PrepareAudioTrackTask.java

	@Override
	protected PlaylistInfo doInBackground(AudioTrack... params) {

		// pull the track out of the single element array...
		final AudioTrack audioTrack = params[0];

		// get the content and segment index
		final Content content = audioTrack.getContent();
		final int segment = audioTrack.getSegment();

		// what kind is this (music or audiobook?)
		final String kindName = content.getKind().getName();

		// build the URI to the playlist
		final String mediaKey = content.getSegments().get(segment).getMediaKey();
		final MediaUri mediaUri = new MediaUri(KindName.fromString(kindName), mediaKey);

		// build the full URL to the playlist
		final String playlistUrlString = context.getString(R.string.playlist_base) + mediaUri.getUri();

		Log.d(TAG, "get playlist at " + playlistUrlString);

		// this gets the CONTENTS of the playlist as a string
		final String playlist = getPlaylist(playlistUrlString);

		// this finds the key URL for the playlist
		final String keyUrlString = getKeyUrlFromPlaylist(playlist);
		Log.d(TAG, "key url from playlist: " + keyUrlString);

		// this gets the actual key bytes
		final byte[] keyBytes = getKeyBytes(keyUrlString);
		// we have to check for an existing session - if one exists, the service will return a non-OK status
		final ResponseStatus responseStatus;
		final String errorMessage;
		if(checkPosition){
			final PlaybackPositionMessage request = new PlaybackPositionMessage();
			final PlaybackPosition position = new PlaybackPosition();
			position.setPatronId(patron.getId());
			position.setContentId(content.getId());
			request.setPlaybackPosition(position);
			final PlaybackPositionMessage message = positionService.get(request);
			responseStatus = message.getResponseStatus();
			if(!responseStatus.equals(ResponseStatus.OK)){
				errorMessage = message.getErrorList().get(0).getText();
			}else {
				errorMessage = null;
			}
		}else {
			responseStatus = ResponseStatus.OK;
			errorMessage = null;
		}

		// this is our (eventual) return value - but we need to save the playlist and key first
		final PlaylistInfo playlistInfo = new PlaylistInfo(
				playlistUrlString,
				keyUrlString,
				playlist,
				keyBytes,
				responseStatus,
				errorMessage,
				mediaKey
		);