is how it’s started from the BroadcastReceiver.

TimerExpiredReceiver.kt

	package com.isscroberto.powernap
	import android.content.BroadcastReceiver
	import android.content.Context
	import android.content.Intent
	import com.isscroberto.powernap.data.NapState
	import com.isscroberto.powernap.util.NotificationUtil
	import com.isscroberto.powernap.util.PrefUtil
	import com.isscroberto.powernap.util.AlarmService
	class TimerExpiredReceiver : BroadcastReceiver() {
	override fun onReceive(context: Context, intent: Intent) {
	// Show notification of expiration.
	NotificationUtil.showTimerExpired(context)
	// Save status in preferences.
	PrefUtil.setTimerState(NapState.Finished, context)
	PrefUtil.setAlarmSetTime(0, context)
	// Play alarm sound.
	context.startService(Intent(context, AlarmService::class.java))
	}
	}

view raw TimerExpiredReceiver.kt hosted with ❤ by GitHub

Finally don’t forget to add your reference to your app’s manifest file.

<service android:name=".util.AlarmService"/>

view raw AndroidManifest.xml hosted with ❤ by GitHub

By using this service I’m able to stop it from anywhere within the application and stop the alarm sound when the user interacts with my app by calling stopService().

	// Stop alarm.
	context!!.stopService(Intent(context!!, AlarmService::class.java))

view raw MainActivity.kt hosted with ❤ by GitHub

I implemented this functionality in PowerNap, an app that will help you take efficient naps by controlling the time you sleep. You can find the source code in GitHub.