Fallback to including track language name if display name is not found

Issue: androidx/media#988
PiperOrigin-RevId: 606193299

RELEASENOTES.md

@@ -22,6 +22,9 @@
 *   IMA extension:
 *   Session:
 *   UI:
+    *   Fallback to include audio track language name if `Locale` cannot
+        identify a display name
+        ([#988](https://github.com/androidx/media/issues/988)).
 *   Downloads:
 *   OkHttp Extension:
 *   Cronet Extension:

libraries/ui/src/main/java/androidx/media3/ui/DefaultTrackNameProvider.java

@@ -56,7 +56,13 @@ public class DefaultTrackNameProvider implements TrackNameProvider {
     } else {
       trackName = buildLanguageOrLabelString(format);
     }
-    return trackName.length() == 0 ? resources.getString(R.string.exo_track_unknown) : trackName;
+    if (trackName.length() != 0) {
+      return trackName;
+    }
+    @Nullable String language = format.language;
+    return (language == null || language.trim().isEmpty())
+        ? resources.getString(R.string.exo_track_unknown)
+        : resources.getString(R.string.exo_track_unknown_name, language);
   }
 
   private String buildResolutionString(Format format) {

libraries/ui/src/main/res/values/strings.xml

@@ -100,6 +100,8 @@
   <string name="exo_track_selection_auto">Auto</string>
   <!-- Name of a media track about which nothing is known. Shown in a list view that allows the user to choose between multiple media tracks. [CHAR LIMIT=20] -->
   <string name="exo_track_unknown">Unknown</string>
+  <!-- Name of a media track of which the language name could not be identified. Shown in a list view that allows the user to choose between multiple media tracks. [CHAR LIMIT=20] -->
+  <string name="exo_track_unknown_name">Unknown (<xliff:g id="name" example="Frengligian">%1$s</xliff:g>)</string>
   <!-- Resolution of a video track. [CHAR LIMIT=20] -->
   <string name="exo_track_resolution"><xliff:g id="width" example="1024">%1$d</xliff:g> × <xliff:g id="height" example="768">%2$d</xliff:g></string>
   <!-- Describes an audio track with one channel. Shown in a list view that allows the user to choose between multiple audio tracks. [CHAR LIMIT=20] -->

libraries/ui/src/test/java/androidx/media3/ui/DefaultTrackNameProviderTest.java

@@ -29,13 +29,46 @@ import org.junit.runner.RunWith;
 public class DefaultTrackNameProviderTest {
 
   @Test
-  public void getTrackName_handlesInvalidLanguage() {
+  public void getTrackName_withInvalidLanguage_returnsUnknownWithLanguage() {
     Resources resources = ApplicationProvider.getApplicationContext().getResources();
     DefaultTrackNameProvider provider = new DefaultTrackNameProvider(resources);
     Format format = new Format.Builder().setLanguage("```").build();
 
     String name = provider.getTrackName(format);
 
+    assertThat(name).isEqualTo(resources.getString(R.string.exo_track_unknown_name, "```"));
+  }
+
+  @Test
+  public void getTrackName_withLanguageEmptyString_returnsUnknown() {
+    Resources resources = ApplicationProvider.getApplicationContext().getResources();
+    DefaultTrackNameProvider provider = new DefaultTrackNameProvider(resources);
+    Format format = new Format.Builder().setLanguage("").build();
+
+    String name = provider.getTrackName(format);
+
     assertThat(name).isEqualTo(resources.getString(R.string.exo_track_unknown));
   }
+
+  @Test
+  public void getTrackName_withLanguageSpacesNewLine_returnsUnknown() {
+    Resources resources = ApplicationProvider.getApplicationContext().getResources();
+    DefaultTrackNameProvider provider = new DefaultTrackNameProvider(resources);
+    Format format = new Format.Builder().setLanguage("   \n ").build();
+
+    String name = provider.getTrackName(format);
+
+    assertThat(name).isEqualTo(resources.getString(R.string.exo_track_unknown));
+  }
+
+  @Test
+  public void getTrackName_withLanguageEmptyStringAndLabel_returnsLabel() {
+    Resources resources = ApplicationProvider.getApplicationContext().getResources();
+    DefaultTrackNameProvider provider = new DefaultTrackNameProvider(resources);
+    Format format = new Format.Builder().setLanguage("").setLabel("Main").build();
+
+    String name = provider.getTrackName(format);
+
+    assertThat(name).isEqualTo("Main");
+  }
 }