Use Optional chaining.

app/src/main/java/org/schabi/newpipe/fragments/detail/VideoDetailFragment.java

@@ -2423,23 +2423,20 @@ public final class VideoDetailFragment
 
     // helpers to check the state of player and playerService
     boolean isPlayerAvailable() {
-        return (player != null);
+        return player != null;
     }
 
     boolean isPlayerServiceAvailable() {
-        return (playerService != null);
+        return playerService != null;
     }
 
     boolean isPlayerAndPlayerServiceAvailable() {
-        return (player != null && playerService != null);
+        return player != null && playerService != null;
     }
 
     public Optional<View> getRoot() {
-        if (player == null) {
-            return Optional.empty();
-        }
-
-        return player.UIs().get(VideoPlayerUi.class)
+        return Optional.ofNullable(player)
+                .flatMap(player1 -> player1.UIs().get(VideoPlayerUi.class))
                 .map(playerUi -> playerUi.getBinding().getRoot());
     }
 

app/src/main/java/org/schabi/newpipe/player/Player.java

@@ -1877,21 +1877,16 @@ public final class Player implements PlaybackListener, Listener {
 
     @Nullable
     public VideoStream getSelectedVideoStream() {
-        @Nullable final MediaItemTag.Quality quality = Optional.ofNullable(currentMetadata)
+        return Optional.ofNullable(currentMetadata)
                 .flatMap(MediaItemTag::getMaybeQuality)
+                .filter(quality -> {
+                    final int selectedStreamIndex = quality.getSelectedVideoStreamIndex();
+                    return selectedStreamIndex >= 0
+                            && selectedStreamIndex < quality.getSortedVideoStreams().size();
+                })
+                .map(quality -> quality.getSortedVideoStreams()
+                        .get(quality.getSelectedVideoStreamIndex()))
                 .orElse(null);
-        if (quality == null) {
-            return null;
-        }
-
-        final List<VideoStream> availableStreams = quality.getSortedVideoStreams();
-        final int selectedStreamIndex = quality.getSelectedVideoStreamIndex();
-
-        if (selectedStreamIndex >= 0 && availableStreams.size() > selectedStreamIndex) {
-            return availableStreams.get(selectedStreamIndex);
-        } else {
-            return null;
-        }
     }
     //endregion
 

app/src/main/java/org/schabi/newpipe/player/mediaitem/MediaItemTag.java

@@ -61,12 +61,11 @@ public interface MediaItemTag {
 
     @NonNull
     static Optional<MediaItemTag> from(@Nullable final MediaItem mediaItem) {
-        if (mediaItem == null || mediaItem.localConfiguration == null
-                || !(mediaItem.localConfiguration.tag instanceof MediaItemTag)) {
-            return Optional.empty();
-        }
-
-        return Optional.of((MediaItemTag) mediaItem.localConfiguration.tag);
+        return Optional.ofNullable(mediaItem)
+                .map(item -> item.localConfiguration)
+                .map(localConfiguration -> localConfiguration.tag)
+                .filter(MediaItemTag.class::isInstance)
+                .map(MediaItemTag.class::cast);
     }
 
     @NonNull

app/src/main/java/org/schabi/newpipe/player/playback/MediaSourceManager.java

@@ -7,8 +7,6 @@ import androidx.annotation.NonNull;
 import androidx.annotation.Nullable;
 import androidx.collection.ArraySet;
 
-import com.google.android.exoplayer2.source.MediaSource;
-
 import org.reactivestreams.Subscriber;
 import org.reactivestreams.Subscription;
 import org.schabi.newpipe.extractor.exceptions.ExtractionException;
@@ -27,6 +25,7 @@ import org.schabi.newpipe.util.ServiceHelper;
 
 import java.util.Collection;
 import java.util.Collections;
+import java.util.Optional;
 import java.util.Set;
 import java.util.concurrent.TimeUnit;
 import java.util.concurrent.atomic.AtomicBoolean;
@@ -422,21 +421,24 @@ public class MediaSourceManager {
 
     private Single<ManagedMediaSource> getLoadedMediaSource(@NonNull final PlayQueueItem stream) {
         return stream.getStream().map(streamInfo -> {
-            final MediaSource source = playbackListener.sourceOf(stream, streamInfo);
-            if (source == null || MediaItemTag.from(source.getMediaItem()).isEmpty()) {
-                final String message = "Unable to resolve source from stream info. "
-                        + "URL: " + stream.getUrl() + ", "
-                        + "audio count: " + streamInfo.getAudioStreams().size() + ", "
-                        + "video count: " + streamInfo.getVideoOnlyStreams().size() + ", "
-                        + streamInfo.getVideoStreams().size();
-                return (ManagedMediaSource)
-                        FailedMediaSource.of(stream, new MediaSourceResolutionException(message));
-            }
+            final var source = playbackListener.sourceOf(stream, streamInfo);
 
-            final MediaItemTag tag = MediaItemTag.from(source.getMediaItem()).get();
-            final long expiration = System.currentTimeMillis()
-                    + ServiceHelper.getCacheExpirationMillis(streamInfo.getServiceId());
-            return new LoadedMediaSource(source, tag, stream, expiration);
+            return Optional.ofNullable(source)
+                    .flatMap(source1 -> MediaItemTag.from(source1.getMediaItem()))
+                    .<ManagedMediaSource>map(tag -> {
+                        final long expiration = System.currentTimeMillis()
+                                + ServiceHelper.getCacheExpirationMillis(streamInfo.getServiceId());
+                        return new LoadedMediaSource(source, tag, stream, expiration);
+                    })
+                    .orElseGet(() -> {
+                        final String message = "Unable to resolve source from stream info. "
+                                + "URL: " + stream.getUrl() + ", "
+                                + "audio count: " + streamInfo.getAudioStreams().size() + ", "
+                                + "video count: " + streamInfo.getVideoOnlyStreams().size() + ", "
+                                + streamInfo.getVideoStreams().size();
+                        return FailedMediaSource.of(stream, new MediaSourceResolutionException(
+                                message));
+                    });
         }).onErrorReturn(throwable -> {
             if (throwable instanceof ExtractionException) {
                 return FailedMediaSource.of(stream, new StreamInfoLoadException(throwable));

app/src/main/java/org/schabi/newpipe/player/seekbarpreview/SeekbarPreviewThumbnailHelper.java

@@ -90,9 +90,8 @@ public final class SeekbarPreviewThumbnailHelper {
             final float scaleFactor = (float) newWidth / srcWidth;
             final int newHeight = (int) (previewThumbnail.getHeight() * scaleFactor);
 
-            currentSeekbarPreviewThumbnail.setImageBitmap(
-                    BitmapCompat.createScaledBitmap(previewThumbnail, newWidth, newHeight, null,
-                            true));
+            currentSeekbarPreviewThumbnail.setImageBitmap(BitmapCompat
+                    .createScaledBitmap(previewThumbnail, newWidth, newHeight, null, true));
         } catch (final Exception ex) {
             Log.e(TAG, "Failed to resize and set seekbar preview thumbnail", ex);
             currentSeekbarPreviewThumbnail.setVisibility(View.GONE);

app/src/main/java/org/schabi/newpipe/player/ui/MainPlayerUi.java

@@ -862,14 +862,11 @@ public final class MainPlayerUi extends VideoPlayerUi implements View.OnLayoutCh
 
     @Override
     protected void onPlaybackSpeedClicked() {
-        final AppCompatActivity activity = getParentActivity().orElse(null);
-        if (activity == null) {
-            return;
-        }
-
-        PlaybackParameterDialog.newInstance(player.getPlaybackSpeed(), player.getPlaybackPitch(),
-                player.getPlaybackSkipSilence(), player::setPlaybackParameters)
-                .show(activity.getSupportFragmentManager(), null);
+        getParentActivity().ifPresent(activity ->
+                PlaybackParameterDialog.newInstance(player.getPlaybackSpeed(),
+                                player.getPlaybackPitch(), player.getPlaybackSkipSilence(),
+                                player::setPlaybackParameters)
+                        .show(activity.getSupportFragmentManager(), null));
     }
 
     @Override
@@ -969,22 +966,22 @@ public final class MainPlayerUi extends VideoPlayerUi implements View.OnLayoutCh
     //////////////////////////////////////////////////////////////////////////*/
     //region Getters
 
+    private Optional<Context> getParentContext() {
+        return Optional.ofNullable(binding.getRoot().getParent())
+                .filter(ViewGroup.class::isInstance)
+                .map(parent -> ((ViewGroup) parent).getContext());
+    }
+
     public Optional<AppCompatActivity> getParentActivity() {
-        final ViewParent rootParent = binding.getRoot().getParent();
-        if (rootParent instanceof ViewGroup) {
-            final Context activity = ((ViewGroup) rootParent).getContext();
-            if (activity instanceof AppCompatActivity) {
-                return Optional.of((AppCompatActivity) activity);
-            }
-        }
-        return Optional.empty();
+        return getParentContext()
+                .filter(AppCompatActivity.class::isInstance)
+                .map(AppCompatActivity.class::cast);
     }
 
     public boolean isLandscape() {
         // DisplayMetrics from activity context knows about MultiWindow feature
         // while DisplayMetrics from app context doesn't
-        return DeviceUtils.isLandscape(
-                getParentActivity().map(Context.class::cast).orElse(player.getService()));
+        return DeviceUtils.isLandscape(getParentContext().orElse(player.getService()));
     }
     //endregion
 }