Use getSystemService() extension.

app/src/main/java/com/github/libretube/extensions/HideKeyboard.kt

@@ -1,11 +1,10 @@
 package com.github.libretube.extensions
 
-import android.app.Activity
 import android.content.Context
 import android.view.View
 import android.view.inputmethod.InputMethodManager
+import androidx.core.content.getSystemService
 
 fun Context.hideKeyboard(view: View) {
-    val inputMethodManager = getSystemService(Activity.INPUT_METHOD_SERVICE) as InputMethodManager
-    inputMethodManager.hideSoftInputFromWindow(view.windowToken, 0)
+    getSystemService<InputMethodManager>()!!.hideSoftInputFromWindow(view.windowToken, 0)
 }

app/src/main/java/com/github/libretube/helpers/NavigationHelper.kt

@@ -4,9 +4,10 @@ import android.app.NotificationManager
 import android.content.Context
 import android.content.ContextWrapper
 import android.content.Intent
-import android.content.pm.PackageManager
 import android.os.Handler
 import android.os.Looper
+import android.os.Process
+import androidx.core.content.getSystemService
 import androidx.core.os.bundleOf
 import androidx.core.os.postDelayed
 import androidx.fragment.app.commitNow
@@ -127,15 +128,13 @@ object NavigationHelper {
      */
     fun restartMainActivity(context: Context) {
         // kill player notification
-        val nManager = context
-            .getSystemService(Context.NOTIFICATION_SERVICE) as NotificationManager
-        nManager.cancelAll()
+        context.getSystemService<NotificationManager>()!!.cancelAll()
         // start a new Intent of the app
-        val pm: PackageManager = context.packageManager
+        val pm = context.packageManager
         val intent = pm.getLaunchIntentForPackage(context.packageName)
         intent?.flags = Intent.FLAG_ACTIVITY_CLEAR_TASK
         context.startActivity(intent)
         // kill the old application
-        android.os.Process.killProcess(android.os.Process.myPid())
+        Process.killProcess(Process.myPid())
     }
 }

app/src/main/java/com/github/libretube/helpers/PlayerHelper.kt

@@ -9,6 +9,7 @@ import android.view.accessibility.CaptioningManager
 import android.widget.Toast
 import androidx.annotation.StringRes
 import androidx.core.app.RemoteActionCompat
+import androidx.core.content.getSystemService
 import androidx.core.graphics.drawable.IconCompat
 import com.github.libretube.R
 import com.github.libretube.api.obj.PipedStream
@@ -75,8 +76,7 @@ object PlayerHelper {
 
     // get the system default caption style
     fun getCaptionStyle(context: Context): CaptionStyleCompat {
-        val captioningManager =
-            context.getSystemService(Context.CAPTIONING_SERVICE) as CaptioningManager
+        val captioningManager = context.getSystemService<CaptioningManager>()!!
         return if (!captioningManager.isEnabled) {
             // system captions are disabled, using android default captions style
             CaptionStyleCompat.DEFAULT

app/src/main/java/com/github/libretube/services/ClosingService.kt

@@ -2,9 +2,9 @@ package com.github.libretube.services
 
 import android.app.NotificationManager
 import android.app.Service
-import android.content.Context
 import android.content.Intent
 import android.os.IBinder
+import androidx.core.content.getSystemService
 import com.github.libretube.constants.PLAYER_NOTIFICATION_ID
 
 class ClosingService : Service() {
@@ -18,8 +18,7 @@ class ClosingService : Service() {
         super.onTaskRemoved(rootIntent)
 
         // destroy the player notification when the app gets destroyed
-        val nManager = this.getSystemService(Context.NOTIFICATION_SERVICE) as NotificationManager
-        nManager.cancel(PLAYER_NOTIFICATION_ID)
+        getSystemService<NotificationManager>()!!.cancel(PLAYER_NOTIFICATION_ID)
 
         // Destroy the service
         stopSelf()

app/src/main/java/com/github/libretube/services/DownloadService.kt

@@ -8,6 +8,7 @@ import android.os.IBinder
 import android.util.SparseBooleanArray
 import androidx.core.app.NotificationCompat
 import androidx.core.app.ServiceCompat
+import androidx.core.content.getSystemService
 import androidx.core.util.set
 import androidx.core.util.valueIterator
 import androidx.lifecycle.LifecycleService
@@ -341,7 +342,7 @@ class DownloadService : LifecycleService() {
     }
 
     private fun notifyForeground() {
-        notificationManager = getSystemService(NOTIFICATION_SERVICE) as NotificationManager
+        notificationManager = getSystemService()!!
 
         summaryNotificationBuilder = NotificationCompat
             .Builder(this, DOWNLOAD_CHANNEL_ID)

app/src/main/java/com/github/libretube/ui/fragments/PlayerFragment.kt

@@ -24,6 +24,7 @@ import android.view.ViewGroup
 import android.widget.TextView
 import android.widget.Toast
 import androidx.constraintlayout.motion.widget.MotionLayout
+import androidx.core.content.getSystemService
 import androidx.core.net.toUri
 import androidx.core.os.bundleOf
 import androidx.core.os.postDelayed
@@ -587,12 +588,11 @@ class PlayerFragment : Fragment(), OnlinePlayerOptions {
         // pauses the player if the screen is turned off
 
         // check whether the screen is on
-        val pm = context?.getSystemService(Context.POWER_SERVICE) as PowerManager
-        val isScreenOn = pm.isInteractive
+        val isInteractive = requireContext().getSystemService<PowerManager>()!!.isInteractive
 
         // pause player if screen off and setting enabled
-        if (
-            this::exoPlayer.isInitialized && !isScreenOn && PlayerHelper.pausePlayerOnScreenOffEnabled
+        if (this::exoPlayer.isInitialized && !isInteractive &&
+            PlayerHelper.pausePlayerOnScreenOffEnabled
         ) {
             exoPlayer.pause()
         }

app/src/main/java/com/github/libretube/util/NowPlayingNotification.kt

@@ -15,6 +15,7 @@ import android.support.v4.media.session.MediaSessionCompat
 import android.support.v4.media.session.PlaybackStateCompat
 import androidx.annotation.DrawableRes
 import androidx.core.app.NotificationCompat
+import androidx.core.content.getSystemService
 import androidx.core.graphics.drawable.toBitmap
 import androidx.core.os.bundleOf
 import coil.request.ImageRequest
@@ -307,10 +308,7 @@ class NowPlayingNotification(
         player.stop()
         player.release()
 
-        val notificationManager = context.getSystemService(
-            Context.NOTIFICATION_SERVICE
-        ) as NotificationManager
-        notificationManager.cancel(PLAYER_NOTIFICATION_ID)
+        context.getSystemService<NotificationManager>()!!.cancel(PLAYER_NOTIFICATION_ID)
     }
 
     companion object {

app/src/main/java/com/github/libretube/workers/NotificationWorker.kt

@@ -7,7 +7,7 @@ import android.content.Intent
 import android.os.Build
 import android.util.Log
 import androidx.core.app.NotificationCompat
-import androidx.core.app.NotificationManagerCompat
+import androidx.core.content.getSystemService
 import androidx.work.CoroutineWorker
 import androidx.work.WorkerParameters
 import com.github.libretube.R
@@ -32,12 +32,11 @@ import kotlinx.coroutines.withContext
 class NotificationWorker(appContext: Context, parameters: WorkerParameters) :
     CoroutineWorker(appContext, parameters) {
 
-    private val notificationManager = NotificationManagerCompat.from(appContext)
+    private val notificationManager = appContext.getSystemService<NotificationManager>()!!
 
     // the id where notification channels start
     private var notificationId = if (Build.VERSION.SDK_INT >= Build.VERSION_CODES.M) {
-        val nManager = appContext.getSystemService(Context.NOTIFICATION_SERVICE) as NotificationManager
-        nManager.activeNotifications.size + DOWNLOAD_PROGRESS_NOTIFICATION_ID
+        notificationManager.activeNotifications.size + DOWNLOAD_PROGRESS_NOTIFICATION_ID
     } else {
         DOWNLOAD_PROGRESS_NOTIFICATION_ID
     }