title: fade in and out music while speaking a text
body: <p>I have an Android application that makes use of TTS (Text to speech) API. Everything is working perfectly, but now i want to fade in/out or even stop music (in case user is playing music with prebuilt Music Player), when application speaks a text. Right now, i think both music and TTS messages are played on the same stream (MUSIC), and it can be difficult to understand the voice messages. </p>
  
  <p>I've tried to play the text on a different stream, like AudioManager.STREAM_NOTIFICATIONS. It does stop the music, but doesn't come back when the text is spoken, so i didn't achieve the goal. Haven't found anything yet, so i hope someone can help here. Thanks!</p>