Universal Music Player says Error Loading Media

Question

I am using Universal Music Player (UMP) sample code provided by Google.

Here, I would like to customize a thing as per my requirement, still UMP works in below process:

Screen 1: Genres (Songs by genre)

Screen 2: List of Genres

Screen 3: List of Songs (under particular Genre)

Now, here is my requirement:

I don't need Screen 1: Genres (Songs by genre) and I would like to start my app directly from Screen 2 (i.e : List of Genres screen)

To get my target, I have made a small change in MusicService.java class.

I have replaced below code :

/**
     * Actual implementation of onLoadChildren that assumes that MusicProvider is already
     * initialized.
     */
    private void loadChildrenImpl(final String parentMediaId,
                                  final Result<List<MediaBrowser.MediaItem>> result) {
        LogHelper.d(TAG, "OnLoadChildren: parentMediaId=", parentMediaId);

        List<MediaBrowser.MediaItem> mediaItems = new ArrayList<>();

        if (MEDIA_ID_ROOT.equals(parentMediaId)) {
            LogHelper.d(TAG, "OnLoadChildren.ROOT");
            mediaItems.add(new MediaBrowser.MediaItem(
                    new MediaDescription.Builder()
                        .setMediaId(MEDIA_ID_MUSICS_BY_GENRE)
                        .setTitle(getString(R.string.browse_genres))
                        .setIconUri(Uri.parse("android.resource://" +
                                "com.example.android.uamp/drawable/ic_by_genre"))
                        .setSubtitle(getString(R.string.browse_genre_subtitle))
                        .build(), MediaBrowser.MediaItem.FLAG_BROWSABLE
            ));

        } else if (MEDIA_ID_MUSICS_BY_GENRE.equals(parentMediaId)) {
            LogHelper.d(TAG, "OnLoadChildren.GENRES");
            for (String genre : mMusicProvider.getGenres()) {
                MediaBrowser.MediaItem item = new MediaBrowser.MediaItem(
                    new MediaDescription.Builder()
                        .setMediaId(createBrowseCategoryMediaID(MEDIA_ID_MUSICS_BY_GENRE, genre))
                        .setTitle(genre)
                        .setSubtitle(getString(R.string.browse_musics_by_genre_subtitle, genre))
                        .build(), MediaBrowser.MediaItem.FLAG_BROWSABLE
                );
                mediaItems.add(item);
            }

        } else if (parentMediaId.startsWith(MEDIA_ID_MUSICS_BY_GENRE)) {
            String genre = MediaIDHelper.getHierarchy(parentMediaId)[1];
            LogHelper.d(TAG, "OnLoadChildren.SONGS_BY_GENRE  genre=", genre);
            for (MediaMetadata track : mMusicProvider.getMusicsByGenre(genre)) {
                // Since mediaMetadata fields are immutable, we need to create a copy, so we
                // can set a hierarchy-aware mediaID. We will need to know the media hierarchy
                // when we get a onPlayFromMusicID call, so we can create the proper queue based
                // on where the music was selected from (by artist, by genre, random, etc)
                String hierarchyAwareMediaID = MediaIDHelper.createMediaID(
                        track.getDescription().getMediaId(), MEDIA_ID_MUSICS_BY_GENRE, genre);
                MediaMetadata trackCopy = new MediaMetadata.Builder(track)
                        .putString(MediaMetadata.METADATA_KEY_MEDIA_ID, hierarchyAwareMediaID)
                        .build();
                MediaBrowser.MediaItem bItem = new MediaBrowser.MediaItem(
                        trackCopy.getDescription(), MediaItem.FLAG_PLAYABLE);
                mediaItems.add(bItem);
            }
        } else {
            LogHelper.w(TAG, "Skipping unmatched parentMediaId: ", parentMediaId);
        }
        LogHelper.d(TAG, "OnLoadChildren sending ", mediaItems.size(),
                " results for ", parentMediaId);
        result.sendResult(mediaItems);
    }

with the following code:

/**
     * Actual implementation of onLoadChildren that assumes that MusicProvider is already
     * initialized.
     */
    private void loadChildrenImpl(final String parentMediaId,
                                  final Result<List<MediaBrowser.MediaItem>> result) {
        LogHelper.d(TAG, "OnLoadChildren: parentMediaId=", parentMediaId);

        List<MediaBrowser.MediaItem> mediaItems = new ArrayList<>();

        if (MEDIA_ID_MUSICS_BY_GENRE.equals(parentMediaId)) {
            LogHelper.d(TAG, "OnLoadChildren.GENRES");
            for (String genre : mMusicProvider.getGenres()) {
                MediaBrowser.MediaItem item = new MediaBrowser.MediaItem(
                    new MediaDescription.Builder()
                        .setMediaId(createBrowseCategoryMediaID(MEDIA_ID_MUSICS_BY_GENRE, genre))
                        .setTitle(genre)
                        .setSubtitle(getString(R.string.browse_musics_by_genre_subtitle, genre))
                        .build(), MediaBrowser.MediaItem.FLAG_BROWSABLE
                );
                mediaItems.add(item);
            }

        } else if (parentMediaId.startsWith(MEDIA_ID_MUSICS_BY_GENRE)) {
            String genre = MediaIDHelper.getHierarchy(parentMediaId)[1];
            LogHelper.d(TAG, "OnLoadChildren.SONGS_BY_GENRE  genre=", genre);
            for (MediaMetadata track : mMusicProvider.getMusicsByGenre(genre)) {
                // Since mediaMetadata fields are immutable, we need to create a copy, so we
                // can set a hierarchy-aware mediaID. We will need to know the media hierarchy
                // when we get a onPlayFromMusicID call, so we can create the proper queue based
                // on where the music was selected from (by artist, by genre, random, etc)
                String hierarchyAwareMediaID = MediaIDHelper.createMediaID(
                        track.getDescription().getMediaId(), MEDIA_ID_MUSICS_BY_GENRE, genre);
                MediaMetadata trackCopy = new MediaMetadata.Builder(track)
                        .putString(MediaMetadata.METADATA_KEY_MEDIA_ID, hierarchyAwareMediaID)
                        .build();
                MediaBrowser.MediaItem bItem = new MediaBrowser.MediaItem(
                        trackCopy.getDescription(), MediaItem.FLAG_PLAYABLE);
                mediaItems.add(bItem);
            }
        } else {
            LogHelper.w(TAG, "Skipping unmatched parentMediaId: ", parentMediaId);
        }
        LogHelper.d(TAG, "OnLoadChildren sending ", mediaItems.size(),
                " results for ", parentMediaId);
        result.sendResult(mediaItems);
    }

And when I launched my app instead of List of Genres I got a message that says : "Error Loading Media"

So what's wrong here, Where I have to make change in my code ? To get List of Genres directly

post your full stacktrace here – therealprashant Jan 04 '16 at 07:40 — therealprashant, Jan 04 '16 at 07:40

Konstantin Loginov · Accepted Answer · 2016-01-04T09:28:39.030

2

The problem is that UMP still calls loadChildrenImpl() with parentMediaId == __ROOT__.

So it can't find proper case in the if-else statement and ends up in

LogHelper.w(TAG, "Skipping unmatched parentMediaId: ", parentMediaId);

And returns empty mediaItems(This is causing "Error Loading Media" error)

The fix is in MusicService class, in onGetRoot() method replace

    return new BrowserRoot(MEDIA_ID_ROOT, null);

with

    return new BrowserRoot(MEDIA_ID_MUSICS_BY_GENRE, null);

edited Jan 04 '16 at 09:28

answered Jan 04 '16 at 09:21

Konstantin Loginov

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thank you :) I did mistake I have not read onGetRoot() method, I ticked your answer as useful and accepted too, will award you bounty after 18 hours... may I know, Why I am not getting Thumb with Genres ? – Sophie Jan 04 '16 at 12:49
@Sophie you're more than welcome. Regarding Thumbs, in `for (String genre : mMusicProvider.getGenres()) { }` you'll have to call `.setIconUri()` for each genre (i.e. to have all images locally), I'm afraid – Konstantin Loginov Jan 04 '16 at 13:58
@Sophie i'm good with Ms Yvette's idea to wait a bit with the bounty :-) – Konstantin Loginov Jan 05 '16 at 08:03

Universal Music Player says Error Loading Media

1 Answers1