Add convenience methods to select multiple audio or text tracks for downloading.

These methods take a list of languages to be downloaded and add selections for
each of the languages.

PiperOrigin-RevId: 231385632

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

@@ -490,6 +490,64 @@ public final class DownloadHelper {
   }
   }
 
 
   /**
   /**
+   * Convenience method to add selections of tracks for all specified audio languages. If an audio
+   * track in one of the specified languages is not available, the default fallback audio track is
+   * used instead. Must not be called until after preparation completes.
+   *
+   * @param languages A list of audio languages for which tracks should be added to the download
+   *     selection, as ISO 639-2/T tags.
+   */
+  public void addAudioLanguagesToSelection(String... languages) {
+    assertPreparedWithMedia();
+    for (int periodIndex = 0; periodIndex < mappedTrackInfos.length; periodIndex++) {
+      DefaultTrackSelector.ParametersBuilder parametersBuilder =
+          DEFAULT_TRACK_SELECTOR_PARAMETERS.buildUpon();
+      MappedTrackInfo mappedTrackInfo = mappedTrackInfos[periodIndex];
+      int rendererCount = mappedTrackInfo.getRendererCount();
+      for (int rendererIndex = 0; rendererIndex < rendererCount; rendererIndex++) {
+        if (mappedTrackInfo.getRendererType(rendererIndex) != C.TRACK_TYPE_AUDIO) {
+          parametersBuilder.setRendererDisabled(rendererIndex, /* disabled= */ true);
+        }
+      }
+      for (String language : languages) {
+        parametersBuilder.setPreferredAudioLanguage(language);
+        addTrackSelection(periodIndex, parametersBuilder.build());
+      }
+    }
+  }
+
+  /**
+   * Convenience method to add selections of tracks for all specified text languages. Must not be
+   * called until after preparation completes.
+   *
+   * @param selectUndeterminedTextLanguage Whether a text track with undetermined language should be
+   *     selected for downloading if no track with one of the specified {@code languages} is
+   *     available.
+   * @param languages A list of text languages for which tracks should be added to the download
+   *     selection, as ISO 639-2/T tags.
+   */
+  public void addTextLanguagesToSelection(
+      boolean selectUndeterminedTextLanguage, String... languages) {
+    assertPreparedWithMedia();
+    for (int periodIndex = 0; periodIndex < mappedTrackInfos.length; periodIndex++) {
+      DefaultTrackSelector.ParametersBuilder parametersBuilder =
+          DEFAULT_TRACK_SELECTOR_PARAMETERS.buildUpon();
+      MappedTrackInfo mappedTrackInfo = mappedTrackInfos[periodIndex];
+      int rendererCount = mappedTrackInfo.getRendererCount();
+      for (int rendererIndex = 0; rendererIndex < rendererCount; rendererIndex++) {
+        if (mappedTrackInfo.getRendererType(rendererIndex) != C.TRACK_TYPE_TEXT) {
+          parametersBuilder.setRendererDisabled(rendererIndex, /* disabled= */ true);
+        }
+      }
+      parametersBuilder.setSelectUndeterminedTextLanguage(selectUndeterminedTextLanguage);
+      for (String language : languages) {
+        parametersBuilder.setPreferredTextLanguage(language);
+        addTrackSelection(periodIndex, parametersBuilder.build());
+      }
+    }
+  }
+
+  /**
    * Builds a {@link DownloadAction} for downloading the selected tracks. Must not be called until
    * Builds a {@link DownloadAction} for downloading the selected tracks. Must not be called until
    * after preparation completes.
    * after preparation completes.
    *
    *

library/core/src/test/java/com/google/android/exoplayer2/offline/DownloadHelperTest.java

@@ -313,6 +313,73 @@ public class DownloadHelperTest {
   }
   }
 
 
   @Test
   @Test
+  public void getTrackSelections_afterAddAudioLanguagesToSelection_returnsCombinedSelections()
+      throws Exception {
+    prepareDownloadHelper(downloadHelper);
+    downloadHelper.clearTrackSelections(/* periodIndex= */ 0);
+    downloadHelper.clearTrackSelections(/* periodIndex= */ 1);
+
+    // Add a non-default language, and a non-existing language (which will select the default).
+    downloadHelper.addAudioLanguagesToSelection("ZH", "Klingonese");
+    List<TrackSelection> selectedText0 =
+        downloadHelper.getTrackSelections(/* periodIndex= */ 0, /* rendererIndex= */ 0);
+    List<TrackSelection> selectedAudio0 =
+        downloadHelper.getTrackSelections(/* periodIndex= */ 0, /* rendererIndex= */ 1);
+    List<TrackSelection> selectedVideo0 =
+        downloadHelper.getTrackSelections(/* periodIndex= */ 0, /* rendererIndex= */ 2);
+    List<TrackSelection> selectedText1 =
+        downloadHelper.getTrackSelections(/* periodIndex= */ 1, /* rendererIndex= */ 0);
+    List<TrackSelection> selectedAudio1 =
+        downloadHelper.getTrackSelections(/* periodIndex= */ 1, /* rendererIndex= */ 1);
+    List<TrackSelection> selectedVideo1 =
+        downloadHelper.getTrackSelections(/* periodIndex= */ 1, /* rendererIndex= */ 2);
+
+    assertThat(selectedVideo0).isEmpty();
+    assertThat(selectedText0).isEmpty();
+    assertThat(selectedAudio0).hasSize(2);
+    assertTrackSelectionEquals(selectedAudio0.get(0), TRACK_GROUP_AUDIO_ZH, 0);
+    assertTrackSelectionEquals(selectedAudio0.get(1), TRACK_GROUP_AUDIO_US, 0);
+
+    assertThat(selectedVideo1).isEmpty();
+    assertThat(selectedText1).isEmpty();
+    assertSingleTrackSelectionEquals(selectedAudio1, TRACK_GROUP_AUDIO_US, 0);
+  }
+
+  @Test
+  public void getTrackSelections_afterAddTextLanguagesToSelection_returnsCombinedSelections()
+      throws Exception {
+    prepareDownloadHelper(downloadHelper);
+    downloadHelper.clearTrackSelections(/* periodIndex= */ 0);
+    downloadHelper.clearTrackSelections(/* periodIndex= */ 1);
+
+    // Add a non-default language, and a non-existing language (which will select the default).
+    downloadHelper.addTextLanguagesToSelection(
+        /* selectUndeterminedTextLanguage= */ true, "ZH", "Klingonese");
+    List<TrackSelection> selectedText0 =
+        downloadHelper.getTrackSelections(/* periodIndex= */ 0, /* rendererIndex= */ 0);
+    List<TrackSelection> selectedAudio0 =
+        downloadHelper.getTrackSelections(/* periodIndex= */ 0, /* rendererIndex= */ 1);
+    List<TrackSelection> selectedVideo0 =
+        downloadHelper.getTrackSelections(/* periodIndex= */ 0, /* rendererIndex= */ 2);
+    List<TrackSelection> selectedText1 =
+        downloadHelper.getTrackSelections(/* periodIndex= */ 1, /* rendererIndex= */ 0);
+    List<TrackSelection> selectedAudio1 =
+        downloadHelper.getTrackSelections(/* periodIndex= */ 1, /* rendererIndex= */ 1);
+    List<TrackSelection> selectedVideo1 =
+        downloadHelper.getTrackSelections(/* periodIndex= */ 1, /* rendererIndex= */ 2);
+
+    assertThat(selectedVideo0).isEmpty();
+    assertThat(selectedAudio0).isEmpty();
+    assertThat(selectedText0).hasSize(2);
+    assertTrackSelectionEquals(selectedText0.get(0), TRACK_GROUP_TEXT_ZH, 0);
+    assertTrackSelectionEquals(selectedText0.get(1), TRACK_GROUP_TEXT_US, 0);
+
+    assertThat(selectedVideo1).isEmpty();
+    assertThat(selectedAudio1).isEmpty();
+    assertThat(selectedText1).isEmpty();
+  }
+
+  @Test
   public void getDownloadAction_createsDownloadAction_withAllSelectedTracks() throws Exception {
   public void getDownloadAction_createsDownloadAction_withAllSelectedTracks() throws Exception {
     prepareDownloadHelper(downloadHelper);
     prepareDownloadHelper(downloadHelper);
     // Ensure we have track groups with multiple indices, renderers with multiple track groups and
     // Ensure we have track groups with multiple indices, renderers with multiple track groups and