Android Auto - click on list entry put nothing happens

Question

I'm struggling with Android Auto using Desktop Head Unit Emulator. So far I create my media app in Android Auto, start it and all media albums where shown.

However, when I click on an entry, nothing happens. It is not clear to me how to catch the click in order to further start an action.

    @Nullable
@Override
public BrowserRoot onGetRoot(@NonNull String clientPackageName, int clientUid, @Nullable Bundle rootHints) {

    int maximumRootChildLimit = rootHints.getInt(
            MediaConstants.BROWSER_ROOT_HINTS_KEY_ROOT_CHILDREN_LIMIT,
            /* defaultValue= */ 4);

    Bundle extras = new Bundle();
    extras.putInt(
            MediaConstants.DESCRIPTION_EXTRAS_KEY_CONTENT_STYLE_BROWSABLE,
            MediaConstants.DESCRIPTION_EXTRAS_VALUE_CONTENT_STYLE_GRID_ITEM);
    extras.putInt(
            MediaConstants.DESCRIPTION_EXTRAS_KEY_CONTENT_STYLE_PLAYABLE,
            MediaConstants.DESCRIPTION_EXTRAS_VALUE_CONTENT_STYLE_LIST_ITEM);
    extras.putBoolean(
            MediaConstants.BROWSER_SERVICE_EXTRAS_KEY_SEARCH_SUPPORTED, true);

    return new BrowserRoot(MY_MEDIA_ROOT_ID, extras);
}

@Override
public void onLoadChildren(@NonNull String parentId, @NonNull Result<List<MediaBrowserCompat.MediaItem>> result) {
     if (MY_MEDIA_ROOT_ID.equals(parentId)) {
          for (Album album : allAlbums) {
          .....
          MediaDescriptionCompat desc =
                    new MediaDescriptionCompat.Builder()
                            .setMediaId(mediaID)
                            .setTitle(title)
                            .setSubtitle(artist)
                            .setIconBitmap(bitmap(mediaID))
                            .setExtras(extras)
                            .build();
          mediaItems.add(albumList);
          }
     }
     result.sendResult(mediaItems);
 }

I set the mediaID in my PlaybackStateCompat.Builder:

Bundle playbackStateExtras = new Bundle();
    playbackStateExtras.putString(
            MediaConstants.PLAYBACK_STATE_EXTRAS_KEY_MEDIA_ID,"mediaID");
    playbackstateBuilder.setExtras(playbackStateExtras);

I set the mediaID in my MediaMetadataCompat.Builder

metadataBuilder.putString(MediaMetadata.METADATA_KEY_MEDIA_ID,"mediaID");
mMediaSessionCompat.setMetadata(metadataBuilder.build());

What have I overlooked in the documentation or didn't understand.

Thanks Alejandro

Answer 1

note the following procedure, please:

FLAG_Browsable: use this flag, then the MediaID is returned in getLoadChildren.

FLAG_PLAYABLE: use this flag, then the MediaID is returned to onPlayFromMediaID. In onPlayFromMediaIDyou have to put the logic how your mediaPlayerknows what to do with the handed over mediaID

I noticed that you didn't define any tabs. In onLoadChildren several queries on the mediaID make sense. The first level defines the tabs - these are missing in the post or in your code.

e.g:

        MediaDescriptionCompat desc =
                new MediaDescriptionCompat.Builder()
                        .setMediaId(AUDIOBOOK_HEADER)
                        .setTitle("Library")
                        .build();

        MediaBrowserCompat.MediaItem albumList =
                new MediaBrowserCompat.MediaItem(desc,
                        MediaBrowserCompat.MediaItem.FLAG_BROWSABLE);
        mediaItems.add(albumList);

        desc =
                new MediaDescriptionCompat.Builder()
                        .setMediaId(LATEST_HEADER)
                        .setTitle("Recently played")
                        .build();

        itemList =
                new MediaBrowserCompat.MediaItem(desc,
                        MediaBrowserCompat.MediaItem.FLAG_BROWSABLE);
        mediaItems.add(itemList);