Improve Kotlin converted from java in various places

app/src/main/java/org/schabi/newpipe/player/PlayerService.kt

@@ -37,7 +37,6 @@ import org.schabi.newpipe.player.notification.NotificationPlayerUi
 import org.schabi.newpipe.util.Localization
 import org.schabi.newpipe.util.ThemeHelper
 import java.lang.ref.WeakReference
-import java.util.function.BiConsumer
 import java.util.function.Consumer
 
 /**
@@ -47,13 +46,13 @@ class PlayerService : MediaBrowserServiceCompat() {
     // These objects are used to cleanly separate the Service implementation (in this file) and the
     // media browser and playback preparer implementations. At the moment the playback preparer is
     // only used in conjunction with the media browser.
-    private var mediaBrowserImpl: MediaBrowserImpl? = null
+    private lateinit var mediaBrowserImpl: MediaBrowserImpl
-    private var mediaBrowserPlaybackPreparer: MediaBrowserPlaybackPreparer? = null
+    private lateinit var mediaBrowserPlaybackPreparer: MediaBrowserPlaybackPreparer
 
     // these are instantiated in onCreate() as per
     // https://developer.android.com/training/cars/media#browser_workflow
-    private var mediaSession: MediaSessionCompat? = null
+    private lateinit var mediaSession: MediaSessionCompat
-    private var sessionConnector: MediaSessionConnector? = null
+    private lateinit var sessionConnector: MediaSessionConnector
 
     /**
      * @return the current active player instance. May be null, since the player service can outlive
@@ -68,7 +67,7 @@ class PlayerService : MediaBrowserServiceCompat() {
      * The parameter taken by this [Consumer] can be null to indicate the player is being
      * stopped.
      */
-    private var onPlayerStartedOrStopped: Consumer<Player?>? = null
+    private var onPlayerStartedOrStopped: ((player: Player?) -> Unit)? = null
 
     //region Service lifecycle
     override fun onCreate() {
@@ -80,14 +79,7 @@ class PlayerService : MediaBrowserServiceCompat() {
         Localization.assureCorrectAppLanguage(this)
         ThemeHelper.setTheme(this)
 
-        mediaBrowserImpl = MediaBrowserImpl(
+        mediaBrowserImpl = MediaBrowserImpl(this, this::notifyChildrenChanged)
-            this,
-            Consumer { parentId: String ->
-                this.notifyChildrenChanged(
-                    parentId
-                )
-            }
-        )
 
         // see https://developer.android.com/training/cars/media#browser_workflow
         val session = MediaSessionCompat(this, "MediaSessionPlayerServ")
@@ -98,17 +90,10 @@ class PlayerService : MediaBrowserServiceCompat() {
         connector.setMetadataDeduplicationEnabled(true)
 
         mediaBrowserPlaybackPreparer = MediaBrowserPlaybackPreparer(
-            this,
+            context = this,
-            BiConsumer { message: String, code: Int ->
+            setMediaSessionError = connector::setCustomErrorMessage,
-                connector.setCustomErrorMessage(
+            clearMediaSessionError = { connector.setCustomErrorMessage(null) },
-                    message,
+            onPrepare = { player?.onPrepare() }
-                    code
-                )
-            },
-            Runnable { connector.setCustomErrorMessage(null) },
-            Consumer { playWhenReady: Boolean? ->
-                player?.onPrepare()
-            }
         )
         connector.setPlaybackPreparer(mediaBrowserPlaybackPreparer)
 
@@ -125,11 +110,8 @@ class PlayerService : MediaBrowserServiceCompat() {
         if (DEBUG) {
             Log.d(
                 TAG,
-                (
+                "onStartCommand() called with: intent = [$intent], extras = [${
-                    "onStartCommand() called with: intent = [" + intent +
+                intent.extras.toDebugString()}], flags = [$flags], startId = [$startId]"
-                        "], extras = [" + intent.extras.toDebugString() +
-                        "], flags = [" + flags + "], startId = [" + startId + "]"
-                    )
             )
         }
 
@@ -140,7 +122,7 @@ class PlayerService : MediaBrowserServiceCompat() {
             val playerWasNull = (player == null)
             if (playerWasNull) {
                 // make sure the player exists, in case the service was resumed
-                player = Player(this, mediaSession!!, sessionConnector!!)
+                player = Player(this, mediaSession, sessionConnector)
             }
 
             // Be sure that the player notification is set and the service is started in foreground,
@@ -150,35 +132,29 @@ class PlayerService : MediaBrowserServiceCompat() {
             // no one already and starting the service in foreground should not create any issues.
             // If the service is already started in foreground, requesting it to be started
             // shouldn't do anything.
-            player!!.UIs().get(NotificationPlayerUi::class.java)
+            player?.UIs()?.get(NotificationPlayerUi::class)?.createNotificationAndStartForeground()
-                ?.createNotificationAndStartForeground()
 
-            val startedOrStopped = onPlayerStartedOrStopped
+            if (playerWasNull) {
-            if (playerWasNull && startedOrStopped != null) {
                 // notify that a new player was created (but do it after creating the foreground
                 // notification just to make sure we don't incur, due to slowness, in
                 // "Context.startForegroundService() did not then call Service.startForeground()")
-                startedOrStopped.accept(player)
+                onPlayerStartedOrStopped?.invoke(player)
             }
         }
 
         val p = player
-        if (Intent.ACTION_MEDIA_BUTTON == intent.action &&
+        if (Intent.ACTION_MEDIA_BUTTON == intent.action && p?.playQueue == null) {
-            (p == null || p.playQueue == null)
+            // No need to process media button's actions if the player is not working, otherwise
-        ) {
+            // the player service would strangely start with nothing to play
-            /*
+            // Stop the service in this case, which will be removed from the foreground and its
-            No need to process media button's actions if the player is not working, otherwise
+            // notification cancelled in its destruction
-            the player service would strangely start with nothing to play
-            Stop the service in this case, which will be removed from the foreground and its
-            notification cancelled in its destruction
-             */
             destroyPlayerAndStopService()
             return START_NOT_STICKY
         }
 
         if (p != null) {
             p.handleIntent(intent)
-            p.UIs().get(MediaSessionPlayerUi::class.java)
+            p.UIs().get(MediaSessionPlayerUi::class)
                 ?.handleMediaButtonIntent(intent)
         }
 
@@ -218,22 +194,22 @@ class PlayerService : MediaBrowserServiceCompat() {
 
         cleanup()
 
-        mediaBrowserPlaybackPreparer?.dispose()
+        mediaBrowserPlaybackPreparer.dispose()
-        mediaSession?.release()
+        mediaSession.release()
-        mediaBrowserImpl?.dispose()
+        mediaBrowserImpl.dispose()
     }
 
     private fun cleanup() {
         val p = player
         if (p != null) {
             // notify that the player is being destroyed
-            onPlayerStartedOrStopped?.accept(null)
+            onPlayerStartedOrStopped?.invoke(null)
             p.saveAndShutdown()
             player = null
         }
 
         // Should already be handled by MediaSessionPlayerUi, but just to be sure.
-        mediaSession?.setActive(false)
+        mediaSession.setActive(false)
 
         // Should already be handled by NotificationUtil.cancelNotificationAndStopForeground() in
         // NotificationPlayerUi, but let's make sure that the foreground service is stopped.
@@ -273,24 +249,22 @@ class PlayerService : MediaBrowserServiceCompat() {
         if (DEBUG) {
             Log.d(
                 TAG,
-                (
+                "onBind() called with: intent = [$intent], extras = [${
-                    "onBind() called with: intent = [" + intent +
+                intent.extras.toDebugString()}]"
-                        "], extras = [" + intent.extras.toDebugString() + "]"
-                    )
             )
         }
 
-        if (BIND_PLAYER_HOLDER_ACTION == intent.action) {
+        return if (BIND_PLAYER_HOLDER_ACTION == intent.action) {
             // Note that this binder might be reused multiple times while the service is alive, even
             // after unbind() has been called: https://stackoverflow.com/a/8794930 .
-            return mBinder
+            mBinder
         } else if (SERVICE_INTERFACE == intent.action) {
             // MediaBrowserService also uses its own binder, so for actions related to the media
             // browser service, pass the onBind to the superclass.
-            return super.onBind(intent)
+            super.onBind(intent)
         } else {
             // This is an unknown request, avoid returning any binder to not leak objects.
-            return null
+            null
         }
     }
 
@@ -307,9 +281,9 @@ class PlayerService : MediaBrowserServiceCompat() {
      * by the [Consumer] can be null to indicate that the player is stopping.
      * @param listener the listener to set or unset
      */
-    fun setPlayerListener(listener: Consumer<Player?>?) {
+    fun setPlayerListener(listener: ((player: Player?) -> Unit)?) {
         this.onPlayerStartedOrStopped = listener
-        listener?.accept(player)
+        listener?.invoke(player)
     }
 
     //endregion
@@ -320,14 +294,14 @@ class PlayerService : MediaBrowserServiceCompat() {
         rootHints: Bundle?
     ): BrowserRoot? {
         // TODO check if the accessing package has permission to view data
-        return mediaBrowserImpl?.onGetRoot(clientPackageName, clientUid, rootHints)
+        return mediaBrowserImpl.onGetRoot(clientPackageName, clientUid, rootHints)
     }
 
     override fun onLoadChildren(
         parentId: String,
         result: Result<List<MediaBrowserCompat.MediaItem>>
     ) {
-        mediaBrowserImpl?.onLoadChildren(parentId, result)
+        mediaBrowserImpl.onLoadChildren(parentId, result)
     }
 
     override fun onSearch(
@@ -335,7 +309,7 @@ class PlayerService : MediaBrowserServiceCompat() {
         extras: Bundle?,
         result: Result<List<MediaBrowserCompat.MediaItem>>
     ) {
-        mediaBrowserImpl?.onSearch(query, result)
+        mediaBrowserImpl.onSearch(query, result)
     } //endregion
 
     companion object {

app/src/main/java/org/schabi/newpipe/player/helper/PlayerHolder.kt

@@ -20,7 +20,6 @@ import org.schabi.newpipe.player.event.PlayerServiceEventListener
 import org.schabi.newpipe.player.event.PlayerServiceExtendedEventListener
 import org.schabi.newpipe.player.playqueue.PlayQueue
 import org.schabi.newpipe.util.NavigationHelper
-import java.util.function.Consumer
 
 private val DEBUG = MainActivity.DEBUG
 private val TAG: String = PlayerHolder::class.java.getSimpleName()
@@ -40,9 +39,9 @@ object PlayerHolder {
     private val player: Player?
         get() = playerService?.player
 
+    // player play queue might be null e.g. while player is starting
     private val playQueue: PlayQueue?
-        get() = // player play queue might be null e.g. while player is starting
+        get() = this.player?.playQueue
-            this.player?.playQueue
 
     val type: PlayerType?
         /**
@@ -78,8 +77,8 @@ object PlayerHolder {
 
         // Force reload data from service
         newListener?.let { listener ->
-            playerService?.let {
+            playerService?.let { service ->
-                listener.onServiceConnected(it)
+                listener.onServiceConnected(service)
                 startPlayerListener()
                 // ^ will call listener.onPlayerConnected() down the line if there is an active player
             }
@@ -103,7 +102,7 @@ object PlayerHolder {
         newListener: PlayerServiceExtendedEventListener?
     ) {
         if (DEBUG) {
-            Log.d(TAG, "startService() called with playAfterConnect=" + playAfterConnect)
+            Log.d(TAG, "startService() called with playAfterConnect=$playAfterConnect")
         }
         val context = this.commonContext
         setListener(newListener)
@@ -162,21 +161,15 @@ object PlayerHolder {
 
             val s = localBinder.service
             requireNotNull(s) {
-                (
+                "PlayerService.LocalBinder.getService() must never be" +
-                    "PlayerService.LocalBinder.getService() must never be" +
+                    "null after the service connects"
-                        "null after the service connects"
-                    )
             }
             playerService = s
-            val l = listener
+            listener?.let { l ->
-            if (l != null) {
                 l.onServiceConnected(s)
-                player?.let {
+                player?.let { l.onPlayerConnected(it, playAfterConnect) }
-                    l.onPlayerConnected(it, playAfterConnect)
-                }
             }
             startPlayerListener()
-
             // ^ will call listener.onPlayerConnected() down the line if there is an active player
 
             // notify the main activity that binding the service has completed, so that it can
@@ -305,9 +298,8 @@ object PlayerHolder {
      * or stopping. This is necessary since the service outlives the player e.g. to answer Android
      * Auto media browser queries.
      */
-    private val playerStateListener = Consumer { player: Player? ->
+    private val playerStateListener: (Player?) -> Unit = { player: Player? ->
-        val l = listener
+        listener?.let { l ->
-        if (l != null) {
             if (player == null) {
                 // player.fragmentListener=null is already done by player.stopActivityBinding(),
                 // which is called by player.destroy(), which is in turn called by PlayerService

app/src/main/java/org/schabi/newpipe/player/mediabrowser/MediaBrowserImpl.kt

@@ -36,7 +36,6 @@ import org.schabi.newpipe.local.playlist.RemotePlaylistManager
 import org.schabi.newpipe.util.ExtractorHelper
 import org.schabi.newpipe.util.ServiceHelper
 import org.schabi.newpipe.util.image.ImageStrategy
-import java.util.function.Consumer
 
 /**
  * This class is used to cleanly separate the Service implementation (in
@@ -46,16 +45,14 @@ import java.util.function.Consumer
  */
 class MediaBrowserImpl(
     private val context: Context,
-    notifyChildrenChanged: Consumer<String>, // parentId
+    notifyChildrenChanged: (parentId: String) -> Unit,
 ) {
     private val database = NewPipeDatabase.getInstance(context)
     private var disposables = CompositeDisposable()
 
     init {
         // this will listen to changes in the bookmarks until this MediaBrowserImpl is dispose()d
-        disposables.add(
+        disposables.add(getMergedPlaylists().subscribe { notifyChildrenChanged(ID_BOOKMARKS) })
-            getMergedPlaylists().subscribe { notifyChildrenChanged.accept(ID_BOOKMARKS) }
-        )
     }
 
     //region Cleanup
@@ -204,6 +201,7 @@ class MediaBrowserImpl(
         val builder = MediaDescriptionCompat.Builder()
         builder.setMediaId(createMediaIdForInfoItem(item))
             .setTitle(item.name)
+            .setIconUri(ImageStrategy.choosePreferredImage(item.thumbnails)?.toUri())
 
         when (item.infoType) {
             InfoType.STREAM -> builder.setSubtitle((item as StreamInfoItem).uploaderName)
@@ -212,10 +210,6 @@ class MediaBrowserImpl(
             else -> return null
         }
 
-        ImageStrategy.choosePreferredImage(item.thumbnails)?.let {
-            builder.setIconUri(imageUriOrNullIfDisabled(it))
-        }
-
         return MediaBrowserCompat.MediaItem(
             builder.build(),
             MediaBrowserCompat.MediaItem.FLAG_PLAYABLE
@@ -276,10 +270,7 @@ class MediaBrowserImpl(
         builder.setMediaId(createMediaIdForPlaylistIndex(true, playlistId, index))
             .setTitle(item.name)
             .setSubtitle(item.uploaderName)
-
+            .setIconUri(ImageStrategy.choosePreferredImage(item.thumbnails)?.toUri())
-        ImageStrategy.choosePreferredImage(item.thumbnails)?.let {
-            builder.setIconUri(imageUriOrNullIfDisabled(it))
-        }
 
         return MediaBrowserCompat.MediaItem(
             builder.build(),

app/src/main/java/org/schabi/newpipe/player/ui/PlayerUiList.kt

@@ -1,6 +1,8 @@
 package org.schabi.newpipe.player.ui
 
 import org.schabi.newpipe.util.GuardedByMutex
+import kotlin.reflect.KClass
+import kotlin.reflect.safeCast
 
 /**
  * Creates a [PlayerUiList] starting with the provided player uis. The provided player uis
@@ -84,20 +86,20 @@ class PlayerUiList(vararg initialPlayerUis: PlayerUi) {
      * @param T the class type parameter
      * @return the first player UI of the required type found in the list, or null
      </T> */
-    fun <T : PlayerUi> get(playerUiType: Class<T>): T? =
+    fun <T : PlayerUi> get(playerUiType: KClass<T>): T? =
         playerUis.runWithLockSync {
             for (ui in lockData) {
                 if (playerUiType.isInstance(ui)) {
-                    when (val r = playerUiType.cast(ui)) {
+                    // try all UIs before returning null
-                        // try all UIs before returning null
+                    playerUiType.safeCast(ui)?.let { return@runWithLockSync it }
-                        null -> continue
-                        else -> return@runWithLockSync r
-                    }
                 }
             }
             return@runWithLockSync null
         }
 
+    fun <T : PlayerUi> get(playerUiType: Class<T>): T? =
+        get(playerUiType.kotlin)
+
     /**
      * Calls the provided consumer on all player UIs in the list, in order of addition.
      * @param consumer the consumer to call with player UIs