When playing a MediaItem on Android Auto the queue only contains the currently selected MediaItem

[vanniktech]

Media3 Version

1.0.0-beta02

Devices that reproduce the issue

Android Auto with Pixel 6 Pro

Devices that do not reproduce the issue

Reproducible in the demo app?

Not tested

Reproduction steps

In my onGetLibraryRoot, I have the following code:

internal val rootMediaItem: MediaItem by lazy {
  MediaItem.Builder()
    .setMediaId(PARENT_ID)
    .setMediaMetadata(
      MediaMetadata.Builder()
        .setFolderType(MediaMetadata.FOLDER_TYPE_MIXED)
        .setIsPlayable(false)
        .build()
    )
    .build()
}
  
  
override fun onGetLibraryRoot(
  session: MediaLibrarySession,
  browser: MediaSession.ControllerInfo,
  params: LibraryParams?,
): ListenableFuture<LibraryResult<MediaItem>> {
  val rootExtras = Bundle().apply {
    putBoolean(
      MediaConstants.BROWSER_SERVICE_EXTRAS_KEY_SEARCH_SUPPORTED,
      true,
    )
    putBoolean("android.media.browse.CONTENT_STYLE_SUPPORTED", true)
    putInt(
      MediaConstants.DESCRIPTION_EXTRAS_KEY_CONTENT_STYLE_BROWSABLE,
      MediaConstants.DESCRIPTION_EXTRAS_VALUE_CONTENT_STYLE_GRID_ITEM,
    )
    putInt(
      MediaConstants.DESCRIPTION_EXTRAS_KEY_CONTENT_STYLE_PLAYABLE,
      MediaConstants.DESCRIPTION_EXTRAS_VALUE_CONTENT_STYLE_LIST_ITEM,
    )
  }
  val libraryParams = LibraryParams.Builder().setExtras(rootExtras).build()
  return Futures.immediateFuture(LibraryResult.ofItem(rootMediaItem, libraryParams))
}

in onGetChildren, I load all of my items and they are being displayed just fine:

Expected result

When selecting one, I'd expect to use the List of MediaItem so that I can automatically skip ahead

Actual result

My queue contains only the selected item:

Media

Bug Report

• You will email the zip file produced by adb bugreport to dev.exoplayer@gmail.com after filing this issue.

[marcbaechinger]

Thanks for reporting!

Android Auto is using the MediaLibraryService to navigate in the catalogue as you describe. When the user selects an item, Android Auto is preparing the player with the given item via MediaControllerCompat.

In Media3 this preparation request from Android Auto calls MediaLibraryService.Callback.onAddMediaItems(MediaSession mediaSession, ControllerInfo controller, List<MediaItem> mediaItems). The mediaItems parameter contains a single MediaItem that is the one the user has selected.

When you implement onAddMediaItems you return a ListenableFuture<List<MediaItem>>. From your report above I think you now return a future that only contains the selected media item. You can instead return a list of items that is then used set as the playlist/queue.

Said this, there is still an issue because playback always starts at media item index 0. This means when a user selects for instance the third item in a category, you can not set the whole category and then start playback at the third item (media item index 2). I don't have a solution for this yet I'm afraid. I tried some hacky ways but I couldn't find a solution that works reliably.

The only thing you can do for now, is putting the selected item at the begin of the list and all the other items after it. That's a regression to what was possible with media1. So keeping the bug label. We need to think about how we can enable the desired behaviour.

[vanniktech]

Thanks for answering Marc! Indeed, this does work. I've used your workaround to shuffle the list. Not perfect but far better than having no queue at all.

[vanniktech]

@marcbaechinger I also find that in the onAddMediaItems method, mediaItems.first().mediaMetadata.extras is always null. Even though I am setting extras in onGetChildren. Is this related or should I file a separate issue? In general mediaMetadata seems to be an empty object, also no title / subtitle for me.

[marcbaechinger]

I don't think there is something the Media3 library can do to avoid that as long as Android Auto is using Media1. When AA is browsing your catalogue they are receiving a MediaBrowserCompat.MediaItem from which they take the mediaId to call Callback.prepareByMediaId(String mediaId).

Media3 then receives this call and creates a androidx.media3.MediaItem with it that only contains the mediaId. This is all the information available. You need to resolve the mediaId to a full androidx.media3.MediaItem in onAddMediaItems.