Fix some Android Studio nullness warning created by new @NonNullApi.

PiperOrigin-RevId: 261888086

extensions/mediasession/src/main/java/com/google/android/exoplayer2/ext/mediasession/MediaSessionConnector.java

@@ -558,7 +558,7 @@ public final class MediaSessionConnector {
    *
    * @param queueNavigator The queue navigator.
    */
-  public void setQueueNavigator(QueueNavigator queueNavigator) {
+  public void setQueueNavigator(@Nullable QueueNavigator queueNavigator) {
     if (this.queueNavigator != queueNavigator) {
       unregisterCommandReceiver(this.queueNavigator);
       this.queueNavigator = queueNavigator;
@@ -571,7 +571,7 @@ public final class MediaSessionConnector {
    *
    * @param queueEditor The queue editor.
    */
-  public void setQueueEditor(QueueEditor queueEditor) {
+  public void setQueueEditor(@Nullable QueueEditor queueEditor) {
     if (this.queueEditor != queueEditor) {
       unregisterCommandReceiver(this.queueEditor);
       this.queueEditor = queueEditor;
@@ -673,7 +673,7 @@ public final class MediaSessionConnector {
         mediaMetadataProvider != null && player != null
             ? mediaMetadataProvider.getMetadata(player)
             : METADATA_EMPTY;
-    mediaSession.setMetadata(metadata != null ? metadata : METADATA_EMPTY);
+    mediaSession.setMetadata(metadata);
   }
 
   /**
@@ -684,7 +684,7 @@ public final class MediaSessionConnector {
    */
   public final void invalidateMediaSessionPlaybackState() {
     PlaybackStateCompat.Builder builder = new PlaybackStateCompat.Builder();
-    Player player = this.player;
+    @Nullable Player player = this.player;
     if (player == null) {
       builder.setActions(buildPrepareActions()).setState(PlaybackStateCompat.STATE_NONE, 0, 0, 0);
       mediaSession.setPlaybackState(builder.build());
@@ -693,6 +693,7 @@ public final class MediaSessionConnector {
 
     Map<String, CustomActionProvider> currentActions = new HashMap<>();
     for (CustomActionProvider customActionProvider : customActionProviders) {
+      @Nullable
       PlaybackStateCompat.CustomAction customAction = customActionProvider.getCustomAction(player);
       if (customAction != null) {
         currentActions.put(customAction.getAction(), customActionProvider);
@@ -703,6 +704,7 @@ public final class MediaSessionConnector {
 
     int playbackState = player.getPlaybackState();
     Bundle extras = new Bundle();
+    @Nullable
     ExoPlaybackException playbackError =
         playbackState == Player.STATE_IDLE ? player.getPlaybackError() : null;
     boolean reportError = playbackError != null || customError != null;
@@ -949,10 +951,10 @@ public final class MediaSessionConnector {
           MediaSessionCompat.QueueItem queueItem = queue.get(i);
           if (queueItem.getQueueId() == activeQueueItemId) {
             MediaDescriptionCompat description = queueItem.getDescription();
-            Bundle extras = description.getExtras();
+            @Nullable Bundle extras = description.getExtras();
             if (extras != null) {
               for (String key : extras.keySet()) {
-                Object value = extras.get(key);
+                @Nullable Object value = extras.get(key);
                 if (value instanceof String) {
                   builder.putString(metadataExtrasPrefix + key, (String) value);
                 } else if (value instanceof CharSequence) {
@@ -968,37 +970,37 @@ public final class MediaSessionConnector {
                 }
               }
             }
-            CharSequence title = description.getTitle();
+            @Nullable CharSequence title = description.getTitle();
             if (title != null) {
               String titleString = String.valueOf(title);
               builder.putString(MediaMetadataCompat.METADATA_KEY_TITLE, titleString);
               builder.putString(MediaMetadataCompat.METADATA_KEY_DISPLAY_TITLE, titleString);
             }
-            CharSequence subtitle = description.getSubtitle();
+            @Nullable CharSequence subtitle = description.getSubtitle();
             if (subtitle != null) {
               builder.putString(
                   MediaMetadataCompat.METADATA_KEY_DISPLAY_SUBTITLE, String.valueOf(subtitle));
             }
-            CharSequence displayDescription = description.getDescription();
+            @Nullable CharSequence displayDescription = description.getDescription();
             if (displayDescription != null) {
               builder.putString(
                   MediaMetadataCompat.METADATA_KEY_DISPLAY_DESCRIPTION,
                   String.valueOf(displayDescription));
             }
-            Bitmap iconBitmap = description.getIconBitmap();
+            @Nullable Bitmap iconBitmap = description.getIconBitmap();
             if (iconBitmap != null) {
               builder.putBitmap(MediaMetadataCompat.METADATA_KEY_DISPLAY_ICON, iconBitmap);
             }
-            Uri iconUri = description.getIconUri();
+            @Nullable Uri iconUri = description.getIconUri();
             if (iconUri != null) {
               builder.putString(
                   MediaMetadataCompat.METADATA_KEY_DISPLAY_ICON_URI, String.valueOf(iconUri));
             }
-            String mediaId = description.getMediaId();
+            @Nullable String mediaId = description.getMediaId();
             if (mediaId != null) {
               builder.putString(MediaMetadataCompat.METADATA_KEY_MEDIA_ID, mediaId);
             }
-            Uri mediaUri = description.getMediaUri();
+            @Nullable Uri mediaUri = description.getMediaUri();
             if (mediaUri != null) {
               builder.putString(
                   MediaMetadataCompat.METADATA_KEY_MEDIA_URI, String.valueOf(mediaUri));

extensions/mediasession/src/main/java/com/google/android/exoplayer2/ext/mediasession/TimelineQueueEditor.java

@@ -166,7 +166,7 @@ public final class TimelineQueueEditor
 
   @Override
   public void onAddQueueItem(Player player, MediaDescriptionCompat description, int index) {
-    MediaSource mediaSource = sourceFactory.createMediaSource(description);
+    @Nullable MediaSource mediaSource = sourceFactory.createMediaSource(description);
     if (mediaSource != null) {
       queueDataAdapter.add(index, description);
       queueMediaSource.addMediaSource(index, mediaSource);

library/core/src/main/java/com/google/android/exoplayer2/offline/ActionFile.java

@@ -68,7 +68,7 @@ import java.util.List;
     if (!exists()) {
       return new DownloadRequest[0];
     }
-    InputStream inputStream = null;
+    @Nullable InputStream inputStream = null;
     try {
       inputStream = atomicFile.openRead();
       DataInputStream dataInputStream = new DataInputStream(inputStream);
@@ -99,7 +99,7 @@ import java.util.List;
     boolean isRemoveAction = input.readBoolean();
 
     int dataLength = input.readInt();
-    byte[] data;
+    @Nullable byte[] data;
     if (dataLength != 0) {
       data = new byte[dataLength];
       input.readFully(data);
@@ -123,7 +123,7 @@ import java.util.List;
             && (DownloadRequest.TYPE_DASH.equals(type)
                 || DownloadRequest.TYPE_HLS.equals(type)
                 || DownloadRequest.TYPE_SS.equals(type));
-    String customCacheKey = null;
+    @Nullable String customCacheKey = null;
     if (!isLegacySegmented) {
       customCacheKey = input.readBoolean() ? input.readUTF() : null;
     }

library/core/src/main/java/com/google/android/exoplayer2/offline/ActionFileUpgradeUtil.java

@@ -97,7 +97,7 @@ public final class ActionFileUpgradeUtil {
       boolean addNewDownloadAsCompleted,
       long nowMs)
       throws IOException {
-    Download download = downloadIndex.getDownload(request.id);
+    @Nullable Download download = downloadIndex.getDownload(request.id);
     if (download != null) {
       download = DownloadManager.mergeRequest(download, request, download.stopReason, nowMs);
     } else {

library/core/src/main/java/com/google/android/exoplayer2/offline/DownloadHelper.java

@@ -390,7 +390,7 @@ public final class DownloadHelper {
    */
   public static MediaSource createMediaSource(
       DownloadRequest downloadRequest, DataSource.Factory dataSourceFactory) {
-    Constructor<? extends MediaSourceFactory> constructor;
+    @Nullable Constructor<? extends MediaSourceFactory> constructor;
     switch (downloadRequest.type) {
       case DownloadRequest.TYPE_DASH:
         constructor = DASH_FACTORY_CONSTRUCTOR;
@@ -808,7 +808,7 @@ public final class DownloadHelper {
               new MediaPeriodId(mediaPreparer.timeline.getUidOfPeriod(periodIndex)),
               mediaPreparer.timeline);
       for (int i = 0; i < trackSelectorResult.length; i++) {
-        TrackSelection newSelection = trackSelectorResult.selections.get(i);
+        @Nullable TrackSelection newSelection = trackSelectorResult.selections.get(i);
         if (newSelection == null) {
           continue;
         }

library/core/src/main/java/com/google/android/exoplayer2/offline/DownloadManager.java

@@ -731,7 +731,7 @@ public final class DownloadManager {
           Log.e(TAG, "Failed to set manual stop reason", e);
         }
       } else {
-        Download download = getDownload(id, /* loadFromIndex= */ false);
+        @Nullable Download download = getDownload(id, /* loadFromIndex= */ false);
         if (download != null) {
           setStopReason(download, stopReason);
         } else {
@@ -779,7 +779,7 @@ public final class DownloadManager {
     }
 
     private void addDownload(DownloadRequest request, int stopReason) {
-      Download download = getDownload(request.id, /* loadFromIndex= */ true);
+      @Nullable Download download = getDownload(request.id, /* loadFromIndex= */ true);
       long nowMs = System.currentTimeMillis();
       if (download != null) {
         putDownload(mergeRequest(download, request, stopReason, nowMs));
@@ -798,7 +798,7 @@ public final class DownloadManager {
     }
 
     private void removeDownload(String id) {
-      Download download = getDownload(id, /* loadFromIndex= */ true);
+      @Nullable Download download = getDownload(id, /* loadFromIndex= */ true);
       if (download == null) {
         Log.e(TAG, "Failed to remove nonexistent download: " + id);
         return;
@@ -860,7 +860,7 @@ public final class DownloadManager {
       int accumulatingDownloadTaskCount = 0;
       for (int i = 0; i < downloads.size(); i++) {
         Download download = downloads.get(i);
-        Task activeTask = activeTasks.get(download.request.id);
+        @Nullable Task activeTask = activeTasks.get(download.request.id);
         switch (download.state) {
           case STATE_STOPPED:
             syncStoppedDownload(activeTask);
@@ -999,7 +999,7 @@ public final class DownloadManager {
         return;
       }
 
-      Throwable finalError = task.finalError;
+      @Nullable Throwable finalError = task.finalError;
       if (finalError != null) {
         Log.e(TAG, "Task failed: " + task.request + ", " + isRemove, finalError);
       }
@@ -1176,7 +1176,7 @@ public final class DownloadManager {
     private final boolean isRemove;
     private final int minRetryCount;
 
-    private volatile InternalHandler internalHandler;
+    @Nullable private volatile InternalHandler internalHandler;
     private volatile boolean isCanceled;
     @Nullable private Throwable finalError;
 
@@ -1246,7 +1246,7 @@ public final class DownloadManager {
       } catch (Throwable e) {
         finalError = e;
       }
-      Handler internalHandler = this.internalHandler;
+      @Nullable Handler internalHandler = this.internalHandler;
       if (internalHandler != null) {
         internalHandler.obtainMessage(MSG_TASK_STOPPED, this).sendToTarget();
       }
@@ -1258,7 +1258,7 @@ public final class DownloadManager {
       downloadProgress.percentDownloaded = percentDownloaded;
       if (contentLength != this.contentLength) {
         this.contentLength = contentLength;
-        Handler internalHandler = this.internalHandler;
+        @Nullable Handler internalHandler = this.internalHandler;
         if (internalHandler != null) {
           internalHandler.obtainMessage(MSG_CONTENT_LENGTH_CHANGED, this).sendToTarget();
         }

library/core/src/main/java/com/google/android/exoplayer2/offline/DownloadService.java

@@ -592,8 +592,8 @@ public abstract class DownloadService extends Service {
   public int onStartCommand(Intent intent, int flags, int startId) {
     lastStartId = startId;
     taskRemoved = false;
-    String intentAction = null;
-    String contentId = null;
+    @Nullable String intentAction = null;
+    @Nullable String contentId = null;
     if (intent != null) {
       intentAction = intent.getAction();
       startedInForeground |=
@@ -611,7 +611,7 @@ public abstract class DownloadService extends Service {
         // Do nothing.
         break;
       case ACTION_ADD_DOWNLOAD:
-        DownloadRequest downloadRequest = intent.getParcelableExtra(KEY_DOWNLOAD_REQUEST);
+        @Nullable DownloadRequest downloadRequest = intent.getParcelableExtra(KEY_DOWNLOAD_REQUEST);
         if (downloadRequest == null) {
           Log.e(TAG, "Ignored ADD_DOWNLOAD: Missing " + KEY_DOWNLOAD_REQUEST + " extra");
         } else {
@@ -644,7 +644,7 @@ public abstract class DownloadService extends Service {
         }
         break;
       case ACTION_SET_REQUIREMENTS:
-        Requirements requirements = intent.getParcelableExtra(KEY_REQUIREMENTS);
+        @Nullable Requirements requirements = intent.getParcelableExtra(KEY_REQUIREMENTS);
         if (requirements == null) {
           Log.e(TAG, "Ignored SET_REQUIREMENTS: Missing " + KEY_REQUIREMENTS + " extra");
         } else {

library/core/src/main/java/com/google/android/exoplayer2/offline/SegmentDownloader.java

@@ -138,7 +138,7 @@ public abstract class SegmentDownloader<M extends FilterableManifest<M>> impleme
       Collections.sort(segments);
 
       // Download the segments.
-      ProgressNotifier progressNotifier = null;
+      @Nullable ProgressNotifier progressNotifier = null;
       if (progressListener != null) {
         progressNotifier =
             new ProgressNotifier(