Android: Incoming call auto answer, play a audio file

Question

In Android, at the time of an incoming call, I want to receive it. Then, from my app, automatically play an audio file during a call and the other party should hear it. Is this

Answer 1

In android there is no option to play against a live call or switch audio source to something other then default Mic! here are details that why you can't play recordings during a live call

However there are some tricks,

1. You can play desired recording from mobile speaker, during a call ! an Mic will pick it from there?
2. Or you can interconnect a handfree Speaker wires to its Mic wire
3. Or use bluetooh from some other device to play desired recording