Improve docs and fix typos

app/src/main/java/org/schabi/newpipe/download/DownloadDialog.java

@@ -924,7 +924,7 @@ private void checkSelectedDownload(final StoredDirectoryHelper mainStorage,
                 } else if (targetFile == null) {
                     // This part is called if:
                     // * the filename is not used in a pending/finished download
-                    // * the file does not exists, create
+                    // * the file does not exist, create
 
                     if (!mainStorage.mkdirs()) {
                         showFailedDialog(R.string.error_path_creation);

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

@@ -186,7 +186,9 @@ public final class Player implements PlaybackListener, Listener {
     // Playback
     //////////////////////////////////////////////////////////////////////////*/
 
-    // play queue might be null e.g. while player is starting
+    /**
+     * The play queue might be {@code null} e.g. while player is starting
+     */
     @Nullable
     private PlayQueue playQueue;
 
@@ -230,8 +232,10 @@ public final class Player implements PlaybackListener, Listener {
     private PlayerType playerType = PlayerType.MAIN;
     private int currentState = STATE_PREFLIGHT;
 
-    // audio only mode does not mean that player type is background, but that the player was
-    // minimized to background but will resume automatically to the original player type
+    /**
+     * Audio-only mode does not mean that player type is background, but that the player was
+     * minimized to background and will change to the original player type automatically.
+     */
     private boolean isAudioOnly = false;
     private boolean isPrepared = false;
 
@@ -934,7 +938,7 @@ public void onSuccess(@NonNull final coil3.Image result) {
 
     private void onThumbnailLoaded(@Nullable final Bitmap bitmap) {
         // Avoid useless thumbnail updates, if the thumbnail has not actually changed. Based on the
-        // thumbnail loading code, this if would be skipped only when both bitmaps are `null`, since
+        // thumbnail loading code, this would be skipped only when both bitmaps are `null`, since
         // onThumbnailLoaded won't be called twice with the same nonnull bitmap by Coil's target.
         if (currentThumbnail != bitmap) {
             currentThumbnail = bitmap;
@@ -1522,7 +1526,7 @@ public void onPrepare() {
      * <li>From {@link PlaybackException#ERROR_CODE_IO_INVALID_HTTP_CONTENT_TYPE BAD_IO} to
      * {@link PlaybackException#ERROR_CODE_PARSING_MANIFEST_UNSUPPORTED UNSUPPORTED_FORMATS}:
      * If the stream source is validated by the extractor but not recognized by the player,
-     * then we can try to recover playback by signalling an error on the {@link PlayQueue}.</li>
+     * then we can try to recover playback by signaling an error on the {@link PlayQueue}.</li>
      * <li>For {@link PlaybackException#ERROR_CODE_TIMEOUT PLAYER_TIMEOUT},
      * {@link PlaybackException#ERROR_CODE_IO_UNSPECIFIED MEDIA_SOURCE_RESOLVER_TIMEOUT} and
      * {@link PlaybackException#ERROR_CODE_IO_NETWORK_CONNECTION_FAILED NO_NETWORK}:
@@ -1541,7 +1545,7 @@ public void onPrepare() {
      */
     // Any error code not explicitly covered here are either unrelated to NewPipe use case
     // (e.g. DRM) or not recoverable (e.g. Decoder error). In both cases, the player should
-    // shutdown.
+    // shut down.
     @SuppressWarnings("SwitchIntDef")
     @Override
     public void onPlayerError(@NonNull final PlaybackException error) {
@@ -2241,7 +2245,7 @@ The current metadata may be null sometimes (for e.g. when using an unstable conn
             reloadPlayQueueManager();
         });
 
-        // Disable or enable video and subtitles renderers depending of the
+        // Disable or enable video and subtitles renderers depending on the
         // videoAndSubtitlesEnabled value
         trackSelector.setParameters(trackSelector.buildUponParameters()
                 .setTrackTypeDisabled(C.TRACK_TYPE_TEXT, !videoAndSubtitlesEnabled)
@@ -2354,7 +2358,7 @@ private boolean isLive() {
         try {
             return !exoPlayerIsNull() && simpleExoPlayer.isCurrentMediaItemDynamic();
         } catch (final IndexOutOfBoundsException e) {
-            // Why would this even happen =(... but lets log it anyway, better safe than sorry
+            // Why would this even happen =(... but let's log it anyway, better safe than sorry
             if (DEBUG) {
                 Log.d(TAG, "player.isCurrentWindowDynamic() failed: ", e);
             }

app/src/main/java/org/schabi/newpipe/player/datasource/NonUriHlsDataSourceFactory.java

@@ -18,7 +18,7 @@
  * <p>
  * If media requests are relative, the URI from which the manifest comes from (either the
  * manifest URI (preferred) or the master URI (if applicable)) must be returned, otherwise the
- * content will be not playable, as it will be an invalid URL, or it may be treat as something
+ * content will be not playable, as it will be an invalid URL, or it may be treated as something
  * unexpected, for instance as a file for
  * {@link com.google.android.exoplayer2.upstream.DefaultDataSource DefaultDataSource}s.
  * </p>

app/src/main/java/org/schabi/newpipe/player/gesture/PopupPlayerGestureListener.kt

@@ -258,7 +258,7 @@ class PopupPlayerGestureListener(
 
         // -- Determine if the ClosingOverlayView (red X) has to be shown or hidden --
         val showClosingOverlayView: Boolean = playerUi.isInsideClosingRadius(movingEvent)
-        // Check if an view is in expected state and if not animate it into the correct state
+        // Check if a view is in expected state and if not animate it into the correct state
         if (binding.closingOverlay.isVisible != showClosingOverlayView) {
             binding.closingOverlay.animate(showClosingOverlayView, 200)
         }

app/src/main/java/org/schabi/newpipe/player/mediasource/FailedMediaSource.java

@@ -98,7 +98,7 @@ public MediaItem getMediaItem() {
      * <br><br>
      * If the exception is not known, e.g. {@link java.net.UnknownHostException} or some
      * other network issue, then no source info is refreshed and
-     * {@link #maybeThrowSourceInfoRefreshError()} be will triggered.
+     * {@link #maybeThrowSourceInfoRefreshError()} will be triggered.
      * <br><br>
      * Note that this method is called only once until {@link #releaseSourceInternal()} is called,
      * so if no action is done in here, playback will stall unless

app/src/main/java/org/schabi/newpipe/player/mediasource/ManagedMediaSource.java

@@ -15,7 +15,7 @@ public interface ManagedMediaSource extends MediaSource {
      *                        {@link ManagedMediaSource}, then it should be replaced.
      * @param isInterruptable specifies if this {@link ManagedMediaSource} potentially
      *                        being played.
-     * @return whether this could be replaces
+     * @return whether this could be replaced
      */
     boolean shouldBeReplacedWith(@NonNull PlayQueueItem newIdentity, boolean isInterruptable);
 

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

@@ -72,7 +72,7 @@ public interface PlaybackListener {
     /**
      * Called when the play queue can no longer be played or used.
      * Currently, this means the play queue is empty and complete.
-     * Signals to the listener that it should shutdown.
+     * Signals to the listener that it should shut down.
      * <p>
      * May be called at any time.
      * </p>

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

@@ -8,11 +8,11 @@
 
 /**
  * Prevent error message: 'Unrecoverable player error occurred'
- * In case of rotation some users see this kind of an error which is preventable
+ * In case of rotation some users see this kind of error which is preventable
  * having a Callback that handles the lifecycle of the surface.
  * <p>
- * How?: In case we are no longer able to write to the surface eg. through rotation/putting in
- * background we set set a DummySurface. Although it it works on API >= 23 only.
+ * How?: In case we are no longer able to write to the surface e.g. through rotation/putting in
+ * background we set a DummySurface. Although it works on API >= 23 only.
  * Result: we get a little video interruption (audio is still fine) but we won't get the
  * 'Unrecoverable player error occurred' error message.
  * <p>

app/src/main/java/org/schabi/newpipe/player/playqueue/PlayQueue.java

@@ -373,7 +373,7 @@ private synchronized void removeInternal(final int removeIndex) {
      * to that of the target.
      * If the moved item is not the currently playing and moves to an index <b>AFTER</b> the
      * current playing index, then the current playing index is decremented.
-     * Vice versa if the an item after the currently playing is moved <b>BEFORE</b>.
+     * Vice versa if an item after the currently playing is moved <b>BEFORE</b>.
      * </p>
      *
      * @param source the original index of the item

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

@@ -243,7 +243,7 @@ public void onBroadcastReceived(final Intent intent) {
     //region Popup position and size
 
     /**
-     * Check if {@link #popupLayoutParams}' position is within a arbitrary boundary
+     * Check if {@link #popupLayoutParams}' position is within an arbitrary boundary
      * that goes from (0, 0) to (screenWidth, screenHeight).
      * <p>
      * If it's out of these boundaries, {@link #popupLayoutParams}' position is changed

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

@@ -810,7 +810,7 @@ public boolean isFullscreen() {
 
     /**
      * Update the play/pause button ({@link R.id.playPauseButton}) to reflect the action
-     * that will be performed when the button is clicked..
+     * that will be performed when the button is clicked.
      * @param action the action that is performed when the play/pause button is clicked
      */
     private void updatePlayPauseButton(final PlayButtonAction action) {