Annotate some NonNulls, some lint cleaning

app/src/main/java/org/schabi/newpipe/MainActivity.java

@@ -225,7 +225,7 @@ private void addDrawerMenuForCurrentService() throws ExtractionException {
             drawerLayoutBinding.navigation.getMenu()
                     .add(R.id.menu_tabs_group, kioskId, 0, KioskTranslator
                             .getTranslatedKioskName(ks, this))
-                    .setIcon(KioskTranslator.getKioskIcon(ks, this));
+                    .setIcon(KioskTranslator.getKioskIcon(ks));
             kioskId++;
         }
 

app/src/main/java/org/schabi/newpipe/fragments/OnScrollBelowItemsListener.java

@@ -1,5 +1,6 @@
 package org.schabi.newpipe.fragments;
 
+import androidx.annotation.NonNull;
 import androidx.recyclerview.widget.LinearLayoutManager;
 import androidx.recyclerview.widget.RecyclerView;
 import androidx.recyclerview.widget.StaggeredGridLayoutManager;
@@ -10,7 +11,7 @@
  */
 public abstract class OnScrollBelowItemsListener extends RecyclerView.OnScrollListener {
     @Override
-    public void onScrolled(final RecyclerView recyclerView, final int dx, final int dy) {
+    public void onScrolled(@NonNull final RecyclerView recyclerView, final int dx, final int dy) {
         super.onScrolled(recyclerView, dx, dy);
         if (dy > 0) {
             int pastVisibleItems = 0;

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

@@ -1,5 +1,7 @@
 package org.schabi.newpipe.fragments.detail;
 
+import androidx.annotation.NonNull;
+
 import org.schabi.newpipe.player.playqueue.PlayQueue;
 
 import java.io.Serializable;
@@ -46,6 +48,7 @@ public PlayQueue getPlayQueue() {
         return playQueue;
     }
 
+    @NonNull
     @Override
     public String toString() {
         return getServiceId() + ":" + getUrl() + " > " + getTitle();

app/src/main/java/org/schabi/newpipe/fragments/list/BaseListFragment.java

@@ -342,7 +342,8 @@ protected void useInitialItemListLoadScrollListener() {
         itemsList.clearOnScrollListeners();
         itemsList.addOnScrollListener(new DefaultItemListOnScrolledDownListener() {
             @Override
-            public void onScrolled(final RecyclerView recyclerView, final int dx, final int dy) {
+            public void onScrolled(@NonNull final RecyclerView recyclerView,
+                                   final int dx, final int dy) {
                 super.onScrolled(recyclerView, dx, dy);
 
                 if (dy != 0) {

app/src/main/java/org/schabi/newpipe/fragments/list/search/SuggestionListAdapter.java

@@ -7,6 +7,7 @@
 import android.widget.ImageView;
 import android.widget.TextView;
 
+import androidx.annotation.NonNull;
 import androidx.recyclerview.widget.RecyclerView;
 
 import org.schabi.newpipe.R;
@@ -34,8 +35,10 @@ public void setListener(final OnSuggestionItemSelected listener) {
         this.listener = listener;
     }
 
+    @NonNull
     @Override
-    public SuggestionItemHolder onCreateViewHolder(final ViewGroup parent, final int viewType) {
+    public SuggestionItemHolder onCreateViewHolder(@NonNull final ViewGroup parent,
+                                                   final int viewType) {
         return new SuggestionItemHolder(LayoutInflater.from(context)
                 .inflate(R.layout.item_search_suggestion, parent, false));
     }

app/src/main/java/org/schabi/newpipe/info_list/dialog/InfoItemDialog.java

@@ -277,11 +277,10 @@ public Builder addStartHereEntries() {
         }
 
         /**
-         * Adds {@link StreamDialogDefaultEntry.MARK_AS_WATCHED} if the watch history is enabled
+         * Adds {@link StreamDialogDefaultEntry#MARK_AS_WATCHED} if the watch history is enabled
          * and the stream is not a livestream.
-         * @return the current {@link Builder} instance
          */
-        public Builder addMarkAsWatchedEntryIfNeeded() {
+        public void addMarkAsWatchedEntryIfNeeded() {
             final boolean isWatchHistoryEnabled = PreferenceManager
                     .getDefaultSharedPreferences(context)
                     .getBoolean(context.getString(R.string.enable_watch_history_key), false);
@@ -290,18 +289,15 @@ public Builder addMarkAsWatchedEntryIfNeeded() {
                     && infoItem.getStreamType() != StreamType.AUDIO_LIVE_STREAM) {
                 addEntry(StreamDialogDefaultEntry.MARK_AS_WATCHED);
             }
-            return this;
         }
 
         /**
-         * Adds the {@link StreamDialogDefaultEntry.PLAY_WITH_KODI} entry if it is needed.
-         * @return the current {@link Builder} instance
+         * Adds the {@link StreamDialogDefaultEntry#PLAY_WITH_KODI} entry if it is needed.
          */
-        public Builder addPlayWithKodiEntryIfNeeded() {
+        public void addPlayWithKodiEntryIfNeeded() {
             if (KoreUtils.shouldShowPlayWithKodi(context, infoItem.getServiceId())) {
                 addEntry(StreamDialogDefaultEntry.PLAY_WITH_KODI);
             }
-            return this;
         }
 
         /**

app/src/main/java/org/schabi/newpipe/local/dialog/PlaylistDialog.java

@@ -97,7 +97,7 @@ public void readFrom(@NonNull final Queue<Object> savedObjects) {
     }
 
     @Override
-    public void onSaveInstanceState(final Bundle outState) {
+    public void onSaveInstanceState(@NonNull final Bundle outState) {
         super.onSaveInstanceState(outState);
         if (getActivity() != null) {
             savedState = StateSaver.tryToSave(getActivity().isChangingConfigurations(),

app/src/main/java/org/schabi/newpipe/local/feed/FeedFragment.kt

@@ -50,7 +50,6 @@ import androidx.recyclerview.widget.GridLayoutManager
 import androidx.recyclerview.widget.RecyclerView
 import com.xwray.groupie.GroupieAdapter
 import com.xwray.groupie.Item
-import com.xwray.groupie.OnAsyncUpdateListener
 import com.xwray.groupie.OnItemClickListener
 import com.xwray.groupie.OnItemLongClickListener
 import icepick.State
@@ -139,7 +138,7 @@ class FeedFragment : BaseStateFragment<FeedState>() {
         val factory = FeedViewModel.Factory(requireContext(), groupId)
         viewModel = ViewModelProvider(this, factory).get(FeedViewModel::class.java)
         showPlayedItems = viewModel.getShowPlayedItemsFromPreferences()
-        viewModel.stateLiveData.observe(viewLifecycleOwner, { it?.let(::handleResult) })
+        viewModel.stateLiveData.observe(viewLifecycleOwner) { it?.let(::handleResult) }
 
         groupAdapter = GroupieAdapter().apply {
             setOnItemClickListener(listenerStreamItem)
@@ -393,14 +392,11 @@ class FeedFragment : BaseStateFragment<FeedState>() {
         // This need to be saved in a variable as the update occurs async
         val oldOldestSubscriptionUpdate = oldestSubscriptionUpdate
 
-        groupAdapter.updateAsync(
-            loadedState.items, false,
-            OnAsyncUpdateListener {
-                oldOldestSubscriptionUpdate?.run {
-                    highlightNewItemsAfter(oldOldestSubscriptionUpdate)
-                }
+        groupAdapter.updateAsync(loadedState.items, false) {
+            oldOldestSubscriptionUpdate?.run {
+                highlightNewItemsAfter(oldOldestSubscriptionUpdate)
             }
-        )
+        }
 
         listState?.run {
             feedBinding.itemsList.layoutManager?.onRestoreInstanceState(listState)

app/src/main/java/org/schabi/newpipe/local/feed/FeedViewModel.kt

@@ -56,7 +56,7 @@ class FeedViewModel(
         .subscribeOn(Schedulers.io())
         .observeOn(Schedulers.io())
         .map { (event, showPlayedItems, notLoadedCount, oldestUpdate) ->
-            var streamItems = if (event is SuccessResultEvent || event is IdleEvent)
+            val streamItems = if (event is SuccessResultEvent || event is IdleEvent)
                 feedDatabaseManager
                     .getStreams(groupId, showPlayedItems)
                     .blockingGet(arrayListOf())

app/src/main/java/org/schabi/newpipe/local/history/HistoryEntryAdapter.java

@@ -84,7 +84,7 @@ public void onBindViewHolder(final VH holder, final int position) {
     }
 
     @Override
-    public void onViewRecycled(final VH holder) {
+    public void onViewRecycled(@NonNull final VH holder) {
         super.onViewRecycled(holder);
         holder.itemView.setOnClickListener(null);
     }

app/src/main/java/org/schabi/newpipe/local/subscription/ImportConfirmationDialog.java

@@ -61,7 +61,7 @@ public void onCreate(@Nullable final Bundle savedInstanceState) {
     }
 
     @Override
-    public void onSaveInstanceState(final Bundle outState) {
+    public void onSaveInstanceState(@NonNull final Bundle outState) {
         super.onSaveInstanceState(outState);
         Icepick.saveInstanceState(this, outState);
     }

app/src/main/java/org/schabi/newpipe/local/subscription/dialog/FeedGroupDialogViewModel.kt

@@ -8,7 +8,6 @@ import androidx.lifecycle.ViewModelProvider
 import io.reactivex.rxjava3.core.Completable
 import io.reactivex.rxjava3.core.Flowable
 import io.reactivex.rxjava3.disposables.Disposable
-import io.reactivex.rxjava3.functions.BiFunction
 import io.reactivex.rxjava3.processors.BehaviorProcessor
 import io.reactivex.rxjava3.schedulers.Schedulers
 import org.schabi.newpipe.database.feed.model.FeedGroupEntity
@@ -33,9 +32,8 @@ class FeedGroupDialogViewModel(
     private var subscriptionsFlowable = Flowable
         .combineLatest(
             filterSubscriptions.startWithItem(initialQuery),
-            toggleShowOnlyUngrouped.startWithItem(initialShowOnlyUngrouped),
-            BiFunction { t1: String, t2: Boolean -> Filter(t1, t2) }
-        )
+            toggleShowOnlyUngrouped.startWithItem(initialShowOnlyUngrouped)
+        ) { t1: String, t2: Boolean -> Filter(t1, t2) }
         .distinctUntilChanged()
         .switchMap { (query, showOnlyUngrouped) ->
             subscriptionManager.getSubscriptions(groupId, query, showOnlyUngrouped)
@@ -56,9 +54,8 @@ class FeedGroupDialogViewModel(
 
     private var subscriptionsDisposable = Flowable
         .combineLatest(
-            subscriptionsFlowable, feedDatabaseManager.subscriptionIdsForGroup(groupId),
-            BiFunction { t1: List<PickerSubscriptionItem>, t2: List<Long> -> t1 to t2.toSet() }
-        )
+            subscriptionsFlowable, feedDatabaseManager.subscriptionIdsForGroup(groupId)
+        ) { t1: List<PickerSubscriptionItem>, t2: List<Long> -> t1 to t2.toSet() }
         .subscribeOn(Schedulers.io())
         .subscribe(mutableSubscriptionsLiveData::postValue)
 

app/src/main/java/org/schabi/newpipe/local/subscription/dialog/FeedGroupReorderDialog.kt

@@ -57,15 +57,12 @@ class FeedGroupReorderDialog : DialogFragment() {
 
         viewModel = ViewModelProvider(this).get(FeedGroupReorderDialogViewModel::class.java)
         viewModel.groupsLiveData.observe(viewLifecycleOwner, Observer(::handleGroups))
-        viewModel.dialogEventLiveData.observe(
-            viewLifecycleOwner,
-            Observer {
-                when (it) {
-                    ProcessingEvent -> disableInput()
-                    SuccessEvent -> dismiss()
-                }
+        viewModel.dialogEventLiveData.observe(viewLifecycleOwner) {
+            when (it) {
+                ProcessingEvent -> disableInput()
+                SuccessEvent -> dismiss()
             }
-        )
+        }
 
         binding.feedGroupsList.layoutManager = LinearLayoutManager(requireContext())
         binding.feedGroupsList.adapter = groupAdapter

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

@@ -5,7 +5,6 @@
 import static org.schabi.newpipe.util.Localization.assureCorrectAppLanguage;
 
 import android.content.ComponentName;
-import android.content.Context;
 import android.content.Intent;
 import android.content.ServiceConnection;
 import android.os.Bundle;
@@ -601,7 +600,6 @@ private void onMaybeMuteChanged() {
 
             //2) Icon change accordingly to current App Theme
             // using rootView.getContext() because getApplicationContext() didn't work
-            final Context context = queueControlBinding.getRoot().getContext();
             item.setIcon(player.isMuted() ? R.drawable.ic_volume_off : R.drawable.ic_volume_up);
         }
     }

app/src/main/java/org/schabi/newpipe/player/helper/AudioReactor.java

@@ -149,7 +149,8 @@ public void onAnimationEnd(final Animator animation) {
     //////////////////////////////////////////////////////////////////////////*/
 
     @Override
-    public void onAudioSessionIdChanged(final EventTime eventTime, final int audioSessionId) {
+    public void onAudioSessionIdChanged(@NonNull final EventTime eventTime,
+                                        final int audioSessionId) {
         notifyAudioSessionUpdate(true, audioSessionId);
     }
     private void notifyAudioSessionUpdate(final boolean active, final int audioSessionId) {

app/src/main/java/org/schabi/newpipe/player/helper/CacheFactory.java

@@ -63,6 +63,7 @@ private CacheFactory(@NonNull final Context context,
         }
     }
 
+    @NonNull
     @Override
     public DataSource createDataSource() {
         Log.d(TAG, "initExoPlayerCache: cacheDir = " + cacheDir.getAbsolutePath());
@@ -86,8 +87,8 @@ public void tryDeleteCacheFiles() {
 
                 Log.d(TAG, "tryDeleteCacheFiles: " + filePath + " deleted = " + deleteSuccessful);
             }
-        } catch (final Exception ignored) {
-            Log.e(TAG, "Failed to delete file.", ignored);
+        } catch (final Exception e) {
+            Log.e(TAG, "Failed to delete file.", e);
         }
     }
 }

app/src/main/java/org/schabi/newpipe/player/helper/MediaSessionManager.java

@@ -135,9 +135,7 @@ public void setMetadata(@NonNull final String title,
         lastTitleHashCode = title.hashCode();
         lastArtistHashCode = artist.hashCode();
         lastDuration = duration;
-        if (optAlbumArt.isPresent()) {
-            lastAlbumArtHashCode = optAlbumArt.get().hashCode();
-        }
+        optAlbumArt.ifPresent(bitmap -> lastAlbumArtHashCode = bitmap.hashCode());
     }
 
     private boolean checkIfMetadataShouldBeSet(

app/src/main/java/org/schabi/newpipe/player/helper/PlaybackParameterDialog.java

@@ -125,7 +125,7 @@ public static PlaybackParameterDialog newInstance(final double playbackTempo,
     //////////////////////////////////////////////////////////////////////////*/
 
     @Override
-    public void onAttach(final Context context) {
+    public void onAttach(@NonNull final Context context) {
         super.onAttach(context);
         if (context instanceof Callback) {
             callback = (Callback) context;
@@ -150,7 +150,7 @@ public void onCreate(@Nullable final Bundle savedInstanceState) {
     }
 
     @Override
-    public void onSaveInstanceState(final Bundle outState) {
+    public void onSaveInstanceState(@NonNull final Bundle outState) {
         super.onSaveInstanceState(outState);
         outState.putDouble(INITIAL_TEMPO_KEY, initialTempo);
         outState.putDouble(INITIAL_PITCH_KEY, initialPitch);

app/src/main/java/org/schabi/newpipe/settings/DownloadSettingsFragment.java

@@ -185,7 +185,7 @@ private void showMessageDialog(@StringRes final int title, @StringRes final int
     }
 
     @Override
-    public boolean onPreferenceTreeClick(final Preference preference) {
+    public boolean onPreferenceTreeClick(@NonNull final Preference preference) {
         if (DEBUG) {
             Log.d(TAG, "onPreferenceTreeClick() called with: "
                     + "preference = [" + preference + "]");

app/src/main/java/org/schabi/newpipe/settings/SettingsActivity.java

@@ -169,7 +169,7 @@ public boolean onOptionsItemSelected(final MenuItem item) {
     }
 
     @Override
-    public boolean onPreferenceStartFragment(final PreferenceFragmentCompat caller,
+    public boolean onPreferenceStartFragment(@NonNull final PreferenceFragmentCompat caller,
                                              final Preference preference) {
         showSettingsFragment(instantiateFragment(preference.getFragment()));
         return true;

app/src/main/java/org/schabi/newpipe/settings/SettingsResourceRegistry.java

@@ -115,6 +115,7 @@ public SettingRegistryEntry setSearchable(final boolean searchable) {
             return this;
         }
 
+        @NonNull
         public Class<? extends Fragment> getFragmentClass() {
             return fragmentClass;
         }

app/src/main/java/org/schabi/newpipe/settings/custom/NotificationActionsPreference.java

@@ -50,7 +50,7 @@ public NotificationActionsPreference(final Context context, final AttributeSet a
     ////////////////////////////////////////////////////////////////////////////
 
     @Override
-    public void onBindViewHolder(final PreferenceViewHolder holder) {
+    public void onBindViewHolder(@NonNull final PreferenceViewHolder holder) {
         super.onBindViewHolder(holder);
 
         holder.itemView.setClickable(false);

app/src/main/java/org/schabi/newpipe/settings/preferencesearch/PreferenceSearchConfiguration.java

@@ -4,14 +4,15 @@
 import androidx.preference.PreferenceScreen;
 
 import java.util.Arrays;
+import java.util.Collections;
 import java.util.List;
 import java.util.Objects;
 import java.util.stream.Stream;
 
 public class PreferenceSearchConfiguration {
     private PreferenceSearchFunction searcher = new PreferenceFuzzySearchFunction();
 
-    private final List<String> parserIgnoreElements = Arrays.asList(
+    private final List<String> parserIgnoreElements = Collections.singletonList(
             PreferenceCategory.class.getSimpleName());
     private final List<String> parserContainerElements = Arrays.asList(
             PreferenceCategory.class.getSimpleName(),

app/src/main/java/org/schabi/newpipe/settings/preferencesearch/PreferenceSearchItem.java

@@ -58,22 +58,27 @@ public PreferenceSearchItem(
         this.searchIndexItemResId = searchIndexItemResId;
     }
 
+    @NonNull
     public String getKey() {
         return key;
     }
 
+    @NonNull
     public String getTitle() {
         return title;
     }
 
+    @NonNull
     public String getSummary() {
         return summary;
     }
 
+    @NonNull
     public String getEntries() {
         return entries;
     }
 
+    @NonNull
     public String getBreadcrumbs() {
         return breadcrumbs;
     }
@@ -94,7 +99,7 @@ public List<String> getAllRelevantSearchFields() {
             getBreadcrumbs());
     }
 
-
+    @NonNull
     @Override
     public String toString() {
         return "PreferenceItem: " + title + " " + summary + " " + key;