Fullscreen mode in android youtube application
private String video_id[] = { "gZiKrWSzNBo", "mzpJq23cuKc" };
private final static String YOUTUBE_URL = "http://www.youtube.com/watch?v=";
private final static String YOUTUBE_APP = "com.google.android.youtube";

Intent youtube_intent = new Intent();
youtube_intent.setPackage(YOUTUBE_APP);
youtube_intent.setAction(Intent.ACTION_VIEW);
youtube_intent.setData(Uri.parse(YOUTUBE_URL + video_id[position]
                + PLAYER_PARAMETERS));
        startActivity(youtube_intent);