Play audio file during ongoing voice call so that caller can hear it
<p>I'm trying to make an answering machine. </p>

<p>When there is an incoming call in my device I'll pick it up and start an audio file enabling speaker so that the microphone can take the speaker voice and the caller can hear it. </p>

<p>The application is working. This is what I implemented. But the problem is when I receive the call and start the audio play, the speaker is set on but the microphone doesn't pick up anything from the speaker though it can pick sounds from other source. Hence caller can't here the audio. </p>

<p>Anyone have an insight of this problem? I mean why won't the microphone pick the voice from the speaker but at the same time pick sounds from other sources?</p>
