If you have a file with .aac extension, it is AAC encoded audio in an ADTS container. If you want to play such file on an Android device, you have problems. Android 2.x does not support this file format at all, and not even the latest version of Android supports reading metadata tags from it.

The solution is to repackage the audio in an MPEG-4 container to a file with .m4a extension. Android can both play and read metadata tags from such files.